[PATCH v3 0/5] add DFL bus support to MODULE_DEVICE_TABLE()

[PATCH v3 0/5] add DFL bus support to MODULE_DEVICE_TABLE()

[Xu Yilun]

I will refactor the code for dfl-n3000-nios driver, so just sent the
fpga-dfl bus code this time. fpga-dfl-emif driver could be the first
use case for fpga-dfl bus.

Main changes from v1:
- A new patch (Patch #3) to fix the description.
- Rename the dfl-bus.h to dfl.h
- Updated the MAINTAINERS under FPGA DFL DRIVERS.
- Improve comments and minor fixes.

Main changes from v2:
- Change the bus name from "dfl" to "fpga-dfl", also rename related
  variables, functions ...
- Changes the data type of fpga_dfl_device_id.type from u8 to u16
- Explicitly defines the values of enum fpga_dfl_id_type
- Delete the comments for the valid bits of type & feature_id
- changes MODALIAS format for fpga dfl devices


Xu Yilun (5):
  fpga: dfl: rename the bus type "dfl" to "fpga-dfl"
  fpga: dfl: fix the definitions of type & feature_id for dfl devices
  fpga: dfl: move fpga_dfl_device_id to mod_devicetable.h
  fpga: dfl: add fpga dfl bus support to MODULE_DEVICE_TABLE()
  fpga: dfl: move fpga dfl bus related APIs to include/linux/fpga/dfl.h

 Documentation/ABI/testing/sysfs-bus-dfl      |  15 --
 Documentation/ABI/testing/sysfs-bus-fpga-dfl |  15 ++
 MAINTAINERS                                  |   3 +-
 drivers/fpga/dfl.c                           | 256 ++++++++++++++-------------
 drivers/fpga/dfl.h                           |  89 +---------
 include/linux/fpga/dfl.h                     |  87 +++++++++
 include/linux/mod_devicetable.h              |  12 ++
 scripts/mod/devicetable-offsets.c            |   4 +
 scripts/mod/file2alias.c                     |  13 ++
 9 files changed, 265 insertions(+), 229 deletions(-)
 delete mode 100644 Documentation/ABI/testing/sysfs-bus-dfl
 create mode 100644 Documentation/ABI/testing/sysfs-bus-fpga-dfl
 create mode 100644 include/linux/fpga/dfl.h

-- 
2.7.4

[PATCH v3 1/5] fpga: dfl: rename the bus type "dfl" to "fpga-dfl"

[Xu Yilun]

Now the DFL device drivers could be made as independent modules and put
in different subsystems according to their functionalities. So the name
should be descriptive and unique in the whole kernel.

The patch changes the naming of dfl bus related structures, functions,
APIs and documentations.

Signed-off-by: Xu Yilun <yilun.xu@intel.com>
---
 Documentation/ABI/testing/sysfs-bus-dfl      |  15 --
 Documentation/ABI/testing/sysfs-bus-fpga-dfl |  15 ++
 MAINTAINERS                                  |   2 +-
 drivers/fpga/dfl.c                           | 254 ++++++++++++++-------------
 drivers/fpga/dfl.h                           |  77 ++++----
 5 files changed, 184 insertions(+), 179 deletions(-)
 delete mode 100644 Documentation/ABI/testing/sysfs-bus-dfl
 create mode 100644 Documentation/ABI/testing/sysfs-bus-fpga-dfl

diff --git a/Documentation/ABI/testing/sysfs-bus-dfl b/Documentation/ABI/testing/sysfs-bus-dfl
deleted file mode 100644
index 23543be..0000000
--- a/Documentation/ABI/testing/sysfs-bus-dfl
+++ /dev/null
@@ -1,15 +0,0 @@
-What:		/sys/bus/dfl/devices/dfl_dev.X/type
-Date:		Aug 2020
-KernelVersion:	5.10
-Contact:	Xu Yilun <yilun.xu@intel.com>
-Description:	Read-only. It returns type of DFL FIU of the device. Now DFL
-		supports 2 FIU types, 0 for FME, 1 for PORT.
-		Format: 0x%x
-
-What:		/sys/bus/dfl/devices/dfl_dev.X/feature_id
-Date:		Aug 2020
-KernelVersion:	5.10
-Contact:	Xu Yilun <yilun.xu@intel.com>
-Description:	Read-only. It returns feature identifier local to its DFL FIU
-		type.
-		Format: 0x%x
diff --git a/Documentation/ABI/testing/sysfs-bus-fpga-dfl b/Documentation/ABI/testing/sysfs-bus-fpga-dfl
new file mode 100644
index 0000000..072decf
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-fpga-dfl
@@ -0,0 +1,15 @@
+What:		/sys/bus/fpga-dfl/devices/fpga_dfl_dev.X/type
+Date:		Aug 2020
+KernelVersion:	5.10
+Contact:	Xu Yilun <yilun.xu@intel.com>
+Description:	Read-only. It returns type of FPGA DFL FIU of the device. Now
+		FPGA DFL supports 2 FIU types, 0 for FME, 1 for PORT.
+		Format: 0x%x
+
+What:		/sys/bus/fpga-dfl/devices/fpga_dfl_dev.X/feature_id
+Date:		Aug 2020
+KernelVersion:	5.10
+Contact:	Xu Yilun <yilun.xu@intel.com>
+Description:	Read-only. It returns feature identifier local to its FPGA DFL
+		FIU type.
+		Format: 0x%x
diff --git a/MAINTAINERS b/MAINTAINERS
index 0924930..48c0859 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6839,7 +6839,7 @@ M:	Wu Hao <hao.wu@intel.com>
 R:	Tom Rix <trix@redhat.com>
 L:	linux-fpga@vger.kernel.org
 S:	Maintained
-F:	Documentation/ABI/testing/sysfs-bus-dfl
+F:	Documentation/ABI/testing/sysfs-bus-fpga-dfl
 F:	Documentation/fpga/dfl.rst
 F:	drivers/fpga/dfl*
 F:	include/uapi/linux/fpga-dfl.h
diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
index b450870..f146cda 100644
--- a/drivers/fpga/dfl.c
+++ b/drivers/fpga/dfl.c
@@ -20,10 +20,10 @@ static DEFINE_MUTEX(dfl_id_mutex);
 
 /*
  * when adding a new feature dev support in DFL framework, it's required to
- * add a new item in enum dfl_id_type and provide related information in below
- * dfl_devs table which is indexed by dfl_id_type, e.g. name string used for
- * platform device creation (define name strings in dfl.h, as they could be
- * reused by platform device drivers).
+ * add a new item in enum fpga_dfl_id_type and provide related information in
+ * below dfl_devs table which is indexed by fpga_dfl_id_type, e.g. name string
+ * used for platform device creation (define name strings in dfl.h, as they
+ * could be reused by platform device drivers).
  *
  * if the new feature dev needs chardev support, then it's required to add
  * a new item in dfl_chardevs table and configure dfl_devs[i].devt_type as
@@ -36,9 +36,9 @@ enum dfl_fpga_devt_type {
 	DFL_FPGA_DEVT_MAX,
 };
 
-static struct lock_class_key dfl_pdata_keys[DFL_ID_MAX];
+static struct lock_class_key dfl_pdata_keys[FPGA_DFL_ID_MAX];
 
-static const char *dfl_pdata_key_strings[DFL_ID_MAX] = {
+static const char *dfl_pdata_key_strings[FPGA_DFL_ID_MAX] = {
 	"dfl-fme-pdata",
 	"dfl-port-pdata",
 };
@@ -57,7 +57,7 @@ struct dfl_dev_info {
 	enum dfl_fpga_devt_type devt_type;
 };
 
-/* it is indexed by dfl_id_type */
+/* it is indexed by fpga_dfl_id_type */
 static struct dfl_dev_info dfl_devs[] = {
 	{.name = DFL_FPGA_FEATURE_DEV_FME, .dfh_id = DFH_ID_FIU_FME,
 	 .devt_type = DFL_FPGA_DEVT_FME},
@@ -97,11 +97,11 @@ static void dfl_ids_destroy(void)
 		idr_destroy(&dfl_devs[i].id);
 }
 
-static int dfl_id_alloc(enum dfl_id_type type, struct device *dev)
+static int dfl_id_alloc(enum fpga_dfl_id_type type, struct device *dev)
 {
 	int id;
 
-	WARN_ON(type >= DFL_ID_MAX);
+	WARN_ON(type >= FPGA_DFL_ID_MAX);
 	mutex_lock(&dfl_id_mutex);
 	id = idr_alloc(&dfl_devs[type].id, dev, 0, 0, GFP_KERNEL);
 	mutex_unlock(&dfl_id_mutex);
@@ -109,15 +109,15 @@ static int dfl_id_alloc(enum dfl_id_type type, struct device *dev)
 	return id;
 }
 
-static void dfl_id_free(enum dfl_id_type type, int id)
+static void dfl_id_free(enum fpga_dfl_id_type type, int id)
 {
-	WARN_ON(type >= DFL_ID_MAX);
+	WARN_ON(type >= FPGA_DFL_ID_MAX);
 	mutex_lock(&dfl_id_mutex);
 	idr_remove(&dfl_devs[type].id, id);
 	mutex_unlock(&dfl_id_mutex);
 }
 
-static enum dfl_id_type feature_dev_id_type(struct platform_device *pdev)
+static enum fpga_dfl_id_type feature_dev_id_type(struct platform_device *pdev)
 {
 	int i;
 
@@ -125,10 +125,10 @@ static enum dfl_id_type feature_dev_id_type(struct platform_device *pdev)
 		if (!strcmp(dfl_devs[i].name, pdev->name))
 			return i;
 
-	return DFL_ID_MAX;
+	return FPGA_DFL_ID_MAX;
 }
 
-static enum dfl_id_type dfh_id_to_type(u16 id)
+static enum fpga_dfl_id_type dfh_id_to_type(u16 id)
 {
 	int i;
 
@@ -136,7 +136,7 @@ static enum dfl_id_type dfh_id_to_type(u16 id)
 		if (dfl_devs[i].dfh_id == id)
 			return i;
 
-	return DFL_ID_MAX;
+	return FPGA_DFL_ID_MAX;
 }
 
 /*
@@ -244,28 +244,29 @@ int dfl_fpga_check_port_id(struct platform_device *pdev, void *pport_id)
 }
 EXPORT_SYMBOL_GPL(dfl_fpga_check_port_id);
 
-static DEFINE_IDA(dfl_device_ida);
+static DEFINE_IDA(fpga_dfl_device_ida);
 
-static const struct dfl_device_id *
-dfl_match_one_device(const struct dfl_device_id *id, struct dfl_device *ddev)
+static const struct fpga_dfl_device_id *
+dfl_match_one_device(const struct fpga_dfl_device_id *id,
+		     struct fpga_dfl_device *fddev)
 {
-	if (id->type == ddev->type && id->feature_id == ddev->feature_id)
+	if (id->type == fddev->type && id->feature_id == fddev->feature_id)
 		return id;
 
 	return NULL;
 }
 
-static int dfl_bus_match(struct device *dev, struct device_driver *drv)
+static int fpga_dfl_bus_match(struct device *dev, struct device_driver *drv)
 {
-	struct dfl_device *ddev = to_dfl_dev(dev);
-	struct dfl_driver *ddrv = to_dfl_drv(drv);
-	const struct dfl_device_id *id_entry;
+	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
+	struct fpga_dfl_driver *fddrv = to_fpga_dfl_drv(drv);
+	const struct fpga_dfl_device_id *id_entry;
 
-	id_entry = ddrv->id_table;
+	id_entry = fddrv->id_table;
 	if (id_entry) {
 		while (id_entry->feature_id) {
-			if (dfl_match_one_device(id_entry, ddev)) {
-				ddev->id_entry = id_entry;
+			if (dfl_match_one_device(id_entry, fddev)) {
+				fddev->id_entry = id_entry;
 				return 1;
 			}
 			id_entry++;
@@ -275,215 +276,216 @@ static int dfl_bus_match(struct device *dev, struct device_driver *drv)
 	return 0;
 }
 
-static int dfl_bus_probe(struct device *dev)
+static int fpga_dfl_bus_probe(struct device *dev)
 {
-	struct dfl_driver *ddrv = to_dfl_drv(dev->driver);
-	struct dfl_device *ddev = to_dfl_dev(dev);
+	struct fpga_dfl_driver *fddrv = to_fpga_dfl_drv(dev->driver);
+	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
 
-	return ddrv->probe(ddev);
+	return fddrv->probe(fddev);
 }
 
-static int dfl_bus_remove(struct device *dev)
+static int fpga_dfl_bus_remove(struct device *dev)
 {
-	struct dfl_driver *ddrv = to_dfl_drv(dev->driver);
-	struct dfl_device *ddev = to_dfl_dev(dev);
+	struct fpga_dfl_driver *fddrv = to_fpga_dfl_drv(dev->driver);
+	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
 
-	if (ddrv->remove)
-		ddrv->remove(ddev);
+	if (fddrv->remove)
+		fddrv->remove(fddev);
 
 	return 0;
 }
 
-static int dfl_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
+static int fpga_dfl_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
-	struct dfl_device *ddev = to_dfl_dev(dev);
+	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
 
 	/* The type has 4 valid bits and feature_id has 12 valid bits */
-	return add_uevent_var(env, "MODALIAS=dfl:t%01Xf%03X",
-			      ddev->type, ddev->feature_id);
+	return add_uevent_var(env, "MODALIAS=fpga-dfl:t%01Xf%03X",
+			      fddev->type, fddev->feature_id);
 }
 
 static ssize_t
 type_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	struct dfl_device *ddev = to_dfl_dev(dev);
+	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
 
-	return sprintf(buf, "0x%x\n", ddev->type);
+	return sprintf(buf, "0x%x\n", fddev->type);
 }
 static DEVICE_ATTR_RO(type);
 
 static ssize_t
 feature_id_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	struct dfl_device *ddev = to_dfl_dev(dev);
+	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
 
-	return sprintf(buf, "0x%x\n", ddev->feature_id);
+	return sprintf(buf, "0x%x\n", fddev->feature_id);
 }
 static DEVICE_ATTR_RO(feature_id);
 
-static struct attribute *dfl_dev_attrs[] = {
+static struct attribute *fpga_dfl_dev_attrs[] = {
 	&dev_attr_type.attr,
 	&dev_attr_feature_id.attr,
 	NULL,
 };
-ATTRIBUTE_GROUPS(dfl_dev);
-
-static struct bus_type dfl_bus_type = {
-	.name		= "dfl",
-	.match		= dfl_bus_match,
-	.probe		= dfl_bus_probe,
-	.remove		= dfl_bus_remove,
-	.uevent		= dfl_bus_uevent,
-	.dev_groups	= dfl_dev_groups,
+ATTRIBUTE_GROUPS(fpga_dfl_dev);
+
+static struct bus_type fpga_dfl_bus_type = {
+	.name		= "fpga-dfl",
+	.match		= fpga_dfl_bus_match,
+	.probe		= fpga_dfl_bus_probe,
+	.remove		= fpga_dfl_bus_remove,
+	.uevent		= fpga_dfl_bus_uevent,
+	.dev_groups	= fpga_dfl_dev_groups,
 };
 
-static void release_dfl_dev(struct device *dev)
+static void release_fpga_dfl_dev(struct device *dev)
 {
-	struct dfl_device *ddev = to_dfl_dev(dev);
+	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
 
-	if (ddev->mmio_res.parent)
-		release_resource(&ddev->mmio_res);
+	if (fddev->mmio_res.parent)
+		release_resource(&fddev->mmio_res);
 
-	ida_simple_remove(&dfl_device_ida, ddev->id);
-	kfree(ddev->irqs);
-	kfree(ddev);
+	ida_simple_remove(&fpga_dfl_device_ida, fddev->id);
+	kfree(fddev->irqs);
+	kfree(fddev);
 }
 
-static struct dfl_device *
-dfl_dev_add(struct dfl_feature_platform_data *pdata,
-	    struct dfl_feature *feature)
+static struct fpga_dfl_device *
+fpga_dfl_dev_add(struct dfl_feature_platform_data *pdata,
+		 struct dfl_feature *feature)
 {
 	struct platform_device *pdev = pdata->dev;
 	struct resource *parent_res;
-	struct dfl_device *ddev;
+	struct fpga_dfl_device *fddev;
 	int id, i, ret;
 
-	ddev = kzalloc(sizeof(*ddev), GFP_KERNEL);
-	if (!ddev)
+	fddev = kzalloc(sizeof(*fddev), GFP_KERNEL);
+	if (!fddev)
 		return ERR_PTR(-ENOMEM);
 
-	id = ida_simple_get(&dfl_device_ida, 0, 0, GFP_KERNEL);
+	id = ida_simple_get(&fpga_dfl_device_ida, 0, 0, GFP_KERNEL);
 	if (id < 0) {
 		dev_err(&pdev->dev, "unable to get id\n");
-		kfree(ddev);
+		kfree(fddev);
 		return ERR_PTR(id);
 	}
 
 	/* freeing resources by put_device() after device_initialize() */
-	device_initialize(&ddev->dev);
-	ddev->dev.parent = &pdev->dev;
-	ddev->dev.bus = &dfl_bus_type;
-	ddev->dev.release = release_dfl_dev;
-	ddev->id = id;
-	ret = dev_set_name(&ddev->dev, "dfl_dev.%d", id);
+	device_initialize(&fddev->dev);
+	fddev->dev.parent = &pdev->dev;
+	fddev->dev.bus = &fpga_dfl_bus_type;
+	fddev->dev.release = release_fpga_dfl_dev;
+	fddev->id = id;
+	ret = dev_set_name(&fddev->dev, "fpga_dfl_dev.%d", id);
 	if (ret)
 		goto put_dev;
 
-	ddev->type = feature_dev_id_type(pdev);
-	ddev->feature_id = feature->id;
-	ddev->cdev = pdata->dfl_cdev;
+	fddev->type = feature_dev_id_type(pdev);
+	fddev->feature_id = feature->id;
+	fddev->cdev = pdata->dfl_cdev;
 
 	/* add mmio resource */
 	parent_res = &pdev->resource[feature->resource_index];
-	ddev->mmio_res.flags = IORESOURCE_MEM;
-	ddev->mmio_res.start = parent_res->start;
-	ddev->mmio_res.end = parent_res->end;
-	ddev->mmio_res.name = dev_name(&ddev->dev);
-	ret = insert_resource(parent_res, &ddev->mmio_res);
+	fddev->mmio_res.flags = IORESOURCE_MEM;
+	fddev->mmio_res.start = parent_res->start;
+	fddev->mmio_res.end = parent_res->end;
+	fddev->mmio_res.name = dev_name(&fddev->dev);
+	ret = insert_resource(parent_res, &fddev->mmio_res);
 	if (ret) {
 		dev_err(&pdev->dev, "%s failed to claim resource: %pR\n",
-			dev_name(&ddev->dev), &ddev->mmio_res);
+			dev_name(&fddev->dev), &fddev->mmio_res);
 		goto put_dev;
 	}
 
 	/* then add irq resource */
 	if (feature->nr_irqs) {
-		ddev->irqs = kcalloc(feature->nr_irqs,
-				     sizeof(*ddev->irqs), GFP_KERNEL);
-		if (!ddev->irqs) {
+		fddev->irqs = kcalloc(feature->nr_irqs,
+				      sizeof(*fddev->irqs), GFP_KERNEL);
+		if (!fddev->irqs) {
 			ret = -ENOMEM;
 			goto put_dev;
 		}
 
 		for (i = 0; i < feature->nr_irqs; i++)
-			ddev->irqs[i] = feature->irq_ctx[i].irq;
+			fddev->irqs[i] = feature->irq_ctx[i].irq;
 
-		ddev->num_irqs = feature->nr_irqs;
+		fddev->num_irqs = feature->nr_irqs;
 	}
 
-	ret = device_add(&ddev->dev);
+	ret = device_add(&fddev->dev);
 	if (ret)
 		goto put_dev;
 
-	dev_dbg(&pdev->dev, "add dfl_dev: %s\n", dev_name(&ddev->dev));
-	return ddev;
+	dev_dbg(&pdev->dev, "add fpga_dfl_dev: %s\n", dev_name(&fddev->dev));
+	return fddev;
 
 put_dev:
-	/* calls release_dfl_dev() which does the clean up  */
-	put_device(&ddev->dev);
+	/* calls release_fpga_dfl_dev() which does the clean up  */
+	put_device(&fddev->dev);
 	return ERR_PTR(ret);
 }
 
-static void dfl_devs_remove(struct dfl_feature_platform_data *pdata)
+static void fpga_dfl_devs_remove(struct dfl_feature_platform_data *pdata)
 {
 	struct dfl_feature *feature;
 
 	dfl_fpga_dev_for_each_feature(pdata, feature) {
-		if (feature->ddev) {
-			device_unregister(&feature->ddev->dev);
-			feature->ddev = NULL;
+		if (feature->fddev) {
+			device_unregister(&feature->fddev->dev);
+			feature->fddev = NULL;
 		}
 	}
 }
 
-static int dfl_devs_add(struct dfl_feature_platform_data *pdata)
+static int fpga_dfl_devs_add(struct dfl_feature_platform_data *pdata)
 {
+	struct fpga_dfl_device *fddev;
 	struct dfl_feature *feature;
-	struct dfl_device *ddev;
 	int ret;
 
 	dfl_fpga_dev_for_each_feature(pdata, feature) {
 		if (feature->ioaddr)
 			continue;
 
-		if (feature->ddev) {
+		if (feature->fddev) {
 			ret = -EEXIST;
 			goto err;
 		}
 
-		ddev = dfl_dev_add(pdata, feature);
-		if (IS_ERR(ddev)) {
-			ret = PTR_ERR(ddev);
+		fddev = fpga_dfl_dev_add(pdata, feature);
+		if (IS_ERR(fddev)) {
+			ret = PTR_ERR(fddev);
 			goto err;
 		}
 
-		feature->ddev = ddev;
+		feature->fddev = fddev;
 	}
 
 	return 0;
 
 err:
-	dfl_devs_remove(pdata);
+	fpga_dfl_devs_remove(pdata);
 	return ret;
 }
 
-int __dfl_driver_register(struct dfl_driver *dfl_drv, struct module *owner)
+int __fpga_dfl_driver_register(struct fpga_dfl_driver *fddrv,
+			       struct module *owner)
 {
-	if (!dfl_drv || !dfl_drv->probe || !dfl_drv->id_table)
+	if (!fddrv || !fddrv->probe || !fddrv->id_table)
 		return -EINVAL;
 
-	dfl_drv->drv.owner = owner;
-	dfl_drv->drv.bus = &dfl_bus_type;
+	fddrv->drv.owner = owner;
+	fddrv->drv.bus = &fpga_dfl_bus_type;
 
-	return driver_register(&dfl_drv->drv);
+	return driver_register(&fddrv->drv);
 }
-EXPORT_SYMBOL(__dfl_driver_register);
+EXPORT_SYMBOL(__fpga_dfl_driver_register);
 
-void dfl_driver_unregister(struct dfl_driver *dfl_drv)
+void fpga_dfl_driver_unregister(struct fpga_dfl_driver *fddrv)
 {
-	driver_unregister(&dfl_drv->drv);
+	driver_unregister(&fddrv->drv);
 }
-EXPORT_SYMBOL(dfl_driver_unregister);
+EXPORT_SYMBOL(fpga_dfl_driver_unregister);
 
 #define is_header_feature(feature) ((feature)->id == FEATURE_ID_FIU_HEADER)
 
@@ -496,7 +498,7 @@ void dfl_fpga_dev_feature_uinit(struct platform_device *pdev)
 	struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
 	struct dfl_feature *feature;
 
-	dfl_devs_remove(pdata);
+	fpga_dfl_devs_remove(pdata);
 
 	dfl_fpga_dev_for_each_feature(pdata, feature) {
 		if (feature->ops) {
@@ -585,7 +587,7 @@ int dfl_fpga_dev_feature_init(struct platform_device *pdev,
 		drv++;
 	}
 
-	ret = dfl_devs_add(pdata);
+	ret = fpga_dfl_devs_add(pdata);
 	if (ret)
 		goto exit;
 
@@ -745,11 +747,11 @@ static int build_info_commit_dev(struct build_feature_devs_info *binfo)
 	struct platform_device *fdev = binfo->feature_dev;
 	struct dfl_feature_platform_data *pdata;
 	struct dfl_feature_info *finfo, *p;
-	enum dfl_id_type type;
+	enum fpga_dfl_id_type type;
 	int ret, index = 0, res_idx = 0;
 
 	type = feature_dev_id_type(fdev);
-	if (WARN_ON_ONCE(type >= DFL_ID_MAX))
+	if (WARN_ON_ONCE(type >= FPGA_DFL_ID_MAX))
 		return -EINVAL;
 
 	/*
@@ -836,7 +838,7 @@ static int build_info_commit_dev(struct build_feature_devs_info *binfo)
 
 	ret = platform_device_add(binfo->feature_dev);
 	if (!ret) {
-		if (type == PORT_ID)
+		if (type == FPGA_DFL_PORT_ID)
 			dfl_fpga_cdev_add_port_dev(binfo->cdev,
 						   binfo->feature_dev);
 		else
@@ -857,11 +859,11 @@ static int build_info_commit_dev(struct build_feature_devs_info *binfo)
 
 static int
 build_info_create_dev(struct build_feature_devs_info *binfo,
-		      enum dfl_id_type type)
+		      enum fpga_dfl_id_type type)
 {
 	struct platform_device *fdev;
 
-	if (type >= DFL_ID_MAX)
+	if (type >= FPGA_DFL_ID_MAX)
 		return -EINVAL;
 
 	/*
@@ -1072,7 +1074,7 @@ static int parse_feature_afu(struct build_feature_devs_info *binfo,
 	}
 
 	switch (feature_dev_id_type(binfo->feature_dev)) {
-	case PORT_ID:
+	case FPGA_DFL_PORT_ID:
 		return parse_feature_port_afu(binfo, ofst);
 	default:
 		dev_info(binfo->dev, "AFU belonging to FIU %s is not supported yet.\n",
@@ -1360,7 +1362,7 @@ EXPORT_SYMBOL_GPL(dfl_fpga_enum_info_add_irq);
 static int remove_feature_dev(struct device *dev, void *data)
 {
 	struct platform_device *pdev = to_platform_device(dev);
-	enum dfl_id_type type = feature_dev_id_type(pdev);
+	enum fpga_dfl_id_type type = feature_dev_id_type(pdev);
 	int id = pdev->id;
 
 	platform_device_unregister(pdev);
@@ -1526,7 +1528,7 @@ static int __init dfl_fpga_init(void)
 {
 	int ret;
 
-	ret = bus_register(&dfl_bus_type);
+	ret = bus_register(&fpga_dfl_bus_type);
 	if (ret)
 		return ret;
 
@@ -1535,7 +1537,7 @@ static int __init dfl_fpga_init(void)
 	ret = dfl_chardev_init();
 	if (ret) {
 		dfl_ids_destroy();
-		bus_unregister(&dfl_bus_type);
+		bus_unregister(&fpga_dfl_bus_type);
 	}
 
 	return ret;
@@ -1874,7 +1876,7 @@ static void __exit dfl_fpga_exit(void)
 {
 	dfl_chardev_uinit();
 	dfl_ids_destroy();
-	bus_unregister(&dfl_bus_type);
+	bus_unregister(&fpga_dfl_bus_type);
 }
 
 module_init(dfl_fpga_init);
diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h
index 5dc758f..ba930a7 100644
--- a/drivers/fpga/dfl.h
+++ b/drivers/fpga/dfl.h
@@ -236,7 +236,7 @@ struct dfl_feature_irq_ctx {
  * @irq_ctx: interrupt context list.
  * @nr_irqs: number of interrupt contexts.
  * @ops: ops of this sub feature.
- * @ddev: ptr to the dfl device of this sub feature.
+ * @fddev: ptr to the fpga dfl device of this sub feature.
  * @priv: priv data of this feature.
  */
 struct dfl_feature {
@@ -247,7 +247,7 @@ struct dfl_feature {
 	struct dfl_feature_irq_ctx *irq_ctx;
 	unsigned int nr_irqs;
 	const struct dfl_feature_ops *ops;
-	struct dfl_device *ddev;
+	struct fpga_dfl_device *fddev;
 	void *priv;
 };
 
@@ -517,40 +517,42 @@ long dfl_feature_ioctl_set_irq(struct platform_device *pdev,
 			       unsigned long arg);
 
 /**
- * enum dfl_id_type - define the DFL FIU types
+ * enum fpga_dfl_id_type - define the FPGA DFL FIU types
  */
-enum dfl_id_type {
-	FME_ID,
-	PORT_ID,
-	DFL_ID_MAX,
+enum fpga_dfl_id_type {
+	FPGA_DFL_FME_ID,
+	FPGA_DFL_PORT_ID,
+	FPGA_DFL_ID_MAX,
 };
 
 /**
- * struct dfl_device_id -  dfl device identifier
- * @type: contains 4 bits DFL FIU type of the device. See enum dfl_id_type.
- * @feature_id: contains 12 bits feature identifier local to its DFL FIU type.
+ * struct fpga_dfl_device_id - fpga dfl device identifier
+ * @type: contains 4 bits FPGA DFL FIU type of the device, see
+ *	  enum fpga_dfl_id_type.
+ * @feature_id: contains 12 bits feature identifier local to its FPGA DFL FIU
+ *		type.
  * @driver_data: driver specific data.
  */
-struct dfl_device_id {
+struct fpga_dfl_device_id {
 	u8 type;
 	u16 feature_id;
 	unsigned long driver_data;
 };
 
 /**
- * struct dfl_device - represent an dfl device on dfl bus
+ * struct fpga_dfl_device - represent an fpga dfl device on fpga dfl bus
  *
  * @dev: generic device interface.
- * @id: id of the dfl device.
- * @type: type of DFL FIU of the device. See enum dfl_id_type.
- * @feature_id: 16 bits feature identifier local to its DFL FIU type.
- * @mmio_res: mmio resource of this dfl device.
- * @irqs: list of Linux IRQ numbers of this dfl device.
- * @num_irqs: number of IRQs supported by this dfl device.
- * @cdev: pointer to DFL FPGA container device this dfl device belongs to.
- * @id_entry: matched id entry in dfl driver's id table.
+ * @id: id of the fpga dfl device.
+ * @type: FPGA DFL FIU type of the device, see enum fpga_dfl_id_type.
+ * @feature_id: 16 bits feature identifier local to its FPGA DFL FIU type.
+ * @mmio_res: mmio resource of this fpga dfl device.
+ * @irqs: list of Linux IRQ numbers of this fpga dfl device.
+ * @num_irqs: number of IRQs supported by this fpga dfl device.
+ * @cdev: pointer to DFL FPGA container device this fpga dfl device belongs to.
+ * @id_entry: matched id entry in fpga dfl driver's id table.
  */
-struct dfl_device {
+struct fpga_dfl_device {
 	struct device dev;
 	int id;
 	u8 type;
@@ -559,11 +561,11 @@ struct dfl_device {
 	int *irqs;
 	unsigned int num_irqs;
 	struct dfl_fpga_cdev *cdev;
-	const struct dfl_device_id *id_entry;
+	const struct fpga_dfl_device_id *id_entry;
 };
 
 /**
- * struct dfl_driver - represent an dfl device driver
+ * struct fpga_dfl_driver - represent a fpga dfl device driver
  *
  * @drv: driver model structure.
  * @id_table: pointer to table of device IDs the driver is interested in.
@@ -571,33 +573,34 @@ struct dfl_device {
  * @probe: mandatory callback for device binding.
  * @remove: callback for device unbinding.
  */
-struct dfl_driver {
+struct fpga_dfl_driver {
 	struct device_driver drv;
-	const struct dfl_device_id *id_table;
+	const struct fpga_dfl_device_id *id_table;
 
-	int (*probe)(struct dfl_device *dfl_dev);
-	void (*remove)(struct dfl_device *dfl_dev);
+	int (*probe)(struct fpga_dfl_device *fddev);
+	void (*remove)(struct fpga_dfl_device *fddev);
 };
 
-#define to_dfl_dev(d) container_of(d, struct dfl_device, dev)
-#define to_dfl_drv(d) container_of(d, struct dfl_driver, drv)
+#define to_fpga_dfl_dev(d) container_of(d, struct fpga_dfl_device, dev)
+#define to_fpga_dfl_drv(d) container_of(d, struct fpga_dfl_driver, drv)
 
 /*
  * use a macro to avoid include chaining to get THIS_MODULE.
  */
-#define dfl_driver_register(drv) \
-	__dfl_driver_register(drv, THIS_MODULE)
-int __dfl_driver_register(struct dfl_driver *dfl_drv, struct module *owner);
-void dfl_driver_unregister(struct dfl_driver *dfl_drv);
+#define fpga_dfl_driver_register(drv) \
+	__fpga_dfl_driver_register(drv, THIS_MODULE)
+int __fpga_dfl_driver_register(struct fpga_dfl_driver *fddrv,
+			       struct module *owner);
+void fpga_dfl_driver_unregister(struct fpga_dfl_driver *fddrv);
 
 /*
- * module_dfl_driver() - Helper macro for drivers that don't do
+ * module_fpga_dfl_driver() - Helper macro for drivers that don't do
  * anything special in module init/exit.  This eliminates a lot of
  * boilerplate.  Each module may only use this macro once, and
  * calling it replaces module_init() and module_exit().
  */
-#define module_dfl_driver(__dfl_driver) \
-	module_driver(__dfl_driver, dfl_driver_register, \
-		      dfl_driver_unregister)
+#define module_fpga_dfl_driver(__fpga_dfl_driver) \
+	module_driver(__fpga_dfl_driver, fpga_dfl_driver_register, \
+		      fpga_dfl_driver_unregister)
 
 #endif /* __FPGA_DFL_H */
-- 
2.7.4

Re: [PATCH v3 1/5] fpga: dfl: rename the bus type "dfl" to "fpga-dfl"

[Moritz Fischer]

Hi Xu,

On Fri, Sep 25, 2020 at 12:59:57AM +0800, Xu Yilun wrote:
> Now the DFL device drivers could be made as independent modules and put
> in different subsystems according to their functionalities. So the name
> should be descriptive and unique in the whole kernel.
> 
> The patch changes the naming of dfl bus related structures, functions,
> APIs and documentations.
> 
> Signed-off-by: Xu Yilun <yilun.xu@intel.com>
> ---
>  Documentation/ABI/testing/sysfs-bus-dfl      |  15 --
>  Documentation/ABI/testing/sysfs-bus-fpga-dfl |  15 ++
>  MAINTAINERS                                  |   2 +-
>  drivers/fpga/dfl.c                           | 254 ++++++++++++++-------------
>  drivers/fpga/dfl.h                           |  77 ++++----
>  5 files changed, 184 insertions(+), 179 deletions(-)
>  delete mode 100644 Documentation/ABI/testing/sysfs-bus-dfl
>  create mode 100644 Documentation/ABI/testing/sysfs-bus-fpga-dfl
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-dfl b/Documentation/ABI/testing/sysfs-bus-dfl
> deleted file mode 100644
> index 23543be..0000000
> --- a/Documentation/ABI/testing/sysfs-bus-dfl
> +++ /dev/null
> @@ -1,15 +0,0 @@
> -What:		/sys/bus/dfl/devices/dfl_dev.X/type
> -Date:		Aug 2020
> -KernelVersion:	5.10
> -Contact:	Xu Yilun <yilun.xu@intel.com>
> -Description:	Read-only. It returns type of DFL FIU of the device. Now DFL
> -		supports 2 FIU types, 0 for FME, 1 for PORT.
> -		Format: 0x%x
> -
> -What:		/sys/bus/dfl/devices/dfl_dev.X/feature_id
> -Date:		Aug 2020
> -KernelVersion:	5.10
> -Contact:	Xu Yilun <yilun.xu@intel.com>
> -Description:	Read-only. It returns feature identifier local to its DFL FIU
> -		type.
> -		Format: 0x%x

You're changing userland facing ABI. I think that's something to avoid,
please check with Greg on the rules since this hasn't been in a release yet.

> diff --git a/Documentation/ABI/testing/sysfs-bus-fpga-dfl b/Documentation/ABI/testing/sysfs-bus-fpga-dfl
> new file mode 100644
> index 0000000..072decf
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-fpga-dfl
> @@ -0,0 +1,15 @@
> +What:		/sys/bus/fpga-dfl/devices/fpga_dfl_dev.X/type
> +Date:		Aug 2020
> +KernelVersion:	5.10
> +Contact:	Xu Yilun <yilun.xu@intel.com>
> +Description:	Read-only. It returns type of FPGA DFL FIU of the device. Now
> +		FPGA DFL supports 2 FIU types, 0 for FME, 1 for PORT.
> +		Format: 0x%x
> +
> +What:		/sys/bus/fpga-dfl/devices/fpga_dfl_dev.X/feature_id
> +Date:		Aug 2020
> +KernelVersion:	5.10
> +Contact:	Xu Yilun <yilun.xu@intel.com>
> +Description:	Read-only. It returns feature identifier local to its FPGA DFL
> +		FIU type.
> +		Format: 0x%x
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 0924930..48c0859 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -6839,7 +6839,7 @@ M:	Wu Hao <hao.wu@intel.com>
>  R:	Tom Rix <trix@redhat.com>
>  L:	linux-fpga@vger.kernel.org
>  S:	Maintained
> -F:	Documentation/ABI/testing/sysfs-bus-dfl
> +F:	Documentation/ABI/testing/sysfs-bus-fpga-dfl
>  F:	Documentation/fpga/dfl.rst
>  F:	drivers/fpga/dfl*
>  F:	include/uapi/linux/fpga-dfl.h
> diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
> index b450870..f146cda 100644
> --- a/drivers/fpga/dfl.c
> +++ b/drivers/fpga/dfl.c
> @@ -20,10 +20,10 @@ static DEFINE_MUTEX(dfl_id_mutex);
>  
>  /*
>   * when adding a new feature dev support in DFL framework, it's required to
> - * add a new item in enum dfl_id_type and provide related information in below
> - * dfl_devs table which is indexed by dfl_id_type, e.g. name string used for
> - * platform device creation (define name strings in dfl.h, as they could be
> - * reused by platform device drivers).
> + * add a new item in enum fpga_dfl_id_type and provide related information in
> + * below dfl_devs table which is indexed by fpga_dfl_id_type, e.g. name string
> + * used for platform device creation (define name strings in dfl.h, as they
> + * could be reused by platform device drivers).
>   *
>   * if the new feature dev needs chardev support, then it's required to add
>   * a new item in dfl_chardevs table and configure dfl_devs[i].devt_type as
> @@ -36,9 +36,9 @@ enum dfl_fpga_devt_type {
>  	DFL_FPGA_DEVT_MAX,
>  };
>  
> -static struct lock_class_key dfl_pdata_keys[DFL_ID_MAX];
> +static struct lock_class_key dfl_pdata_keys[FPGA_DFL_ID_MAX];
>  
> -static const char *dfl_pdata_key_strings[DFL_ID_MAX] = {
> +static const char *dfl_pdata_key_strings[FPGA_DFL_ID_MAX] = {
>  	"dfl-fme-pdata",
>  	"dfl-port-pdata",
>  };
> @@ -57,7 +57,7 @@ struct dfl_dev_info {
>  	enum dfl_fpga_devt_type devt_type;
>  };
>  
> -/* it is indexed by dfl_id_type */
> +/* it is indexed by fpga_dfl_id_type */
>  static struct dfl_dev_info dfl_devs[] = {
>  	{.name = DFL_FPGA_FEATURE_DEV_FME, .dfh_id = DFH_ID_FIU_FME,
>  	 .devt_type = DFL_FPGA_DEVT_FME},
> @@ -97,11 +97,11 @@ static void dfl_ids_destroy(void)
>  		idr_destroy(&dfl_devs[i].id);
>  }
>  
> -static int dfl_id_alloc(enum dfl_id_type type, struct device *dev)
> +static int dfl_id_alloc(enum fpga_dfl_id_type type, struct device *dev)
>  {
>  	int id;
>  
> -	WARN_ON(type >= DFL_ID_MAX);
> +	WARN_ON(type >= FPGA_DFL_ID_MAX);
>  	mutex_lock(&dfl_id_mutex);
>  	id = idr_alloc(&dfl_devs[type].id, dev, 0, 0, GFP_KERNEL);
>  	mutex_unlock(&dfl_id_mutex);
> @@ -109,15 +109,15 @@ static int dfl_id_alloc(enum dfl_id_type type, struct device *dev)
>  	return id;
>  }
>  
> -static void dfl_id_free(enum dfl_id_type type, int id)
> +static void dfl_id_free(enum fpga_dfl_id_type type, int id)
>  {
> -	WARN_ON(type >= DFL_ID_MAX);
> +	WARN_ON(type >= FPGA_DFL_ID_MAX);
>  	mutex_lock(&dfl_id_mutex);
>  	idr_remove(&dfl_devs[type].id, id);
>  	mutex_unlock(&dfl_id_mutex);
>  }
>  
> -static enum dfl_id_type feature_dev_id_type(struct platform_device *pdev)
> +static enum fpga_dfl_id_type feature_dev_id_type(struct platform_device *pdev)
>  {
>  	int i;
>  
> @@ -125,10 +125,10 @@ static enum dfl_id_type feature_dev_id_type(struct platform_device *pdev)
>  		if (!strcmp(dfl_devs[i].name, pdev->name))
>  			return i;
>  
> -	return DFL_ID_MAX;
> +	return FPGA_DFL_ID_MAX;
>  }
>  
> -static enum dfl_id_type dfh_id_to_type(u16 id)
> +static enum fpga_dfl_id_type dfh_id_to_type(u16 id)
>  {
>  	int i;
>  
> @@ -136,7 +136,7 @@ static enum dfl_id_type dfh_id_to_type(u16 id)
>  		if (dfl_devs[i].dfh_id == id)
>  			return i;
>  
> -	return DFL_ID_MAX;
> +	return FPGA_DFL_ID_MAX;
>  }
>  
>  /*
> @@ -244,28 +244,29 @@ int dfl_fpga_check_port_id(struct platform_device *pdev, void *pport_id)
>  }
>  EXPORT_SYMBOL_GPL(dfl_fpga_check_port_id);
>  
> -static DEFINE_IDA(dfl_device_ida);
> +static DEFINE_IDA(fpga_dfl_device_ida);
>  
> -static const struct dfl_device_id *
> -dfl_match_one_device(const struct dfl_device_id *id, struct dfl_device *ddev)
> +static const struct fpga_dfl_device_id *
> +dfl_match_one_device(const struct fpga_dfl_device_id *id,
> +		     struct fpga_dfl_device *fddev)
>  {
> -	if (id->type == ddev->type && id->feature_id == ddev->feature_id)
> +	if (id->type == fddev->type && id->feature_id == fddev->feature_id)
>  		return id;
>  
>  	return NULL;
>  }
>  
> -static int dfl_bus_match(struct device *dev, struct device_driver *drv)
> +static int fpga_dfl_bus_match(struct device *dev, struct device_driver *drv)
>  {
> -	struct dfl_device *ddev = to_dfl_dev(dev);
> -	struct dfl_driver *ddrv = to_dfl_drv(drv);
> -	const struct dfl_device_id *id_entry;
> +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
> +	struct fpga_dfl_driver *fddrv = to_fpga_dfl_drv(drv);
> +	const struct fpga_dfl_device_id *id_entry;
>  
> -	id_entry = ddrv->id_table;
> +	id_entry = fddrv->id_table;
>  	if (id_entry) {
>  		while (id_entry->feature_id) {
> -			if (dfl_match_one_device(id_entry, ddev)) {
> -				ddev->id_entry = id_entry;
> +			if (dfl_match_one_device(id_entry, fddev)) {
> +				fddev->id_entry = id_entry;
>  				return 1;
>  			}
>  			id_entry++;
> @@ -275,215 +276,216 @@ static int dfl_bus_match(struct device *dev, struct device_driver *drv)
>  	return 0;
>  }
>  
> -static int dfl_bus_probe(struct device *dev)
> +static int fpga_dfl_bus_probe(struct device *dev)
>  {
> -	struct dfl_driver *ddrv = to_dfl_drv(dev->driver);
> -	struct dfl_device *ddev = to_dfl_dev(dev);
> +	struct fpga_dfl_driver *fddrv = to_fpga_dfl_drv(dev->driver);
> +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
>  
> -	return ddrv->probe(ddev);
> +	return fddrv->probe(fddev);
>  }
>  
> -static int dfl_bus_remove(struct device *dev)
> +static int fpga_dfl_bus_remove(struct device *dev)
>  {
> -	struct dfl_driver *ddrv = to_dfl_drv(dev->driver);
> -	struct dfl_device *ddev = to_dfl_dev(dev);
> +	struct fpga_dfl_driver *fddrv = to_fpga_dfl_drv(dev->driver);
> +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
>  
> -	if (ddrv->remove)
> -		ddrv->remove(ddev);
> +	if (fddrv->remove)
> +		fddrv->remove(fddev);
>  
>  	return 0;
>  }
>  
> -static int dfl_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
> +static int fpga_dfl_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
>  {
> -	struct dfl_device *ddev = to_dfl_dev(dev);
> +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
>  
>  	/* The type has 4 valid bits and feature_id has 12 valid bits */
> -	return add_uevent_var(env, "MODALIAS=dfl:t%01Xf%03X",
> -			      ddev->type, ddev->feature_id);
> +	return add_uevent_var(env, "MODALIAS=fpga-dfl:t%01Xf%03X",
> +			      fddev->type, fddev->feature_id);
>  }
>  
>  static ssize_t
>  type_show(struct device *dev, struct device_attribute *attr, char *buf)
>  {
> -	struct dfl_device *ddev = to_dfl_dev(dev);
> +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
>  
> -	return sprintf(buf, "0x%x\n", ddev->type);
> +	return sprintf(buf, "0x%x\n", fddev->type);
>  }
>  static DEVICE_ATTR_RO(type);
>  
>  static ssize_t
>  feature_id_show(struct device *dev, struct device_attribute *attr, char *buf)
>  {
> -	struct dfl_device *ddev = to_dfl_dev(dev);
> +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
>  
> -	return sprintf(buf, "0x%x\n", ddev->feature_id);
> +	return sprintf(buf, "0x%x\n", fddev->feature_id);
>  }
>  static DEVICE_ATTR_RO(feature_id);
>  
> -static struct attribute *dfl_dev_attrs[] = {
> +static struct attribute *fpga_dfl_dev_attrs[] = {
>  	&dev_attr_type.attr,
>  	&dev_attr_feature_id.attr,
>  	NULL,
>  };
> -ATTRIBUTE_GROUPS(dfl_dev);
> -
> -static struct bus_type dfl_bus_type = {
> -	.name		= "dfl",
> -	.match		= dfl_bus_match,
> -	.probe		= dfl_bus_probe,
> -	.remove		= dfl_bus_remove,
> -	.uevent		= dfl_bus_uevent,
> -	.dev_groups	= dfl_dev_groups,
> +ATTRIBUTE_GROUPS(fpga_dfl_dev);
> +
> +static struct bus_type fpga_dfl_bus_type = {
> +	.name		= "fpga-dfl",
> +	.match		= fpga_dfl_bus_match,
> +	.probe		= fpga_dfl_bus_probe,
> +	.remove		= fpga_dfl_bus_remove,
> +	.uevent		= fpga_dfl_bus_uevent,
> +	.dev_groups	= fpga_dfl_dev_groups,
>  };
>  
> -static void release_dfl_dev(struct device *dev)
> +static void release_fpga_dfl_dev(struct device *dev)
>  {
> -	struct dfl_device *ddev = to_dfl_dev(dev);
> +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
>  
> -	if (ddev->mmio_res.parent)
> -		release_resource(&ddev->mmio_res);
> +	if (fddev->mmio_res.parent)
> +		release_resource(&fddev->mmio_res);
>  
> -	ida_simple_remove(&dfl_device_ida, ddev->id);
> -	kfree(ddev->irqs);
> -	kfree(ddev);
> +	ida_simple_remove(&fpga_dfl_device_ida, fddev->id);
> +	kfree(fddev->irqs);
> +	kfree(fddev);
>  }
>  
> -static struct dfl_device *
> -dfl_dev_add(struct dfl_feature_platform_data *pdata,
> -	    struct dfl_feature *feature)
> +static struct fpga_dfl_device *
> +fpga_dfl_dev_add(struct dfl_feature_platform_data *pdata,
> +		 struct dfl_feature *feature)
>  {
>  	struct platform_device *pdev = pdata->dev;
>  	struct resource *parent_res;
> -	struct dfl_device *ddev;
> +	struct fpga_dfl_device *fddev;
>  	int id, i, ret;
>  
> -	ddev = kzalloc(sizeof(*ddev), GFP_KERNEL);
> -	if (!ddev)
> +	fddev = kzalloc(sizeof(*fddev), GFP_KERNEL);
> +	if (!fddev)
>  		return ERR_PTR(-ENOMEM);
>  
> -	id = ida_simple_get(&dfl_device_ida, 0, 0, GFP_KERNEL);
> +	id = ida_simple_get(&fpga_dfl_device_ida, 0, 0, GFP_KERNEL);
>  	if (id < 0) {
>  		dev_err(&pdev->dev, "unable to get id\n");
> -		kfree(ddev);
> +		kfree(fddev);
>  		return ERR_PTR(id);
>  	}
>  
>  	/* freeing resources by put_device() after device_initialize() */
> -	device_initialize(&ddev->dev);
> -	ddev->dev.parent = &pdev->dev;
> -	ddev->dev.bus = &dfl_bus_type;
> -	ddev->dev.release = release_dfl_dev;
> -	ddev->id = id;
> -	ret = dev_set_name(&ddev->dev, "dfl_dev.%d", id);
> +	device_initialize(&fddev->dev);
> +	fddev->dev.parent = &pdev->dev;
> +	fddev->dev.bus = &fpga_dfl_bus_type;
> +	fddev->dev.release = release_fpga_dfl_dev;
> +	fddev->id = id;
> +	ret = dev_set_name(&fddev->dev, "fpga_dfl_dev.%d", id);
>  	if (ret)
>  		goto put_dev;
>  
> -	ddev->type = feature_dev_id_type(pdev);
> -	ddev->feature_id = feature->id;
> -	ddev->cdev = pdata->dfl_cdev;
> +	fddev->type = feature_dev_id_type(pdev);
> +	fddev->feature_id = feature->id;
> +	fddev->cdev = pdata->dfl_cdev;
>  
>  	/* add mmio resource */
>  	parent_res = &pdev->resource[feature->resource_index];
> -	ddev->mmio_res.flags = IORESOURCE_MEM;
> -	ddev->mmio_res.start = parent_res->start;
> -	ddev->mmio_res.end = parent_res->end;
> -	ddev->mmio_res.name = dev_name(&ddev->dev);
> -	ret = insert_resource(parent_res, &ddev->mmio_res);
> +	fddev->mmio_res.flags = IORESOURCE_MEM;
> +	fddev->mmio_res.start = parent_res->start;
> +	fddev->mmio_res.end = parent_res->end;
> +	fddev->mmio_res.name = dev_name(&fddev->dev);
> +	ret = insert_resource(parent_res, &fddev->mmio_res);
>  	if (ret) {
>  		dev_err(&pdev->dev, "%s failed to claim resource: %pR\n",
> -			dev_name(&ddev->dev), &ddev->mmio_res);
> +			dev_name(&fddev->dev), &fddev->mmio_res);
>  		goto put_dev;
>  	}
>  
>  	/* then add irq resource */
>  	if (feature->nr_irqs) {
> -		ddev->irqs = kcalloc(feature->nr_irqs,
> -				     sizeof(*ddev->irqs), GFP_KERNEL);
> -		if (!ddev->irqs) {
> +		fddev->irqs = kcalloc(feature->nr_irqs,
> +				      sizeof(*fddev->irqs), GFP_KERNEL);
> +		if (!fddev->irqs) {
>  			ret = -ENOMEM;
>  			goto put_dev;
>  		}
>  
>  		for (i = 0; i < feature->nr_irqs; i++)
> -			ddev->irqs[i] = feature->irq_ctx[i].irq;
> +			fddev->irqs[i] = feature->irq_ctx[i].irq;
>  
> -		ddev->num_irqs = feature->nr_irqs;
> +		fddev->num_irqs = feature->nr_irqs;
>  	}
>  
> -	ret = device_add(&ddev->dev);
> +	ret = device_add(&fddev->dev);
>  	if (ret)
>  		goto put_dev;
>  
> -	dev_dbg(&pdev->dev, "add dfl_dev: %s\n", dev_name(&ddev->dev));
> -	return ddev;
> +	dev_dbg(&pdev->dev, "add fpga_dfl_dev: %s\n", dev_name(&fddev->dev));
> +	return fddev;
>  
>  put_dev:
> -	/* calls release_dfl_dev() which does the clean up  */
> -	put_device(&ddev->dev);
> +	/* calls release_fpga_dfl_dev() which does the clean up  */
> +	put_device(&fddev->dev);
>  	return ERR_PTR(ret);
>  }
>  
> -static void dfl_devs_remove(struct dfl_feature_platform_data *pdata)
> +static void fpga_dfl_devs_remove(struct dfl_feature_platform_data *pdata)
>  {
>  	struct dfl_feature *feature;
>  
>  	dfl_fpga_dev_for_each_feature(pdata, feature) {
> -		if (feature->ddev) {
> -			device_unregister(&feature->ddev->dev);
> -			feature->ddev = NULL;
> +		if (feature->fddev) {
> +			device_unregister(&feature->fddev->dev);
> +			feature->fddev = NULL;
>  		}
>  	}
>  }
>  
> -static int dfl_devs_add(struct dfl_feature_platform_data *pdata)
> +static int fpga_dfl_devs_add(struct dfl_feature_platform_data *pdata)
>  {
> +	struct fpga_dfl_device *fddev;
>  	struct dfl_feature *feature;
> -	struct dfl_device *ddev;
>  	int ret;
>  
>  	dfl_fpga_dev_for_each_feature(pdata, feature) {
>  		if (feature->ioaddr)
>  			continue;
>  
> -		if (feature->ddev) {
> +		if (feature->fddev) {
>  			ret = -EEXIST;
>  			goto err;
>  		}
>  
> -		ddev = dfl_dev_add(pdata, feature);
> -		if (IS_ERR(ddev)) {
> -			ret = PTR_ERR(ddev);
> +		fddev = fpga_dfl_dev_add(pdata, feature);
> +		if (IS_ERR(fddev)) {
> +			ret = PTR_ERR(fddev);
>  			goto err;
>  		}
>  
> -		feature->ddev = ddev;
> +		feature->fddev = fddev;
>  	}
>  
>  	return 0;
>  
>  err:
> -	dfl_devs_remove(pdata);
> +	fpga_dfl_devs_remove(pdata);
>  	return ret;
>  }
>  
> -int __dfl_driver_register(struct dfl_driver *dfl_drv, struct module *owner)
> +int __fpga_dfl_driver_register(struct fpga_dfl_driver *fddrv,
> +			       struct module *owner)
>  {
> -	if (!dfl_drv || !dfl_drv->probe || !dfl_drv->id_table)
> +	if (!fddrv || !fddrv->probe || !fddrv->id_table)
>  		return -EINVAL;
>  
> -	dfl_drv->drv.owner = owner;
> -	dfl_drv->drv.bus = &dfl_bus_type;
> +	fddrv->drv.owner = owner;
> +	fddrv->drv.bus = &fpga_dfl_bus_type;
>  
> -	return driver_register(&dfl_drv->drv);
> +	return driver_register(&fddrv->drv);
>  }
> -EXPORT_SYMBOL(__dfl_driver_register);
> +EXPORT_SYMBOL(__fpga_dfl_driver_register);
>  
> -void dfl_driver_unregister(struct dfl_driver *dfl_drv)
> +void fpga_dfl_driver_unregister(struct fpga_dfl_driver *fddrv)
>  {
> -	driver_unregister(&dfl_drv->drv);
> +	driver_unregister(&fddrv->drv);
>  }
> -EXPORT_SYMBOL(dfl_driver_unregister);
> +EXPORT_SYMBOL(fpga_dfl_driver_unregister);
>  
>  #define is_header_feature(feature) ((feature)->id == FEATURE_ID_FIU_HEADER)
>  
> @@ -496,7 +498,7 @@ void dfl_fpga_dev_feature_uinit(struct platform_device *pdev)
>  	struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
>  	struct dfl_feature *feature;
>  
> -	dfl_devs_remove(pdata);
> +	fpga_dfl_devs_remove(pdata);
>  
>  	dfl_fpga_dev_for_each_feature(pdata, feature) {
>  		if (feature->ops) {
> @@ -585,7 +587,7 @@ int dfl_fpga_dev_feature_init(struct platform_device *pdev,
>  		drv++;
>  	}
>  
> -	ret = dfl_devs_add(pdata);
> +	ret = fpga_dfl_devs_add(pdata);
>  	if (ret)
>  		goto exit;
>  
> @@ -745,11 +747,11 @@ static int build_info_commit_dev(struct build_feature_devs_info *binfo)
>  	struct platform_device *fdev = binfo->feature_dev;
>  	struct dfl_feature_platform_data *pdata;
>  	struct dfl_feature_info *finfo, *p;
> -	enum dfl_id_type type;
> +	enum fpga_dfl_id_type type;
>  	int ret, index = 0, res_idx = 0;
>  
>  	type = feature_dev_id_type(fdev);
> -	if (WARN_ON_ONCE(type >= DFL_ID_MAX))
> +	if (WARN_ON_ONCE(type >= FPGA_DFL_ID_MAX))
>  		return -EINVAL;
>  
>  	/*
> @@ -836,7 +838,7 @@ static int build_info_commit_dev(struct build_feature_devs_info *binfo)
>  
>  	ret = platform_device_add(binfo->feature_dev);
>  	if (!ret) {
> -		if (type == PORT_ID)
> +		if (type == FPGA_DFL_PORT_ID)
>  			dfl_fpga_cdev_add_port_dev(binfo->cdev,
>  						   binfo->feature_dev);
>  		else
> @@ -857,11 +859,11 @@ static int build_info_commit_dev(struct build_feature_devs_info *binfo)
>  
>  static int
>  build_info_create_dev(struct build_feature_devs_info *binfo,
> -		      enum dfl_id_type type)
> +		      enum fpga_dfl_id_type type)
>  {
>  	struct platform_device *fdev;
>  
> -	if (type >= DFL_ID_MAX)
> +	if (type >= FPGA_DFL_ID_MAX)
>  		return -EINVAL;
>  
>  	/*
> @@ -1072,7 +1074,7 @@ static int parse_feature_afu(struct build_feature_devs_info *binfo,
>  	}
>  
>  	switch (feature_dev_id_type(binfo->feature_dev)) {
> -	case PORT_ID:
> +	case FPGA_DFL_PORT_ID:
>  		return parse_feature_port_afu(binfo, ofst);
>  	default:
>  		dev_info(binfo->dev, "AFU belonging to FIU %s is not supported yet.\n",
> @@ -1360,7 +1362,7 @@ EXPORT_SYMBOL_GPL(dfl_fpga_enum_info_add_irq);
>  static int remove_feature_dev(struct device *dev, void *data)
>  {
>  	struct platform_device *pdev = to_platform_device(dev);
> -	enum dfl_id_type type = feature_dev_id_type(pdev);
> +	enum fpga_dfl_id_type type = feature_dev_id_type(pdev);
>  	int id = pdev->id;
>  
>  	platform_device_unregister(pdev);
> @@ -1526,7 +1528,7 @@ static int __init dfl_fpga_init(void)
>  {
>  	int ret;
>  
> -	ret = bus_register(&dfl_bus_type);
> +	ret = bus_register(&fpga_dfl_bus_type);
>  	if (ret)
>  		return ret;
>  
> @@ -1535,7 +1537,7 @@ static int __init dfl_fpga_init(void)
>  	ret = dfl_chardev_init();
>  	if (ret) {
>  		dfl_ids_destroy();
> -		bus_unregister(&dfl_bus_type);
> +		bus_unregister(&fpga_dfl_bus_type);
>  	}
>  
>  	return ret;
> @@ -1874,7 +1876,7 @@ static void __exit dfl_fpga_exit(void)
>  {
>  	dfl_chardev_uinit();
>  	dfl_ids_destroy();
> -	bus_unregister(&dfl_bus_type);
> +	bus_unregister(&fpga_dfl_bus_type);
>  }
>  
>  module_init(dfl_fpga_init);
> diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h
> index 5dc758f..ba930a7 100644
> --- a/drivers/fpga/dfl.h
> +++ b/drivers/fpga/dfl.h
> @@ -236,7 +236,7 @@ struct dfl_feature_irq_ctx {
>   * @irq_ctx: interrupt context list.
>   * @nr_irqs: number of interrupt contexts.
>   * @ops: ops of this sub feature.
> - * @ddev: ptr to the dfl device of this sub feature.
> + * @fddev: ptr to the fpga dfl device of this sub feature.
>   * @priv: priv data of this feature.
>   */
>  struct dfl_feature {
> @@ -247,7 +247,7 @@ struct dfl_feature {
>  	struct dfl_feature_irq_ctx *irq_ctx;
>  	unsigned int nr_irqs;
>  	const struct dfl_feature_ops *ops;
> -	struct dfl_device *ddev;
> +	struct fpga_dfl_device *fddev;
>  	void *priv;
>  };
>  
> @@ -517,40 +517,42 @@ long dfl_feature_ioctl_set_irq(struct platform_device *pdev,
>  			       unsigned long arg);
>  
>  /**
> - * enum dfl_id_type - define the DFL FIU types
> + * enum fpga_dfl_id_type - define the FPGA DFL FIU types
>   */
> -enum dfl_id_type {
> -	FME_ID,
> -	PORT_ID,
> -	DFL_ID_MAX,
> +enum fpga_dfl_id_type {
> +	FPGA_DFL_FME_ID,
> +	FPGA_DFL_PORT_ID,
> +	FPGA_DFL_ID_MAX,
>  };
>  
>  /**
> - * struct dfl_device_id -  dfl device identifier
> - * @type: contains 4 bits DFL FIU type of the device. See enum dfl_id_type.
> - * @feature_id: contains 12 bits feature identifier local to its DFL FIU type.
> + * struct fpga_dfl_device_id - fpga dfl device identifier
> + * @type: contains 4 bits FPGA DFL FIU type of the device, see
> + *	  enum fpga_dfl_id_type.
> + * @feature_id: contains 12 bits feature identifier local to its FPGA DFL FIU
> + *		type.
>   * @driver_data: driver specific data.
>   */
> -struct dfl_device_id {
> +struct fpga_dfl_device_id {
>  	u8 type;
>  	u16 feature_id;
>  	unsigned long driver_data;
>  };
>  
>  /**
> - * struct dfl_device - represent an dfl device on dfl bus
> + * struct fpga_dfl_device - represent an fpga dfl device on fpga dfl bus
>   *
>   * @dev: generic device interface.
> - * @id: id of the dfl device.
> - * @type: type of DFL FIU of the device. See enum dfl_id_type.
> - * @feature_id: 16 bits feature identifier local to its DFL FIU type.
> - * @mmio_res: mmio resource of this dfl device.
> - * @irqs: list of Linux IRQ numbers of this dfl device.
> - * @num_irqs: number of IRQs supported by this dfl device.
> - * @cdev: pointer to DFL FPGA container device this dfl device belongs to.
> - * @id_entry: matched id entry in dfl driver's id table.
> + * @id: id of the fpga dfl device.
> + * @type: FPGA DFL FIU type of the device, see enum fpga_dfl_id_type.
> + * @feature_id: 16 bits feature identifier local to its FPGA DFL FIU type.
> + * @mmio_res: mmio resource of this fpga dfl device.
> + * @irqs: list of Linux IRQ numbers of this fpga dfl device.
> + * @num_irqs: number of IRQs supported by this fpga dfl device.
> + * @cdev: pointer to DFL FPGA container device this fpga dfl device belongs to.
> + * @id_entry: matched id entry in fpga dfl driver's id table.
>   */
> -struct dfl_device {
> +struct fpga_dfl_device {
>  	struct device dev;
>  	int id;
>  	u8 type;
> @@ -559,11 +561,11 @@ struct dfl_device {
>  	int *irqs;
>  	unsigned int num_irqs;
>  	struct dfl_fpga_cdev *cdev;
> -	const struct dfl_device_id *id_entry;
> +	const struct fpga_dfl_device_id *id_entry;
>  };
>  
>  /**
> - * struct dfl_driver - represent an dfl device driver
> + * struct fpga_dfl_driver - represent a fpga dfl device driver
>   *
>   * @drv: driver model structure.
>   * @id_table: pointer to table of device IDs the driver is interested in.
> @@ -571,33 +573,34 @@ struct dfl_device {
>   * @probe: mandatory callback for device binding.
>   * @remove: callback for device unbinding.
>   */
> -struct dfl_driver {
> +struct fpga_dfl_driver {
>  	struct device_driver drv;
> -	const struct dfl_device_id *id_table;
> +	const struct fpga_dfl_device_id *id_table;
>  
> -	int (*probe)(struct dfl_device *dfl_dev);
> -	void (*remove)(struct dfl_device *dfl_dev);
> +	int (*probe)(struct fpga_dfl_device *fddev);
> +	void (*remove)(struct fpga_dfl_device *fddev);
>  };
>  
> -#define to_dfl_dev(d) container_of(d, struct dfl_device, dev)
> -#define to_dfl_drv(d) container_of(d, struct dfl_driver, drv)
> +#define to_fpga_dfl_dev(d) container_of(d, struct fpga_dfl_device, dev)
> +#define to_fpga_dfl_drv(d) container_of(d, struct fpga_dfl_driver, drv)
>  
>  /*
>   * use a macro to avoid include chaining to get THIS_MODULE.
>   */
> -#define dfl_driver_register(drv) \
> -	__dfl_driver_register(drv, THIS_MODULE)
> -int __dfl_driver_register(struct dfl_driver *dfl_drv, struct module *owner);
> -void dfl_driver_unregister(struct dfl_driver *dfl_drv);
> +#define fpga_dfl_driver_register(drv) \
> +	__fpga_dfl_driver_register(drv, THIS_MODULE)
> +int __fpga_dfl_driver_register(struct fpga_dfl_driver *fddrv,
> +			       struct module *owner);
> +void fpga_dfl_driver_unregister(struct fpga_dfl_driver *fddrv);
>  
>  /*
> - * module_dfl_driver() - Helper macro for drivers that don't do
> + * module_fpga_dfl_driver() - Helper macro for drivers that don't do
>   * anything special in module init/exit.  This eliminates a lot of
>   * boilerplate.  Each module may only use this macro once, and
>   * calling it replaces module_init() and module_exit().
>   */
> -#define module_dfl_driver(__dfl_driver) \
> -	module_driver(__dfl_driver, dfl_driver_register, \
> -		      dfl_driver_unregister)
> +#define module_fpga_dfl_driver(__fpga_dfl_driver) \
> +	module_driver(__fpga_dfl_driver, fpga_dfl_driver_register, \
> +		      fpga_dfl_driver_unregister)
>  
>  #endif /* __FPGA_DFL_H */
> -- 
> 2.7.4
> 
Thanks,
Moritz

Re: [PATCH v3 1/5] fpga: dfl: rename the bus type "dfl" to "fpga-dfl"

[Greg KH]

On Sat, Sep 26, 2020 at 10:23:46AM +0800, Xu Yilun wrote:
> Hi greg,
> 
> About the bus naming, I summarized some questions we've discussed to check
> with you. See inline.
> 
> On Thu, Sep 24, 2020 at 10:27:00AM -0700, Moritz Fischer wrote:
> > Hi Xu,
> > 
> > On Fri, Sep 25, 2020 at 12:59:57AM +0800, Xu Yilun wrote:
> > > Now the DFL device drivers could be made as independent modules and put
> > > in different subsystems according to their functionalities. So the name
> > > should be descriptive and unique in the whole kernel.
> > > 
> > > The patch changes the naming of dfl bus related structures, functions,
> > > APIs and documentations.
> > > 
> > > Signed-off-by: Xu Yilun <yilun.xu@intel.com>
> > > ---
> > >  Documentation/ABI/testing/sysfs-bus-dfl      |  15 --
> > >  Documentation/ABI/testing/sysfs-bus-fpga-dfl |  15 ++
> > >  MAINTAINERS                                  |   2 +-
> > >  drivers/fpga/dfl.c                           | 254 ++++++++++++++-------------
> > >  drivers/fpga/dfl.h                           |  77 ++++----
> > >  5 files changed, 184 insertions(+), 179 deletions(-)
> > >  delete mode 100644 Documentation/ABI/testing/sysfs-bus-dfl
> > >  create mode 100644 Documentation/ABI/testing/sysfs-bus-fpga-dfl
> > > 
> > > diff --git a/Documentation/ABI/testing/sysfs-bus-dfl b/Documentation/ABI/testing/sysfs-bus-dfl
> > > deleted file mode 100644
> > > index 23543be..0000000
> > > --- a/Documentation/ABI/testing/sysfs-bus-dfl
> > > +++ /dev/null
> > > @@ -1,15 +0,0 @@
> > > -What:		/sys/bus/dfl/devices/dfl_dev.X/type
> > > -Date:		Aug 2020
> > > -KernelVersion:	5.10
> > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > -Description:	Read-only. It returns type of DFL FIU of the device. Now DFL
> > > -		supports 2 FIU types, 0 for FME, 1 for PORT.
> > > -		Format: 0x%x
> > > -
> > > -What:		/sys/bus/dfl/devices/dfl_dev.X/feature_id
> > > -Date:		Aug 2020
> > > -KernelVersion:	5.10
> > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > -Description:	Read-only. It returns feature identifier local to its DFL FIU
> > > -		type.
> > > -		Format: 0x%x
> > 
> > You're changing userland facing ABI. I think that's something to avoid,
> > please check with Greg on the rules since this hasn't been in a release yet.
> > 
> 
> I'm going to change the name of bus stuff for other subsystems, to be
> aligned, I also consider change the bus_type.name and dfl dev_name. But
> it will cause the changing of user ABIs. No user case for these user ABI
> now cause they are just queued, is it good I change them?

Why change the user name here?  No need for that, right?  Unless you
really want to, and think that no one will notice.  If so, fine, change
them :)

> It is mentioned that although Device Feature List is introduced in FPGA,
> but it doesn't limit the usage in FPGA only. It's just a method to
> discover features from a device, for sure it can be extended and used
> in other devices too. So it can be bigger namespace than FPGA. Like in
> our existing code, we picked dfl_fpga (DFL based FPGA) for uapi (ioctl)
> and internal functions. This is suggested by Alan (The previous FPGA
> maintainer). It's possible to have "DFL based XXX" in the future, even
> currently only FPGA uses DFL. This is the reason we thought just "dfl"
> in the whole kernel space is OK.
> So, is there a chance we keep the "dfl" naming in the whole kernel?

No one knows what "DFL" is, and odds are, if a different subsystem wants
to use it, they will have their own variant, right?

And why didn't you all use device tree?  How did this sneak in past
everyone?

thanks,

greg k-h

Re: [PATCH v3 1/5] fpga: dfl: rename the bus type "dfl" to "fpga-dfl"

[Moritz Fischer]

Hi Greg,

On Sat, Sep 26, 2020 at 08:09:13AM +0200, Greg KH wrote:
> On Sat, Sep 26, 2020 at 10:23:46AM +0800, Xu Yilun wrote:
> > Hi greg,
> > 
> > About the bus naming, I summarized some questions we've discussed to check
> > with you. See inline.
> > 
> > On Thu, Sep 24, 2020 at 10:27:00AM -0700, Moritz Fischer wrote:
> > > Hi Xu,
> > > 
> > > On Fri, Sep 25, 2020 at 12:59:57AM +0800, Xu Yilun wrote:
> > > > Now the DFL device drivers could be made as independent modules and put
> > > > in different subsystems according to their functionalities. So the name
> > > > should be descriptive and unique in the whole kernel.
> > > > 
> > > > The patch changes the naming of dfl bus related structures, functions,
> > > > APIs and documentations.
> > > > 
> > > > Signed-off-by: Xu Yilun <yilun.xu@intel.com>
> > > > ---
> > > >  Documentation/ABI/testing/sysfs-bus-dfl      |  15 --
> > > >  Documentation/ABI/testing/sysfs-bus-fpga-dfl |  15 ++
> > > >  MAINTAINERS                                  |   2 +-
> > > >  drivers/fpga/dfl.c                           | 254 ++++++++++++++-------------
> > > >  drivers/fpga/dfl.h                           |  77 ++++----
> > > >  5 files changed, 184 insertions(+), 179 deletions(-)
> > > >  delete mode 100644 Documentation/ABI/testing/sysfs-bus-dfl
> > > >  create mode 100644 Documentation/ABI/testing/sysfs-bus-fpga-dfl
> > > > 
> > > > diff --git a/Documentation/ABI/testing/sysfs-bus-dfl b/Documentation/ABI/testing/sysfs-bus-dfl
> > > > deleted file mode 100644
> > > > index 23543be..0000000
> > > > --- a/Documentation/ABI/testing/sysfs-bus-dfl
> > > > +++ /dev/null
> > > > @@ -1,15 +0,0 @@
> > > > -What:		/sys/bus/dfl/devices/dfl_dev.X/type
> > > > -Date:		Aug 2020
> > > > -KernelVersion:	5.10
> > > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > > -Description:	Read-only. It returns type of DFL FIU of the device. Now DFL
> > > > -		supports 2 FIU types, 0 for FME, 1 for PORT.
> > > > -		Format: 0x%x
> > > > -
> > > > -What:		/sys/bus/dfl/devices/dfl_dev.X/feature_id
> > > > -Date:		Aug 2020
> > > > -KernelVersion:	5.10
> > > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > > -Description:	Read-only. It returns feature identifier local to its DFL FIU
> > > > -		type.
> > > > -		Format: 0x%x
> > > 
> > > You're changing userland facing ABI. I think that's something to avoid,
> > > please check with Greg on the rules since this hasn't been in a release yet.
> > > 
> > 
> > I'm going to change the name of bus stuff for other subsystems, to be
> > aligned, I also consider change the bus_type.name and dfl dev_name. But
> > it will cause the changing of user ABIs. No user case for these user ABI
> > now cause they are just queued, is it good I change them?
> 
> Why change the user name here?  No need for that, right?  Unless you
> really want to, and think that no one will notice.  If so, fine, change
> them :)

Let's leave it as is -- An FPGA is one possible implementation and as for
other buses, you wouldn't call it fpga-usb or usb-fpga just because the
USB bus is implemented in an FPGA if it behaves like a normal USB bus.
Having an ASIC based DFL bus show up under dfl-fpga / fpga-dfl in sysfs
would be super confusing.

> > It is mentioned that although Device Feature List is introduced in FPGA,
> > but it doesn't limit the usage in FPGA only. It's just a method to
> > discover features from a device, for sure it can be extended and used
> > in other devices too. So it can be bigger namespace than FPGA. Like in
> > our existing code, we picked dfl_fpga (DFL based FPGA) for uapi (ioctl)
> > and internal functions. This is suggested by Alan (The previous FPGA
> > maintainer). It's possible to have "DFL based XXX" in the future, even
> > currently only FPGA uses DFL. This is the reason we thought just "dfl"
> > in the whole kernel space is OK.
> > So, is there a chance we keep the "dfl" naming in the whole kernel?
> 
> No one knows what "DFL" is, and odds are, if a different subsystem wants
> to use it, they will have their own variant, right?
> 
> And why didn't you all use device tree?  How did this sneak in past
> everyone?

DFL is a pretty efficient implementation in terms of resource
utilization on the FPGA end (a couple of registers / memories) vs
several kilobytes of memory for a device-tree blob.

The hardware using DFL to describe its internal structure exists in the
form of deployed accelerator cards and telling all its users to go and
change their hardware design would be feasible -- If you think about an
FPGA as a (albeit reconfigurable) ASIC you wouldn't go and tell people
to redesign their ASIC to use Device-Tree? :)

I'm not sure where the 'sneaking in' anything comes from. It's been
reviewed on the list (and by yourself back then). If you feel any of
this wasn't kosher, let's talk about it, to make sure it doesn't happen
again.

Cheers,
Moritz

Re: [PATCH v3 1/5] fpga: dfl: rename the bus type "dfl" to "fpga-dfl"

[Greg KH]

On Sat, Sep 26, 2020 at 12:22:19PM -0700, Moritz Fischer wrote:
> Hi Greg,
> 
> On Sat, Sep 26, 2020 at 08:09:13AM +0200, Greg KH wrote:
> > On Sat, Sep 26, 2020 at 10:23:46AM +0800, Xu Yilun wrote:
> > > Hi greg,
> > > 
> > > About the bus naming, I summarized some questions we've discussed to check
> > > with you. See inline.
> > > 
> > > On Thu, Sep 24, 2020 at 10:27:00AM -0700, Moritz Fischer wrote:
> > > > Hi Xu,
> > > > 
> > > > On Fri, Sep 25, 2020 at 12:59:57AM +0800, Xu Yilun wrote:
> > > > > Now the DFL device drivers could be made as independent modules and put
> > > > > in different subsystems according to their functionalities. So the name
> > > > > should be descriptive and unique in the whole kernel.
> > > > > 
> > > > > The patch changes the naming of dfl bus related structures, functions,
> > > > > APIs and documentations.
> > > > > 
> > > > > Signed-off-by: Xu Yilun <yilun.xu@intel.com>
> > > > > ---
> > > > >  Documentation/ABI/testing/sysfs-bus-dfl      |  15 --
> > > > >  Documentation/ABI/testing/sysfs-bus-fpga-dfl |  15 ++
> > > > >  MAINTAINERS                                  |   2 +-
> > > > >  drivers/fpga/dfl.c                           | 254 ++++++++++++++-------------
> > > > >  drivers/fpga/dfl.h                           |  77 ++++----
> > > > >  5 files changed, 184 insertions(+), 179 deletions(-)
> > > > >  delete mode 100644 Documentation/ABI/testing/sysfs-bus-dfl
> > > > >  create mode 100644 Documentation/ABI/testing/sysfs-bus-fpga-dfl
> > > > > 
> > > > > diff --git a/Documentation/ABI/testing/sysfs-bus-dfl b/Documentation/ABI/testing/sysfs-bus-dfl
> > > > > deleted file mode 100644
> > > > > index 23543be..0000000
> > > > > --- a/Documentation/ABI/testing/sysfs-bus-dfl
> > > > > +++ /dev/null
> > > > > @@ -1,15 +0,0 @@
> > > > > -What:		/sys/bus/dfl/devices/dfl_dev.X/type
> > > > > -Date:		Aug 2020
> > > > > -KernelVersion:	5.10
> > > > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > > > -Description:	Read-only. It returns type of DFL FIU of the device. Now DFL
> > > > > -		supports 2 FIU types, 0 for FME, 1 for PORT.
> > > > > -		Format: 0x%x
> > > > > -
> > > > > -What:		/sys/bus/dfl/devices/dfl_dev.X/feature_id
> > > > > -Date:		Aug 2020
> > > > > -KernelVersion:	5.10
> > > > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > > > -Description:	Read-only. It returns feature identifier local to its DFL FIU
> > > > > -		type.
> > > > > -		Format: 0x%x
> > > > 
> > > > You're changing userland facing ABI. I think that's something to avoid,
> > > > please check with Greg on the rules since this hasn't been in a release yet.
> > > > 
> > > 
> > > I'm going to change the name of bus stuff for other subsystems, to be
> > > aligned, I also consider change the bus_type.name and dfl dev_name. But
> > > it will cause the changing of user ABIs. No user case for these user ABI
> > > now cause they are just queued, is it good I change them?
> > 
> > Why change the user name here?  No need for that, right?  Unless you
> > really want to, and think that no one will notice.  If so, fine, change
> > them :)
> 
> Let's leave it as is -- An FPGA is one possible implementation and as for
> other buses, you wouldn't call it fpga-usb or usb-fpga just because the
> USB bus is implemented in an FPGA if it behaves like a normal USB bus.
> Having an ASIC based DFL bus show up under dfl-fpga / fpga-dfl in sysfs
> would be super confusing.
> 
> > > It is mentioned that although Device Feature List is introduced in FPGA,
> > > but it doesn't limit the usage in FPGA only. It's just a method to
> > > discover features from a device, for sure it can be extended and used
> > > in other devices too. So it can be bigger namespace than FPGA. Like in
> > > our existing code, we picked dfl_fpga (DFL based FPGA) for uapi (ioctl)
> > > and internal functions. This is suggested by Alan (The previous FPGA
> > > maintainer). It's possible to have "DFL based XXX" in the future, even
> > > currently only FPGA uses DFL. This is the reason we thought just "dfl"
> > > in the whole kernel space is OK.
> > > So, is there a chance we keep the "dfl" naming in the whole kernel?
> > 
> > No one knows what "DFL" is, and odds are, if a different subsystem wants
> > to use it, they will have their own variant, right?
> > 
> > And why didn't you all use device tree?  How did this sneak in past
> > everyone?
> 
> DFL is a pretty efficient implementation in terms of resource
> utilization on the FPGA end (a couple of registers / memories) vs
> several kilobytes of memory for a device-tree blob.
> 
> The hardware using DFL to describe its internal structure exists in the
> form of deployed accelerator cards and telling all its users to go and
> change their hardware design would be feasible -- If you think about an
> FPGA as a (albeit reconfigurable) ASIC you wouldn't go and tell people
> to redesign their ASIC to use Device-Tree? :)
> 
> I'm not sure where the 'sneaking in' anything comes from. It's been
> reviewed on the list (and by yourself back then). If you feel any of
> this wasn't kosher, let's talk about it, to make sure it doesn't happen
> again.

I can't remember reviewing it, sorry, too many patches, I probably was
only worrying about functionality issues, not what the code actually did
:)

So it's fine, just a surprise to me, no big deal.

thanks,

greg k-h

Re: [PATCH v3 1/5] fpga: dfl: rename the bus type "dfl" to "fpga-dfl"

[Xu Yilun]

Hi Greg,

On Sun, Sep 27, 2020 at 07:51:08AM +0200, Greg KH wrote:
> On Sat, Sep 26, 2020 at 12:22:19PM -0700, Moritz Fischer wrote:
> > Hi Greg,
> > 
> > On Sat, Sep 26, 2020 at 08:09:13AM +0200, Greg KH wrote:
> > > On Sat, Sep 26, 2020 at 10:23:46AM +0800, Xu Yilun wrote:
> > > > Hi greg,
> > > > 
> > > > About the bus naming, I summarized some questions we've discussed to check
> > > > with you. See inline.
> > > > 
> > > > On Thu, Sep 24, 2020 at 10:27:00AM -0700, Moritz Fischer wrote:
> > > > > Hi Xu,
> > > > > 
> > > > > On Fri, Sep 25, 2020 at 12:59:57AM +0800, Xu Yilun wrote:
> > > > > > Now the DFL device drivers could be made as independent modules and put
> > > > > > in different subsystems according to their functionalities. So the name
> > > > > > should be descriptive and unique in the whole kernel.
> > > > > > 
> > > > > > The patch changes the naming of dfl bus related structures, functions,
> > > > > > APIs and documentations.
> > > > > > 
> > > > > > Signed-off-by: Xu Yilun <yilun.xu@intel.com>
> > > > > > ---
> > > > > >  Documentation/ABI/testing/sysfs-bus-dfl      |  15 --
> > > > > >  Documentation/ABI/testing/sysfs-bus-fpga-dfl |  15 ++
> > > > > >  MAINTAINERS                                  |   2 +-
> > > > > >  drivers/fpga/dfl.c                           | 254 ++++++++++++++-------------
> > > > > >  drivers/fpga/dfl.h                           |  77 ++++----
> > > > > >  5 files changed, 184 insertions(+), 179 deletions(-)
> > > > > >  delete mode 100644 Documentation/ABI/testing/sysfs-bus-dfl
> > > > > >  create mode 100644 Documentation/ABI/testing/sysfs-bus-fpga-dfl
> > > > > > 
> > > > > > diff --git a/Documentation/ABI/testing/sysfs-bus-dfl b/Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > deleted file mode 100644
> > > > > > index 23543be..0000000
> > > > > > --- a/Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > +++ /dev/null
> > > > > > @@ -1,15 +0,0 @@
> > > > > > -What:		/sys/bus/dfl/devices/dfl_dev.X/type
> > > > > > -Date:		Aug 2020
> > > > > > -KernelVersion:	5.10
> > > > > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > > > > -Description:	Read-only. It returns type of DFL FIU of the device. Now DFL
> > > > > > -		supports 2 FIU types, 0 for FME, 1 for PORT.
> > > > > > -		Format: 0x%x
> > > > > > -
> > > > > > -What:		/sys/bus/dfl/devices/dfl_dev.X/feature_id
> > > > > > -Date:		Aug 2020
> > > > > > -KernelVersion:	5.10
> > > > > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > > > > -Description:	Read-only. It returns feature identifier local to its DFL FIU
> > > > > > -		type.
> > > > > > -		Format: 0x%x
> > > > > 
> > > > > You're changing userland facing ABI. I think that's something to avoid,
> > > > > please check with Greg on the rules since this hasn't been in a release yet.
> > > > > 
> > > > 
> > > > I'm going to change the name of bus stuff for other subsystems, to be
> > > > aligned, I also consider change the bus_type.name and dfl dev_name. But
> > > > it will cause the changing of user ABIs. No user case for these user ABI
> > > > now cause they are just queued, is it good I change them?
> > > 
> > > Why change the user name here?  No need for that, right?  Unless you
> > > really want to, and think that no one will notice.  If so, fine, change
> > > them :)
> > 
> > Let's leave it as is -- An FPGA is one possible implementation and as for
> > other buses, you wouldn't call it fpga-usb or usb-fpga just because the
> > USB bus is implemented in an FPGA if it behaves like a normal USB bus.
> > Having an ASIC based DFL bus show up under dfl-fpga / fpga-dfl in sysfs
> > would be super confusing.
> > 
> > > > It is mentioned that although Device Feature List is introduced in FPGA,
> > > > but it doesn't limit the usage in FPGA only. It's just a method to
> > > > discover features from a device, for sure it can be extended and used
> > > > in other devices too. So it can be bigger namespace than FPGA. Like in
> > > > our existing code, we picked dfl_fpga (DFL based FPGA) for uapi (ioctl)
> > > > and internal functions. This is suggested by Alan (The previous FPGA
> > > > maintainer). It's possible to have "DFL based XXX" in the future, even
> > > > currently only FPGA uses DFL. This is the reason we thought just "dfl"
> > > > in the whole kernel space is OK.
> > > > So, is there a chance we keep the "dfl" naming in the whole kernel?
> > > 
> > > No one knows what "DFL" is, and odds are, if a different subsystem wants
> > > to use it, they will have their own variant, right?

DFL is a method to discover devices. If a different subsystem (e.g. ASIC based
DFL bus) want to use DFL and follows the DFL spec, they could just use the DFL
stuff for enumeration, no need to have new variants.

> > > 
> > > And why didn't you all use device tree?  How did this sneak in past
> > > everyone?
> > 
> > DFL is a pretty efficient implementation in terms of resource
> > utilization on the FPGA end (a couple of registers / memories) vs
> > several kilobytes of memory for a device-tree blob.
> > 
> > The hardware using DFL to describe its internal structure exists in the
> > form of deployed accelerator cards and telling all its users to go and
> > change their hardware design would be feasible -- If you think about an
> > FPGA as a (albeit reconfigurable) ASIC you wouldn't go and tell people
> > to redesign their ASIC to use Device-Tree? :)
> > 
> > I'm not sure where the 'sneaking in' anything comes from. It's been
> > reviewed on the list (and by yourself back then). If you feel any of
> > this wasn't kosher, let's talk about it, to make sure it doesn't happen
> > again.
> 
> I can't remember reviewing it, sorry, too many patches, I probably was
> only worrying about functionality issues, not what the code actually did
> :)
> 
> So it's fine, just a surprise to me, no big deal.

I'm glad that we made it clear. And the bus name & user APIs cound be
kept as "dfl". So I assume the name "dfl" is OK to be used and could
be recognized by people out of FPGA domain, is it?

If so, I still want to keep the name "dfl_device_id" in mod_devicetable.h
as well. We want to keep the device id name of the bus aligned with the
bus name. And it would be confusing as well if a driver for ASIC based
DFL device uses the "dfl_fpga_device_id" structure.

How do you think?

Thanks,
Yilun

> 
> thanks,
> 
> greg k-h

Re: [PATCH v3 1/5] fpga: dfl: rename the bus type "dfl" to "fpga-dfl"

[Greg KH]

On Sun, Sep 27, 2020 at 03:37:54PM +0800, Xu Yilun wrote:
> Hi Greg,
> 
> On Sun, Sep 27, 2020 at 07:51:08AM +0200, Greg KH wrote:
> > On Sat, Sep 26, 2020 at 12:22:19PM -0700, Moritz Fischer wrote:
> > > Hi Greg,
> > > 
> > > On Sat, Sep 26, 2020 at 08:09:13AM +0200, Greg KH wrote:
> > > > On Sat, Sep 26, 2020 at 10:23:46AM +0800, Xu Yilun wrote:
> > > > > Hi greg,
> > > > > 
> > > > > About the bus naming, I summarized some questions we've discussed to check
> > > > > with you. See inline.
> > > > > 
> > > > > On Thu, Sep 24, 2020 at 10:27:00AM -0700, Moritz Fischer wrote:
> > > > > > Hi Xu,
> > > > > > 
> > > > > > On Fri, Sep 25, 2020 at 12:59:57AM +0800, Xu Yilun wrote:
> > > > > > > Now the DFL device drivers could be made as independent modules and put
> > > > > > > in different subsystems according to their functionalities. So the name
> > > > > > > should be descriptive and unique in the whole kernel.
> > > > > > > 
> > > > > > > The patch changes the naming of dfl bus related structures, functions,
> > > > > > > APIs and documentations.
> > > > > > > 
> > > > > > > Signed-off-by: Xu Yilun <yilun.xu@intel.com>
> > > > > > > ---
> > > > > > >  Documentation/ABI/testing/sysfs-bus-dfl      |  15 --
> > > > > > >  Documentation/ABI/testing/sysfs-bus-fpga-dfl |  15 ++
> > > > > > >  MAINTAINERS                                  |   2 +-
> > > > > > >  drivers/fpga/dfl.c                           | 254 ++++++++++++++-------------
> > > > > > >  drivers/fpga/dfl.h                           |  77 ++++----
> > > > > > >  5 files changed, 184 insertions(+), 179 deletions(-)
> > > > > > >  delete mode 100644 Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > >  create mode 100644 Documentation/ABI/testing/sysfs-bus-fpga-dfl
> > > > > > > 
> > > > > > > diff --git a/Documentation/ABI/testing/sysfs-bus-dfl b/Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > deleted file mode 100644
> > > > > > > index 23543be..0000000
> > > > > > > --- a/Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > +++ /dev/null
> > > > > > > @@ -1,15 +0,0 @@
> > > > > > > -What:		/sys/bus/dfl/devices/dfl_dev.X/type
> > > > > > > -Date:		Aug 2020
> > > > > > > -KernelVersion:	5.10
> > > > > > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > > > > > -Description:	Read-only. It returns type of DFL FIU of the device. Now DFL
> > > > > > > -		supports 2 FIU types, 0 for FME, 1 for PORT.
> > > > > > > -		Format: 0x%x
> > > > > > > -
> > > > > > > -What:		/sys/bus/dfl/devices/dfl_dev.X/feature_id
> > > > > > > -Date:		Aug 2020
> > > > > > > -KernelVersion:	5.10
> > > > > > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > > > > > -Description:	Read-only. It returns feature identifier local to its DFL FIU
> > > > > > > -		type.
> > > > > > > -		Format: 0x%x
> > > > > > 
> > > > > > You're changing userland facing ABI. I think that's something to avoid,
> > > > > > please check with Greg on the rules since this hasn't been in a release yet.
> > > > > > 
> > > > > 
> > > > > I'm going to change the name of bus stuff for other subsystems, to be
> > > > > aligned, I also consider change the bus_type.name and dfl dev_name. But
> > > > > it will cause the changing of user ABIs. No user case for these user ABI
> > > > > now cause they are just queued, is it good I change them?
> > > > 
> > > > Why change the user name here?  No need for that, right?  Unless you
> > > > really want to, and think that no one will notice.  If so, fine, change
> > > > them :)
> > > 
> > > Let's leave it as is -- An FPGA is one possible implementation and as for
> > > other buses, you wouldn't call it fpga-usb or usb-fpga just because the
> > > USB bus is implemented in an FPGA if it behaves like a normal USB bus.
> > > Having an ASIC based DFL bus show up under dfl-fpga / fpga-dfl in sysfs
> > > would be super confusing.
> > > 
> > > > > It is mentioned that although Device Feature List is introduced in FPGA,
> > > > > but it doesn't limit the usage in FPGA only. It's just a method to
> > > > > discover features from a device, for sure it can be extended and used
> > > > > in other devices too. So it can be bigger namespace than FPGA. Like in
> > > > > our existing code, we picked dfl_fpga (DFL based FPGA) for uapi (ioctl)
> > > > > and internal functions. This is suggested by Alan (The previous FPGA
> > > > > maintainer). It's possible to have "DFL based XXX" in the future, even
> > > > > currently only FPGA uses DFL. This is the reason we thought just "dfl"
> > > > > in the whole kernel space is OK.
> > > > > So, is there a chance we keep the "dfl" naming in the whole kernel?
> > > > 
> > > > No one knows what "DFL" is, and odds are, if a different subsystem wants
> > > > to use it, they will have their own variant, right?
> 
> DFL is a method to discover devices. If a different subsystem (e.g. ASIC based
> DFL bus) want to use DFL and follows the DFL spec, they could just use the DFL
> stuff for enumeration, no need to have new variants.
> 
> > > > 
> > > > And why didn't you all use device tree?  How did this sneak in past
> > > > everyone?
> > > 
> > > DFL is a pretty efficient implementation in terms of resource
> > > utilization on the FPGA end (a couple of registers / memories) vs
> > > several kilobytes of memory for a device-tree blob.
> > > 
> > > The hardware using DFL to describe its internal structure exists in the
> > > form of deployed accelerator cards and telling all its users to go and
> > > change their hardware design would be feasible -- If you think about an
> > > FPGA as a (albeit reconfigurable) ASIC you wouldn't go and tell people
> > > to redesign their ASIC to use Device-Tree? :)
> > > 
> > > I'm not sure where the 'sneaking in' anything comes from. It's been
> > > reviewed on the list (and by yourself back then). If you feel any of
> > > this wasn't kosher, let's talk about it, to make sure it doesn't happen
> > > again.
> > 
> > I can't remember reviewing it, sorry, too many patches, I probably was
> > only worrying about functionality issues, not what the code actually did
> > :)
> > 
> > So it's fine, just a surprise to me, no big deal.
> 
> I'm glad that we made it clear. And the bus name & user APIs cound be
> kept as "dfl". So I assume the name "dfl" is OK to be used and could
> be recognized by people out of FPGA domain, is it?
> 
> If so, I still want to keep the name "dfl_device_id" in mod_devicetable.h
> as well.

No, this is specific to the fpga subsystem, right?  So please put fpga
in the name.

> We want to keep the device id name of the bus aligned with the
> bus name. And it would be confusing as well if a driver for ASIC based
> DFL device uses the "dfl_fpga_device_id" structure.

Do we have that in the kernel today?

thanks,

greg "naming is hard" k-h

Re: [PATCH v3 1/5] fpga: dfl: rename the bus type "dfl" to "fpga-dfl"

[Xu Yilun]

Hi moritz:

On Sun, Sep 27, 2020 at 04:36:47PM +0800, Xu Yilun wrote:
> Hi Greg,
> 
> On Sun, Sep 27, 2020 at 09:54:01AM +0200, Greg KH wrote:
> > On Sun, Sep 27, 2020 at 03:37:54PM +0800, Xu Yilun wrote:
> > > Hi Greg,
> > > 
> > > On Sun, Sep 27, 2020 at 07:51:08AM +0200, Greg KH wrote:
> > > > On Sat, Sep 26, 2020 at 12:22:19PM -0700, Moritz Fischer wrote:
> > > > > Hi Greg,
> > > > > 
> > > > > On Sat, Sep 26, 2020 at 08:09:13AM +0200, Greg KH wrote:
> > > > > > On Sat, Sep 26, 2020 at 10:23:46AM +0800, Xu Yilun wrote:
> > > > > > > Hi greg,
> > > > > > > 
> > > > > > > About the bus naming, I summarized some questions we've discussed to check
> > > > > > > with you. See inline.
> > > > > > > 
> > > > > > > On Thu, Sep 24, 2020 at 10:27:00AM -0700, Moritz Fischer wrote:
> > > > > > > > Hi Xu,
> > > > > > > > 
> > > > > > > > On Fri, Sep 25, 2020 at 12:59:57AM +0800, Xu Yilun wrote:
> > > > > > > > > Now the DFL device drivers could be made as independent modules and put
> > > > > > > > > in different subsystems according to their functionalities. So the name
> > > > > > > > > should be descriptive and unique in the whole kernel.
> > > > > > > > > 
> > > > > > > > > The patch changes the naming of dfl bus related structures, functions,
> > > > > > > > > APIs and documentations.
> > > > > > > > > 
> > > > > > > > > Signed-off-by: Xu Yilun <yilun.xu@intel.com>
> > > > > > > > > ---
> > > > > > > > >  Documentation/ABI/testing/sysfs-bus-dfl      |  15 --
> > > > > > > > >  Documentation/ABI/testing/sysfs-bus-fpga-dfl |  15 ++
> > > > > > > > >  MAINTAINERS                                  |   2 +-
> > > > > > > > >  drivers/fpga/dfl.c                           | 254 ++++++++++++++-------------
> > > > > > > > >  drivers/fpga/dfl.h                           |  77 ++++----
> > > > > > > > >  5 files changed, 184 insertions(+), 179 deletions(-)
> > > > > > > > >  delete mode 100644 Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > > >  create mode 100644 Documentation/ABI/testing/sysfs-bus-fpga-dfl
> > > > > > > > > 
> > > > > > > > > diff --git a/Documentation/ABI/testing/sysfs-bus-dfl b/Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > > > deleted file mode 100644
> > > > > > > > > index 23543be..0000000
> > > > > > > > > --- a/Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > > > +++ /dev/null
> > > > > > > > > @@ -1,15 +0,0 @@
> > > > > > > > > -What:		/sys/bus/dfl/devices/dfl_dev.X/type
> > > > > > > > > -Date:		Aug 2020
> > > > > > > > > -KernelVersion:	5.10
> > > > > > > > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > > > > > > > -Description:	Read-only. It returns type of DFL FIU of the device. Now DFL
> > > > > > > > > -		supports 2 FIU types, 0 for FME, 1 for PORT.
> > > > > > > > > -		Format: 0x%x
> > > > > > > > > -
> > > > > > > > > -What:		/sys/bus/dfl/devices/dfl_dev.X/feature_id
> > > > > > > > > -Date:		Aug 2020
> > > > > > > > > -KernelVersion:	5.10
> > > > > > > > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > > > > > > > -Description:	Read-only. It returns feature identifier local to its DFL FIU
> > > > > > > > > -		type.
> > > > > > > > > -		Format: 0x%x
> > > > > > > > 
> > > > > > > > You're changing userland facing ABI. I think that's something to avoid,
> > > > > > > > please check with Greg on the rules since this hasn't been in a release yet.
> > > > > > > > 
> > > > > > > 
> > > > > > > I'm going to change the name of bus stuff for other subsystems, to be
> > > > > > > aligned, I also consider change the bus_type.name and dfl dev_name. But
> > > > > > > it will cause the changing of user ABIs. No user case for these user ABI
> > > > > > > now cause they are just queued, is it good I change them?
> > > > > > 
> > > > > > Why change the user name here?  No need for that, right?  Unless you
> > > > > > really want to, and think that no one will notice.  If so, fine, change
> > > > > > them :)
> > > > > 
> > > > > Let's leave it as is -- An FPGA is one possible implementation and as for
> > > > > other buses, you wouldn't call it fpga-usb or usb-fpga just because the
> > > > > USB bus is implemented in an FPGA if it behaves like a normal USB bus.
> > > > > Having an ASIC based DFL bus show up under dfl-fpga / fpga-dfl in sysfs
> > > > > would be super confusing.
> 
> I thought we have consensus that "dfl" could be used out of fpga domain.
> And we are all good that we keep the user ABIs & the bus name - "dfl", so "dfl"
> is good as a global name from linux user's point of view, is it?
> 
> But why we reject the "dfl" in kernel code domain? I thought it is very
> similar situation.
> 
> 
> I think we have 2 options, to make the dfl self-consistent:
> 
> 1. "dfl-fpga" for everything - bus name, user ABIs, structures & APIs for
>    other kernel subsystems. Then we lose the chance to support ASIC based DFL,
>    it would be hard if we change user ABIs later.
> 
> 2. "dfl" for everything.
> 
> BTW, no ASIC based DFL devices in kernel today.
> 
> I fully understand the word "naming is hard" now, help me :)

Seems now we have different opinions on this:

- Hao thinks self-consistent is important to dfl framework.
- "dfl" for everything seems not preferable to Greg.
- From your previous mail, I assume you prefer to keep the bus name as "dfl"
but change the stuff for other subsystem, is it?

So I got a little stuck here.

Do you think "dfl-fpga" for everything would be an acceptable solution
for you?


Thanks,
Yilun

> 
> > > > > 
> > > > > > > It is mentioned that although Device Feature List is introduced in FPGA,
> > > > > > > but it doesn't limit the usage in FPGA only. It's just a method to
> > > > > > > discover features from a device, for sure it can be extended and used
> > > > > > > in other devices too. So it can be bigger namespace than FPGA. Like in
> > > > > > > our existing code, we picked dfl_fpga (DFL based FPGA) for uapi (ioctl)
> > > > > > > and internal functions. This is suggested by Alan (The previous FPGA
> > > > > > > maintainer). It's possible to have "DFL based XXX" in the future, even
> > > > > > > currently only FPGA uses DFL. This is the reason we thought just "dfl"
> > > > > > > in the whole kernel space is OK.
> > > > > > > So, is there a chance we keep the "dfl" naming in the whole kernel?
> > > > > > 
> > > > > > No one knows what "DFL" is, and odds are, if a different subsystem wants
> > > > > > to use it, they will have their own variant, right?
> > > 
> > > DFL is a method to discover devices. If a different subsystem (e.g. ASIC based
> > > DFL bus) want to use DFL and follows the DFL spec, they could just use the DFL
> > > stuff for enumeration, no need to have new variants.
> > > 
> > > > > > 
> > > > > > And why didn't you all use device tree?  How did this sneak in past
> > > > > > everyone?
> > > > > 
> > > > > DFL is a pretty efficient implementation in terms of resource
> > > > > utilization on the FPGA end (a couple of registers / memories) vs
> > > > > several kilobytes of memory for a device-tree blob.
> > > > > 
> > > > > The hardware using DFL to describe its internal structure exists in the
> > > > > form of deployed accelerator cards and telling all its users to go and
> > > > > change their hardware design would be feasible -- If you think about an
> > > > > FPGA as a (albeit reconfigurable) ASIC you wouldn't go and tell people
> > > > > to redesign their ASIC to use Device-Tree? :)
> > > > > 
> > > > > I'm not sure where the 'sneaking in' anything comes from. It's been
> > > > > reviewed on the list (and by yourself back then). If you feel any of
> > > > > this wasn't kosher, let's talk about it, to make sure it doesn't happen
> > > > > again.
> > > > 
> > > > I can't remember reviewing it, sorry, too many patches, I probably was
> > > > only worrying about functionality issues, not what the code actually did
> > > > :)
> > > > 
> > > > So it's fine, just a surprise to me, no big deal.
> > > 
> > > I'm glad that we made it clear. And the bus name & user APIs cound be
> > > kept as "dfl". So I assume the name "dfl" is OK to be used and could
> > > be recognized by people out of FPGA domain, is it?
> > > 
> > > If so, I still want to keep the name "dfl_device_id" in mod_devicetable.h
> > > as well.
> > 
> > No, this is specific to the fpga subsystem, right?  So please put fpga
> > in the name.
> 
> I put my comments under Moritz's lines above, hope it makes clear.
> 
> > 
> > > We want to keep the device id name of the bus aligned with the
> > > bus name. And it would be confusing as well if a driver for ASIC based
> > > DFL device uses the "dfl_fpga_device_id" structure.
> > 
> > Do we have that in the kernel today?
> 
> Actually no.
> 
> Thanks,
> Yilun
> 
> > 
> > thanks,
> > 
> > greg "naming is hard" k-h

Re: [PATCH v3 1/5] fpga: dfl: rename the bus type "dfl" to "fpga-dfl"

[Moritz Fischer]

Hi Xu,

On Tue, Sep 29, 2020 at 09:23:23AM +0800, Xu Yilun wrote:
> Hi moritz:
> 
> On Sun, Sep 27, 2020 at 04:36:47PM +0800, Xu Yilun wrote:
> > Hi Greg,
> > 
> > On Sun, Sep 27, 2020 at 09:54:01AM +0200, Greg KH wrote:
> > > On Sun, Sep 27, 2020 at 03:37:54PM +0800, Xu Yilun wrote:
> > > > Hi Greg,
> > > > 
> > > > On Sun, Sep 27, 2020 at 07:51:08AM +0200, Greg KH wrote:
> > > > > On Sat, Sep 26, 2020 at 12:22:19PM -0700, Moritz Fischer wrote:
> > > > > > Hi Greg,
> > > > > > 
> > > > > > On Sat, Sep 26, 2020 at 08:09:13AM +0200, Greg KH wrote:
> > > > > > > On Sat, Sep 26, 2020 at 10:23:46AM +0800, Xu Yilun wrote:
> > > > > > > > Hi greg,
> > > > > > > > 
> > > > > > > > About the bus naming, I summarized some questions we've discussed to check
> > > > > > > > with you. See inline.
> > > > > > > > 
> > > > > > > > On Thu, Sep 24, 2020 at 10:27:00AM -0700, Moritz Fischer wrote:
> > > > > > > > > Hi Xu,
> > > > > > > > > 
> > > > > > > > > On Fri, Sep 25, 2020 at 12:59:57AM +0800, Xu Yilun wrote:
> > > > > > > > > > Now the DFL device drivers could be made as independent modules and put
> > > > > > > > > > in different subsystems according to their functionalities. So the name
> > > > > > > > > > should be descriptive and unique in the whole kernel.
> > > > > > > > > > 
> > > > > > > > > > The patch changes the naming of dfl bus related structures, functions,
> > > > > > > > > > APIs and documentations.
> > > > > > > > > > 
> > > > > > > > > > Signed-off-by: Xu Yilun <yilun.xu@intel.com>
> > > > > > > > > > ---
> > > > > > > > > >  Documentation/ABI/testing/sysfs-bus-dfl      |  15 --
> > > > > > > > > >  Documentation/ABI/testing/sysfs-bus-fpga-dfl |  15 ++
> > > > > > > > > >  MAINTAINERS                                  |   2 +-
> > > > > > > > > >  drivers/fpga/dfl.c                           | 254 ++++++++++++++-------------
> > > > > > > > > >  drivers/fpga/dfl.h                           |  77 ++++----
> > > > > > > > > >  5 files changed, 184 insertions(+), 179 deletions(-)
> > > > > > > > > >  delete mode 100644 Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > > > >  create mode 100644 Documentation/ABI/testing/sysfs-bus-fpga-dfl
> > > > > > > > > > 
> > > > > > > > > > diff --git a/Documentation/ABI/testing/sysfs-bus-dfl b/Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > > > > deleted file mode 100644
> > > > > > > > > > index 23543be..0000000
> > > > > > > > > > --- a/Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > > > > +++ /dev/null
> > > > > > > > > > @@ -1,15 +0,0 @@
> > > > > > > > > > -What:		/sys/bus/dfl/devices/dfl_dev.X/type
> > > > > > > > > > -Date:		Aug 2020
> > > > > > > > > > -KernelVersion:	5.10
> > > > > > > > > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > > > > > > > > -Description:	Read-only. It returns type of DFL FIU of the device. Now DFL
> > > > > > > > > > -		supports 2 FIU types, 0 for FME, 1 for PORT.
> > > > > > > > > > -		Format: 0x%x
> > > > > > > > > > -
> > > > > > > > > > -What:		/sys/bus/dfl/devices/dfl_dev.X/feature_id
> > > > > > > > > > -Date:		Aug 2020
> > > > > > > > > > -KernelVersion:	5.10
> > > > > > > > > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > > > > > > > > -Description:	Read-only. It returns feature identifier local to its DFL FIU
> > > > > > > > > > -		type.
> > > > > > > > > > -		Format: 0x%x
> > > > > > > > > 
> > > > > > > > > You're changing userland facing ABI. I think that's something to avoid,
> > > > > > > > > please check with Greg on the rules since this hasn't been in a release yet.
> > > > > > > > > 
> > > > > > > > 
> > > > > > > > I'm going to change the name of bus stuff for other subsystems, to be
> > > > > > > > aligned, I also consider change the bus_type.name and dfl dev_name. But
> > > > > > > > it will cause the changing of user ABIs. No user case for these user ABI
> > > > > > > > now cause they are just queued, is it good I change them?
> > > > > > > 
> > > > > > > Why change the user name here?  No need for that, right?  Unless you
> > > > > > > really want to, and think that no one will notice.  If so, fine, change
> > > > > > > them :)
> > > > > > 
> > > > > > Let's leave it as is -- An FPGA is one possible implementation and as for
> > > > > > other buses, you wouldn't call it fpga-usb or usb-fpga just because the
> > > > > > USB bus is implemented in an FPGA if it behaves like a normal USB bus.
> > > > > > Having an ASIC based DFL bus show up under dfl-fpga / fpga-dfl in sysfs
> > > > > > would be super confusing.
> > 
> > I thought we have consensus that "dfl" could be used out of fpga domain.
> > And we are all good that we keep the user ABIs & the bus name - "dfl", so "dfl"
> > is good as a global name from linux user's point of view, is it?
> > 
> > But why we reject the "dfl" in kernel code domain? I thought it is very
> > similar situation.
> > 
> > 
> > I think we have 2 options, to make the dfl self-consistent:
> > 
> > 1. "dfl-fpga" for everything - bus name, user ABIs, structures & APIs for
> >    other kernel subsystems. Then we lose the chance to support ASIC based DFL,
> >    it would be hard if we change user ABIs later.
> > 
> > 2. "dfl" for everything.
> > 
> > BTW, no ASIC based DFL devices in kernel today.
> > 
> > I fully understand the word "naming is hard" now, help me :)
> 
> Seems now we have different opinions on this:
> 
> - Hao thinks self-consistent is important to dfl framework.
Agreed. I mostly care about userspace facing ABI, though.

> - "dfl" for everything seems not preferable to Greg.
Maybe now that we re-explained, we can take another look at that?

> - From your previous mail, I assume you prefer to keep the bus name as "dfl"
> but change the stuff for other subsystem, is it?

I mostly think we should keep DFL generic where it touches userspace and
defines ABI, since we cannot change it afterwards.

I rest my point with the bus being independent of FPGAs despite the FPGA
being the (currently) only user.

> So I got a little stuck here.
> 
> Do you think "dfl-fpga" for everything would be an acceptable solution
> for you?

I just think it doesn't make a lot of sense to call it fpga-dfl or
dfl-fpga. But if everyone else disagrees ... naming is hard :-)

Cheers,
Moritz

Re: [PATCH v3 1/5] fpga: dfl: rename the bus type "dfl" to "fpga-dfl"

[Xu Yilun]

On Mon, Sep 28, 2020 at 09:19:00PM -0700, Moritz Fischer wrote:
> Hi Xu,
> 
> On Tue, Sep 29, 2020 at 09:23:23AM +0800, Xu Yilun wrote:
> > Hi moritz:
> > 
> > On Sun, Sep 27, 2020 at 04:36:47PM +0800, Xu Yilun wrote:
> > > Hi Greg,
> > > 
> > > On Sun, Sep 27, 2020 at 09:54:01AM +0200, Greg KH wrote:
> > > > On Sun, Sep 27, 2020 at 03:37:54PM +0800, Xu Yilun wrote:
> > > > > Hi Greg,
> > > > > 
> > > > > On Sun, Sep 27, 2020 at 07:51:08AM +0200, Greg KH wrote:
> > > > > > On Sat, Sep 26, 2020 at 12:22:19PM -0700, Moritz Fischer wrote:
> > > > > > > Hi Greg,
> > > > > > > 
> > > > > > > On Sat, Sep 26, 2020 at 08:09:13AM +0200, Greg KH wrote:
> > > > > > > > On Sat, Sep 26, 2020 at 10:23:46AM +0800, Xu Yilun wrote:
> > > > > > > > > Hi greg,
> > > > > > > > > 
> > > > > > > > > About the bus naming, I summarized some questions we've discussed to check
> > > > > > > > > with you. See inline.
> > > > > > > > > 
> > > > > > > > > On Thu, Sep 24, 2020 at 10:27:00AM -0700, Moritz Fischer wrote:
> > > > > > > > > > Hi Xu,
> > > > > > > > > > 
> > > > > > > > > > On Fri, Sep 25, 2020 at 12:59:57AM +0800, Xu Yilun wrote:
> > > > > > > > > > > Now the DFL device drivers could be made as independent modules and put
> > > > > > > > > > > in different subsystems according to their functionalities. So the name
> > > > > > > > > > > should be descriptive and unique in the whole kernel.
> > > > > > > > > > > 
> > > > > > > > > > > The patch changes the naming of dfl bus related structures, functions,
> > > > > > > > > > > APIs and documentations.
> > > > > > > > > > > 
> > > > > > > > > > > Signed-off-by: Xu Yilun <yilun.xu@intel.com>
> > > > > > > > > > > ---
> > > > > > > > > > >  Documentation/ABI/testing/sysfs-bus-dfl      |  15 --
> > > > > > > > > > >  Documentation/ABI/testing/sysfs-bus-fpga-dfl |  15 ++
> > > > > > > > > > >  MAINTAINERS                                  |   2 +-
> > > > > > > > > > >  drivers/fpga/dfl.c                           | 254 ++++++++++++++-------------
> > > > > > > > > > >  drivers/fpga/dfl.h                           |  77 ++++----
> > > > > > > > > > >  5 files changed, 184 insertions(+), 179 deletions(-)
> > > > > > > > > > >  delete mode 100644 Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > > > > >  create mode 100644 Documentation/ABI/testing/sysfs-bus-fpga-dfl
> > > > > > > > > > > 
> > > > > > > > > > > diff --git a/Documentation/ABI/testing/sysfs-bus-dfl b/Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > > > > > deleted file mode 100644
> > > > > > > > > > > index 23543be..0000000
> > > > > > > > > > > --- a/Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > > > > > +++ /dev/null
> > > > > > > > > > > @@ -1,15 +0,0 @@
> > > > > > > > > > > -What:		/sys/bus/dfl/devices/dfl_dev.X/type
> > > > > > > > > > > -Date:		Aug 2020
> > > > > > > > > > > -KernelVersion:	5.10
> > > > > > > > > > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > > > > > > > > > -Description:	Read-only. It returns type of DFL FIU of the device. Now DFL
> > > > > > > > > > > -		supports 2 FIU types, 0 for FME, 1 for PORT.
> > > > > > > > > > > -		Format: 0x%x
> > > > > > > > > > > -
> > > > > > > > > > > -What:		/sys/bus/dfl/devices/dfl_dev.X/feature_id
> > > > > > > > > > > -Date:		Aug 2020
> > > > > > > > > > > -KernelVersion:	5.10
> > > > > > > > > > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > > > > > > > > > -Description:	Read-only. It returns feature identifier local to its DFL FIU
> > > > > > > > > > > -		type.
> > > > > > > > > > > -		Format: 0x%x
> > > > > > > > > > 
> > > > > > > > > > You're changing userland facing ABI. I think that's something to avoid,
> > > > > > > > > > please check with Greg on the rules since this hasn't been in a release yet.
> > > > > > > > > > 
> > > > > > > > > 
> > > > > > > > > I'm going to change the name of bus stuff for other subsystems, to be
> > > > > > > > > aligned, I also consider change the bus_type.name and dfl dev_name. But
> > > > > > > > > it will cause the changing of user ABIs. No user case for these user ABI
> > > > > > > > > now cause they are just queued, is it good I change them?
> > > > > > > > 
> > > > > > > > Why change the user name here?  No need for that, right?  Unless you
> > > > > > > > really want to, and think that no one will notice.  If so, fine, change
> > > > > > > > them :)
> > > > > > > 
> > > > > > > Let's leave it as is -- An FPGA is one possible implementation and as for
> > > > > > > other buses, you wouldn't call it fpga-usb or usb-fpga just because the
> > > > > > > USB bus is implemented in an FPGA if it behaves like a normal USB bus.
> > > > > > > Having an ASIC based DFL bus show up under dfl-fpga / fpga-dfl in sysfs
> > > > > > > would be super confusing.
> > > 
> > > I thought we have consensus that "dfl" could be used out of fpga domain.
> > > And we are all good that we keep the user ABIs & the bus name - "dfl", so "dfl"
> > > is good as a global name from linux user's point of view, is it?
> > > 
> > > But why we reject the "dfl" in kernel code domain? I thought it is very
> > > similar situation.
> > > 
> > > 
> > > I think we have 2 options, to make the dfl self-consistent:
> > > 
> > > 1. "dfl-fpga" for everything - bus name, user ABIs, structures & APIs for
> > >    other kernel subsystems. Then we lose the chance to support ASIC based DFL,
> > >    it would be hard if we change user ABIs later.
> > > 
> > > 2. "dfl" for everything.
> > > 
> > > BTW, no ASIC based DFL devices in kernel today.
> > > 
> > > I fully understand the word "naming is hard" now, help me :)
> > 
> > Seems now we have different opinions on this:
> > 
> > - Hao thinks self-consistent is important to dfl framework.
> Agreed. I mostly care about userspace facing ABI, though.
> 
> > - "dfl" for everything seems not preferable to Greg.
> Maybe now that we re-explained, we can take another look at that?

Seems "dfl" for everything is the one, agreed by Moritz, Hao and Yilun.

I'll wait for some time, to see if Greg could comment on it.

Thanks,
Yilun

> 
> > - From your previous mail, I assume you prefer to keep the bus name as "dfl"
> > but change the stuff for other subsystem, is it?
> 
> I mostly think we should keep DFL generic where it touches userspace and
> defines ABI, since we cannot change it afterwards.
> 
> I rest my point with the bus being independent of FPGAs despite the FPGA
> being the (currently) only user.
> 
> > So I got a little stuck here.
> > 
> > Do you think "dfl-fpga" for everything would be an acceptable solution
> > for you?
> 
> I just think it doesn't make a lot of sense to call it fpga-dfl or
> dfl-fpga. But if everyone else disagrees ... naming is hard :-)
> 
> Cheers,
> Moritz

Re: [PATCH v3 1/5] fpga: dfl: rename the bus type "dfl" to "fpga-dfl"

[Xu Yilun]

Hi Greg:

On Mon, Sep 28, 2020 at 09:19:00PM -0700, Moritz Fischer wrote:
> Hi Xu,
> 
> On Tue, Sep 29, 2020 at 09:23:23AM +0800, Xu Yilun wrote:
> > Hi moritz:
> > 
> > On Sun, Sep 27, 2020 at 04:36:47PM +0800, Xu Yilun wrote:
> > > Hi Greg,
> > > 
> > > On Sun, Sep 27, 2020 at 09:54:01AM +0200, Greg KH wrote:
> > > > On Sun, Sep 27, 2020 at 03:37:54PM +0800, Xu Yilun wrote:
> > > > > Hi Greg,
> > > > > 
> > > > > On Sun, Sep 27, 2020 at 07:51:08AM +0200, Greg KH wrote:
> > > > > > On Sat, Sep 26, 2020 at 12:22:19PM -0700, Moritz Fischer wrote:
> > > > > > > Hi Greg,
> > > > > > > 
> > > > > > > On Sat, Sep 26, 2020 at 08:09:13AM +0200, Greg KH wrote:
> > > > > > > > On Sat, Sep 26, 2020 at 10:23:46AM +0800, Xu Yilun wrote:
> > > > > > > > > Hi greg,
> > > > > > > > > 
> > > > > > > > > About the bus naming, I summarized some questions we've discussed to check
> > > > > > > > > with you. See inline.
> > > > > > > > > 
> > > > > > > > > On Thu, Sep 24, 2020 at 10:27:00AM -0700, Moritz Fischer wrote:
> > > > > > > > > > Hi Xu,
> > > > > > > > > > 
> > > > > > > > > > On Fri, Sep 25, 2020 at 12:59:57AM +0800, Xu Yilun wrote:
> > > > > > > > > > > Now the DFL device drivers could be made as independent modules and put
> > > > > > > > > > > in different subsystems according to their functionalities. So the name
> > > > > > > > > > > should be descriptive and unique in the whole kernel.
> > > > > > > > > > > 
> > > > > > > > > > > The patch changes the naming of dfl bus related structures, functions,
> > > > > > > > > > > APIs and documentations.
> > > > > > > > > > > 
> > > > > > > > > > > Signed-off-by: Xu Yilun <yilun.xu@intel.com>
> > > > > > > > > > > ---
> > > > > > > > > > >  Documentation/ABI/testing/sysfs-bus-dfl      |  15 --
> > > > > > > > > > >  Documentation/ABI/testing/sysfs-bus-fpga-dfl |  15 ++
> > > > > > > > > > >  MAINTAINERS                                  |   2 +-
> > > > > > > > > > >  drivers/fpga/dfl.c                           | 254 ++++++++++++++-------------
> > > > > > > > > > >  drivers/fpga/dfl.h                           |  77 ++++----
> > > > > > > > > > >  5 files changed, 184 insertions(+), 179 deletions(-)
> > > > > > > > > > >  delete mode 100644 Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > > > > >  create mode 100644 Documentation/ABI/testing/sysfs-bus-fpga-dfl
> > > > > > > > > > > 
> > > > > > > > > > > diff --git a/Documentation/ABI/testing/sysfs-bus-dfl b/Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > > > > > deleted file mode 100644
> > > > > > > > > > > index 23543be..0000000
> > > > > > > > > > > --- a/Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > > > > > +++ /dev/null
> > > > > > > > > > > @@ -1,15 +0,0 @@
> > > > > > > > > > > -What:		/sys/bus/dfl/devices/dfl_dev.X/type
> > > > > > > > > > > -Date:		Aug 2020
> > > > > > > > > > > -KernelVersion:	5.10
> > > > > > > > > > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > > > > > > > > > -Description:	Read-only. It returns type of DFL FIU of the device. Now DFL
> > > > > > > > > > > -		supports 2 FIU types, 0 for FME, 1 for PORT.
> > > > > > > > > > > -		Format: 0x%x
> > > > > > > > > > > -
> > > > > > > > > > > -What:		/sys/bus/dfl/devices/dfl_dev.X/feature_id
> > > > > > > > > > > -Date:		Aug 2020
> > > > > > > > > > > -KernelVersion:	5.10
> > > > > > > > > > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > > > > > > > > > -Description:	Read-only. It returns feature identifier local to its DFL FIU
> > > > > > > > > > > -		type.
> > > > > > > > > > > -		Format: 0x%x
> > > > > > > > > > 
> > > > > > > > > > You're changing userland facing ABI. I think that's something to avoid,
> > > > > > > > > > please check with Greg on the rules since this hasn't been in a release yet.
> > > > > > > > > > 
> > > > > > > > > 
> > > > > > > > > I'm going to change the name of bus stuff for other subsystems, to be
> > > > > > > > > aligned, I also consider change the bus_type.name and dfl dev_name. But
> > > > > > > > > it will cause the changing of user ABIs. No user case for these user ABI
> > > > > > > > > now cause they are just queued, is it good I change them?
> > > > > > > > 
> > > > > > > > Why change the user name here?  No need for that, right?  Unless you
> > > > > > > > really want to, and think that no one will notice.  If so, fine, change
> > > > > > > > them :)
> > > > > > > 
> > > > > > > Let's leave it as is -- An FPGA is one possible implementation and as for
> > > > > > > other buses, you wouldn't call it fpga-usb or usb-fpga just because the
> > > > > > > USB bus is implemented in an FPGA if it behaves like a normal USB bus.
> > > > > > > Having an ASIC based DFL bus show up under dfl-fpga / fpga-dfl in sysfs
> > > > > > > would be super confusing.
> > > 
> > > I thought we have consensus that "dfl" could be used out of fpga domain.
> > > And we are all good that we keep the user ABIs & the bus name - "dfl", so "dfl"
> > > is good as a global name from linux user's point of view, is it?
> > > 
> > > But why we reject the "dfl" in kernel code domain? I thought it is very
> > > similar situation.
> > > 
> > > 
> > > I think we have 2 options, to make the dfl self-consistent:
> > > 
> > > 1. "dfl-fpga" for everything - bus name, user ABIs, structures & APIs for
> > >    other kernel subsystems. Then we lose the chance to support ASIC based DFL,
> > >    it would be hard if we change user ABIs later.
> > > 
> > > 2. "dfl" for everything.
> > > 
> > > BTW, no ASIC based DFL devices in kernel today.
> > > 
> > > I fully understand the word "naming is hard" now, help me :)
> > 
> > Seems now we have different opinions on this:
> > 
> > - Hao thinks self-consistent is important to dfl framework.
> Agreed. I mostly care about userspace facing ABI, though.
> 
> > - "dfl" for everything seems not preferable to Greg.
> Maybe now that we re-explained, we can take another look at that?
> 
> > - From your previous mail, I assume you prefer to keep the bus name as "dfl"
> > but change the stuff for other subsystem, is it?
> 
> I mostly think we should keep DFL generic where it touches userspace and
> defines ABI, since we cannot change it afterwards.
> 
> I rest my point with the bus being independent of FPGAs despite the FPGA
> being the (currently) only user.
> 
> > So I got a little stuck here.
> > 
> > Do you think "dfl-fpga" for everything would be an acceptable solution
> > for you?
> 
> I just think it doesn't make a lot of sense to call it fpga-dfl or
> dfl-fpga. But if everyone else disagrees ... naming is hard :-)

Hi Greg,

We made some re-explanation why "dfl" could be independent of the fpga
subsystem in this mail thread. And now the name "dfl" for all bus stuff is good
to Moritz, Hao & Yilun. Could you help take another look at this?

Thanks,
Yilun

> 
> Cheers,
> Moritz

Re: [PATCH v3 1/5] fpga: dfl: rename the bus type "dfl" to "fpga-dfl"

[Greg KH]

On Fri, Oct 09, 2020 at 02:20:59PM +0800, Xu Yilun wrote:
> Hi Greg:
> 
> On Mon, Sep 28, 2020 at 09:19:00PM -0700, Moritz Fischer wrote:
> > Hi Xu,
> > 
> > On Tue, Sep 29, 2020 at 09:23:23AM +0800, Xu Yilun wrote:
> > > Hi moritz:
> > > 
> > > On Sun, Sep 27, 2020 at 04:36:47PM +0800, Xu Yilun wrote:
> > > > Hi Greg,
> > > > 
> > > > On Sun, Sep 27, 2020 at 09:54:01AM +0200, Greg KH wrote:
> > > > > On Sun, Sep 27, 2020 at 03:37:54PM +0800, Xu Yilun wrote:
> > > > > > Hi Greg,
> > > > > > 
> > > > > > On Sun, Sep 27, 2020 at 07:51:08AM +0200, Greg KH wrote:
> > > > > > > On Sat, Sep 26, 2020 at 12:22:19PM -0700, Moritz Fischer wrote:
> > > > > > > > Hi Greg,
> > > > > > > > 
> > > > > > > > On Sat, Sep 26, 2020 at 08:09:13AM +0200, Greg KH wrote:
> > > > > > > > > On Sat, Sep 26, 2020 at 10:23:46AM +0800, Xu Yilun wrote:
> > > > > > > > > > Hi greg,
> > > > > > > > > > 
> > > > > > > > > > About the bus naming, I summarized some questions we've discussed to check
> > > > > > > > > > with you. See inline.
> > > > > > > > > > 
> > > > > > > > > > On Thu, Sep 24, 2020 at 10:27:00AM -0700, Moritz Fischer wrote:
> > > > > > > > > > > Hi Xu,
> > > > > > > > > > > 
> > > > > > > > > > > On Fri, Sep 25, 2020 at 12:59:57AM +0800, Xu Yilun wrote:
> > > > > > > > > > > > Now the DFL device drivers could be made as independent modules and put
> > > > > > > > > > > > in different subsystems according to their functionalities. So the name
> > > > > > > > > > > > should be descriptive and unique in the whole kernel.
> > > > > > > > > > > > 
> > > > > > > > > > > > The patch changes the naming of dfl bus related structures, functions,
> > > > > > > > > > > > APIs and documentations.
> > > > > > > > > > > > 
> > > > > > > > > > > > Signed-off-by: Xu Yilun <yilun.xu@intel.com>
> > > > > > > > > > > > ---
> > > > > > > > > > > >  Documentation/ABI/testing/sysfs-bus-dfl      |  15 --
> > > > > > > > > > > >  Documentation/ABI/testing/sysfs-bus-fpga-dfl |  15 ++
> > > > > > > > > > > >  MAINTAINERS                                  |   2 +-
> > > > > > > > > > > >  drivers/fpga/dfl.c                           | 254 ++++++++++++++-------------
> > > > > > > > > > > >  drivers/fpga/dfl.h                           |  77 ++++----
> > > > > > > > > > > >  5 files changed, 184 insertions(+), 179 deletions(-)
> > > > > > > > > > > >  delete mode 100644 Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > > > > > >  create mode 100644 Documentation/ABI/testing/sysfs-bus-fpga-dfl
> > > > > > > > > > > > 
> > > > > > > > > > > > diff --git a/Documentation/ABI/testing/sysfs-bus-dfl b/Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > > > > > > deleted file mode 100644
> > > > > > > > > > > > index 23543be..0000000
> > > > > > > > > > > > --- a/Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > > > > > > +++ /dev/null
> > > > > > > > > > > > @@ -1,15 +0,0 @@
> > > > > > > > > > > > -What:		/sys/bus/dfl/devices/dfl_dev.X/type
> > > > > > > > > > > > -Date:		Aug 2020
> > > > > > > > > > > > -KernelVersion:	5.10
> > > > > > > > > > > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > > > > > > > > > > -Description:	Read-only. It returns type of DFL FIU of the device. Now DFL
> > > > > > > > > > > > -		supports 2 FIU types, 0 for FME, 1 for PORT.
> > > > > > > > > > > > -		Format: 0x%x
> > > > > > > > > > > > -
> > > > > > > > > > > > -What:		/sys/bus/dfl/devices/dfl_dev.X/feature_id
> > > > > > > > > > > > -Date:		Aug 2020
> > > > > > > > > > > > -KernelVersion:	5.10
> > > > > > > > > > > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > > > > > > > > > > -Description:	Read-only. It returns feature identifier local to its DFL FIU
> > > > > > > > > > > > -		type.
> > > > > > > > > > > > -		Format: 0x%x
> > > > > > > > > > > 
> > > > > > > > > > > You're changing userland facing ABI. I think that's something to avoid,
> > > > > > > > > > > please check with Greg on the rules since this hasn't been in a release yet.
> > > > > > > > > > > 
> > > > > > > > > > 
> > > > > > > > > > I'm going to change the name of bus stuff for other subsystems, to be
> > > > > > > > > > aligned, I also consider change the bus_type.name and dfl dev_name. But
> > > > > > > > > > it will cause the changing of user ABIs. No user case for these user ABI
> > > > > > > > > > now cause they are just queued, is it good I change them?
> > > > > > > > > 
> > > > > > > > > Why change the user name here?  No need for that, right?  Unless you
> > > > > > > > > really want to, and think that no one will notice.  If so, fine, change
> > > > > > > > > them :)
> > > > > > > > 
> > > > > > > > Let's leave it as is -- An FPGA is one possible implementation and as for
> > > > > > > > other buses, you wouldn't call it fpga-usb or usb-fpga just because the
> > > > > > > > USB bus is implemented in an FPGA if it behaves like a normal USB bus.
> > > > > > > > Having an ASIC based DFL bus show up under dfl-fpga / fpga-dfl in sysfs
> > > > > > > > would be super confusing.
> > > > 
> > > > I thought we have consensus that "dfl" could be used out of fpga domain.
> > > > And we are all good that we keep the user ABIs & the bus name - "dfl", so "dfl"
> > > > is good as a global name from linux user's point of view, is it?
> > > > 
> > > > But why we reject the "dfl" in kernel code domain? I thought it is very
> > > > similar situation.
> > > > 
> > > > 
> > > > I think we have 2 options, to make the dfl self-consistent:
> > > > 
> > > > 1. "dfl-fpga" for everything - bus name, user ABIs, structures & APIs for
> > > >    other kernel subsystems. Then we lose the chance to support ASIC based DFL,
> > > >    it would be hard if we change user ABIs later.
> > > > 
> > > > 2. "dfl" for everything.
> > > > 
> > > > BTW, no ASIC based DFL devices in kernel today.
> > > > 
> > > > I fully understand the word "naming is hard" now, help me :)
> > > 
> > > Seems now we have different opinions on this:
> > > 
> > > - Hao thinks self-consistent is important to dfl framework.
> > Agreed. I mostly care about userspace facing ABI, though.
> > 
> > > - "dfl" for everything seems not preferable to Greg.
> > Maybe now that we re-explained, we can take another look at that?
> > 
> > > - From your previous mail, I assume you prefer to keep the bus name as "dfl"
> > > but change the stuff for other subsystem, is it?
> > 
> > I mostly think we should keep DFL generic where it touches userspace and
> > defines ABI, since we cannot change it afterwards.
> > 
> > I rest my point with the bus being independent of FPGAs despite the FPGA
> > being the (currently) only user.
> > 
> > > So I got a little stuck here.
> > > 
> > > Do you think "dfl-fpga" for everything would be an acceptable solution
> > > for you?
> > 
> > I just think it doesn't make a lot of sense to call it fpga-dfl or
> > dfl-fpga. But if everyone else disagrees ... naming is hard :-)
> 
> Hi Greg,
> 
> We made some re-explanation why "dfl" could be independent of the fpga
> subsystem in this mail thread. And now the name "dfl" for all bus stuff is good
> to Moritz, Hao & Yilun. Could you help take another look at this?

What is "this"?  I don't see any fpga patches in my inbox anywhere...

Re: [PATCH v3 1/5] fpga: dfl: rename the bus type "dfl" to "fpga-dfl"

[Xu Yilun]

On Fri, Oct 09, 2020 at 08:41:18AM +0200, Greg KH wrote:
> On Fri, Oct 09, 2020 at 02:20:59PM +0800, Xu Yilun wrote:
> > Hi Greg:
> > 
> > On Mon, Sep 28, 2020 at 09:19:00PM -0700, Moritz Fischer wrote:
> > > Hi Xu,
> > > 
> > > On Tue, Sep 29, 2020 at 09:23:23AM +0800, Xu Yilun wrote:
> > > > Hi moritz:
> > > > 
> > > > On Sun, Sep 27, 2020 at 04:36:47PM +0800, Xu Yilun wrote:
> > > > > Hi Greg,
> > > > > 
> > > > > On Sun, Sep 27, 2020 at 09:54:01AM +0200, Greg KH wrote:
> > > > > > On Sun, Sep 27, 2020 at 03:37:54PM +0800, Xu Yilun wrote:
> > > > > > > Hi Greg,
> > > > > > > 
> > > > > > > On Sun, Sep 27, 2020 at 07:51:08AM +0200, Greg KH wrote:
> > > > > > > > On Sat, Sep 26, 2020 at 12:22:19PM -0700, Moritz Fischer wrote:
> > > > > > > > > Hi Greg,
> > > > > > > > > 
> > > > > > > > > On Sat, Sep 26, 2020 at 08:09:13AM +0200, Greg KH wrote:
> > > > > > > > > > On Sat, Sep 26, 2020 at 10:23:46AM +0800, Xu Yilun wrote:
> > > > > > > > > > > Hi greg,
> > > > > > > > > > > 
> > > > > > > > > > > About the bus naming, I summarized some questions we've discussed to check
> > > > > > > > > > > with you. See inline.
> > > > > > > > > > > 
> > > > > > > > > > > On Thu, Sep 24, 2020 at 10:27:00AM -0700, Moritz Fischer wrote:
> > > > > > > > > > > > Hi Xu,
> > > > > > > > > > > > 
> > > > > > > > > > > > On Fri, Sep 25, 2020 at 12:59:57AM +0800, Xu Yilun wrote:
> > > > > > > > > > > > > Now the DFL device drivers could be made as independent modules and put
> > > > > > > > > > > > > in different subsystems according to their functionalities. So the name
> > > > > > > > > > > > > should be descriptive and unique in the whole kernel.
> > > > > > > > > > > > > 
> > > > > > > > > > > > > The patch changes the naming of dfl bus related structures, functions,
> > > > > > > > > > > > > APIs and documentations.
> > > > > > > > > > > > > 
> > > > > > > > > > > > > Signed-off-by: Xu Yilun <yilun.xu@intel.com>
> > > > > > > > > > > > > ---
> > > > > > > > > > > > >  Documentation/ABI/testing/sysfs-bus-dfl      |  15 --
> > > > > > > > > > > > >  Documentation/ABI/testing/sysfs-bus-fpga-dfl |  15 ++
> > > > > > > > > > > > >  MAINTAINERS                                  |   2 +-
> > > > > > > > > > > > >  drivers/fpga/dfl.c                           | 254 ++++++++++++++-------------
> > > > > > > > > > > > >  drivers/fpga/dfl.h                           |  77 ++++----
> > > > > > > > > > > > >  5 files changed, 184 insertions(+), 179 deletions(-)
> > > > > > > > > > > > >  delete mode 100644 Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > > > > > > >  create mode 100644 Documentation/ABI/testing/sysfs-bus-fpga-dfl
> > > > > > > > > > > > > 
> > > > > > > > > > > > > diff --git a/Documentation/ABI/testing/sysfs-bus-dfl b/Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > > > > > > > deleted file mode 100644
> > > > > > > > > > > > > index 23543be..0000000
> > > > > > > > > > > > > --- a/Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > > > > > > > +++ /dev/null
> > > > > > > > > > > > > @@ -1,15 +0,0 @@
> > > > > > > > > > > > > -What:		/sys/bus/dfl/devices/dfl_dev.X/type
> > > > > > > > > > > > > -Date:		Aug 2020
> > > > > > > > > > > > > -KernelVersion:	5.10
> > > > > > > > > > > > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > > > > > > > > > > > -Description:	Read-only. It returns type of DFL FIU of the device. Now DFL
> > > > > > > > > > > > > -		supports 2 FIU types, 0 for FME, 1 for PORT.
> > > > > > > > > > > > > -		Format: 0x%x
> > > > > > > > > > > > > -
> > > > > > > > > > > > > -What:		/sys/bus/dfl/devices/dfl_dev.X/feature_id
> > > > > > > > > > > > > -Date:		Aug 2020
> > > > > > > > > > > > > -KernelVersion:	5.10
> > > > > > > > > > > > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > > > > > > > > > > > -Description:	Read-only. It returns feature identifier local to its DFL FIU
> > > > > > > > > > > > > -		type.
> > > > > > > > > > > > > -		Format: 0x%x
> > > > > > > > > > > > 
> > > > > > > > > > > > You're changing userland facing ABI. I think that's something to avoid,
> > > > > > > > > > > > please check with Greg on the rules since this hasn't been in a release yet.
> > > > > > > > > > > > 
> > > > > > > > > > > 
> > > > > > > > > > > I'm going to change the name of bus stuff for other subsystems, to be
> > > > > > > > > > > aligned, I also consider change the bus_type.name and dfl dev_name. But
> > > > > > > > > > > it will cause the changing of user ABIs. No user case for these user ABI
> > > > > > > > > > > now cause they are just queued, is it good I change them?
> > > > > > > > > > 
> > > > > > > > > > Why change the user name here?  No need for that, right?  Unless you
> > > > > > > > > > really want to, and think that no one will notice.  If so, fine, change
> > > > > > > > > > them :)
> > > > > > > > > 
> > > > > > > > > Let's leave it as is -- An FPGA is one possible implementation and as for
> > > > > > > > > other buses, you wouldn't call it fpga-usb or usb-fpga just because the
> > > > > > > > > USB bus is implemented in an FPGA if it behaves like a normal USB bus.
> > > > > > > > > Having an ASIC based DFL bus show up under dfl-fpga / fpga-dfl in sysfs
> > > > > > > > > would be super confusing.
> > > > > 
> > > > > I thought we have consensus that "dfl" could be used out of fpga domain.
> > > > > And we are all good that we keep the user ABIs & the bus name - "dfl", so "dfl"
> > > > > is good as a global name from linux user's point of view, is it?
> > > > > 
> > > > > But why we reject the "dfl" in kernel code domain? I thought it is very
> > > > > similar situation.
> > > > > 
> > > > > 
> > > > > I think we have 2 options, to make the dfl self-consistent:
> > > > > 
> > > > > 1. "dfl-fpga" for everything - bus name, user ABIs, structures & APIs for
> > > > >    other kernel subsystems. Then we lose the chance to support ASIC based DFL,
> > > > >    it would be hard if we change user ABIs later.
> > > > > 
> > > > > 2. "dfl" for everything.
> > > > > 
> > > > > BTW, no ASIC based DFL devices in kernel today.
> > > > > 
> > > > > I fully understand the word "naming is hard" now, help me :)
> > > > 
> > > > Seems now we have different opinions on this:
> > > > 
> > > > - Hao thinks self-consistent is important to dfl framework.
> > > Agreed. I mostly care about userspace facing ABI, though.
> > > 
> > > > - "dfl" for everything seems not preferable to Greg.
> > > Maybe now that we re-explained, we can take another look at that?
> > > 
> > > > - From your previous mail, I assume you prefer to keep the bus name as "dfl"
> > > > but change the stuff for other subsystem, is it?
> > > 
> > > I mostly think we should keep DFL generic where it touches userspace and
> > > defines ABI, since we cannot change it afterwards.
> > > 
> > > I rest my point with the bus being independent of FPGAs despite the FPGA
> > > being the (currently) only user.
> > > 
> > > > So I got a little stuck here.
> > > > 
> > > > Do you think "dfl-fpga" for everything would be an acceptable solution
> > > > for you?
> > > 
> > > I just think it doesn't make a lot of sense to call it fpga-dfl or
> > > dfl-fpga. But if everyone else disagrees ... naming is hard :-)
> > 
> > Hi Greg,
> > 
> > We made some re-explanation why "dfl" could be independent of the fpga
> > subsystem in this mail thread. And now the name "dfl" for all bus stuff is good
> > to Moritz, Hao & Yilun. Could you help take another look at this?
> 
> What is "this"?  I don't see any fpga patches in my inbox anywhere...

Sorry, the discussion lasts more than 2 weeks, so I'm trying to collect
the comments here.

We are trying to confirm if the new added bus name "dfl" should be
OK, instead of "fpga-dfl"? Cause dfl could be an enumeration method
independent of the fpga subsystem, although the FPGA is currently the
only user.


The first mail is
	[GIT PULL] FPGA Manager additional changes for 5.10
	https://lore.kernel.org/linux-fpga/20200921000855.GA15612@epycbox.lan/T/#u

In this mail you have some comments for this patch:

	0002-fpga-dfl-move-dfl_device_id-to-mod_devicetable.h.patch
	https://lore.kernel.org/linux-fpga/20200915035909.GA2217@epycbox.lan/T/#u

	[Greg's comments]
	- dfl_device_id is not descriptive, it means nothing to anyone outside
	  of the fpga subsystem.
	- fpga_dfl_device_id perhaps instead?  That gives people a chance to know
	  where to look for this

	[More Greg's comments]
	You are now "playing in the namespace of the whole kernel", so yes, you
	need to be as descriptive as possible so that everyone knows what is
	happening as all subsystems touch these files.

	No one knows what "dfl_" means.  Heck, I have no idea, I keep thinking
	"Device Firmware Loader" or something like that.

	So making it obvious, and unique, and "short enough" is the requirement.

	Naming is hard :)


And then we are trying to explain "dfl" could be an enumeration method
independent of the fpga subsystem, so we want to keep the naming "dfl".

	[Hao's comments]
	Actually Device Feature List is introduced in FPGA, but it doesn't limit
	the usage in FPGA only. It's just a method to discover features from a
	device in case we don't have Device Tree, for sure it can be extended and used
	in other devices too. So it can be bigger namespace than FPGA. This is the
	reason we picked dfl_fpga (DFL based FPGA) before (suggested by Alan),
	for sure it's possible to have "DFL based XXX" in the future, even
	currently only FPGA uses DFL. This is the reason I think bus type "dfl" sounds ok
	in bus code submission review, DFL based FPGA has its own dfl_fpga specific
	ioctl definition, but bus for driver matching can be reused, so it seems
	we fine, if we need to support other devices reusing DFL.

	[Moritz's comments] in this mail thread:
	Let's leave it as is -- An FPGA is one possible implementation and as for
	other buses, you wouldn't call it fpga-usb or usb-fpga
	just because the USB bus is implemented in an FPGA if it behaves like a
	normal USB bus.
	Having an ASIC based DFL bus show up under dfl-fpga /
	fpga-dfl in sysfs would be super confusing.
										
	I mostly think we should keep DFL generic where it touches userspace and
	defines ABI, since we cannot change it afterwards.

	I rest my point with the bus being independent of FPGAs despite
	the FPGA being the (currently) only user.

	I just think it doesn't make a lot of sense to call it
	fpga-dfl or dfl-fpga. But if everyone else disagrees ... naming is hard :-)


Also the main code for dfl bus (we name it "dfl" in this patch) is already merged to
linux-next, see this patch:

	fpga: dfl: create a dfl bus type to support DFL devices
	https://lore.kernel.org/linux-fpga/20200905003231.GB3157@epycbox.lan/T/#u	

So we also want to keep the naming of bus stuff aligned with the name of user
ABIs, to keep the driver self-consistent.


Hope I make things clear.

Thanks,
Yilun

Re: [PATCH v3 1/5] fpga: dfl: rename the bus type "dfl" to "fpga-dfl"

[Moritz Fischer]

Hi Xu,

On Fri, Oct 09, 2020 at 03:34:24PM +0800, Xu Yilun wrote:
> On Fri, Oct 09, 2020 at 08:41:18AM +0200, Greg KH wrote:
> > On Fri, Oct 09, 2020 at 02:20:59PM +0800, Xu Yilun wrote:
> > > Hi Greg:
> > > 
> > > On Mon, Sep 28, 2020 at 09:19:00PM -0700, Moritz Fischer wrote:
> > > > Hi Xu,
> > > > 
> > > > On Tue, Sep 29, 2020 at 09:23:23AM +0800, Xu Yilun wrote:
> > > > > Hi moritz:
> > > > > 
> > > > > On Sun, Sep 27, 2020 at 04:36:47PM +0800, Xu Yilun wrote:
> > > > > > Hi Greg,
> > > > > > 
> > > > > > On Sun, Sep 27, 2020 at 09:54:01AM +0200, Greg KH wrote:
> > > > > > > On Sun, Sep 27, 2020 at 03:37:54PM +0800, Xu Yilun wrote:
> > > > > > > > Hi Greg,
> > > > > > > > 
> > > > > > > > On Sun, Sep 27, 2020 at 07:51:08AM +0200, Greg KH wrote:
> > > > > > > > > On Sat, Sep 26, 2020 at 12:22:19PM -0700, Moritz Fischer wrote:
> > > > > > > > > > Hi Greg,
> > > > > > > > > > 
> > > > > > > > > > On Sat, Sep 26, 2020 at 08:09:13AM +0200, Greg KH wrote:
> > > > > > > > > > > On Sat, Sep 26, 2020 at 10:23:46AM +0800, Xu Yilun wrote:
> > > > > > > > > > > > Hi greg,
> > > > > > > > > > > > 
> > > > > > > > > > > > About the bus naming, I summarized some questions we've discussed to check
> > > > > > > > > > > > with you. See inline.
> > > > > > > > > > > > 
> > > > > > > > > > > > On Thu, Sep 24, 2020 at 10:27:00AM -0700, Moritz Fischer wrote:
> > > > > > > > > > > > > Hi Xu,
> > > > > > > > > > > > > 
> > > > > > > > > > > > > On Fri, Sep 25, 2020 at 12:59:57AM +0800, Xu Yilun wrote:
> > > > > > > > > > > > > > Now the DFL device drivers could be made as independent modules and put
> > > > > > > > > > > > > > in different subsystems according to their functionalities. So the name
> > > > > > > > > > > > > > should be descriptive and unique in the whole kernel.
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > The patch changes the naming of dfl bus related structures, functions,
> > > > > > > > > > > > > > APIs and documentations.
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > Signed-off-by: Xu Yilun <yilun.xu@intel.com>
> > > > > > > > > > > > > > ---
> > > > > > > > > > > > > >  Documentation/ABI/testing/sysfs-bus-dfl      |  15 --
> > > > > > > > > > > > > >  Documentation/ABI/testing/sysfs-bus-fpga-dfl |  15 ++
> > > > > > > > > > > > > >  MAINTAINERS                                  |   2 +-
> > > > > > > > > > > > > >  drivers/fpga/dfl.c                           | 254 ++++++++++++++-------------
> > > > > > > > > > > > > >  drivers/fpga/dfl.h                           |  77 ++++----
> > > > > > > > > > > > > >  5 files changed, 184 insertions(+), 179 deletions(-)
> > > > > > > > > > > > > >  delete mode 100644 Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > > > > > > > >  create mode 100644 Documentation/ABI/testing/sysfs-bus-fpga-dfl
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > diff --git a/Documentation/ABI/testing/sysfs-bus-dfl b/Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > > > > > > > > deleted file mode 100644
> > > > > > > > > > > > > > index 23543be..0000000
> > > > > > > > > > > > > > --- a/Documentation/ABI/testing/sysfs-bus-dfl
> > > > > > > > > > > > > > +++ /dev/null
> > > > > > > > > > > > > > @@ -1,15 +0,0 @@
> > > > > > > > > > > > > > -What:		/sys/bus/dfl/devices/dfl_dev.X/type
> > > > > > > > > > > > > > -Date:		Aug 2020
> > > > > > > > > > > > > > -KernelVersion:	5.10
> > > > > > > > > > > > > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > > > > > > > > > > > > -Description:	Read-only. It returns type of DFL FIU of the device. Now DFL
> > > > > > > > > > > > > > -		supports 2 FIU types, 0 for FME, 1 for PORT.
> > > > > > > > > > > > > > -		Format: 0x%x
> > > > > > > > > > > > > > -
> > > > > > > > > > > > > > -What:		/sys/bus/dfl/devices/dfl_dev.X/feature_id
> > > > > > > > > > > > > > -Date:		Aug 2020
> > > > > > > > > > > > > > -KernelVersion:	5.10
> > > > > > > > > > > > > > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > > > > > > > > > > > > > -Description:	Read-only. It returns feature identifier local to its DFL FIU
> > > > > > > > > > > > > > -		type.
> > > > > > > > > > > > > > -		Format: 0x%x
> > > > > > > > > > > > > 
> > > > > > > > > > > > > You're changing userland facing ABI. I think that's something to avoid,
> > > > > > > > > > > > > please check with Greg on the rules since this hasn't been in a release yet.
> > > > > > > > > > > > > 
> > > > > > > > > > > > 
> > > > > > > > > > > > I'm going to change the name of bus stuff for other subsystems, to be
> > > > > > > > > > > > aligned, I also consider change the bus_type.name and dfl dev_name. But
> > > > > > > > > > > > it will cause the changing of user ABIs. No user case for these user ABI
> > > > > > > > > > > > now cause they are just queued, is it good I change them?
> > > > > > > > > > > 
> > > > > > > > > > > Why change the user name here?  No need for that, right?  Unless you
> > > > > > > > > > > really want to, and think that no one will notice.  If so, fine, change
> > > > > > > > > > > them :)
> > > > > > > > > > 
> > > > > > > > > > Let's leave it as is -- An FPGA is one possible implementation and as for
> > > > > > > > > > other buses, you wouldn't call it fpga-usb or usb-fpga just because the
> > > > > > > > > > USB bus is implemented in an FPGA if it behaves like a normal USB bus.
> > > > > > > > > > Having an ASIC based DFL bus show up under dfl-fpga / fpga-dfl in sysfs
> > > > > > > > > > would be super confusing.
> > > > > > 
> > > > > > I thought we have consensus that "dfl" could be used out of fpga domain.
> > > > > > And we are all good that we keep the user ABIs & the bus name - "dfl", so "dfl"
> > > > > > is good as a global name from linux user's point of view, is it?
> > > > > > 
> > > > > > But why we reject the "dfl" in kernel code domain? I thought it is very
> > > > > > similar situation.
> > > > > > 
> > > > > > 
> > > > > > I think we have 2 options, to make the dfl self-consistent:
> > > > > > 
> > > > > > 1. "dfl-fpga" for everything - bus name, user ABIs, structures & APIs for
> > > > > >    other kernel subsystems. Then we lose the chance to support ASIC based DFL,
> > > > > >    it would be hard if we change user ABIs later.
> > > > > > 
> > > > > > 2. "dfl" for everything.
> > > > > > 
> > > > > > BTW, no ASIC based DFL devices in kernel today.
> > > > > > 
> > > > > > I fully understand the word "naming is hard" now, help me :)
> > > > > 
> > > > > Seems now we have different opinions on this:
> > > > > 
> > > > > - Hao thinks self-consistent is important to dfl framework.
> > > > Agreed. I mostly care about userspace facing ABI, though.
> > > > 
> > > > > - "dfl" for everything seems not preferable to Greg.
> > > > Maybe now that we re-explained, we can take another look at that?
> > > > 
> > > > > - From your previous mail, I assume you prefer to keep the bus name as "dfl"
> > > > > but change the stuff for other subsystem, is it?
> > > > 
> > > > I mostly think we should keep DFL generic where it touches userspace and
> > > > defines ABI, since we cannot change it afterwards.
> > > > 
> > > > I rest my point with the bus being independent of FPGAs despite the FPGA
> > > > being the (currently) only user.
> > > > 
> > > > > So I got a little stuck here.
> > > > > 
> > > > > Do you think "dfl-fpga" for everything would be an acceptable solution
> > > > > for you?
> > > > 
> > > > I just think it doesn't make a lot of sense to call it fpga-dfl or
> > > > dfl-fpga. But if everyone else disagrees ... naming is hard :-)
> > > 
> > > Hi Greg,
> > > 
> > > We made some re-explanation why "dfl" could be independent of the fpga
> > > subsystem in this mail thread. And now the name "dfl" for all bus stuff is good
> > > to Moritz, Hao & Yilun. Could you help take another look at this?
> > 
> > What is "this"?  I don't see any fpga patches in my inbox anywhere...
> 
> Sorry, the discussion lasts more than 2 weeks, so I'm trying to collect
> the comments here.
> 
> We are trying to confirm if the new added bus name "dfl" should be
> OK, instead of "fpga-dfl"? Cause dfl could be an enumeration method
> independent of the fpga subsystem, although the FPGA is currently the
> only user.
> 
> 
> The first mail is
> 	[GIT PULL] FPGA Manager additional changes for 5.10
> 	https://lore.kernel.org/linux-fpga/20200921000855.GA15612@epycbox.lan/T/#u
> 
> In this mail you have some comments for this patch:
> 
> 	0002-fpga-dfl-move-dfl_device_id-to-mod_devicetable.h.patch
> 	https://lore.kernel.org/linux-fpga/20200915035909.GA2217@epycbox.lan/T/#u
> 
> 	[Greg's comments]
> 	- dfl_device_id is not descriptive, it means nothing to anyone outside
> 	  of the fpga subsystem.
> 	- fpga_dfl_device_id perhaps instead?  That gives people a chance to know
> 	  where to look for this
> 
> 	[More Greg's comments]
> 	You are now "playing in the namespace of the whole kernel", so yes, you
> 	need to be as descriptive as possible so that everyone knows what is
> 	happening as all subsystems touch these files.
> 
> 	No one knows what "dfl_" means.  Heck, I have no idea, I keep thinking
> 	"Device Firmware Loader" or something like that.
> 
> 	So making it obvious, and unique, and "short enough" is the requirement.
> 
> 	Naming is hard :)
> 
> 
> And then we are trying to explain "dfl" could be an enumeration method
> independent of the fpga subsystem, so we want to keep the naming "dfl".
> 
> 	[Hao's comments]
> 	Actually Device Feature List is introduced in FPGA, but it doesn't limit
> 	the usage in FPGA only. It's just a method to discover features from a
> 	device in case we don't have Device Tree, for sure it can be extended and used
> 	in other devices too. So it can be bigger namespace than FPGA. This is the
> 	reason we picked dfl_fpga (DFL based FPGA) before (suggested by Alan),
> 	for sure it's possible to have "DFL based XXX" in the future, even
> 	currently only FPGA uses DFL. This is the reason I think bus type "dfl" sounds ok
> 	in bus code submission review, DFL based FPGA has its own dfl_fpga specific
> 	ioctl definition, but bus for driver matching can be reused, so it seems
> 	we fine, if we need to support other devices reusing DFL.
> 
> 	[Moritz's comments] in this mail thread:
> 	Let's leave it as is -- An FPGA is one possible implementation and as for
> 	other buses, you wouldn't call it fpga-usb or usb-fpga
> 	just because the USB bus is implemented in an FPGA if it behaves like a
> 	normal USB bus.
> 	Having an ASIC based DFL bus show up under dfl-fpga /
> 	fpga-dfl in sysfs would be super confusing.
> 										
> 	I mostly think we should keep DFL generic where it touches userspace and
> 	defines ABI, since we cannot change it afterwards.
> 
> 	I rest my point with the bus being independent of FPGAs despite
> 	the FPGA being the (currently) only user.
> 
> 	I just think it doesn't make a lot of sense to call it
> 	fpga-dfl or dfl-fpga. But if everyone else disagrees ... naming is hard :-)
> 
> 
> Also the main code for dfl bus (we name it "dfl" in this patch) is already merged to
> linux-next, see this patch:
> 
> 	fpga: dfl: create a dfl bus type to support DFL devices
> 	https://lore.kernel.org/linux-fpga/20200905003231.GB3157@epycbox.lan/T/#u	
> 
> So we also want to keep the naming of bus stuff aligned with the name of user
> ABIs, to keep the driver self-consistent.
> 
> 
> Hope I make things clear.
> 
> Thanks,
> Yilun

Can you resend your latest, and CC Greg?

We're pretty late in the cycle, so this is gonna wait till the next cycle most likely.
The one patch that introduces the bus doesn't collidee with the plan, so
what is queued right now for 5.10 in Greg's tree is fine.

Thanks,
Moritz

Re: [PATCH v3 1/5] fpga: dfl: rename the bus type "dfl" to "fpga-dfl"

[Greg KH]

On Fri, Oct 09, 2020 at 02:28:39PM -0700, Moritz Fischer wrote:
> We're pretty late in the cycle, so this is gonna wait till the next cycle most likely.

My trees are closed for new stuff for 5.10-rc1, so yes, it has to be for
the next round.

I'll try to get to the "wall of text" next week...

greg k-h

Re: [PATCH v3 1/5] fpga: dfl: rename the bus type "dfl" to "fpga-dfl"

[Tom Rix]

On 9/24/20 9:59 AM, Xu Yilun wrote:
> Now the DFL device drivers could be made as independent modules and put
> in different subsystems according to their functionalities. So the name
> should be descriptive and unique in the whole kernel.
>
> The patch changes the naming of dfl bus related structures, functions,
> APIs and documentations.

This set is largely a mechanical change, it looks ok.


The big thing i would recommend giving some thought is

include/uabi/linux/fpga-dfl.h uses the prefix DFL_FPGA

this change uses fpga_dfl.

I do not think it matters where 'fpga' is in the internal names,

so for consistency with the external interface the prefix should dfl_fpga.

>
> Signed-off-by: Xu Yilun <yilun.xu@intel.com>
> ---
>  Documentation/ABI/testing/sysfs-bus-dfl      |  15 --
>  Documentation/ABI/testing/sysfs-bus-fpga-dfl |  15 ++
>  MAINTAINERS                                  |   2 +-
>  drivers/fpga/dfl.c                           | 254 ++++++++++++++-------------
>  drivers/fpga/dfl.h                           |  77 ++++----
>  5 files changed, 184 insertions(+), 179 deletions(-)
>  delete mode 100644 Documentation/ABI/testing/sysfs-bus-dfl
>  create mode 100644 Documentation/ABI/testing/sysfs-bus-fpga-dfl
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-dfl b/Documentation/ABI/testing/sysfs-bus-dfl
> deleted file mode 100644
> index 23543be..0000000
> --- a/Documentation/ABI/testing/sysfs-bus-dfl
> +++ /dev/null
> @@ -1,15 +0,0 @@
> -What:		/sys/bus/dfl/devices/dfl_dev.X/type
> -Date:		Aug 2020
> -KernelVersion:	5.10
> -Contact:	Xu Yilun <yilun.xu@intel.com>
> -Description:	Read-only. It returns type of DFL FIU of the device. Now DFL
> -		supports 2 FIU types, 0 for FME, 1 for PORT.
> -		Format: 0x%x
> -
> -What:		/sys/bus/dfl/devices/dfl_dev.X/feature_id
> -Date:		Aug 2020
> -KernelVersion:	5.10
> -Contact:	Xu Yilun <yilun.xu@intel.com>
> -Description:	Read-only. It returns feature identifier local to its DFL FIU
> -		type.
> -		Format: 0x%x
> diff --git a/Documentation/ABI/testing/sysfs-bus-fpga-dfl b/Documentation/ABI/testing/sysfs-bus-fpga-dfl
> new file mode 100644
> index 0000000..072decf
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-fpga-dfl
> @@ -0,0 +1,15 @@
> +What:		/sys/bus/fpga-dfl/devices/fpga_dfl_dev.X/type
> +Date:		Aug 2020
> +KernelVersion:	5.10
> +Contact:	Xu Yilun <yilun.xu@intel.com>
> +Description:	Read-only. It returns type of FPGA DFL FIU of the device. Now
> +		FPGA DFL supports 2 FIU types, 0 for FME, 1 for PORT.
> +		Format: 0x%x
> +
> +What:		/sys/bus/fpga-dfl/devices/fpga_dfl_dev.X/feature_id

fpga-dfl and fpga_dfl, the prefix needs to be consistent or..

sys/bus/fpga-dfl/ already has the fpga, dfl info and the second one is redundant so could be

/sys/bus/fpga-dfl/devices/dev.X/feature_id


re: mfd's comment.

This is a new, unreleased interface, now is the only we can change it, so lets do it now.

I'd even suggest splitting the patch to get the change into 5.10.

Tom

> +Date:		Aug 2020
> +KernelVersion:	5.10
> +Contact:	Xu Yilun <yilun.xu@intel.com>
> +Description:	Read-only. It returns feature identifier local to its FPGA DFL
> +		FIU type.
> +		Format: 0x%x
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 0924930..48c0859 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -6839,7 +6839,7 @@ M:	Wu Hao <hao.wu@intel.com>
>  R:	Tom Rix <trix@redhat.com>
>  L:	linux-fpga@vger.kernel.org
>  S:	Maintained
> -F:	Documentation/ABI/testing/sysfs-bus-dfl
> +F:	Documentation/ABI/testing/sysfs-bus-fpga-dfl
>  F:	Documentation/fpga/dfl.rst
>  F:	drivers/fpga/dfl*
>  F:	include/uapi/linux/fpga-dfl.h
> diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
> index b450870..f146cda 100644
> --- a/drivers/fpga/dfl.c
> +++ b/drivers/fpga/dfl.c
> @@ -20,10 +20,10 @@ static DEFINE_MUTEX(dfl_id_mutex);
>  
>  /*
>   * when adding a new feature dev support in DFL framework, it's required to
> - * add a new item in enum dfl_id_type and provide related information in below
> - * dfl_devs table which is indexed by dfl_id_type, e.g. name string used for
> - * platform device creation (define name strings in dfl.h, as they could be
> - * reused by platform device drivers).
> + * add a new item in enum fpga_dfl_id_type and provide related information in
> + * below dfl_devs table which is indexed by fpga_dfl_id_type, e.g. name string
> + * used for platform device creation (define name strings in dfl.h, as they
> + * could be reused by platform device drivers).
>   *
>   * if the new feature dev needs chardev support, then it's required to add
>   * a new item in dfl_chardevs table and configure dfl_devs[i].devt_type as
> @@ -36,9 +36,9 @@ enum dfl_fpga_devt_type {
>  	DFL_FPGA_DEVT_MAX,
>  };
>  
> -static struct lock_class_key dfl_pdata_keys[DFL_ID_MAX];
> +static struct lock_class_key dfl_pdata_keys[FPGA_DFL_ID_MAX];
>  
> -static const char *dfl_pdata_key_strings[DFL_ID_MAX] = {
> +static const char *dfl_pdata_key_strings[FPGA_DFL_ID_MAX] = {
>  	"dfl-fme-pdata",
>  	"dfl-port-pdata",
>  };
> @@ -57,7 +57,7 @@ struct dfl_dev_info {
>  	enum dfl_fpga_devt_type devt_type;
>  };
>  
> -/* it is indexed by dfl_id_type */
> +/* it is indexed by fpga_dfl_id_type */
>  static struct dfl_dev_info dfl_devs[] = {
>  	{.name = DFL_FPGA_FEATURE_DEV_FME, .dfh_id = DFH_ID_FIU_FME,
>  	 .devt_type = DFL_FPGA_DEVT_FME},
> @@ -97,11 +97,11 @@ static void dfl_ids_destroy(void)
>  		idr_destroy(&dfl_devs[i].id);
>  }
>  
> -static int dfl_id_alloc(enum dfl_id_type type, struct device *dev)
> +static int dfl_id_alloc(enum fpga_dfl_id_type type, struct device *dev)
>  {
>  	int id;
>  
> -	WARN_ON(type >= DFL_ID_MAX);
> +	WARN_ON(type >= FPGA_DFL_ID_MAX);
>  	mutex_lock(&dfl_id_mutex);
>  	id = idr_alloc(&dfl_devs[type].id, dev, 0, 0, GFP_KERNEL);
>  	mutex_unlock(&dfl_id_mutex);
> @@ -109,15 +109,15 @@ static int dfl_id_alloc(enum dfl_id_type type, struct device *dev)
>  	return id;
>  }
>  
> -static void dfl_id_free(enum dfl_id_type type, int id)
> +static void dfl_id_free(enum fpga_dfl_id_type type, int id)
>  {
> -	WARN_ON(type >= DFL_ID_MAX);
> +	WARN_ON(type >= FPGA_DFL_ID_MAX);
>  	mutex_lock(&dfl_id_mutex);
>  	idr_remove(&dfl_devs[type].id, id);
>  	mutex_unlock(&dfl_id_mutex);
>  }
>  
> -static enum dfl_id_type feature_dev_id_type(struct platform_device *pdev)
> +static enum fpga_dfl_id_type feature_dev_id_type(struct platform_device *pdev)
>  {
>  	int i;
>  
> @@ -125,10 +125,10 @@ static enum dfl_id_type feature_dev_id_type(struct platform_device *pdev)
>  		if (!strcmp(dfl_devs[i].name, pdev->name))
>  			return i;
>  
> -	return DFL_ID_MAX;
> +	return FPGA_DFL_ID_MAX;
>  }
>  
> -static enum dfl_id_type dfh_id_to_type(u16 id)
> +static enum fpga_dfl_id_type dfh_id_to_type(u16 id)
>  {
>  	int i;
>  
> @@ -136,7 +136,7 @@ static enum dfl_id_type dfh_id_to_type(u16 id)
>  		if (dfl_devs[i].dfh_id == id)
>  			return i;
>  
> -	return DFL_ID_MAX;
> +	return FPGA_DFL_ID_MAX;
>  }
>  
>  /*
> @@ -244,28 +244,29 @@ int dfl_fpga_check_port_id(struct platform_device *pdev, void *pport_id)
>  }
>  EXPORT_SYMBOL_GPL(dfl_fpga_check_port_id);
>  
> -static DEFINE_IDA(dfl_device_ida);
> +static DEFINE_IDA(fpga_dfl_device_ida);
>  
> -static const struct dfl_device_id *
> -dfl_match_one_device(const struct dfl_device_id *id, struct dfl_device *ddev)
> +static const struct fpga_dfl_device_id *
> +dfl_match_one_device(const struct fpga_dfl_device_id *id,
> +		     struct fpga_dfl_device *fddev)
>  {
> -	if (id->type == ddev->type && id->feature_id == ddev->feature_id)
> +	if (id->type == fddev->type && id->feature_id == fddev->feature_id)
>  		return id;
>  
>  	return NULL;
>  }
>  
> -static int dfl_bus_match(struct device *dev, struct device_driver *drv)
> +static int fpga_dfl_bus_match(struct device *dev, struct device_driver *drv)
>  {
> -	struct dfl_device *ddev = to_dfl_dev(dev);
> -	struct dfl_driver *ddrv = to_dfl_drv(drv);
> -	const struct dfl_device_id *id_entry;
> +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
> +	struct fpga_dfl_driver *fddrv = to_fpga_dfl_drv(drv);
> +	const struct fpga_dfl_device_id *id_entry;
>  
> -	id_entry = ddrv->id_table;
> +	id_entry = fddrv->id_table;
>  	if (id_entry) {
>  		while (id_entry->feature_id) {
> -			if (dfl_match_one_device(id_entry, ddev)) {
> -				ddev->id_entry = id_entry;
> +			if (dfl_match_one_device(id_entry, fddev)) {
> +				fddev->id_entry = id_entry;
>  				return 1;
>  			}
>  			id_entry++;
> @@ -275,215 +276,216 @@ static int dfl_bus_match(struct device *dev, struct device_driver *drv)
>  	return 0;
>  }
>  
> -static int dfl_bus_probe(struct device *dev)
> +static int fpga_dfl_bus_probe(struct device *dev)
>  {
> -	struct dfl_driver *ddrv = to_dfl_drv(dev->driver);
> -	struct dfl_device *ddev = to_dfl_dev(dev);
> +	struct fpga_dfl_driver *fddrv = to_fpga_dfl_drv(dev->driver);
> +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
>  
> -	return ddrv->probe(ddev);
> +	return fddrv->probe(fddev);
>  }
>  
> -static int dfl_bus_remove(struct device *dev)
> +static int fpga_dfl_bus_remove(struct device *dev)
>  {
> -	struct dfl_driver *ddrv = to_dfl_drv(dev->driver);
> -	struct dfl_device *ddev = to_dfl_dev(dev);
> +	struct fpga_dfl_driver *fddrv = to_fpga_dfl_drv(dev->driver);
> +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
>  
> -	if (ddrv->remove)
> -		ddrv->remove(ddev);
> +	if (fddrv->remove)
> +		fddrv->remove(fddev);
>  
>  	return 0;
>  }
>  
> -static int dfl_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
> +static int fpga_dfl_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
>  {
> -	struct dfl_device *ddev = to_dfl_dev(dev);
> +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
>  
>  	/* The type has 4 valid bits and feature_id has 12 valid bits */
> -	return add_uevent_var(env, "MODALIAS=dfl:t%01Xf%03X",
> -			      ddev->type, ddev->feature_id);
> +	return add_uevent_var(env, "MODALIAS=fpga-dfl:t%01Xf%03X",
> +			      fddev->type, fddev->feature_id);
>  }
>  
>  static ssize_t
>  type_show(struct device *dev, struct device_attribute *attr, char *buf)
>  {
> -	struct dfl_device *ddev = to_dfl_dev(dev);
> +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
>  
> -	return sprintf(buf, "0x%x\n", ddev->type);
> +	return sprintf(buf, "0x%x\n", fddev->type);
>  }
>  static DEVICE_ATTR_RO(type);
>  
>  static ssize_t
>  feature_id_show(struct device *dev, struct device_attribute *attr, char *buf)
>  {
> -	struct dfl_device *ddev = to_dfl_dev(dev);
> +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
>  
> -	return sprintf(buf, "0x%x\n", ddev->feature_id);
> +	return sprintf(buf, "0x%x\n", fddev->feature_id);
>  }
>  static DEVICE_ATTR_RO(feature_id);
>  
> -static struct attribute *dfl_dev_attrs[] = {
> +static struct attribute *fpga_dfl_dev_attrs[] = {
>  	&dev_attr_type.attr,
>  	&dev_attr_feature_id.attr,
>  	NULL,
>  };
> -ATTRIBUTE_GROUPS(dfl_dev);
> -
> -static struct bus_type dfl_bus_type = {
> -	.name		= "dfl",
> -	.match		= dfl_bus_match,
> -	.probe		= dfl_bus_probe,
> -	.remove		= dfl_bus_remove,
> -	.uevent		= dfl_bus_uevent,
> -	.dev_groups	= dfl_dev_groups,
> +ATTRIBUTE_GROUPS(fpga_dfl_dev);
> +
> +static struct bus_type fpga_dfl_bus_type = {
> +	.name		= "fpga-dfl",
> +	.match		= fpga_dfl_bus_match,
> +	.probe		= fpga_dfl_bus_probe,
> +	.remove		= fpga_dfl_bus_remove,
> +	.uevent		= fpga_dfl_bus_uevent,
> +	.dev_groups	= fpga_dfl_dev_groups,
>  };
>  
> -static void release_dfl_dev(struct device *dev)
> +static void release_fpga_dfl_dev(struct device *dev)
>  {
> -	struct dfl_device *ddev = to_dfl_dev(dev);
> +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
>  
> -	if (ddev->mmio_res.parent)
> -		release_resource(&ddev->mmio_res);
> +	if (fddev->mmio_res.parent)
> +		release_resource(&fddev->mmio_res);
>  
> -	ida_simple_remove(&dfl_device_ida, ddev->id);
> -	kfree(ddev->irqs);
> -	kfree(ddev);
> +	ida_simple_remove(&fpga_dfl_device_ida, fddev->id);
> +	kfree(fddev->irqs);
> +	kfree(fddev);
>  }
>  
> -static struct dfl_device *
> -dfl_dev_add(struct dfl_feature_platform_data *pdata,
> -	    struct dfl_feature *feature)
> +static struct fpga_dfl_device *
> +fpga_dfl_dev_add(struct dfl_feature_platform_data *pdata,
> +		 struct dfl_feature *feature)
>  {
>  	struct platform_device *pdev = pdata->dev;
>  	struct resource *parent_res;
> -	struct dfl_device *ddev;
> +	struct fpga_dfl_device *fddev;
>  	int id, i, ret;
>  
> -	ddev = kzalloc(sizeof(*ddev), GFP_KERNEL);
> -	if (!ddev)
> +	fddev = kzalloc(sizeof(*fddev), GFP_KERNEL);
> +	if (!fddev)
>  		return ERR_PTR(-ENOMEM);
>  
> -	id = ida_simple_get(&dfl_device_ida, 0, 0, GFP_KERNEL);
> +	id = ida_simple_get(&fpga_dfl_device_ida, 0, 0, GFP_KERNEL);
>  	if (id < 0) {
>  		dev_err(&pdev->dev, "unable to get id\n");
> -		kfree(ddev);
> +		kfree(fddev);
>  		return ERR_PTR(id);
>  	}
>  
>  	/* freeing resources by put_device() after device_initialize() */
> -	device_initialize(&ddev->dev);
> -	ddev->dev.parent = &pdev->dev;
> -	ddev->dev.bus = &dfl_bus_type;
> -	ddev->dev.release = release_dfl_dev;
> -	ddev->id = id;
> -	ret = dev_set_name(&ddev->dev, "dfl_dev.%d", id);
> +	device_initialize(&fddev->dev);
> +	fddev->dev.parent = &pdev->dev;
> +	fddev->dev.bus = &fpga_dfl_bus_type;
> +	fddev->dev.release = release_fpga_dfl_dev;
> +	fddev->id = id;
> +	ret = dev_set_name(&fddev->dev, "fpga_dfl_dev.%d", id);
>  	if (ret)
>  		goto put_dev;
>  
> -	ddev->type = feature_dev_id_type(pdev);
> -	ddev->feature_id = feature->id;
> -	ddev->cdev = pdata->dfl_cdev;
> +	fddev->type = feature_dev_id_type(pdev);
> +	fddev->feature_id = feature->id;
> +	fddev->cdev = pdata->dfl_cdev;
>  
>  	/* add mmio resource */
>  	parent_res = &pdev->resource[feature->resource_index];
> -	ddev->mmio_res.flags = IORESOURCE_MEM;
> -	ddev->mmio_res.start = parent_res->start;
> -	ddev->mmio_res.end = parent_res->end;
> -	ddev->mmio_res.name = dev_name(&ddev->dev);
> -	ret = insert_resource(parent_res, &ddev->mmio_res);
> +	fddev->mmio_res.flags = IORESOURCE_MEM;
> +	fddev->mmio_res.start = parent_res->start;
> +	fddev->mmio_res.end = parent_res->end;
> +	fddev->mmio_res.name = dev_name(&fddev->dev);
> +	ret = insert_resource(parent_res, &fddev->mmio_res);
>  	if (ret) {
>  		dev_err(&pdev->dev, "%s failed to claim resource: %pR\n",
> -			dev_name(&ddev->dev), &ddev->mmio_res);
> +			dev_name(&fddev->dev), &fddev->mmio_res);
>  		goto put_dev;
>  	}
>  
>  	/* then add irq resource */
>  	if (feature->nr_irqs) {
> -		ddev->irqs = kcalloc(feature->nr_irqs,
> -				     sizeof(*ddev->irqs), GFP_KERNEL);
> -		if (!ddev->irqs) {
> +		fddev->irqs = kcalloc(feature->nr_irqs,
> +				      sizeof(*fddev->irqs), GFP_KERNEL);
> +		if (!fddev->irqs) {
>  			ret = -ENOMEM;
>  			goto put_dev;
>  		}
>  
>  		for (i = 0; i < feature->nr_irqs; i++)
> -			ddev->irqs[i] = feature->irq_ctx[i].irq;
> +			fddev->irqs[i] = feature->irq_ctx[i].irq;
>  
> -		ddev->num_irqs = feature->nr_irqs;
> +		fddev->num_irqs = feature->nr_irqs;
>  	}
>  
> -	ret = device_add(&ddev->dev);
> +	ret = device_add(&fddev->dev);
>  	if (ret)
>  		goto put_dev;
>  
> -	dev_dbg(&pdev->dev, "add dfl_dev: %s\n", dev_name(&ddev->dev));
> -	return ddev;
> +	dev_dbg(&pdev->dev, "add fpga_dfl_dev: %s\n", dev_name(&fddev->dev));
> +	return fddev;
>  
>  put_dev:
> -	/* calls release_dfl_dev() which does the clean up  */
> -	put_device(&ddev->dev);
> +	/* calls release_fpga_dfl_dev() which does the clean up  */
> +	put_device(&fddev->dev);
>  	return ERR_PTR(ret);
>  }
>  
> -static void dfl_devs_remove(struct dfl_feature_platform_data *pdata)
> +static void fpga_dfl_devs_remove(struct dfl_feature_platform_data *pdata)
>  {
>  	struct dfl_feature *feature;
>  
>  	dfl_fpga_dev_for_each_feature(pdata, feature) {
> -		if (feature->ddev) {
> -			device_unregister(&feature->ddev->dev);
> -			feature->ddev = NULL;
> +		if (feature->fddev) {
> +			device_unregister(&feature->fddev->dev);
> +			feature->fddev = NULL;
>  		}
>  	}
>  }
>  
> -static int dfl_devs_add(struct dfl_feature_platform_data *pdata)
> +static int fpga_dfl_devs_add(struct dfl_feature_platform_data *pdata)
>  {
> +	struct fpga_dfl_device *fddev;
>  	struct dfl_feature *feature;
> -	struct dfl_device *ddev;
>  	int ret;
>  
>  	dfl_fpga_dev_for_each_feature(pdata, feature) {
>  		if (feature->ioaddr)
>  			continue;
>  
> -		if (feature->ddev) {
> +		if (feature->fddev) {
>  			ret = -EEXIST;
>  			goto err;
>  		}
>  
> -		ddev = dfl_dev_add(pdata, feature);
> -		if (IS_ERR(ddev)) {
> -			ret = PTR_ERR(ddev);
> +		fddev = fpga_dfl_dev_add(pdata, feature);
> +		if (IS_ERR(fddev)) {
> +			ret = PTR_ERR(fddev);
>  			goto err;
>  		}
>  
> -		feature->ddev = ddev;
> +		feature->fddev = fddev;
>  	}
>  
>  	return 0;
>  
>  err:
> -	dfl_devs_remove(pdata);
> +	fpga_dfl_devs_remove(pdata);
>  	return ret;
>  }
>  
> -int __dfl_driver_register(struct dfl_driver *dfl_drv, struct module *owner)
> +int __fpga_dfl_driver_register(struct fpga_dfl_driver *fddrv,
> +			       struct module *owner)
>  {
> -	if (!dfl_drv || !dfl_drv->probe || !dfl_drv->id_table)
> +	if (!fddrv || !fddrv->probe || !fddrv->id_table)
>  		return -EINVAL;
>  
> -	dfl_drv->drv.owner = owner;
> -	dfl_drv->drv.bus = &dfl_bus_type;
> +	fddrv->drv.owner = owner;
> +	fddrv->drv.bus = &fpga_dfl_bus_type;
>  
> -	return driver_register(&dfl_drv->drv);
> +	return driver_register(&fddrv->drv);
>  }
> -EXPORT_SYMBOL(__dfl_driver_register);
> +EXPORT_SYMBOL(__fpga_dfl_driver_register);
>  
> -void dfl_driver_unregister(struct dfl_driver *dfl_drv)
> +void fpga_dfl_driver_unregister(struct fpga_dfl_driver *fddrv)
>  {
> -	driver_unregister(&dfl_drv->drv);
> +	driver_unregister(&fddrv->drv);
>  }
> -EXPORT_SYMBOL(dfl_driver_unregister);
> +EXPORT_SYMBOL(fpga_dfl_driver_unregister);
>  
>  #define is_header_feature(feature) ((feature)->id == FEATURE_ID_FIU_HEADER)
>  
> @@ -496,7 +498,7 @@ void dfl_fpga_dev_feature_uinit(struct platform_device *pdev)
>  	struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
>  	struct dfl_feature *feature;
>  
> -	dfl_devs_remove(pdata);
> +	fpga_dfl_devs_remove(pdata);
>  
>  	dfl_fpga_dev_for_each_feature(pdata, feature) {
>  		if (feature->ops) {
> @@ -585,7 +587,7 @@ int dfl_fpga_dev_feature_init(struct platform_device *pdev,
>  		drv++;
>  	}
>  
> -	ret = dfl_devs_add(pdata);
> +	ret = fpga_dfl_devs_add(pdata);
>  	if (ret)
>  		goto exit;
>  
> @@ -745,11 +747,11 @@ static int build_info_commit_dev(struct build_feature_devs_info *binfo)
>  	struct platform_device *fdev = binfo->feature_dev;
>  	struct dfl_feature_platform_data *pdata;
>  	struct dfl_feature_info *finfo, *p;
> -	enum dfl_id_type type;
> +	enum fpga_dfl_id_type type;
>  	int ret, index = 0, res_idx = 0;
>  
>  	type = feature_dev_id_type(fdev);
> -	if (WARN_ON_ONCE(type >= DFL_ID_MAX))
> +	if (WARN_ON_ONCE(type >= FPGA_DFL_ID_MAX))
>  		return -EINVAL;
>  
>  	/*
> @@ -836,7 +838,7 @@ static int build_info_commit_dev(struct build_feature_devs_info *binfo)
>  
>  	ret = platform_device_add(binfo->feature_dev);
>  	if (!ret) {
> -		if (type == PORT_ID)
> +		if (type == FPGA_DFL_PORT_ID)
>  			dfl_fpga_cdev_add_port_dev(binfo->cdev,
>  						   binfo->feature_dev);
>  		else
> @@ -857,11 +859,11 @@ static int build_info_commit_dev(struct build_feature_devs_info *binfo)
>  
>  static int
>  build_info_create_dev(struct build_feature_devs_info *binfo,
> -		      enum dfl_id_type type)
> +		      enum fpga_dfl_id_type type)
>  {
>  	struct platform_device *fdev;
>  
> -	if (type >= DFL_ID_MAX)
> +	if (type >= FPGA_DFL_ID_MAX)
>  		return -EINVAL;
>  
>  	/*
> @@ -1072,7 +1074,7 @@ static int parse_feature_afu(struct build_feature_devs_info *binfo,
>  	}
>  
>  	switch (feature_dev_id_type(binfo->feature_dev)) {
> -	case PORT_ID:
> +	case FPGA_DFL_PORT_ID:
>  		return parse_feature_port_afu(binfo, ofst);
>  	default:
>  		dev_info(binfo->dev, "AFU belonging to FIU %s is not supported yet.\n",
> @@ -1360,7 +1362,7 @@ EXPORT_SYMBOL_GPL(dfl_fpga_enum_info_add_irq);
>  static int remove_feature_dev(struct device *dev, void *data)
>  {
>  	struct platform_device *pdev = to_platform_device(dev);
> -	enum dfl_id_type type = feature_dev_id_type(pdev);
> +	enum fpga_dfl_id_type type = feature_dev_id_type(pdev);
>  	int id = pdev->id;
>  
>  	platform_device_unregister(pdev);
> @@ -1526,7 +1528,7 @@ static int __init dfl_fpga_init(void)
>  {
>  	int ret;
>  
> -	ret = bus_register(&dfl_bus_type);
> +	ret = bus_register(&fpga_dfl_bus_type);
>  	if (ret)
>  		return ret;
>  
> @@ -1535,7 +1537,7 @@ static int __init dfl_fpga_init(void)
>  	ret = dfl_chardev_init();
>  	if (ret) {
>  		dfl_ids_destroy();
> -		bus_unregister(&dfl_bus_type);
> +		bus_unregister(&fpga_dfl_bus_type);
>  	}
>  
>  	return ret;
> @@ -1874,7 +1876,7 @@ static void __exit dfl_fpga_exit(void)
>  {
>  	dfl_chardev_uinit();
>  	dfl_ids_destroy();
> -	bus_unregister(&dfl_bus_type);
> +	bus_unregister(&fpga_dfl_bus_type);
>  }
>  
>  module_init(dfl_fpga_init);
> diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h
> index 5dc758f..ba930a7 100644
> --- a/drivers/fpga/dfl.h
> +++ b/drivers/fpga/dfl.h
> @@ -236,7 +236,7 @@ struct dfl_feature_irq_ctx {
>   * @irq_ctx: interrupt context list.
>   * @nr_irqs: number of interrupt contexts.
>   * @ops: ops of this sub feature.
> - * @ddev: ptr to the dfl device of this sub feature.
> + * @fddev: ptr to the fpga dfl device of this sub feature.
>   * @priv: priv data of this feature.
>   */
>  struct dfl_feature {
> @@ -247,7 +247,7 @@ struct dfl_feature {
>  	struct dfl_feature_irq_ctx *irq_ctx;
>  	unsigned int nr_irqs;
>  	const struct dfl_feature_ops *ops;
> -	struct dfl_device *ddev;
> +	struct fpga_dfl_device *fddev;
>  	void *priv;
>  };
>  
> @@ -517,40 +517,42 @@ long dfl_feature_ioctl_set_irq(struct platform_device *pdev,
>  			       unsigned long arg);
>  
>  /**
> - * enum dfl_id_type - define the DFL FIU types
> + * enum fpga_dfl_id_type - define the FPGA DFL FIU types
>   */
> -enum dfl_id_type {
> -	FME_ID,
> -	PORT_ID,
> -	DFL_ID_MAX,
> +enum fpga_dfl_id_type {
> +	FPGA_DFL_FME_ID,
> +	FPGA_DFL_PORT_ID,
> +	FPGA_DFL_ID_MAX,
>  };
>  
>  /**
> - * struct dfl_device_id -  dfl device identifier
> - * @type: contains 4 bits DFL FIU type of the device. See enum dfl_id_type.
> - * @feature_id: contains 12 bits feature identifier local to its DFL FIU type.
> + * struct fpga_dfl_device_id - fpga dfl device identifier
> + * @type: contains 4 bits FPGA DFL FIU type of the device, see
> + *	  enum fpga_dfl_id_type.
> + * @feature_id: contains 12 bits feature identifier local to its FPGA DFL FIU
> + *		type.
>   * @driver_data: driver specific data.
>   */
> -struct dfl_device_id {
> +struct fpga_dfl_device_id {
>  	u8 type;
>  	u16 feature_id;
>  	unsigned long driver_data;
>  };
>  
>  /**
> - * struct dfl_device - represent an dfl device on dfl bus
> + * struct fpga_dfl_device - represent an fpga dfl device on fpga dfl bus
>   *
>   * @dev: generic device interface.
> - * @id: id of the dfl device.
> - * @type: type of DFL FIU of the device. See enum dfl_id_type.
> - * @feature_id: 16 bits feature identifier local to its DFL FIU type.
> - * @mmio_res: mmio resource of this dfl device.
> - * @irqs: list of Linux IRQ numbers of this dfl device.
> - * @num_irqs: number of IRQs supported by this dfl device.
> - * @cdev: pointer to DFL FPGA container device this dfl device belongs to.
> - * @id_entry: matched id entry in dfl driver's id table.
> + * @id: id of the fpga dfl device.
> + * @type: FPGA DFL FIU type of the device, see enum fpga_dfl_id_type.
> + * @feature_id: 16 bits feature identifier local to its FPGA DFL FIU type.
> + * @mmio_res: mmio resource of this fpga dfl device.
> + * @irqs: list of Linux IRQ numbers of this fpga dfl device.
> + * @num_irqs: number of IRQs supported by this fpga dfl device.
> + * @cdev: pointer to DFL FPGA container device this fpga dfl device belongs to.
> + * @id_entry: matched id entry in fpga dfl driver's id table.
>   */
> -struct dfl_device {
> +struct fpga_dfl_device {
>  	struct device dev;
>  	int id;
>  	u8 type;
> @@ -559,11 +561,11 @@ struct dfl_device {
>  	int *irqs;
>  	unsigned int num_irqs;
>  	struct dfl_fpga_cdev *cdev;
> -	const struct dfl_device_id *id_entry;
> +	const struct fpga_dfl_device_id *id_entry;
>  };
>  
>  /**
> - * struct dfl_driver - represent an dfl device driver
> + * struct fpga_dfl_driver - represent a fpga dfl device driver
>   *
>   * @drv: driver model structure.
>   * @id_table: pointer to table of device IDs the driver is interested in.
> @@ -571,33 +573,34 @@ struct dfl_device {
>   * @probe: mandatory callback for device binding.
>   * @remove: callback for device unbinding.
>   */
> -struct dfl_driver {
> +struct fpga_dfl_driver {
>  	struct device_driver drv;
> -	const struct dfl_device_id *id_table;
> +	const struct fpga_dfl_device_id *id_table;
>  
> -	int (*probe)(struct dfl_device *dfl_dev);
> -	void (*remove)(struct dfl_device *dfl_dev);
> +	int (*probe)(struct fpga_dfl_device *fddev);
> +	void (*remove)(struct fpga_dfl_device *fddev);
>  };
>  
> -#define to_dfl_dev(d) container_of(d, struct dfl_device, dev)
> -#define to_dfl_drv(d) container_of(d, struct dfl_driver, drv)
> +#define to_fpga_dfl_dev(d) container_of(d, struct fpga_dfl_device, dev)
> +#define to_fpga_dfl_drv(d) container_of(d, struct fpga_dfl_driver, drv)
>  
>  /*
>   * use a macro to avoid include chaining to get THIS_MODULE.
>   */
> -#define dfl_driver_register(drv) \
> -	__dfl_driver_register(drv, THIS_MODULE)
> -int __dfl_driver_register(struct dfl_driver *dfl_drv, struct module *owner);
> -void dfl_driver_unregister(struct dfl_driver *dfl_drv);
> +#define fpga_dfl_driver_register(drv) \
> +	__fpga_dfl_driver_register(drv, THIS_MODULE)
> +int __fpga_dfl_driver_register(struct fpga_dfl_driver *fddrv,
> +			       struct module *owner);
> +void fpga_dfl_driver_unregister(struct fpga_dfl_driver *fddrv);
>  
>  /*
> - * module_dfl_driver() - Helper macro for drivers that don't do
> + * module_fpga_dfl_driver() - Helper macro for drivers that don't do
>   * anything special in module init/exit.  This eliminates a lot of
>   * boilerplate.  Each module may only use this macro once, and
>   * calling it replaces module_init() and module_exit().
>   */
> -#define module_dfl_driver(__dfl_driver) \
> -	module_driver(__dfl_driver, dfl_driver_register, \
> -		      dfl_driver_unregister)
> +#define module_fpga_dfl_driver(__fpga_dfl_driver) \
> +	module_driver(__fpga_dfl_driver, fpga_dfl_driver_register, \
> +		      fpga_dfl_driver_unregister)
>  
>  #endif /* __FPGA_DFL_H */

Re: [PATCH v3 1/5] fpga: dfl: rename the bus type "dfl" to "fpga-dfl"

[Moritz Fischer]

On Thu, Sep 24, 2020 at 12:01:55PM -0700, Tom Rix wrote:
> 
> On 9/24/20 9:59 AM, Xu Yilun wrote:
> > Now the DFL device drivers could be made as independent modules and put
> > in different subsystems according to their functionalities. So the name
> > should be descriptive and unique in the whole kernel.
> >
> > The patch changes the naming of dfl bus related structures, functions,
> > APIs and documentations.
> 
> This set is largely a mechanical change, it looks ok.
> 
> 
> The big thing i would recommend giving some thought is
> 
> include/uabi/linux/fpga-dfl.h uses the prefix DFL_FPGA
> 
> this change uses fpga_dfl.
> 
> I do not think it matters where 'fpga' is in the internal names,
> 
> so for consistency with the external interface the prefix should dfl_fpga.
> 
> >
> > Signed-off-by: Xu Yilun <yilun.xu@intel.com>
> > ---
> >  Documentation/ABI/testing/sysfs-bus-dfl      |  15 --
> >  Documentation/ABI/testing/sysfs-bus-fpga-dfl |  15 ++
> >  MAINTAINERS                                  |   2 +-
> >  drivers/fpga/dfl.c                           | 254 ++++++++++++++-------------
> >  drivers/fpga/dfl.h                           |  77 ++++----
> >  5 files changed, 184 insertions(+), 179 deletions(-)
> >  delete mode 100644 Documentation/ABI/testing/sysfs-bus-dfl
> >  create mode 100644 Documentation/ABI/testing/sysfs-bus-fpga-dfl
> >
> > diff --git a/Documentation/ABI/testing/sysfs-bus-dfl b/Documentation/ABI/testing/sysfs-bus-dfl
> > deleted file mode 100644
> > index 23543be..0000000
> > --- a/Documentation/ABI/testing/sysfs-bus-dfl
> > +++ /dev/null
> > @@ -1,15 +0,0 @@
> > -What:		/sys/bus/dfl/devices/dfl_dev.X/type
> > -Date:		Aug 2020
> > -KernelVersion:	5.10
> > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > -Description:	Read-only. It returns type of DFL FIU of the device. Now DFL
> > -		supports 2 FIU types, 0 for FME, 1 for PORT.
> > -		Format: 0x%x
> > -
> > -What:		/sys/bus/dfl/devices/dfl_dev.X/feature_id
> > -Date:		Aug 2020
> > -KernelVersion:	5.10
> > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > -Description:	Read-only. It returns feature identifier local to its DFL FIU
> > -		type.
> > -		Format: 0x%x
> > diff --git a/Documentation/ABI/testing/sysfs-bus-fpga-dfl b/Documentation/ABI/testing/sysfs-bus-fpga-dfl
> > new file mode 100644
> > index 0000000..072decf
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/sysfs-bus-fpga-dfl
> > @@ -0,0 +1,15 @@
> > +What:		/sys/bus/fpga-dfl/devices/fpga_dfl_dev.X/type
> > +Date:		Aug 2020
> > +KernelVersion:	5.10
> > +Contact:	Xu Yilun <yilun.xu@intel.com>
> > +Description:	Read-only. It returns type of FPGA DFL FIU of the device. Now
> > +		FPGA DFL supports 2 FIU types, 0 for FME, 1 for PORT.
> > +		Format: 0x%x
> > +
> > +What:		/sys/bus/fpga-dfl/devices/fpga_dfl_dev.X/feature_id
> 
> fpga-dfl and fpga_dfl, the prefix needs to be consistent or..
> 
> sys/bus/fpga-dfl/ already has the fpga, dfl info and the second one is redundant so could be
> 
> /sys/bus/fpga-dfl/devices/dev.X/feature_id
> 
> 
> re: mfd's comment.
> 
> This is a new, unreleased interface, now is the only we can change it, so lets do it now.

Imho the question is more whether it is worth the churn on the sysfs
part or not ...

I think changing the stuff that touches files where other subsystems are
involved is more critical, and that's how I read Greg's comment.
> 
> I'd even suggest splitting the patch to get the change into 5.10.

If we think that's enough of a big deal that this needs to happen, then
yes, splitting the sysfs part out into a separate patch will increase
the likelihood of it actually happening.

> 
> Tom
> 
> > +Date:		Aug 2020
> > +KernelVersion:	5.10
> > +Contact:	Xu Yilun <yilun.xu@intel.com>
> > +Description:	Read-only. It returns feature identifier local to its FPGA DFL
> > +		FIU type.
> > +		Format: 0x%x
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 0924930..48c0859 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -6839,7 +6839,7 @@ M:	Wu Hao <hao.wu@intel.com>
> >  R:	Tom Rix <trix@redhat.com>
> >  L:	linux-fpga@vger.kernel.org
> >  S:	Maintained
> > -F:	Documentation/ABI/testing/sysfs-bus-dfl
> > +F:	Documentation/ABI/testing/sysfs-bus-fpga-dfl
> >  F:	Documentation/fpga/dfl.rst
> >  F:	drivers/fpga/dfl*
> >  F:	include/uapi/linux/fpga-dfl.h
> > diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
> > index b450870..f146cda 100644
> > --- a/drivers/fpga/dfl.c
> > +++ b/drivers/fpga/dfl.c
> > @@ -20,10 +20,10 @@ static DEFINE_MUTEX(dfl_id_mutex);
> >  
> >  /*
> >   * when adding a new feature dev support in DFL framework, it's required to
> > - * add a new item in enum dfl_id_type and provide related information in below
> > - * dfl_devs table which is indexed by dfl_id_type, e.g. name string used for
> > - * platform device creation (define name strings in dfl.h, as they could be
> > - * reused by platform device drivers).
> > + * add a new item in enum fpga_dfl_id_type and provide related information in
> > + * below dfl_devs table which is indexed by fpga_dfl_id_type, e.g. name string
> > + * used for platform device creation (define name strings in dfl.h, as they
> > + * could be reused by platform device drivers).
> >   *
> >   * if the new feature dev needs chardev support, then it's required to add
> >   * a new item in dfl_chardevs table and configure dfl_devs[i].devt_type as
> > @@ -36,9 +36,9 @@ enum dfl_fpga_devt_type {
> >  	DFL_FPGA_DEVT_MAX,
> >  };
> >  
> > -static struct lock_class_key dfl_pdata_keys[DFL_ID_MAX];
> > +static struct lock_class_key dfl_pdata_keys[FPGA_DFL_ID_MAX];
> >  
> > -static const char *dfl_pdata_key_strings[DFL_ID_MAX] = {
> > +static const char *dfl_pdata_key_strings[FPGA_DFL_ID_MAX] = {
> >  	"dfl-fme-pdata",
> >  	"dfl-port-pdata",
> >  };
> > @@ -57,7 +57,7 @@ struct dfl_dev_info {
> >  	enum dfl_fpga_devt_type devt_type;
> >  };
> >  
> > -/* it is indexed by dfl_id_type */
> > +/* it is indexed by fpga_dfl_id_type */
> >  static struct dfl_dev_info dfl_devs[] = {
> >  	{.name = DFL_FPGA_FEATURE_DEV_FME, .dfh_id = DFH_ID_FIU_FME,
> >  	 .devt_type = DFL_FPGA_DEVT_FME},
> > @@ -97,11 +97,11 @@ static void dfl_ids_destroy(void)
> >  		idr_destroy(&dfl_devs[i].id);
> >  }
> >  
> > -static int dfl_id_alloc(enum dfl_id_type type, struct device *dev)
> > +static int dfl_id_alloc(enum fpga_dfl_id_type type, struct device *dev)
> >  {
> >  	int id;
> >  
> > -	WARN_ON(type >= DFL_ID_MAX);
> > +	WARN_ON(type >= FPGA_DFL_ID_MAX);
> >  	mutex_lock(&dfl_id_mutex);
> >  	id = idr_alloc(&dfl_devs[type].id, dev, 0, 0, GFP_KERNEL);
> >  	mutex_unlock(&dfl_id_mutex);
> > @@ -109,15 +109,15 @@ static int dfl_id_alloc(enum dfl_id_type type, struct device *dev)
> >  	return id;
> >  }
> >  
> > -static void dfl_id_free(enum dfl_id_type type, int id)
> > +static void dfl_id_free(enum fpga_dfl_id_type type, int id)
> >  {
> > -	WARN_ON(type >= DFL_ID_MAX);
> > +	WARN_ON(type >= FPGA_DFL_ID_MAX);
> >  	mutex_lock(&dfl_id_mutex);
> >  	idr_remove(&dfl_devs[type].id, id);
> >  	mutex_unlock(&dfl_id_mutex);
> >  }
> >  
> > -static enum dfl_id_type feature_dev_id_type(struct platform_device *pdev)
> > +static enum fpga_dfl_id_type feature_dev_id_type(struct platform_device *pdev)
> >  {
> >  	int i;
> >  
> > @@ -125,10 +125,10 @@ static enum dfl_id_type feature_dev_id_type(struct platform_device *pdev)
> >  		if (!strcmp(dfl_devs[i].name, pdev->name))
> >  			return i;
> >  
> > -	return DFL_ID_MAX;
> > +	return FPGA_DFL_ID_MAX;
> >  }
> >  
> > -static enum dfl_id_type dfh_id_to_type(u16 id)
> > +static enum fpga_dfl_id_type dfh_id_to_type(u16 id)
> >  {
> >  	int i;
> >  
> > @@ -136,7 +136,7 @@ static enum dfl_id_type dfh_id_to_type(u16 id)
> >  		if (dfl_devs[i].dfh_id == id)
> >  			return i;
> >  
> > -	return DFL_ID_MAX;
> > +	return FPGA_DFL_ID_MAX;
> >  }
> >  
> >  /*
> > @@ -244,28 +244,29 @@ int dfl_fpga_check_port_id(struct platform_device *pdev, void *pport_id)
> >  }
> >  EXPORT_SYMBOL_GPL(dfl_fpga_check_port_id);
> >  
> > -static DEFINE_IDA(dfl_device_ida);
> > +static DEFINE_IDA(fpga_dfl_device_ida);
> >  
> > -static const struct dfl_device_id *
> > -dfl_match_one_device(const struct dfl_device_id *id, struct dfl_device *ddev)
> > +static const struct fpga_dfl_device_id *
> > +dfl_match_one_device(const struct fpga_dfl_device_id *id,
> > +		     struct fpga_dfl_device *fddev)
> >  {
> > -	if (id->type == ddev->type && id->feature_id == ddev->feature_id)
> > +	if (id->type == fddev->type && id->feature_id == fddev->feature_id)
> >  		return id;
> >  
> >  	return NULL;
> >  }
> >  
> > -static int dfl_bus_match(struct device *dev, struct device_driver *drv)
> > +static int fpga_dfl_bus_match(struct device *dev, struct device_driver *drv)
> >  {
> > -	struct dfl_device *ddev = to_dfl_dev(dev);
> > -	struct dfl_driver *ddrv = to_dfl_drv(drv);
> > -	const struct dfl_device_id *id_entry;
> > +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
> > +	struct fpga_dfl_driver *fddrv = to_fpga_dfl_drv(drv);
> > +	const struct fpga_dfl_device_id *id_entry;
> >  
> > -	id_entry = ddrv->id_table;
> > +	id_entry = fddrv->id_table;
> >  	if (id_entry) {
> >  		while (id_entry->feature_id) {
> > -			if (dfl_match_one_device(id_entry, ddev)) {
> > -				ddev->id_entry = id_entry;
> > +			if (dfl_match_one_device(id_entry, fddev)) {
> > +				fddev->id_entry = id_entry;
> >  				return 1;
> >  			}
> >  			id_entry++;
> > @@ -275,215 +276,216 @@ static int dfl_bus_match(struct device *dev, struct device_driver *drv)
> >  	return 0;
> >  }
> >  
> > -static int dfl_bus_probe(struct device *dev)
> > +static int fpga_dfl_bus_probe(struct device *dev)
> >  {
> > -	struct dfl_driver *ddrv = to_dfl_drv(dev->driver);
> > -	struct dfl_device *ddev = to_dfl_dev(dev);
> > +	struct fpga_dfl_driver *fddrv = to_fpga_dfl_drv(dev->driver);
> > +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
> >  
> > -	return ddrv->probe(ddev);
> > +	return fddrv->probe(fddev);
> >  }
> >  
> > -static int dfl_bus_remove(struct device *dev)
> > +static int fpga_dfl_bus_remove(struct device *dev)
> >  {
> > -	struct dfl_driver *ddrv = to_dfl_drv(dev->driver);
> > -	struct dfl_device *ddev = to_dfl_dev(dev);
> > +	struct fpga_dfl_driver *fddrv = to_fpga_dfl_drv(dev->driver);
> > +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
> >  
> > -	if (ddrv->remove)
> > -		ddrv->remove(ddev);
> > +	if (fddrv->remove)
> > +		fddrv->remove(fddev);
> >  
> >  	return 0;
> >  }
> >  
> > -static int dfl_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
> > +static int fpga_dfl_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
> >  {
> > -	struct dfl_device *ddev = to_dfl_dev(dev);
> > +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
> >  
> >  	/* The type has 4 valid bits and feature_id has 12 valid bits */
> > -	return add_uevent_var(env, "MODALIAS=dfl:t%01Xf%03X",
> > -			      ddev->type, ddev->feature_id);
> > +	return add_uevent_var(env, "MODALIAS=fpga-dfl:t%01Xf%03X",
> > +			      fddev->type, fddev->feature_id);
> >  }
> >  
> >  static ssize_t
> >  type_show(struct device *dev, struct device_attribute *attr, char *buf)
> >  {
> > -	struct dfl_device *ddev = to_dfl_dev(dev);
> > +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
> >  
> > -	return sprintf(buf, "0x%x\n", ddev->type);
> > +	return sprintf(buf, "0x%x\n", fddev->type);
> >  }
> >  static DEVICE_ATTR_RO(type);
> >  
> >  static ssize_t
> >  feature_id_show(struct device *dev, struct device_attribute *attr, char *buf)
> >  {
> > -	struct dfl_device *ddev = to_dfl_dev(dev);
> > +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
> >  
> > -	return sprintf(buf, "0x%x\n", ddev->feature_id);
> > +	return sprintf(buf, "0x%x\n", fddev->feature_id);
> >  }
> >  static DEVICE_ATTR_RO(feature_id);
> >  
> > -static struct attribute *dfl_dev_attrs[] = {
> > +static struct attribute *fpga_dfl_dev_attrs[] = {
> >  	&dev_attr_type.attr,
> >  	&dev_attr_feature_id.attr,
> >  	NULL,
> >  };
> > -ATTRIBUTE_GROUPS(dfl_dev);
> > -
> > -static struct bus_type dfl_bus_type = {
> > -	.name		= "dfl",
> > -	.match		= dfl_bus_match,
> > -	.probe		= dfl_bus_probe,
> > -	.remove		= dfl_bus_remove,
> > -	.uevent		= dfl_bus_uevent,
> > -	.dev_groups	= dfl_dev_groups,
> > +ATTRIBUTE_GROUPS(fpga_dfl_dev);
> > +
> > +static struct bus_type fpga_dfl_bus_type = {
> > +	.name		= "fpga-dfl",
> > +	.match		= fpga_dfl_bus_match,
> > +	.probe		= fpga_dfl_bus_probe,
> > +	.remove		= fpga_dfl_bus_remove,
> > +	.uevent		= fpga_dfl_bus_uevent,
> > +	.dev_groups	= fpga_dfl_dev_groups,
> >  };
> >  
> > -static void release_dfl_dev(struct device *dev)
> > +static void release_fpga_dfl_dev(struct device *dev)
> >  {
> > -	struct dfl_device *ddev = to_dfl_dev(dev);
> > +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
> >  
> > -	if (ddev->mmio_res.parent)
> > -		release_resource(&ddev->mmio_res);
> > +	if (fddev->mmio_res.parent)
> > +		release_resource(&fddev->mmio_res);
> >  
> > -	ida_simple_remove(&dfl_device_ida, ddev->id);
> > -	kfree(ddev->irqs);
> > -	kfree(ddev);
> > +	ida_simple_remove(&fpga_dfl_device_ida, fddev->id);
> > +	kfree(fddev->irqs);
> > +	kfree(fddev);
> >  }
> >  
> > -static struct dfl_device *
> > -dfl_dev_add(struct dfl_feature_platform_data *pdata,
> > -	    struct dfl_feature *feature)
> > +static struct fpga_dfl_device *
> > +fpga_dfl_dev_add(struct dfl_feature_platform_data *pdata,
> > +		 struct dfl_feature *feature)
> >  {
> >  	struct platform_device *pdev = pdata->dev;
> >  	struct resource *parent_res;
> > -	struct dfl_device *ddev;
> > +	struct fpga_dfl_device *fddev;
> >  	int id, i, ret;
> >  
> > -	ddev = kzalloc(sizeof(*ddev), GFP_KERNEL);
> > -	if (!ddev)
> > +	fddev = kzalloc(sizeof(*fddev), GFP_KERNEL);
> > +	if (!fddev)
> >  		return ERR_PTR(-ENOMEM);
> >  
> > -	id = ida_simple_get(&dfl_device_ida, 0, 0, GFP_KERNEL);
> > +	id = ida_simple_get(&fpga_dfl_device_ida, 0, 0, GFP_KERNEL);
> >  	if (id < 0) {
> >  		dev_err(&pdev->dev, "unable to get id\n");
> > -		kfree(ddev);
> > +		kfree(fddev);
> >  		return ERR_PTR(id);
> >  	}
> >  
> >  	/* freeing resources by put_device() after device_initialize() */
> > -	device_initialize(&ddev->dev);
> > -	ddev->dev.parent = &pdev->dev;
> > -	ddev->dev.bus = &dfl_bus_type;
> > -	ddev->dev.release = release_dfl_dev;
> > -	ddev->id = id;
> > -	ret = dev_set_name(&ddev->dev, "dfl_dev.%d", id);
> > +	device_initialize(&fddev->dev);
> > +	fddev->dev.parent = &pdev->dev;
> > +	fddev->dev.bus = &fpga_dfl_bus_type;
> > +	fddev->dev.release = release_fpga_dfl_dev;
> > +	fddev->id = id;
> > +	ret = dev_set_name(&fddev->dev, "fpga_dfl_dev.%d", id);
> >  	if (ret)
> >  		goto put_dev;
> >  
> > -	ddev->type = feature_dev_id_type(pdev);
> > -	ddev->feature_id = feature->id;
> > -	ddev->cdev = pdata->dfl_cdev;
> > +	fddev->type = feature_dev_id_type(pdev);
> > +	fddev->feature_id = feature->id;
> > +	fddev->cdev = pdata->dfl_cdev;
> >  
> >  	/* add mmio resource */
> >  	parent_res = &pdev->resource[feature->resource_index];
> > -	ddev->mmio_res.flags = IORESOURCE_MEM;
> > -	ddev->mmio_res.start = parent_res->start;
> > -	ddev->mmio_res.end = parent_res->end;
> > -	ddev->mmio_res.name = dev_name(&ddev->dev);
> > -	ret = insert_resource(parent_res, &ddev->mmio_res);
> > +	fddev->mmio_res.flags = IORESOURCE_MEM;
> > +	fddev->mmio_res.start = parent_res->start;
> > +	fddev->mmio_res.end = parent_res->end;
> > +	fddev->mmio_res.name = dev_name(&fddev->dev);
> > +	ret = insert_resource(parent_res, &fddev->mmio_res);
> >  	if (ret) {
> >  		dev_err(&pdev->dev, "%s failed to claim resource: %pR\n",
> > -			dev_name(&ddev->dev), &ddev->mmio_res);
> > +			dev_name(&fddev->dev), &fddev->mmio_res);
> >  		goto put_dev;
> >  	}
> >  
> >  	/* then add irq resource */
> >  	if (feature->nr_irqs) {
> > -		ddev->irqs = kcalloc(feature->nr_irqs,
> > -				     sizeof(*ddev->irqs), GFP_KERNEL);
> > -		if (!ddev->irqs) {
> > +		fddev->irqs = kcalloc(feature->nr_irqs,
> > +				      sizeof(*fddev->irqs), GFP_KERNEL);
> > +		if (!fddev->irqs) {
> >  			ret = -ENOMEM;
> >  			goto put_dev;
> >  		}
> >  
> >  		for (i = 0; i < feature->nr_irqs; i++)
> > -			ddev->irqs[i] = feature->irq_ctx[i].irq;
> > +			fddev->irqs[i] = feature->irq_ctx[i].irq;
> >  
> > -		ddev->num_irqs = feature->nr_irqs;
> > +		fddev->num_irqs = feature->nr_irqs;
> >  	}
> >  
> > -	ret = device_add(&ddev->dev);
> > +	ret = device_add(&fddev->dev);
> >  	if (ret)
> >  		goto put_dev;
> >  
> > -	dev_dbg(&pdev->dev, "add dfl_dev: %s\n", dev_name(&ddev->dev));
> > -	return ddev;
> > +	dev_dbg(&pdev->dev, "add fpga_dfl_dev: %s\n", dev_name(&fddev->dev));
> > +	return fddev;
> >  
> >  put_dev:
> > -	/* calls release_dfl_dev() which does the clean up  */
> > -	put_device(&ddev->dev);
> > +	/* calls release_fpga_dfl_dev() which does the clean up  */
> > +	put_device(&fddev->dev);
> >  	return ERR_PTR(ret);
> >  }
> >  
> > -static void dfl_devs_remove(struct dfl_feature_platform_data *pdata)
> > +static void fpga_dfl_devs_remove(struct dfl_feature_platform_data *pdata)
> >  {
> >  	struct dfl_feature *feature;
> >  
> >  	dfl_fpga_dev_for_each_feature(pdata, feature) {
> > -		if (feature->ddev) {
> > -			device_unregister(&feature->ddev->dev);
> > -			feature->ddev = NULL;
> > +		if (feature->fddev) {
> > +			device_unregister(&feature->fddev->dev);
> > +			feature->fddev = NULL;
> >  		}
> >  	}
> >  }
> >  
> > -static int dfl_devs_add(struct dfl_feature_platform_data *pdata)
> > +static int fpga_dfl_devs_add(struct dfl_feature_platform_data *pdata)
> >  {
> > +	struct fpga_dfl_device *fddev;
> >  	struct dfl_feature *feature;
> > -	struct dfl_device *ddev;
> >  	int ret;
> >  
> >  	dfl_fpga_dev_for_each_feature(pdata, feature) {
> >  		if (feature->ioaddr)
> >  			continue;
> >  
> > -		if (feature->ddev) {
> > +		if (feature->fddev) {
> >  			ret = -EEXIST;
> >  			goto err;
> >  		}
> >  
> > -		ddev = dfl_dev_add(pdata, feature);
> > -		if (IS_ERR(ddev)) {
> > -			ret = PTR_ERR(ddev);
> > +		fddev = fpga_dfl_dev_add(pdata, feature);
> > +		if (IS_ERR(fddev)) {
> > +			ret = PTR_ERR(fddev);
> >  			goto err;
> >  		}
> >  
> > -		feature->ddev = ddev;
> > +		feature->fddev = fddev;
> >  	}
> >  
> >  	return 0;
> >  
> >  err:
> > -	dfl_devs_remove(pdata);
> > +	fpga_dfl_devs_remove(pdata);
> >  	return ret;
> >  }
> >  
> > -int __dfl_driver_register(struct dfl_driver *dfl_drv, struct module *owner)
> > +int __fpga_dfl_driver_register(struct fpga_dfl_driver *fddrv,
> > +			       struct module *owner)
> >  {
> > -	if (!dfl_drv || !dfl_drv->probe || !dfl_drv->id_table)
> > +	if (!fddrv || !fddrv->probe || !fddrv->id_table)
> >  		return -EINVAL;
> >  
> > -	dfl_drv->drv.owner = owner;
> > -	dfl_drv->drv.bus = &dfl_bus_type;
> > +	fddrv->drv.owner = owner;
> > +	fddrv->drv.bus = &fpga_dfl_bus_type;
> >  
> > -	return driver_register(&dfl_drv->drv);
> > +	return driver_register(&fddrv->drv);
> >  }
> > -EXPORT_SYMBOL(__dfl_driver_register);
> > +EXPORT_SYMBOL(__fpga_dfl_driver_register);
> >  
> > -void dfl_driver_unregister(struct dfl_driver *dfl_drv)
> > +void fpga_dfl_driver_unregister(struct fpga_dfl_driver *fddrv)
> >  {
> > -	driver_unregister(&dfl_drv->drv);
> > +	driver_unregister(&fddrv->drv);
> >  }
> > -EXPORT_SYMBOL(dfl_driver_unregister);
> > +EXPORT_SYMBOL(fpga_dfl_driver_unregister);
> >  
> >  #define is_header_feature(feature) ((feature)->id == FEATURE_ID_FIU_HEADER)
> >  
> > @@ -496,7 +498,7 @@ void dfl_fpga_dev_feature_uinit(struct platform_device *pdev)
> >  	struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
> >  	struct dfl_feature *feature;
> >  
> > -	dfl_devs_remove(pdata);
> > +	fpga_dfl_devs_remove(pdata);
> >  
> >  	dfl_fpga_dev_for_each_feature(pdata, feature) {
> >  		if (feature->ops) {
> > @@ -585,7 +587,7 @@ int dfl_fpga_dev_feature_init(struct platform_device *pdev,
> >  		drv++;
> >  	}
> >  
> > -	ret = dfl_devs_add(pdata);
> > +	ret = fpga_dfl_devs_add(pdata);
> >  	if (ret)
> >  		goto exit;
> >  
> > @@ -745,11 +747,11 @@ static int build_info_commit_dev(struct build_feature_devs_info *binfo)
> >  	struct platform_device *fdev = binfo->feature_dev;
> >  	struct dfl_feature_platform_data *pdata;
> >  	struct dfl_feature_info *finfo, *p;
> > -	enum dfl_id_type type;
> > +	enum fpga_dfl_id_type type;
> >  	int ret, index = 0, res_idx = 0;
> >  
> >  	type = feature_dev_id_type(fdev);
> > -	if (WARN_ON_ONCE(type >= DFL_ID_MAX))
> > +	if (WARN_ON_ONCE(type >= FPGA_DFL_ID_MAX))
> >  		return -EINVAL;
> >  
> >  	/*
> > @@ -836,7 +838,7 @@ static int build_info_commit_dev(struct build_feature_devs_info *binfo)
> >  
> >  	ret = platform_device_add(binfo->feature_dev);
> >  	if (!ret) {
> > -		if (type == PORT_ID)
> > +		if (type == FPGA_DFL_PORT_ID)
> >  			dfl_fpga_cdev_add_port_dev(binfo->cdev,
> >  						   binfo->feature_dev);
> >  		else
> > @@ -857,11 +859,11 @@ static int build_info_commit_dev(struct build_feature_devs_info *binfo)
> >  
> >  static int
> >  build_info_create_dev(struct build_feature_devs_info *binfo,
> > -		      enum dfl_id_type type)
> > +		      enum fpga_dfl_id_type type)
> >  {
> >  	struct platform_device *fdev;
> >  
> > -	if (type >= DFL_ID_MAX)
> > +	if (type >= FPGA_DFL_ID_MAX)
> >  		return -EINVAL;
> >  
> >  	/*
> > @@ -1072,7 +1074,7 @@ static int parse_feature_afu(struct build_feature_devs_info *binfo,
> >  	}
> >  
> >  	switch (feature_dev_id_type(binfo->feature_dev)) {
> > -	case PORT_ID:
> > +	case FPGA_DFL_PORT_ID:
> >  		return parse_feature_port_afu(binfo, ofst);
> >  	default:
> >  		dev_info(binfo->dev, "AFU belonging to FIU %s is not supported yet.\n",
> > @@ -1360,7 +1362,7 @@ EXPORT_SYMBOL_GPL(dfl_fpga_enum_info_add_irq);
> >  static int remove_feature_dev(struct device *dev, void *data)
> >  {
> >  	struct platform_device *pdev = to_platform_device(dev);
> > -	enum dfl_id_type type = feature_dev_id_type(pdev);
> > +	enum fpga_dfl_id_type type = feature_dev_id_type(pdev);
> >  	int id = pdev->id;
> >  
> >  	platform_device_unregister(pdev);
> > @@ -1526,7 +1528,7 @@ static int __init dfl_fpga_init(void)
> >  {
> >  	int ret;
> >  
> > -	ret = bus_register(&dfl_bus_type);
> > +	ret = bus_register(&fpga_dfl_bus_type);
> >  	if (ret)
> >  		return ret;
> >  
> > @@ -1535,7 +1537,7 @@ static int __init dfl_fpga_init(void)
> >  	ret = dfl_chardev_init();
> >  	if (ret) {
> >  		dfl_ids_destroy();
> > -		bus_unregister(&dfl_bus_type);
> > +		bus_unregister(&fpga_dfl_bus_type);
> >  	}
> >  
> >  	return ret;
> > @@ -1874,7 +1876,7 @@ static void __exit dfl_fpga_exit(void)
> >  {
> >  	dfl_chardev_uinit();
> >  	dfl_ids_destroy();
> > -	bus_unregister(&dfl_bus_type);
> > +	bus_unregister(&fpga_dfl_bus_type);
> >  }
> >  
> >  module_init(dfl_fpga_init);
> > diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h
> > index 5dc758f..ba930a7 100644
> > --- a/drivers/fpga/dfl.h
> > +++ b/drivers/fpga/dfl.h
> > @@ -236,7 +236,7 @@ struct dfl_feature_irq_ctx {
> >   * @irq_ctx: interrupt context list.
> >   * @nr_irqs: number of interrupt contexts.
> >   * @ops: ops of this sub feature.
> > - * @ddev: ptr to the dfl device of this sub feature.
> > + * @fddev: ptr to the fpga dfl device of this sub feature.
> >   * @priv: priv data of this feature.
> >   */
> >  struct dfl_feature {
> > @@ -247,7 +247,7 @@ struct dfl_feature {
> >  	struct dfl_feature_irq_ctx *irq_ctx;
> >  	unsigned int nr_irqs;
> >  	const struct dfl_feature_ops *ops;
> > -	struct dfl_device *ddev;
> > +	struct fpga_dfl_device *fddev;
> >  	void *priv;
> >  };
> >  
> > @@ -517,40 +517,42 @@ long dfl_feature_ioctl_set_irq(struct platform_device *pdev,
> >  			       unsigned long arg);
> >  
> >  /**
> > - * enum dfl_id_type - define the DFL FIU types
> > + * enum fpga_dfl_id_type - define the FPGA DFL FIU types
> >   */
> > -enum dfl_id_type {
> > -	FME_ID,
> > -	PORT_ID,
> > -	DFL_ID_MAX,
> > +enum fpga_dfl_id_type {
> > +	FPGA_DFL_FME_ID,
> > +	FPGA_DFL_PORT_ID,
> > +	FPGA_DFL_ID_MAX,
> >  };
> >  
> >  /**
> > - * struct dfl_device_id -  dfl device identifier
> > - * @type: contains 4 bits DFL FIU type of the device. See enum dfl_id_type.
> > - * @feature_id: contains 12 bits feature identifier local to its DFL FIU type.
> > + * struct fpga_dfl_device_id - fpga dfl device identifier
> > + * @type: contains 4 bits FPGA DFL FIU type of the device, see
> > + *	  enum fpga_dfl_id_type.
> > + * @feature_id: contains 12 bits feature identifier local to its FPGA DFL FIU
> > + *		type.
> >   * @driver_data: driver specific data.
> >   */
> > -struct dfl_device_id {
> > +struct fpga_dfl_device_id {
> >  	u8 type;
> >  	u16 feature_id;
> >  	unsigned long driver_data;
> >  };
> >  
> >  /**
> > - * struct dfl_device - represent an dfl device on dfl bus
> > + * struct fpga_dfl_device - represent an fpga dfl device on fpga dfl bus
> >   *
> >   * @dev: generic device interface.
> > - * @id: id of the dfl device.
> > - * @type: type of DFL FIU of the device. See enum dfl_id_type.
> > - * @feature_id: 16 bits feature identifier local to its DFL FIU type.
> > - * @mmio_res: mmio resource of this dfl device.
> > - * @irqs: list of Linux IRQ numbers of this dfl device.
> > - * @num_irqs: number of IRQs supported by this dfl device.
> > - * @cdev: pointer to DFL FPGA container device this dfl device belongs to.
> > - * @id_entry: matched id entry in dfl driver's id table.
> > + * @id: id of the fpga dfl device.
> > + * @type: FPGA DFL FIU type of the device, see enum fpga_dfl_id_type.
> > + * @feature_id: 16 bits feature identifier local to its FPGA DFL FIU type.
> > + * @mmio_res: mmio resource of this fpga dfl device.
> > + * @irqs: list of Linux IRQ numbers of this fpga dfl device.
> > + * @num_irqs: number of IRQs supported by this fpga dfl device.
> > + * @cdev: pointer to DFL FPGA container device this fpga dfl device belongs to.
> > + * @id_entry: matched id entry in fpga dfl driver's id table.
> >   */
> > -struct dfl_device {
> > +struct fpga_dfl_device {
> >  	struct device dev;
> >  	int id;
> >  	u8 type;
> > @@ -559,11 +561,11 @@ struct dfl_device {
> >  	int *irqs;
> >  	unsigned int num_irqs;
> >  	struct dfl_fpga_cdev *cdev;
> > -	const struct dfl_device_id *id_entry;
> > +	const struct fpga_dfl_device_id *id_entry;
> >  };
> >  
> >  /**
> > - * struct dfl_driver - represent an dfl device driver
> > + * struct fpga_dfl_driver - represent a fpga dfl device driver
> >   *
> >   * @drv: driver model structure.
> >   * @id_table: pointer to table of device IDs the driver is interested in.
> > @@ -571,33 +573,34 @@ struct dfl_device {
> >   * @probe: mandatory callback for device binding.
> >   * @remove: callback for device unbinding.
> >   */
> > -struct dfl_driver {
> > +struct fpga_dfl_driver {
> >  	struct device_driver drv;
> > -	const struct dfl_device_id *id_table;
> > +	const struct fpga_dfl_device_id *id_table;
> >  
> > -	int (*probe)(struct dfl_device *dfl_dev);
> > -	void (*remove)(struct dfl_device *dfl_dev);
> > +	int (*probe)(struct fpga_dfl_device *fddev);
> > +	void (*remove)(struct fpga_dfl_device *fddev);
> >  };
> >  
> > -#define to_dfl_dev(d) container_of(d, struct dfl_device, dev)
> > -#define to_dfl_drv(d) container_of(d, struct dfl_driver, drv)
> > +#define to_fpga_dfl_dev(d) container_of(d, struct fpga_dfl_device, dev)
> > +#define to_fpga_dfl_drv(d) container_of(d, struct fpga_dfl_driver, drv)
> >  
> >  /*
> >   * use a macro to avoid include chaining to get THIS_MODULE.
> >   */
> > -#define dfl_driver_register(drv) \
> > -	__dfl_driver_register(drv, THIS_MODULE)
> > -int __dfl_driver_register(struct dfl_driver *dfl_drv, struct module *owner);
> > -void dfl_driver_unregister(struct dfl_driver *dfl_drv);
> > +#define fpga_dfl_driver_register(drv) \
> > +	__fpga_dfl_driver_register(drv, THIS_MODULE)
> > +int __fpga_dfl_driver_register(struct fpga_dfl_driver *fddrv,
> > +			       struct module *owner);
> > +void fpga_dfl_driver_unregister(struct fpga_dfl_driver *fddrv);
> >  
> >  /*
> > - * module_dfl_driver() - Helper macro for drivers that don't do
> > + * module_fpga_dfl_driver() - Helper macro for drivers that don't do
> >   * anything special in module init/exit.  This eliminates a lot of
> >   * boilerplate.  Each module may only use this macro once, and
> >   * calling it replaces module_init() and module_exit().
> >   */
> > -#define module_dfl_driver(__dfl_driver) \
> > -	module_driver(__dfl_driver, dfl_driver_register, \
> > -		      dfl_driver_unregister)
> > +#define module_fpga_dfl_driver(__fpga_dfl_driver) \
> > +	module_driver(__fpga_dfl_driver, fpga_dfl_driver_register, \
> > +		      fpga_dfl_driver_unregister)
> >  
> >  #endif /* __FPGA_DFL_H */
> 
- Moritz

Re: [PATCH v3 1/5] fpga: dfl: rename the bus type "dfl" to "fpga-dfl"

[Xu Yilun]

On Thu, Sep 24, 2020 at 12:01:55PM -0700, Tom Rix wrote:
> 
> On 9/24/20 9:59 AM, Xu Yilun wrote:
> > Now the DFL device drivers could be made as independent modules and put
> > in different subsystems according to their functionalities. So the name
> > should be descriptive and unique in the whole kernel.
> >
> > The patch changes the naming of dfl bus related structures, functions,
> > APIs and documentations.
> 
> This set is largely a mechanical change, it looks ok.
> 
> 
> The big thing i would recommend giving some thought is
> 
> include/uabi/linux/fpga-dfl.h uses the prefix DFL_FPGA
> 
> this change uses fpga_dfl.
> 
> I do not think it matters where 'fpga' is in the internal names,
> 
> so for consistency with the external interface the prefix should dfl_fpga.

I think fpga_dfl should be a more descriptive name from the perspective
of other subsystem. Usually the biger namespace comes first. Actually I
see we are so far consistent on stuff for the whole kernel namespace,
Kconfig, head file names, they all have prefix FPGA_DFL or fpga_dfl

Thanks,
Yilun

> 
> >
> > Signed-off-by: Xu Yilun <yilun.xu@intel.com>
> > ---
> >  Documentation/ABI/testing/sysfs-bus-dfl      |  15 --
> >  Documentation/ABI/testing/sysfs-bus-fpga-dfl |  15 ++
> >  MAINTAINERS                                  |   2 +-
> >  drivers/fpga/dfl.c                           | 254 ++++++++++++++-------------
> >  drivers/fpga/dfl.h                           |  77 ++++----
> >  5 files changed, 184 insertions(+), 179 deletions(-)
> >  delete mode 100644 Documentation/ABI/testing/sysfs-bus-dfl
> >  create mode 100644 Documentation/ABI/testing/sysfs-bus-fpga-dfl
> >
> > diff --git a/Documentation/ABI/testing/sysfs-bus-dfl b/Documentation/ABI/testing/sysfs-bus-dfl
> > deleted file mode 100644
> > index 23543be..0000000
> > --- a/Documentation/ABI/testing/sysfs-bus-dfl
> > +++ /dev/null
> > @@ -1,15 +0,0 @@
> > -What:		/sys/bus/dfl/devices/dfl_dev.X/type
> > -Date:		Aug 2020
> > -KernelVersion:	5.10
> > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > -Description:	Read-only. It returns type of DFL FIU of the device. Now DFL
> > -		supports 2 FIU types, 0 for FME, 1 for PORT.
> > -		Format: 0x%x
> > -
> > -What:		/sys/bus/dfl/devices/dfl_dev.X/feature_id
> > -Date:		Aug 2020
> > -KernelVersion:	5.10
> > -Contact:	Xu Yilun <yilun.xu@intel.com>
> > -Description:	Read-only. It returns feature identifier local to its DFL FIU
> > -		type.
> > -		Format: 0x%x
> > diff --git a/Documentation/ABI/testing/sysfs-bus-fpga-dfl b/Documentation/ABI/testing/sysfs-bus-fpga-dfl
> > new file mode 100644
> > index 0000000..072decf
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/sysfs-bus-fpga-dfl
> > @@ -0,0 +1,15 @@
> > +What:		/sys/bus/fpga-dfl/devices/fpga_dfl_dev.X/type
> > +Date:		Aug 2020
> > +KernelVersion:	5.10
> > +Contact:	Xu Yilun <yilun.xu@intel.com>
> > +Description:	Read-only. It returns type of FPGA DFL FIU of the device. Now
> > +		FPGA DFL supports 2 FIU types, 0 for FME, 1 for PORT.
> > +		Format: 0x%x
> > +
> > +What:		/sys/bus/fpga-dfl/devices/fpga_dfl_dev.X/feature_id
> 
> fpga-dfl and fpga_dfl, the prefix needs to be consistent or..
> 
> sys/bus/fpga-dfl/ already has the fpga, dfl info and the second one is redundant so could be
> 
> /sys/bus/fpga-dfl/devices/dev.X/feature_id
> 
> 
> re: mfd's comment.
> 
> This is a new, unreleased interface, now is the only we can change it, so lets do it now.
> 
> I'd even suggest splitting the patch to get the change into 5.10.
> 
> Tom
> 
> > +Date:		Aug 2020
> > +KernelVersion:	5.10
> > +Contact:	Xu Yilun <yilun.xu@intel.com>
> > +Description:	Read-only. It returns feature identifier local to its FPGA DFL
> > +		FIU type.
> > +		Format: 0x%x
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 0924930..48c0859 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -6839,7 +6839,7 @@ M:	Wu Hao <hao.wu@intel.com>
> >  R:	Tom Rix <trix@redhat.com>
> >  L:	linux-fpga@vger.kernel.org
> >  S:	Maintained
> > -F:	Documentation/ABI/testing/sysfs-bus-dfl
> > +F:	Documentation/ABI/testing/sysfs-bus-fpga-dfl
> >  F:	Documentation/fpga/dfl.rst
> >  F:	drivers/fpga/dfl*
> >  F:	include/uapi/linux/fpga-dfl.h
> > diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
> > index b450870..f146cda 100644
> > --- a/drivers/fpga/dfl.c
> > +++ b/drivers/fpga/dfl.c
> > @@ -20,10 +20,10 @@ static DEFINE_MUTEX(dfl_id_mutex);
> >  
> >  /*
> >   * when adding a new feature dev support in DFL framework, it's required to
> > - * add a new item in enum dfl_id_type and provide related information in below
> > - * dfl_devs table which is indexed by dfl_id_type, e.g. name string used for
> > - * platform device creation (define name strings in dfl.h, as they could be
> > - * reused by platform device drivers).
> > + * add a new item in enum fpga_dfl_id_type and provide related information in
> > + * below dfl_devs table which is indexed by fpga_dfl_id_type, e.g. name string
> > + * used for platform device creation (define name strings in dfl.h, as they
> > + * could be reused by platform device drivers).
> >   *
> >   * if the new feature dev needs chardev support, then it's required to add
> >   * a new item in dfl_chardevs table and configure dfl_devs[i].devt_type as
> > @@ -36,9 +36,9 @@ enum dfl_fpga_devt_type {
> >  	DFL_FPGA_DEVT_MAX,
> >  };
> >  
> > -static struct lock_class_key dfl_pdata_keys[DFL_ID_MAX];
> > +static struct lock_class_key dfl_pdata_keys[FPGA_DFL_ID_MAX];
> >  
> > -static const char *dfl_pdata_key_strings[DFL_ID_MAX] = {
> > +static const char *dfl_pdata_key_strings[FPGA_DFL_ID_MAX] = {
> >  	"dfl-fme-pdata",
> >  	"dfl-port-pdata",
> >  };
> > @@ -57,7 +57,7 @@ struct dfl_dev_info {
> >  	enum dfl_fpga_devt_type devt_type;
> >  };
> >  
> > -/* it is indexed by dfl_id_type */
> > +/* it is indexed by fpga_dfl_id_type */
> >  static struct dfl_dev_info dfl_devs[] = {
> >  	{.name = DFL_FPGA_FEATURE_DEV_FME, .dfh_id = DFH_ID_FIU_FME,
> >  	 .devt_type = DFL_FPGA_DEVT_FME},
> > @@ -97,11 +97,11 @@ static void dfl_ids_destroy(void)
> >  		idr_destroy(&dfl_devs[i].id);
> >  }
> >  
> > -static int dfl_id_alloc(enum dfl_id_type type, struct device *dev)
> > +static int dfl_id_alloc(enum fpga_dfl_id_type type, struct device *dev)
> >  {
> >  	int id;
> >  
> > -	WARN_ON(type >= DFL_ID_MAX);
> > +	WARN_ON(type >= FPGA_DFL_ID_MAX);
> >  	mutex_lock(&dfl_id_mutex);
> >  	id = idr_alloc(&dfl_devs[type].id, dev, 0, 0, GFP_KERNEL);
> >  	mutex_unlock(&dfl_id_mutex);
> > @@ -109,15 +109,15 @@ static int dfl_id_alloc(enum dfl_id_type type, struct device *dev)
> >  	return id;
> >  }
> >  
> > -static void dfl_id_free(enum dfl_id_type type, int id)
> > +static void dfl_id_free(enum fpga_dfl_id_type type, int id)
> >  {
> > -	WARN_ON(type >= DFL_ID_MAX);
> > +	WARN_ON(type >= FPGA_DFL_ID_MAX);
> >  	mutex_lock(&dfl_id_mutex);
> >  	idr_remove(&dfl_devs[type].id, id);
> >  	mutex_unlock(&dfl_id_mutex);
> >  }
> >  
> > -static enum dfl_id_type feature_dev_id_type(struct platform_device *pdev)
> > +static enum fpga_dfl_id_type feature_dev_id_type(struct platform_device *pdev)
> >  {
> >  	int i;
> >  
> > @@ -125,10 +125,10 @@ static enum dfl_id_type feature_dev_id_type(struct platform_device *pdev)
> >  		if (!strcmp(dfl_devs[i].name, pdev->name))
> >  			return i;
> >  
> > -	return DFL_ID_MAX;
> > +	return FPGA_DFL_ID_MAX;
> >  }
> >  
> > -static enum dfl_id_type dfh_id_to_type(u16 id)
> > +static enum fpga_dfl_id_type dfh_id_to_type(u16 id)
> >  {
> >  	int i;
> >  
> > @@ -136,7 +136,7 @@ static enum dfl_id_type dfh_id_to_type(u16 id)
> >  		if (dfl_devs[i].dfh_id == id)
> >  			return i;
> >  
> > -	return DFL_ID_MAX;
> > +	return FPGA_DFL_ID_MAX;
> >  }
> >  
> >  /*
> > @@ -244,28 +244,29 @@ int dfl_fpga_check_port_id(struct platform_device *pdev, void *pport_id)
> >  }
> >  EXPORT_SYMBOL_GPL(dfl_fpga_check_port_id);
> >  
> > -static DEFINE_IDA(dfl_device_ida);
> > +static DEFINE_IDA(fpga_dfl_device_ida);
> >  
> > -static const struct dfl_device_id *
> > -dfl_match_one_device(const struct dfl_device_id *id, struct dfl_device *ddev)
> > +static const struct fpga_dfl_device_id *
> > +dfl_match_one_device(const struct fpga_dfl_device_id *id,
> > +		     struct fpga_dfl_device *fddev)
> >  {
> > -	if (id->type == ddev->type && id->feature_id == ddev->feature_id)
> > +	if (id->type == fddev->type && id->feature_id == fddev->feature_id)
> >  		return id;
> >  
> >  	return NULL;
> >  }
> >  
> > -static int dfl_bus_match(struct device *dev, struct device_driver *drv)
> > +static int fpga_dfl_bus_match(struct device *dev, struct device_driver *drv)
> >  {
> > -	struct dfl_device *ddev = to_dfl_dev(dev);
> > -	struct dfl_driver *ddrv = to_dfl_drv(drv);
> > -	const struct dfl_device_id *id_entry;
> > +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
> > +	struct fpga_dfl_driver *fddrv = to_fpga_dfl_drv(drv);
> > +	const struct fpga_dfl_device_id *id_entry;
> >  
> > -	id_entry = ddrv->id_table;
> > +	id_entry = fddrv->id_table;
> >  	if (id_entry) {
> >  		while (id_entry->feature_id) {
> > -			if (dfl_match_one_device(id_entry, ddev)) {
> > -				ddev->id_entry = id_entry;
> > +			if (dfl_match_one_device(id_entry, fddev)) {
> > +				fddev->id_entry = id_entry;
> >  				return 1;
> >  			}
> >  			id_entry++;
> > @@ -275,215 +276,216 @@ static int dfl_bus_match(struct device *dev, struct device_driver *drv)
> >  	return 0;
> >  }
> >  
> > -static int dfl_bus_probe(struct device *dev)
> > +static int fpga_dfl_bus_probe(struct device *dev)
> >  {
> > -	struct dfl_driver *ddrv = to_dfl_drv(dev->driver);
> > -	struct dfl_device *ddev = to_dfl_dev(dev);
> > +	struct fpga_dfl_driver *fddrv = to_fpga_dfl_drv(dev->driver);
> > +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
> >  
> > -	return ddrv->probe(ddev);
> > +	return fddrv->probe(fddev);
> >  }
> >  
> > -static int dfl_bus_remove(struct device *dev)
> > +static int fpga_dfl_bus_remove(struct device *dev)
> >  {
> > -	struct dfl_driver *ddrv = to_dfl_drv(dev->driver);
> > -	struct dfl_device *ddev = to_dfl_dev(dev);
> > +	struct fpga_dfl_driver *fddrv = to_fpga_dfl_drv(dev->driver);
> > +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
> >  
> > -	if (ddrv->remove)
> > -		ddrv->remove(ddev);
> > +	if (fddrv->remove)
> > +		fddrv->remove(fddev);
> >  
> >  	return 0;
> >  }
> >  
> > -static int dfl_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
> > +static int fpga_dfl_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
> >  {
> > -	struct dfl_device *ddev = to_dfl_dev(dev);
> > +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
> >  
> >  	/* The type has 4 valid bits and feature_id has 12 valid bits */
> > -	return add_uevent_var(env, "MODALIAS=dfl:t%01Xf%03X",
> > -			      ddev->type, ddev->feature_id);
> > +	return add_uevent_var(env, "MODALIAS=fpga-dfl:t%01Xf%03X",
> > +			      fddev->type, fddev->feature_id);
> >  }
> >  
> >  static ssize_t
> >  type_show(struct device *dev, struct device_attribute *attr, char *buf)
> >  {
> > -	struct dfl_device *ddev = to_dfl_dev(dev);
> > +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
> >  
> > -	return sprintf(buf, "0x%x\n", ddev->type);
> > +	return sprintf(buf, "0x%x\n", fddev->type);
> >  }
> >  static DEVICE_ATTR_RO(type);
> >  
> >  static ssize_t
> >  feature_id_show(struct device *dev, struct device_attribute *attr, char *buf)
> >  {
> > -	struct dfl_device *ddev = to_dfl_dev(dev);
> > +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
> >  
> > -	return sprintf(buf, "0x%x\n", ddev->feature_id);
> > +	return sprintf(buf, "0x%x\n", fddev->feature_id);
> >  }
> >  static DEVICE_ATTR_RO(feature_id);
> >  
> > -static struct attribute *dfl_dev_attrs[] = {
> > +static struct attribute *fpga_dfl_dev_attrs[] = {
> >  	&dev_attr_type.attr,
> >  	&dev_attr_feature_id.attr,
> >  	NULL,
> >  };
> > -ATTRIBUTE_GROUPS(dfl_dev);
> > -
> > -static struct bus_type dfl_bus_type = {
> > -	.name		= "dfl",
> > -	.match		= dfl_bus_match,
> > -	.probe		= dfl_bus_probe,
> > -	.remove		= dfl_bus_remove,
> > -	.uevent		= dfl_bus_uevent,
> > -	.dev_groups	= dfl_dev_groups,
> > +ATTRIBUTE_GROUPS(fpga_dfl_dev);
> > +
> > +static struct bus_type fpga_dfl_bus_type = {
> > +	.name		= "fpga-dfl",
> > +	.match		= fpga_dfl_bus_match,
> > +	.probe		= fpga_dfl_bus_probe,
> > +	.remove		= fpga_dfl_bus_remove,
> > +	.uevent		= fpga_dfl_bus_uevent,
> > +	.dev_groups	= fpga_dfl_dev_groups,
> >  };
> >  
> > -static void release_dfl_dev(struct device *dev)
> > +static void release_fpga_dfl_dev(struct device *dev)
> >  {
> > -	struct dfl_device *ddev = to_dfl_dev(dev);
> > +	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
> >  
> > -	if (ddev->mmio_res.parent)
> > -		release_resource(&ddev->mmio_res);
> > +	if (fddev->mmio_res.parent)
> > +		release_resource(&fddev->mmio_res);
> >  
> > -	ida_simple_remove(&dfl_device_ida, ddev->id);
> > -	kfree(ddev->irqs);
> > -	kfree(ddev);
> > +	ida_simple_remove(&fpga_dfl_device_ida, fddev->id);
> > +	kfree(fddev->irqs);
> > +	kfree(fddev);
> >  }
> >  
> > -static struct dfl_device *
> > -dfl_dev_add(struct dfl_feature_platform_data *pdata,
> > -	    struct dfl_feature *feature)
> > +static struct fpga_dfl_device *
> > +fpga_dfl_dev_add(struct dfl_feature_platform_data *pdata,
> > +		 struct dfl_feature *feature)
> >  {
> >  	struct platform_device *pdev = pdata->dev;
> >  	struct resource *parent_res;
> > -	struct dfl_device *ddev;
> > +	struct fpga_dfl_device *fddev;
> >  	int id, i, ret;
> >  
> > -	ddev = kzalloc(sizeof(*ddev), GFP_KERNEL);
> > -	if (!ddev)
> > +	fddev = kzalloc(sizeof(*fddev), GFP_KERNEL);
> > +	if (!fddev)
> >  		return ERR_PTR(-ENOMEM);
> >  
> > -	id = ida_simple_get(&dfl_device_ida, 0, 0, GFP_KERNEL);
> > +	id = ida_simple_get(&fpga_dfl_device_ida, 0, 0, GFP_KERNEL);
> >  	if (id < 0) {
> >  		dev_err(&pdev->dev, "unable to get id\n");
> > -		kfree(ddev);
> > +		kfree(fddev);
> >  		return ERR_PTR(id);
> >  	}
> >  
> >  	/* freeing resources by put_device() after device_initialize() */
> > -	device_initialize(&ddev->dev);
> > -	ddev->dev.parent = &pdev->dev;
> > -	ddev->dev.bus = &dfl_bus_type;
> > -	ddev->dev.release = release_dfl_dev;
> > -	ddev->id = id;
> > -	ret = dev_set_name(&ddev->dev, "dfl_dev.%d", id);
> > +	device_initialize(&fddev->dev);
> > +	fddev->dev.parent = &pdev->dev;
> > +	fddev->dev.bus = &fpga_dfl_bus_type;
> > +	fddev->dev.release = release_fpga_dfl_dev;
> > +	fddev->id = id;
> > +	ret = dev_set_name(&fddev->dev, "fpga_dfl_dev.%d", id);
> >  	if (ret)
> >  		goto put_dev;
> >  
> > -	ddev->type = feature_dev_id_type(pdev);
> > -	ddev->feature_id = feature->id;
> > -	ddev->cdev = pdata->dfl_cdev;
> > +	fddev->type = feature_dev_id_type(pdev);
> > +	fddev->feature_id = feature->id;
> > +	fddev->cdev = pdata->dfl_cdev;
> >  
> >  	/* add mmio resource */
> >  	parent_res = &pdev->resource[feature->resource_index];
> > -	ddev->mmio_res.flags = IORESOURCE_MEM;
> > -	ddev->mmio_res.start = parent_res->start;
> > -	ddev->mmio_res.end = parent_res->end;
> > -	ddev->mmio_res.name = dev_name(&ddev->dev);
> > -	ret = insert_resource(parent_res, &ddev->mmio_res);
> > +	fddev->mmio_res.flags = IORESOURCE_MEM;
> > +	fddev->mmio_res.start = parent_res->start;
> > +	fddev->mmio_res.end = parent_res->end;
> > +	fddev->mmio_res.name = dev_name(&fddev->dev);
> > +	ret = insert_resource(parent_res, &fddev->mmio_res);
> >  	if (ret) {
> >  		dev_err(&pdev->dev, "%s failed to claim resource: %pR\n",
> > -			dev_name(&ddev->dev), &ddev->mmio_res);
> > +			dev_name(&fddev->dev), &fddev->mmio_res);
> >  		goto put_dev;
> >  	}
> >  
> >  	/* then add irq resource */
> >  	if (feature->nr_irqs) {
> > -		ddev->irqs = kcalloc(feature->nr_irqs,
> > -				     sizeof(*ddev->irqs), GFP_KERNEL);
> > -		if (!ddev->irqs) {
> > +		fddev->irqs = kcalloc(feature->nr_irqs,
> > +				      sizeof(*fddev->irqs), GFP_KERNEL);
> > +		if (!fddev->irqs) {
> >  			ret = -ENOMEM;
> >  			goto put_dev;
> >  		}
> >  
> >  		for (i = 0; i < feature->nr_irqs; i++)
> > -			ddev->irqs[i] = feature->irq_ctx[i].irq;
> > +			fddev->irqs[i] = feature->irq_ctx[i].irq;
> >  
> > -		ddev->num_irqs = feature->nr_irqs;
> > +		fddev->num_irqs = feature->nr_irqs;
> >  	}
> >  
> > -	ret = device_add(&ddev->dev);
> > +	ret = device_add(&fddev->dev);
> >  	if (ret)
> >  		goto put_dev;
> >  
> > -	dev_dbg(&pdev->dev, "add dfl_dev: %s\n", dev_name(&ddev->dev));
> > -	return ddev;
> > +	dev_dbg(&pdev->dev, "add fpga_dfl_dev: %s\n", dev_name(&fddev->dev));
> > +	return fddev;
> >  
> >  put_dev:
> > -	/* calls release_dfl_dev() which does the clean up  */
> > -	put_device(&ddev->dev);
> > +	/* calls release_fpga_dfl_dev() which does the clean up  */
> > +	put_device(&fddev->dev);
> >  	return ERR_PTR(ret);
> >  }
> >  
> > -static void dfl_devs_remove(struct dfl_feature_platform_data *pdata)
> > +static void fpga_dfl_devs_remove(struct dfl_feature_platform_data *pdata)
> >  {
> >  	struct dfl_feature *feature;
> >  
> >  	dfl_fpga_dev_for_each_feature(pdata, feature) {
> > -		if (feature->ddev) {
> > -			device_unregister(&feature->ddev->dev);
> > -			feature->ddev = NULL;
> > +		if (feature->fddev) {
> > +			device_unregister(&feature->fddev->dev);
> > +			feature->fddev = NULL;
> >  		}
> >  	}
> >  }
> >  
> > -static int dfl_devs_add(struct dfl_feature_platform_data *pdata)
> > +static int fpga_dfl_devs_add(struct dfl_feature_platform_data *pdata)
> >  {
> > +	struct fpga_dfl_device *fddev;
> >  	struct dfl_feature *feature;
> > -	struct dfl_device *ddev;
> >  	int ret;
> >  
> >  	dfl_fpga_dev_for_each_feature(pdata, feature) {
> >  		if (feature->ioaddr)
> >  			continue;
> >  
> > -		if (feature->ddev) {
> > +		if (feature->fddev) {
> >  			ret = -EEXIST;
> >  			goto err;
> >  		}
> >  
> > -		ddev = dfl_dev_add(pdata, feature);
> > -		if (IS_ERR(ddev)) {
> > -			ret = PTR_ERR(ddev);
> > +		fddev = fpga_dfl_dev_add(pdata, feature);
> > +		if (IS_ERR(fddev)) {
> > +			ret = PTR_ERR(fddev);
> >  			goto err;
> >  		}
> >  
> > -		feature->ddev = ddev;
> > +		feature->fddev = fddev;
> >  	}
> >  
> >  	return 0;
> >  
> >  err:
> > -	dfl_devs_remove(pdata);
> > +	fpga_dfl_devs_remove(pdata);
> >  	return ret;
> >  }
> >  
> > -int __dfl_driver_register(struct dfl_driver *dfl_drv, struct module *owner)
> > +int __fpga_dfl_driver_register(struct fpga_dfl_driver *fddrv,
> > +			       struct module *owner)
> >  {
> > -	if (!dfl_drv || !dfl_drv->probe || !dfl_drv->id_table)
> > +	if (!fddrv || !fddrv->probe || !fddrv->id_table)
> >  		return -EINVAL;
> >  
> > -	dfl_drv->drv.owner = owner;
> > -	dfl_drv->drv.bus = &dfl_bus_type;
> > +	fddrv->drv.owner = owner;
> > +	fddrv->drv.bus = &fpga_dfl_bus_type;
> >  
> > -	return driver_register(&dfl_drv->drv);
> > +	return driver_register(&fddrv->drv);
> >  }
> > -EXPORT_SYMBOL(__dfl_driver_register);
> > +EXPORT_SYMBOL(__fpga_dfl_driver_register);
> >  
> > -void dfl_driver_unregister(struct dfl_driver *dfl_drv)
> > +void fpga_dfl_driver_unregister(struct fpga_dfl_driver *fddrv)
> >  {
> > -	driver_unregister(&dfl_drv->drv);
> > +	driver_unregister(&fddrv->drv);
> >  }
> > -EXPORT_SYMBOL(dfl_driver_unregister);
> > +EXPORT_SYMBOL(fpga_dfl_driver_unregister);
> >  
> >  #define is_header_feature(feature) ((feature)->id == FEATURE_ID_FIU_HEADER)
> >  
> > @@ -496,7 +498,7 @@ void dfl_fpga_dev_feature_uinit(struct platform_device *pdev)
> >  	struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
> >  	struct dfl_feature *feature;
> >  
> > -	dfl_devs_remove(pdata);
> > +	fpga_dfl_devs_remove(pdata);
> >  
> >  	dfl_fpga_dev_for_each_feature(pdata, feature) {
> >  		if (feature->ops) {
> > @@ -585,7 +587,7 @@ int dfl_fpga_dev_feature_init(struct platform_device *pdev,
> >  		drv++;
> >  	}
> >  
> > -	ret = dfl_devs_add(pdata);
> > +	ret = fpga_dfl_devs_add(pdata);
> >  	if (ret)
> >  		goto exit;
> >  
> > @@ -745,11 +747,11 @@ static int build_info_commit_dev(struct build_feature_devs_info *binfo)
> >  	struct platform_device *fdev = binfo->feature_dev;
> >  	struct dfl_feature_platform_data *pdata;
> >  	struct dfl_feature_info *finfo, *p;
> > -	enum dfl_id_type type;
> > +	enum fpga_dfl_id_type type;
> >  	int ret, index = 0, res_idx = 0;
> >  
> >  	type = feature_dev_id_type(fdev);
> > -	if (WARN_ON_ONCE(type >= DFL_ID_MAX))
> > +	if (WARN_ON_ONCE(type >= FPGA_DFL_ID_MAX))
> >  		return -EINVAL;
> >  
> >  	/*
> > @@ -836,7 +838,7 @@ static int build_info_commit_dev(struct build_feature_devs_info *binfo)
> >  
> >  	ret = platform_device_add(binfo->feature_dev);
> >  	if (!ret) {
> > -		if (type == PORT_ID)
> > +		if (type == FPGA_DFL_PORT_ID)
> >  			dfl_fpga_cdev_add_port_dev(binfo->cdev,
> >  						   binfo->feature_dev);
> >  		else
> > @@ -857,11 +859,11 @@ static int build_info_commit_dev(struct build_feature_devs_info *binfo)
> >  
> >  static int
> >  build_info_create_dev(struct build_feature_devs_info *binfo,
> > -		      enum dfl_id_type type)
> > +		      enum fpga_dfl_id_type type)
> >  {
> >  	struct platform_device *fdev;
> >  
> > -	if (type >= DFL_ID_MAX)
> > +	if (type >= FPGA_DFL_ID_MAX)
> >  		return -EINVAL;
> >  
> >  	/*
> > @@ -1072,7 +1074,7 @@ static int parse_feature_afu(struct build_feature_devs_info *binfo,
> >  	}
> >  
> >  	switch (feature_dev_id_type(binfo->feature_dev)) {
> > -	case PORT_ID:
> > +	case FPGA_DFL_PORT_ID:
> >  		return parse_feature_port_afu(binfo, ofst);
> >  	default:
> >  		dev_info(binfo->dev, "AFU belonging to FIU %s is not supported yet.\n",
> > @@ -1360,7 +1362,7 @@ EXPORT_SYMBOL_GPL(dfl_fpga_enum_info_add_irq);
> >  static int remove_feature_dev(struct device *dev, void *data)
> >  {
> >  	struct platform_device *pdev = to_platform_device(dev);
> > -	enum dfl_id_type type = feature_dev_id_type(pdev);
> > +	enum fpga_dfl_id_type type = feature_dev_id_type(pdev);
> >  	int id = pdev->id;
> >  
> >  	platform_device_unregister(pdev);
> > @@ -1526,7 +1528,7 @@ static int __init dfl_fpga_init(void)
> >  {
> >  	int ret;
> >  
> > -	ret = bus_register(&dfl_bus_type);
> > +	ret = bus_register(&fpga_dfl_bus_type);
> >  	if (ret)
> >  		return ret;
> >  
> > @@ -1535,7 +1537,7 @@ static int __init dfl_fpga_init(void)
> >  	ret = dfl_chardev_init();
> >  	if (ret) {
> >  		dfl_ids_destroy();
> > -		bus_unregister(&dfl_bus_type);
> > +		bus_unregister(&fpga_dfl_bus_type);
> >  	}
> >  
> >  	return ret;
> > @@ -1874,7 +1876,7 @@ static void __exit dfl_fpga_exit(void)
> >  {
> >  	dfl_chardev_uinit();
> >  	dfl_ids_destroy();
> > -	bus_unregister(&dfl_bus_type);
> > +	bus_unregister(&fpga_dfl_bus_type);
> >  }
> >  
> >  module_init(dfl_fpga_init);
> > diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h
> > index 5dc758f..ba930a7 100644
> > --- a/drivers/fpga/dfl.h
> > +++ b/drivers/fpga/dfl.h
> > @@ -236,7 +236,7 @@ struct dfl_feature_irq_ctx {
> >   * @irq_ctx: interrupt context list.
> >   * @nr_irqs: number of interrupt contexts.
> >   * @ops: ops of this sub feature.
> > - * @ddev: ptr to the dfl device of this sub feature.
> > + * @fddev: ptr to the fpga dfl device of this sub feature.
> >   * @priv: priv data of this feature.
> >   */
> >  struct dfl_feature {
> > @@ -247,7 +247,7 @@ struct dfl_feature {
> >  	struct dfl_feature_irq_ctx *irq_ctx;
> >  	unsigned int nr_irqs;
> >  	const struct dfl_feature_ops *ops;
> > -	struct dfl_device *ddev;
> > +	struct fpga_dfl_device *fddev;
> >  	void *priv;
> >  };
> >  
> > @@ -517,40 +517,42 @@ long dfl_feature_ioctl_set_irq(struct platform_device *pdev,
> >  			       unsigned long arg);
> >  
> >  /**
> > - * enum dfl_id_type - define the DFL FIU types
> > + * enum fpga_dfl_id_type - define the FPGA DFL FIU types
> >   */
> > -enum dfl_id_type {
> > -	FME_ID,
> > -	PORT_ID,
> > -	DFL_ID_MAX,
> > +enum fpga_dfl_id_type {
> > +	FPGA_DFL_FME_ID,
> > +	FPGA_DFL_PORT_ID,
> > +	FPGA_DFL_ID_MAX,
> >  };
> >  
> >  /**
> > - * struct dfl_device_id -  dfl device identifier
> > - * @type: contains 4 bits DFL FIU type of the device. See enum dfl_id_type.
> > - * @feature_id: contains 12 bits feature identifier local to its DFL FIU type.
> > + * struct fpga_dfl_device_id - fpga dfl device identifier
> > + * @type: contains 4 bits FPGA DFL FIU type of the device, see
> > + *	  enum fpga_dfl_id_type.
> > + * @feature_id: contains 12 bits feature identifier local to its FPGA DFL FIU
> > + *		type.
> >   * @driver_data: driver specific data.
> >   */
> > -struct dfl_device_id {
> > +struct fpga_dfl_device_id {
> >  	u8 type;
> >  	u16 feature_id;
> >  	unsigned long driver_data;
> >  };
> >  
> >  /**
> > - * struct dfl_device - represent an dfl device on dfl bus
> > + * struct fpga_dfl_device - represent an fpga dfl device on fpga dfl bus
> >   *
> >   * @dev: generic device interface.
> > - * @id: id of the dfl device.
> > - * @type: type of DFL FIU of the device. See enum dfl_id_type.
> > - * @feature_id: 16 bits feature identifier local to its DFL FIU type.
> > - * @mmio_res: mmio resource of this dfl device.
> > - * @irqs: list of Linux IRQ numbers of this dfl device.
> > - * @num_irqs: number of IRQs supported by this dfl device.
> > - * @cdev: pointer to DFL FPGA container device this dfl device belongs to.
> > - * @id_entry: matched id entry in dfl driver's id table.
> > + * @id: id of the fpga dfl device.
> > + * @type: FPGA DFL FIU type of the device, see enum fpga_dfl_id_type.
> > + * @feature_id: 16 bits feature identifier local to its FPGA DFL FIU type.
> > + * @mmio_res: mmio resource of this fpga dfl device.
> > + * @irqs: list of Linux IRQ numbers of this fpga dfl device.
> > + * @num_irqs: number of IRQs supported by this fpga dfl device.
> > + * @cdev: pointer to DFL FPGA container device this fpga dfl device belongs to.
> > + * @id_entry: matched id entry in fpga dfl driver's id table.
> >   */
> > -struct dfl_device {
> > +struct fpga_dfl_device {
> >  	struct device dev;
> >  	int id;
> >  	u8 type;
> > @@ -559,11 +561,11 @@ struct dfl_device {
> >  	int *irqs;
> >  	unsigned int num_irqs;
> >  	struct dfl_fpga_cdev *cdev;
> > -	const struct dfl_device_id *id_entry;
> > +	const struct fpga_dfl_device_id *id_entry;
> >  };
> >  
> >  /**
> > - * struct dfl_driver - represent an dfl device driver
> > + * struct fpga_dfl_driver - represent a fpga dfl device driver
> >   *
> >   * @drv: driver model structure.
> >   * @id_table: pointer to table of device IDs the driver is interested in.
> > @@ -571,33 +573,34 @@ struct dfl_device {
> >   * @probe: mandatory callback for device binding.
> >   * @remove: callback for device unbinding.
> >   */
> > -struct dfl_driver {
> > +struct fpga_dfl_driver {
> >  	struct device_driver drv;
> > -	const struct dfl_device_id *id_table;
> > +	const struct fpga_dfl_device_id *id_table;
> >  
> > -	int (*probe)(struct dfl_device *dfl_dev);
> > -	void (*remove)(struct dfl_device *dfl_dev);
> > +	int (*probe)(struct fpga_dfl_device *fddev);
> > +	void (*remove)(struct fpga_dfl_device *fddev);
> >  };
> >  
> > -#define to_dfl_dev(d) container_of(d, struct dfl_device, dev)
> > -#define to_dfl_drv(d) container_of(d, struct dfl_driver, drv)
> > +#define to_fpga_dfl_dev(d) container_of(d, struct fpga_dfl_device, dev)
> > +#define to_fpga_dfl_drv(d) container_of(d, struct fpga_dfl_driver, drv)
> >  
> >  /*
> >   * use a macro to avoid include chaining to get THIS_MODULE.
> >   */
> > -#define dfl_driver_register(drv) \
> > -	__dfl_driver_register(drv, THIS_MODULE)
> > -int __dfl_driver_register(struct dfl_driver *dfl_drv, struct module *owner);
> > -void dfl_driver_unregister(struct dfl_driver *dfl_drv);
> > +#define fpga_dfl_driver_register(drv) \
> > +	__fpga_dfl_driver_register(drv, THIS_MODULE)
> > +int __fpga_dfl_driver_register(struct fpga_dfl_driver *fddrv,
> > +			       struct module *owner);
> > +void fpga_dfl_driver_unregister(struct fpga_dfl_driver *fddrv);
> >  
> >  /*
> > - * module_dfl_driver() - Helper macro for drivers that don't do
> > + * module_fpga_dfl_driver() - Helper macro for drivers that don't do
> >   * anything special in module init/exit.  This eliminates a lot of
> >   * boilerplate.  Each module may only use this macro once, and
> >   * calling it replaces module_init() and module_exit().
> >   */
> > -#define module_dfl_driver(__dfl_driver) \
> > -	module_driver(__dfl_driver, dfl_driver_register, \
> > -		      dfl_driver_unregister)
> > +#define module_fpga_dfl_driver(__fpga_dfl_driver) \
> > +	module_driver(__fpga_dfl_driver, fpga_dfl_driver_register, \
> > +		      fpga_dfl_driver_unregister)
> >  
> >  #endif /* __FPGA_DFL_H */

[PATCH v3 2/5] fpga: dfl: fix the definitions of type & feature_id for dfl devices

[Xu Yilun]

The value of the field fpga_dfl_device.type comes from the 12 bits
register field DFH_ID according to DFL spec. So this patch changes the
definition of the type field to u16.

Also it is not necessary to illustrate the valid bits of the type field
in comments. Instead we should explicitly define the possible values in
the enumeration type for it, because they are shared by hardware spec.
We should not let the compiler decide these values.

Similar changes are also applied to fpga_dfl_device.feature_id.

This patch also fixed the MODALIAS format according to the changes
above.

Signed-off-by: Xu Yilun <yilun.xu@intel.com>
---
 drivers/fpga/dfl.c |  3 +--
 drivers/fpga/dfl.h | 16 +++++++---------
 2 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
index f146cda..a906fa7 100644
--- a/drivers/fpga/dfl.c
+++ b/drivers/fpga/dfl.c
@@ -299,8 +299,7 @@ static int fpga_dfl_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct fpga_dfl_device *fddev = to_fpga_dfl_dev(dev);
 
-	/* The type has 4 valid bits and feature_id has 12 valid bits */
-	return add_uevent_var(env, "MODALIAS=fpga-dfl:t%01Xf%03X",
+	return add_uevent_var(env, "MODALIAS=fpga-dfl:t%04Xf%04X",
 			      fddev->type, fddev->feature_id);
 }
 
diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h
index ba930a7..78f7c6f 100644
--- a/drivers/fpga/dfl.h
+++ b/drivers/fpga/dfl.h
@@ -520,21 +520,19 @@ long dfl_feature_ioctl_set_irq(struct platform_device *pdev,
  * enum fpga_dfl_id_type - define the FPGA DFL FIU types
  */
 enum fpga_dfl_id_type {
-	FPGA_DFL_FME_ID,
-	FPGA_DFL_PORT_ID,
+	FPGA_DFL_FME_ID = 0,
+	FPGA_DFL_PORT_ID = 1,
 	FPGA_DFL_ID_MAX,
 };
 
 /**
  * struct fpga_dfl_device_id - fpga dfl device identifier
- * @type: contains 4 bits FPGA DFL FIU type of the device, see
- *	  enum fpga_dfl_id_type.
- * @feature_id: contains 12 bits feature identifier local to its FPGA DFL FIU
- *		type.
+ * @type: FPGA DFL FIU type of the device, see enum fpga_dfl_id_type.
+ * @feature_id: feature identifier local to its FPGA DFL FIU type.
  * @driver_data: driver specific data.
  */
 struct fpga_dfl_device_id {
-	u8 type;
+	u16 type;
 	u16 feature_id;
 	unsigned long driver_data;
 };
@@ -545,7 +543,7 @@ struct fpga_dfl_device_id {
  * @dev: generic device interface.
  * @id: id of the fpga dfl device.
  * @type: FPGA DFL FIU type of the device, see enum fpga_dfl_id_type.
- * @feature_id: 16 bits feature identifier local to its FPGA DFL FIU type.
+ * @feature_id: feature identifier local to its FPGA DFL FIU type.
  * @mmio_res: mmio resource of this fpga dfl device.
  * @irqs: list of Linux IRQ numbers of this fpga dfl device.
  * @num_irqs: number of IRQs supported by this fpga dfl device.
@@ -555,7 +553,7 @@ struct fpga_dfl_device_id {
 struct fpga_dfl_device {
 	struct device dev;
 	int id;
-	u8 type;
+	u16 type;
 	u16 feature_id;
 	struct resource mmio_res;
 	int *irqs;
-- 
2.7.4

[PATCH v3 3/5] fpga: dfl: move fpga_dfl_device_id to mod_devicetable.h

[Xu Yilun]

In order to support MODULE_DEVICE_TABLE() for dfl device driver, this
patch moves struct fpga_dfl_device_id to mod_devicetable.h

Signed-off-by: Xu Yilun <yilun.xu@intel.com>
Signed-off-by: Wu Hao <hao.wu@intel.com>
Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
Signed-off-by: Russ Weight <russell.h.weight@intel.com>
Reviewed-by: Tom Rix <trix@redhat.com>
Acked-by: Wu Hao <hao.wu@intel.com>
Signed-off-by: Moritz Fischer <mdf@kernel.org>
---
v2: fix the order for the header file
v3: rebase the patch for dfl bus name change
---
 drivers/fpga/dfl.h              | 13 +------------
 include/linux/mod_devicetable.h | 12 ++++++++++++
 2 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h
index 78f7c6f..4a42d26 100644
--- a/drivers/fpga/dfl.h
+++ b/drivers/fpga/dfl.h
@@ -22,6 +22,7 @@
 #include <linux/interrupt.h>
 #include <linux/iopoll.h>
 #include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/mod_devicetable.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/uuid.h>
@@ -526,18 +527,6 @@ enum fpga_dfl_id_type {
 };
 
 /**
- * struct fpga_dfl_device_id - fpga dfl device identifier
- * @type: FPGA DFL FIU type of the device, see enum fpga_dfl_id_type.
- * @feature_id: feature identifier local to its FPGA DFL FIU type.
- * @driver_data: driver specific data.
- */
-struct fpga_dfl_device_id {
-	u16 type;
-	u16 feature_id;
-	unsigned long driver_data;
-};
-
-/**
  * struct fpga_dfl_device - represent an fpga dfl device on fpga dfl bus
  *
  * @dev: generic device interface.
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 5b08a47..ca24a4b 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -838,4 +838,16 @@ struct mhi_device_id {
 	kernel_ulong_t driver_data;
 };
 
+/**
+ * struct fpga_dfl_device_id - fpga dfl device identifier
+ * @type: FPGA DFL FIU type of the device, see enum fpga_dfl_id_type.
+ * @feature_id: feature identifier local to its FPGA DFL FIU type.
+ * @driver_data: driver specific data.
+ */
+struct fpga_dfl_device_id {
+	__u16 type;
+	__u16 feature_id;
+	unsigned long driver_data;
+};
+
 #endif /* LINUX_MOD_DEVICETABLE_H */
-- 
2.7.4

[PATCH v3 4/5] fpga: dfl: add fpga dfl bus support to MODULE_DEVICE_TABLE()

[Xu Yilun]

Device Feature List (DFL) is a linked list of feature headers within the
device MMIO space. It is used by FPGA to enumerate multiple sub features
within it. Each feature can be uniquely identified by DFL type and
feature id, which can be read out from feature headers.

A fpga dfl bus helps DFL framework modularize DFL device drivers for
different sub features. The fpga dfl bus matches its devices and drivers
by DFL type and feature id.

This patch adds fpga dfl bus support to MODULE_DEVICE_TABLE() by adding
info about struct fpga_dfl_device_id in devicetable-offsets.c and add a
fpga dfl entry point in file2alias.c.

Signed-off-by: Xu Yilun <yilun.xu@intel.com>
Signed-off-by: Wu Hao <hao.wu@intel.com>
Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
Signed-off-by: Russ Weight <russell.h.weight@intel.com>
Acked-by: Wu Hao <hao.wu@intel.com>
Signed-off-by: Moritz Fischer <mdf@kernel.org>
---
v2: add comments for the format of modalias
v3: changes the names from dfl_XXX to fpga_dfl_XXX
    delete the comments of valid bits for modalias format
---
 scripts/mod/devicetable-offsets.c |  4 ++++
 scripts/mod/file2alias.c          | 13 +++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-offsets.c
index 27007c1..25fe19b 100644
--- a/scripts/mod/devicetable-offsets.c
+++ b/scripts/mod/devicetable-offsets.c
@@ -243,5 +243,9 @@ int main(void)
 	DEVID(mhi_device_id);
 	DEVID_FIELD(mhi_device_id, chan);
 
+	DEVID(fpga_dfl_device_id);
+	DEVID_FIELD(fpga_dfl_device_id, type);
+	DEVID_FIELD(fpga_dfl_device_id, feature_id);
+
 	return 0;
 }
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index 2417dd1..4fffdd5 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -1368,6 +1368,18 @@ static int do_mhi_entry(const char *filename, void *symval, char *alias)
 	return 1;
 }
 
+/* Looks like: fpga-dfl:tNfN */
+static int do_fpga_dfl_entry(const char *filename, void *symval, char *alias)
+{
+	DEF_FIELD(symval, fpga_dfl_device_id, type);
+	DEF_FIELD(symval, fpga_dfl_device_id, feature_id);
+
+	sprintf(alias, "fpga-dfl:t%04Xf%04X", type, feature_id);
+
+	add_wildcard(alias);
+	return 1;
+}
+
 /* Does namelen bytes of name exactly match the symbol? */
 static bool sym_is(const char *name, unsigned namelen, const char *symbol)
 {
@@ -1442,6 +1454,7 @@ static const struct devtable devtable[] = {
 	{"tee", SIZE_tee_client_device_id, do_tee_entry},
 	{"wmi", SIZE_wmi_device_id, do_wmi_entry},
 	{"mhi", SIZE_mhi_device_id, do_mhi_entry},
+	{"fpgadfl", SIZE_fpga_dfl_device_id, do_fpga_dfl_entry},
 };
 
 /* Create MODULE_ALIAS() statements.
-- 
2.7.4

[PATCH v3 5/5] fpga: dfl: move fpga dfl bus related APIs to include/linux/fpga/dfl.h

[Xu Yilun]

Now the fpga dfl drivers could be made as independent modules and put
in different folders according to their functionalities. In order for
scattered fpga dfl device drivers to include fpga dfl bus APIs, move the
fpga dfl bus APIs to a new header file in the public folder.

[mdf@kernel.org: Fixed up MAINTAINERS entry merge]
Signed-off-by: Xu Yilun <yilun.xu@intel.com>
Reviewed-by: Tom Rix <trix@redhat.com>
Acked-by: Wu Hao <hao.wu@intel.com>
Signed-off-by: Moritz Fischer <mdf@kernel.org>
---
v2: updated the MAINTAINERS under FPGA DFL DRIVERS
    improve the comments
    rename the dfl-bus.h to dfl.h
v3: rebase the patch for previous changes
---
 MAINTAINERS              |  1 +
 drivers/fpga/dfl.c       |  1 +
 drivers/fpga/dfl.h       | 73 ----------------------------------------
 include/linux/fpga/dfl.h | 87 ++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 89 insertions(+), 73 deletions(-)
 create mode 100644 include/linux/fpga/dfl.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 48c0859..01c3c84 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6842,6 +6842,7 @@ S:	Maintained
 F:	Documentation/ABI/testing/sysfs-bus-fpga-dfl
 F:	Documentation/fpga/dfl.rst
 F:	drivers/fpga/dfl*
+F:	include/linux/fpga/dfl.h
 F:	include/uapi/linux/fpga-dfl.h
 
 FPGA MANAGER FRAMEWORK
diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
index a906fa7..d045344b 100644
--- a/drivers/fpga/dfl.c
+++ b/drivers/fpga/dfl.c
@@ -11,6 +11,7 @@
  *   Xiao Guangrong <guangrong.xiao@linux.intel.com>
  */
 #include <linux/fpga-dfl.h>
+#include <linux/fpga/dfl.h>
 #include <linux/module.h>
 #include <linux/uaccess.h>
 
diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h
index 4a42d26..97a81b6 100644
--- a/drivers/fpga/dfl.h
+++ b/drivers/fpga/dfl.h
@@ -517,77 +517,4 @@ long dfl_feature_ioctl_set_irq(struct platform_device *pdev,
 			       struct dfl_feature *feature,
 			       unsigned long arg);
 
-/**
- * enum fpga_dfl_id_type - define the FPGA DFL FIU types
- */
-enum fpga_dfl_id_type {
-	FPGA_DFL_FME_ID = 0,
-	FPGA_DFL_PORT_ID = 1,
-	FPGA_DFL_ID_MAX,
-};
-
-/**
- * struct fpga_dfl_device - represent an fpga dfl device on fpga dfl bus
- *
- * @dev: generic device interface.
- * @id: id of the fpga dfl device.
- * @type: FPGA DFL FIU type of the device, see enum fpga_dfl_id_type.
- * @feature_id: feature identifier local to its FPGA DFL FIU type.
- * @mmio_res: mmio resource of this fpga dfl device.
- * @irqs: list of Linux IRQ numbers of this fpga dfl device.
- * @num_irqs: number of IRQs supported by this fpga dfl device.
- * @cdev: pointer to DFL FPGA container device this fpga dfl device belongs to.
- * @id_entry: matched id entry in fpga dfl driver's id table.
- */
-struct fpga_dfl_device {
-	struct device dev;
-	int id;
-	u16 type;
-	u16 feature_id;
-	struct resource mmio_res;
-	int *irqs;
-	unsigned int num_irqs;
-	struct dfl_fpga_cdev *cdev;
-	const struct fpga_dfl_device_id *id_entry;
-};
-
-/**
- * struct fpga_dfl_driver - represent a fpga dfl device driver
- *
- * @drv: driver model structure.
- * @id_table: pointer to table of device IDs the driver is interested in.
- *	      { } member terminated.
- * @probe: mandatory callback for device binding.
- * @remove: callback for device unbinding.
- */
-struct fpga_dfl_driver {
-	struct device_driver drv;
-	const struct fpga_dfl_device_id *id_table;
-
-	int (*probe)(struct fpga_dfl_device *fddev);
-	void (*remove)(struct fpga_dfl_device *fddev);
-};
-
-#define to_fpga_dfl_dev(d) container_of(d, struct fpga_dfl_device, dev)
-#define to_fpga_dfl_drv(d) container_of(d, struct fpga_dfl_driver, drv)
-
-/*
- * use a macro to avoid include chaining to get THIS_MODULE.
- */
-#define fpga_dfl_driver_register(drv) \
-	__fpga_dfl_driver_register(drv, THIS_MODULE)
-int __fpga_dfl_driver_register(struct fpga_dfl_driver *fddrv,
-			       struct module *owner);
-void fpga_dfl_driver_unregister(struct fpga_dfl_driver *fddrv);
-
-/*
- * module_fpga_dfl_driver() - Helper macro for drivers that don't do
- * anything special in module init/exit.  This eliminates a lot of
- * boilerplate.  Each module may only use this macro once, and
- * calling it replaces module_init() and module_exit().
- */
-#define module_fpga_dfl_driver(__fpga_dfl_driver) \
-	module_driver(__fpga_dfl_driver, fpga_dfl_driver_register, \
-		      fpga_dfl_driver_unregister)
-
 #endif /* __FPGA_DFL_H */
diff --git a/include/linux/fpga/dfl.h b/include/linux/fpga/dfl.h
new file mode 100644
index 0000000..0715d0a
--- /dev/null
+++ b/include/linux/fpga/dfl.h
@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Header file for FPGA DFL driver and device API
+ *
+ * Copyright (C) 2020 Intel Corporation, Inc.
+ */
+
+#ifndef __LINUX_FPGA_DFL_H
+#define __LINUX_FPGA_DFL_H
+
+#include <linux/device.h>
+#include <linux/mod_devicetable.h>
+
+/**
+ * enum fpga_dfl_id_type - define the FPGA DFL FIU types
+ */
+enum fpga_dfl_id_type {
+	FPGA_DFL_FME_ID = 0,
+	FPGA_DFL_PORT_ID = 1,
+	FPGA_DFL_ID_MAX,
+};
+
+/**
+ * struct fpga_dfl_device - represent an fpga dfl device on fpga dfl bus
+ *
+ * @dev: generic device interface.
+ * @id: id of the fpga dfl device.
+ * @type: FPGA DFL FIU type of the device, see enum fpga_dfl_id_type.
+ * @feature_id: feature identifier local to its FPGA DFL FIU type.
+ * @mmio_res: mmio resource of this fpga dfl device.
+ * @irqs: list of Linux IRQ numbers of this fpga dfl device.
+ * @num_irqs: number of IRQs supported by this fpga dfl device.
+ * @cdev: pointer to DFL FPGA container device this fpga dfl device belongs to.
+ * @id_entry: matched id entry in fpga dfl driver's id table.
+ */
+struct fpga_dfl_device {
+	struct device dev;
+	int id;
+	u16 type;
+	u16 feature_id;
+	struct resource mmio_res;
+	int *irqs;
+	unsigned int num_irqs;
+	struct dfl_fpga_cdev *cdev;
+	const struct fpga_dfl_device_id *id_entry;
+};
+
+/**
+ * struct fpga_dfl_driver - represent a fpga dfl device driver
+ *
+ * @drv: driver model structure.
+ * @id_table: pointer to table of device IDs the driver is interested in.
+ *	      { } member terminated.
+ * @probe: mandatory callback for device binding.
+ * @remove: callback for device unbinding.
+ */
+struct fpga_dfl_driver {
+	struct device_driver drv;
+	const struct fpga_dfl_device_id *id_table;
+
+	int (*probe)(struct fpga_dfl_device *fddev);
+	void (*remove)(struct fpga_dfl_device *fddev);
+};
+
+#define to_fpga_dfl_dev(d) container_of(d, struct fpga_dfl_device, dev)
+#define to_fpga_dfl_drv(d) container_of(d, struct fpga_dfl_driver, drv)
+
+/*
+ * use a macro to avoid include chaining to get THIS_MODULE.
+ */
+#define fpga_dfl_driver_register(drv) \
+	__fpga_dfl_driver_register(drv, THIS_MODULE)
+int __fpga_dfl_driver_register(struct fpga_dfl_driver *fddrv,
+			       struct module *owner);
+void fpga_dfl_driver_unregister(struct fpga_dfl_driver *fddrv);
+
+/*
+ * module_fpga_dfl_driver() - Helper macro for drivers that don't do
+ * anything special in module init/exit.  This eliminates a lot of
+ * boilerplate.  Each module may only use this macro once, and
+ * calling it replaces module_init() and module_exit().
+ */
+#define module_fpga_dfl_driver(__fpga_dfl_driver) \
+	module_driver(__fpga_dfl_driver, fpga_dfl_driver_register, \
+		      fpga_dfl_driver_unregister)
+
+#endif /* __LINUX_FPGA_DFL_H */
-- 
2.7.4