[PATCH v3 0/3] drivers: soc: xilinx: Add support for ZynqMP PM driver

[PATCH v3 0/3] drivers: soc: xilinx: Add support for ZynqMP PM driver

[Jolly Shah]

Add ZynqMP PM driver. PM driver provides power management
support for ZynqMP.

This patch series is based on top of Xilinx firmware patch set:
https://patchwork.kernel.org/cover/10555405/

v3:
 - Updated DT bindings as per v2 review comments
v2:
 - Rebased on top of latest firmware driver patch series
 - Updated driver to use shared interrupt instead of mailbox
 
 
Rajan Vaja (3):
  dt-bindings: soc: Add ZynqMP PM bindings
  firmware: xilinx: Implement ZynqMP power management APIs
  drivers: soc: xilinx: Add ZynqMP PM driver

 .../bindings/power/reset/xlnx,zynqmp-power.txt     |  22 ++
 drivers/firmware/xilinx/zynqmp.c                   |  29 +++
 drivers/soc/xilinx/Kconfig                         |  11 +
 drivers/soc/xilinx/Makefile                        |   1 +
 drivers/soc/xilinx/zynqmp_power.c                  | 230 +++++++++++++++++++++
 include/linux/firmware/xlnx-zynqmp.h               |  20 ++
 6 files changed, 313 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/power/reset/xlnx,zynqmp-power.txt
 create mode 100644 drivers/soc/xilinx/zynqmp_power.c

-- 
2.7.4

[PATCH v3 1/3] dt-bindings: soc: Add ZynqMP PM bindings

[Jolly Shah]

From: Rajan Vaja <rajan.vaja@xilinx.com>

Add documentation to describe Xilinx ZynqMP power management
bindings.

Signed-off-by: Rajan Vaja <rajan.vaja@xilinx.com>
Signed-off-by: Jolly Shah <jollys@xilinx.com>
---
 .../bindings/power/reset/xlnx,zynqmp-power.txt     | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/power/reset/xlnx,zynqmp-power.txt

diff --git a/Documentation/devicetree/bindings/power/reset/xlnx,zynqmp-power.txt b/Documentation/devicetree/bindings/power/reset/xlnx,zynqmp-power.txt
new file mode 100644
index 0000000..925d17d
--- /dev/null
+++ b/Documentation/devicetree/bindings/power/reset/xlnx,zynqmp-power.txt
@@ -0,0 +1,22 @@
+--------------------------------------------------------------------
+Device Tree Bindings for the Xilinx Zynq MPSoC Power Management
+--------------------------------------------------------------------
+The zynqmp-power node describes the power management configurations.
+It will control remote suspend/shutdown interfaces.
+
+Required properties:
+ - compatible:		Must contain:	"xlnx,zynqmp-power"
+ - interrupts:		Interrupt specifier
+
+-------
+Example
+-------
+
+firmware {
+	zynqmp_firmware: zynqmp-firmware {
+		zynqmp_power: zynqmp-power {
+			compatible = "xlnx,zynqmp-power";
+			interrupts = <0 35 4>;
+		};
+	};
+};
-- 
2.7.4

[PATCH v3 2/3] firmware: xilinx: Implement ZynqMP power management APIs

[Jolly Shah]

From: Rajan Vaja <rajan.vaja@xilinx.com>

Add Xilinx ZynqMP firmware APIs to set suspend mode
and inform firmware that master has initialized its
own power management.

Signed-off-by: Rajan Vaja <rajan.vaja@xilinx.com>
Signed-off-by: Jolly Shah <jollys@xilinx.com>
---
 drivers/firmware/xilinx/zynqmp.c     | 29 +++++++++++++++++++++++++++++
 include/linux/firmware/xlnx-zynqmp.h | 20 ++++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/drivers/firmware/xilinx/zynqmp.c b/drivers/firmware/xilinx/zynqmp.c
index ce6c746..97818e8 100644
--- a/drivers/firmware/xilinx/zynqmp.c
+++ b/drivers/firmware/xilinx/zynqmp.c
@@ -447,6 +447,33 @@ static int zynqmp_pm_clock_getparent(u32 clock_id, u32 *parent_id)
 	return ret;
 }
 
+/**
+ * zynqmp_pm_init_finalize() - PM call to inform firmware that the caller
+ *			       master has initialized its own power management
+ *
+ * This API function is to be used for notify the power management controller
+ * about the completed power management initialization.
+ *
+ * Return: Returns status, either success or error+reason
+ */
+static int zynqmp_pm_init_finalize(void)
+{
+	return zynqmp_pm_invoke_fn(PM_PM_INIT_FINALIZE, 0, 0, 0, 0, NULL);
+}
+
+/**
+ * zynqmp_pm_set_suspend_mode()	- Set system suspend mode
+ * @mode:	Mode to set for system suspend
+ *
+ * This API function is used to set mode of system suspend.
+ *
+ * Return: Returns status, either success or error+reason
+ */
+static int zynqmp_pm_set_suspend_mode(u32 mode)
+{
+	return zynqmp_pm_invoke_fn(PM_SET_SUSPEND_MODE, mode, 0, 0, 0, NULL);
+}
+
 static const struct zynqmp_eemi_ops eemi_ops = {
 	.get_api_version = zynqmp_pm_get_api_version,
 	.ioctl = zynqmp_pm_ioctl,
@@ -460,6 +487,8 @@ static const struct zynqmp_eemi_ops eemi_ops = {
 	.clock_getrate = zynqmp_pm_clock_getrate,
 	.clock_setparent = zynqmp_pm_clock_setparent,
 	.clock_getparent = zynqmp_pm_clock_getparent,
+	.init_finalize = zynqmp_pm_init_finalize,
+	.set_suspend_mode = zynqmp_pm_set_suspend_mode,
 };
 
 /**
diff --git a/include/linux/firmware/xlnx-zynqmp.h b/include/linux/firmware/xlnx-zynqmp.h
index a3ef7d6..fd8f99e 100644
--- a/include/linux/firmware/xlnx-zynqmp.h
+++ b/include/linux/firmware/xlnx-zynqmp.h
@@ -28,12 +28,21 @@
 /* SMC SIP service Call Function Identifier Prefix */
 #define PM_SIP_SVC			0xC2000000
 #define PM_GET_TRUSTZONE_VERSION	0xa03
+#define PM_SET_SUSPEND_MODE		0xa02
+#define GET_CALLBACK_DATA		0xa01
 
 /* Number of 32bits values in payload */
 #define PAYLOAD_ARG_CNT	4U
 
+/* Number of arguments for a callback */
+#define CB_ARG_CNT	4
+
+/* Payload size (consists of callback API ID + arguments) */
+#define CB_PAYLOAD_SIZE (CB_ARG_CNT + 1)
+
 enum pm_api_id {
 	PM_GET_API_VERSION = 1,
+	PM_PM_INIT_FINALIZE = 21,
 	PM_IOCTL = 34,
 	PM_QUERY_DATA,
 	PM_CLOCK_ENABLE,
@@ -75,6 +84,12 @@ enum pm_query_id {
 	PM_QID_CLOCK_GET_NUM_CLOCKS = 12,
 };
 
+enum zynqmp_pm_suspend_reason {
+	ZYNQMP_PM_SUSPEND_REASON_POWER_UNIT_REQUEST = 201,
+	ZYNQMP_PM_SUSPEND_REASON_ALERT,
+	ZYNQMP_PM_SUSPEND_REASON_SYSTEM_SHUTDOWN,
+};
+
 /**
  * struct zynqmp_pm_query_data - PM query data
  * @qid:	query ID
@@ -102,8 +117,13 @@ struct zynqmp_eemi_ops {
 	int (*clock_getrate)(u32 clock_id, u64 *rate);
 	int (*clock_setparent)(u32 clock_id, u32 parent_id);
 	int (*clock_getparent)(u32 clock_id, u32 *parent_id);
+	int (*init_finalize)(void);
+	int (*set_suspend_mode)(u32 mode);
 };
 
+int zynqmp_pm_invoke_fn(u32 pm_api_id, u32 arg0, u32 arg1,
+			u32 arg2, u32 arg3, u32 *ret_payload);
+
 #if IS_REACHABLE(CONFIG_ARCH_ZYNQMP)
 const struct zynqmp_eemi_ops *zynqmp_pm_get_eemi_ops(void);
 #else
-- 
2.7.4

[PATCH v3 3/3] drivers: soc: xilinx: Add ZynqMP PM driver

[Jolly Shah]

From: Rajan Vaja <rajan.vaja@xilinx.com>

Add ZynqMP PM driver. PM driver provides power management
support for ZynqMP.

Signed-off-by: Rajan Vaja <rajan.vaja@xilinx.com>
Signed-off-by: Jolly Shah <jollys@xilinx.com>
---
 drivers/soc/xilinx/Kconfig        |  11 ++
 drivers/soc/xilinx/Makefile       |   1 +
 drivers/soc/xilinx/zynqmp_power.c | 230 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 242 insertions(+)
 create mode 100644 drivers/soc/xilinx/zynqmp_power.c

diff --git a/drivers/soc/xilinx/Kconfig b/drivers/soc/xilinx/Kconfig
index 687c8f3..5025e0e 100644
--- a/drivers/soc/xilinx/Kconfig
+++ b/drivers/soc/xilinx/Kconfig
@@ -17,4 +17,15 @@ config XILINX_VCU
 	  To compile this driver as a module, choose M here: the
 	  module will be called xlnx_vcu.
 
+config ZYNQMP_POWER
+	bool "Enable Xilinx Zynq MPSoC Power Management driver"
+	depends on PM && ARCH_ZYNQMP
+	default y
+	help
+	  Say yes to enable power management support for ZyqnMP SoC.
+	  This driver uses firmware driver as an interface for power
+	  management request to firmware. It registers isr to handle
+	  power management callbacks from firmware.
+	  If in doubt, say N.
+
 endmenu
diff --git a/drivers/soc/xilinx/Makefile b/drivers/soc/xilinx/Makefile
index dee8fd5..428b9db 100644
--- a/drivers/soc/xilinx/Makefile
+++ b/drivers/soc/xilinx/Makefile
@@ -1,2 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_XILINX_VCU)	+= xlnx_vcu.o
+obj-$(CONFIG_ZYNQMP_POWER)	+= zynqmp_power.o
diff --git a/drivers/soc/xilinx/zynqmp_power.c b/drivers/soc/xilinx/zynqmp_power.c
new file mode 100644
index 0000000..9071948
--- /dev/null
+++ b/drivers/soc/xilinx/zynqmp_power.c
@@ -0,0 +1,230 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Xilinx Zynq MPSoC Power Management
+ *
+ *  Copyright (C) 2014-2018 Xilinx, Inc.
+ *
+ *  Davorin Mista <davorin.mista@aggios.com>
+ *  Jolly Shah <jollys@xilinx.com>
+ *  Rajan Vaja <rajan.vaja@xilinx.com>
+ */
+
+#include <linux/mailbox_client.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/suspend.h>
+
+#include <linux/firmware/xlnx-zynqmp.h>
+
+/**
+ * struct zynqmp_pm_work_struct - Wrapper for struct work_struct
+ * @callback_work:	Work structure
+ * @args:		Callback arguments
+ */
+struct zynqmp_pm_work_struct {
+	struct work_struct callback_work;
+	u32 args[CB_ARG_CNT];
+};
+
+static struct zynqmp_pm_work_struct *zynqmp_pm_init_suspend_work;
+
+enum pm_suspend_mode {
+	PM_SUSPEND_MODE_FIRST = 0,
+	PM_SUSPEND_MODE_STD = PM_SUSPEND_MODE_FIRST,
+	PM_SUSPEND_MODE_POWER_OFF,
+};
+
+#define PM_SUSPEND_MODE_FIRST	PM_SUSPEND_MODE_STD
+
+static const char *const suspend_modes[] = {
+	[PM_SUSPEND_MODE_STD] = "standard",
+	[PM_SUSPEND_MODE_POWER_OFF] = "power-off",
+};
+
+static enum pm_suspend_mode suspend_mode = PM_SUSPEND_MODE_STD;
+
+enum pm_api_cb_id {
+	PM_INIT_SUSPEND_CB = 30,
+	PM_ACKNOWLEDGE_CB,
+	PM_NOTIFY_CB,
+};
+
+static void zynqmp_pm_get_callback_data(u32 *buf)
+{
+	zynqmp_pm_invoke_fn(GET_CALLBACK_DATA, 0, 0, 0, 0, buf);
+}
+
+static irqreturn_t zynqmp_pm_isr(int irq, void *data)
+{
+	u32 payload[CB_PAYLOAD_SIZE];
+
+	zynqmp_pm_get_callback_data(payload);
+
+	/* First element is callback API ID, others are callback arguments */
+	if (payload[0] == PM_INIT_SUSPEND_CB) {
+		if (work_pending(&zynqmp_pm_init_suspend_work->callback_work))
+			goto done;
+
+		/* Copy callback arguments into work's structure */
+		memcpy(zynqmp_pm_init_suspend_work->args, &payload[1],
+		       sizeof(zynqmp_pm_init_suspend_work->args));
+
+		queue_work(system_unbound_wq,
+			   &zynqmp_pm_init_suspend_work->callback_work);
+	}
+
+done:
+	return IRQ_HANDLED;
+}
+
+/**
+ * zynqmp_pm_init_suspend_work_fn() - Initialize suspend
+ * @work:	Pointer to work_struct
+ *
+ * Bottom-half of PM callback IRQ handler.
+ */
+static void zynqmp_pm_init_suspend_work_fn(struct work_struct *work)
+{
+	struct zynqmp_pm_work_struct *pm_work =
+		container_of(work, struct zynqmp_pm_work_struct, callback_work);
+
+	if (pm_work->args[0] == ZYNQMP_PM_SUSPEND_REASON_SYSTEM_SHUTDOWN) {
+		orderly_poweroff(true);
+	} else if (pm_work->args[0] ==
+		   ZYNQMP_PM_SUSPEND_REASON_POWER_UNIT_REQUEST) {
+		pm_suspend(PM_SUSPEND_MEM);
+	} else {
+		pr_err("%s Unsupported InitSuspendCb reason code %d.\n",
+		       __func__, pm_work->args[0]);
+	}
+}
+
+static ssize_t suspend_mode_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	char *s = buf;
+	int md;
+
+	for (md = PM_SUSPEND_MODE_FIRST; md < ARRAY_SIZE(suspend_modes); md++)
+		if (suspend_modes[md]) {
+			if (md == suspend_mode)
+				s += sprintf(s, "[%s] ", suspend_modes[md]);
+			else
+				s += sprintf(s, "%s ", suspend_modes[md]);
+		}
+
+	/* Convert last space to newline */
+	if (s != buf)
+		*(s - 1) = '\n';
+	return (s - buf);
+}
+
+static ssize_t suspend_mode_store(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf, size_t count)
+{
+	int md, ret = -EINVAL;
+	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
+
+	if (!eemi_ops || !eemi_ops->set_suspend_mode)
+		return ret;
+
+	for (md = PM_SUSPEND_MODE_FIRST; md < ARRAY_SIZE(suspend_modes); md++)
+		if (suspend_modes[md] &&
+		    sysfs_streq(suspend_modes[md], buf)) {
+			ret = 0;
+			break;
+		}
+
+	if (!ret && md != suspend_mode) {
+		ret = eemi_ops->set_suspend_mode(md);
+		if (likely(!ret))
+			suspend_mode = md;
+	}
+
+	return ret ? ret : count;
+}
+
+static DEVICE_ATTR_RW(suspend_mode);
+
+/**
+ * zynqmp_pm_sysfs_init() - Initialize PM driver sysfs interface
+ * @dev:	Pointer to device structure
+ *
+ * Return: 0 on success, negative error code otherwise
+ */
+static int zynqmp_pm_sysfs_init(struct device *dev)
+{
+	return sysfs_create_file(&dev->kobj, &dev_attr_suspend_mode.attr);
+}
+
+/**
+ * zynqmp_pm_probe() - Probe existence of the PMU Firmware
+ *		       and initialize debugfs interface
+ *
+ * @pdev:	Pointer to the platform_device structure
+ *
+ * Return: Returns 0 on success, negative error code otherwise
+ */
+static int zynqmp_pm_probe(struct platform_device *pdev)
+{
+	int ret, irq;
+	u32 pm_api_version;
+
+	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
+
+	if (!eemi_ops || !eemi_ops->get_api_version || !eemi_ops->init_finalize)
+		return -ENXIO;
+
+	eemi_ops->init_finalize();
+	eemi_ops->get_api_version(&pm_api_version);
+
+	/* Check PM API version number */
+	if (pm_api_version < ZYNQMP_PM_VERSION)
+		return -ENODEV;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq <= 0)
+		return -ENXIO;
+
+	ret = devm_request_irq(&pdev->dev, irq, zynqmp_pm_isr, IRQF_SHARED,
+			       dev_name(&pdev->dev), pdev);
+	if (ret) {
+		dev_err(&pdev->dev, "request_irq '%d' failed with %d\n",
+			irq, ret);
+		return ret;
+	}
+
+	zynqmp_pm_init_suspend_work =
+		devm_kzalloc(&pdev->dev, sizeof(struct zynqmp_pm_work_struct),
+			     GFP_KERNEL);
+	if (!zynqmp_pm_init_suspend_work)
+		return -ENOMEM;
+
+	INIT_WORK(&zynqmp_pm_init_suspend_work->callback_work,
+		  zynqmp_pm_init_suspend_work_fn);
+
+	ret = zynqmp_pm_sysfs_init(&pdev->dev);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to initialize sysfs interface\n");
+		return ret;
+	}
+
+	return ret;
+}
+
+static const struct of_device_id pm_of_match[] = {
+	{ .compatible = "xlnx,zynqmp-power", },
+	{ /* end of table */ },
+};
+MODULE_DEVICE_TABLE(of, pm_of_match);
+
+static struct platform_driver zynqmp_pm_platform_driver = {
+	.probe = zynqmp_pm_probe,
+	.driver = {
+		.name = "zynqmp_power",
+		.of_match_table = pm_of_match,
+	},
+};
+module_platform_driver(zynqmp_pm_platform_driver);
-- 
2.7.4

Re: [PATCH v3 3/3] drivers: soc: xilinx: Add ZynqMP PM driver

[Ahmed S. Darwish]

Hi!

[ Thanks a lot for upstreaming this.. ]

On Tue, Sep 11, 2018 at 02:34:57PM -0700, Jolly Shah wrote:
> From: Rajan Vaja <rajan.vaja@xilinx.com>
>
> Add ZynqMP PM driver. PM driver provides power management
> support for ZynqMP.
>
> Signed-off-by: Rajan Vaja <rajan.vaja@xilinx.com>
> Signed-off-by: Jolly Shah <jollys@xilinx.com>
> ---

[...]

> +static irqreturn_t zynqmp_pm_isr(int irq, void *data)
> +{
> +	u32 payload[CB_PAYLOAD_SIZE];
> +
> +	zynqmp_pm_get_callback_data(payload);
> +
> +	/* First element is callback API ID, others are callback arguments */
> +	if (payload[0] == PM_INIT_SUSPEND_CB) {
> +		if (work_pending(&zynqmp_pm_init_suspend_work->callback_work))
> +			goto done;
> +
> +		/* Copy callback arguments into work's structure */
> +		memcpy(zynqmp_pm_init_suspend_work->args, &payload[1],
> +		       sizeof(zynqmp_pm_init_suspend_work->args));
> +
> +		queue_work(system_unbound_wq,
> +			   &zynqmp_pm_init_suspend_work->callback_work);

We already have devm_request_threaded_irq() which can does this
automatically for us.

Use that method to register the ISR instead, then if there's more
work to do, just do the memcpy and return IRQ_WAKE_THREAD.

> +	}
> +
> +done:
> +	return IRQ_HANDLED;
> +}
> +
> +/**
> + * zynqmp_pm_init_suspend_work_fn() - Initialize suspend
> + * @work:	Pointer to work_struct
> + *
> + * Bottom-half of PM callback IRQ handler.
> + */
> +static void zynqmp_pm_init_suspend_work_fn(struct work_struct *work)
> +{
> +	struct zynqmp_pm_work_struct *pm_work =
> +		container_of(work, struct zynqmp_pm_work_struct, callback_work);
> +
> +	if (pm_work->args[0] == ZYNQMP_PM_SUSPEND_REASON_SYSTEM_SHUTDOWN) {

we_really_seem_to_love_long_40_col_names_for_some_reason

> +		orderly_poweroff(true);
> +	} else if (pm_work->args[0] ==
> +		   ZYNQMP_PM_SUSPEND_REASON_POWER_UNIT_REQUEST) {

Ditto

[...]

> +/**
> + * zynqmp_pm_sysfs_init() - Initialize PM driver sysfs interface
> + * @dev:	Pointer to device structure
> + *
> + * Return: 0 on success, negative error code otherwise
> + */
> +static int zynqmp_pm_sysfs_init(struct device *dev)
> +{
> +	return sysfs_create_file(&dev->kobj, &dev_attr_suspend_mode.attr);
> +}
> +

Sysfs file is created in platform driver's probe(), but is not
removed anywhere in the code.

What happens if this is built as a module? Am I missing something
obvious?

Moreover, what's the wisdom of creating a one-liner function with
a huge six-line comment that:

    a) _purely_ wraps sysfs_create_file(); no extra logic
    b) is called only once
    c) and not passed as a function pointer anywhere

IMO Such one-liner translators obfuscate the code and review
process with no apparent gain..

> +/**
> + * zynqmp_pm_probe() - Probe existence of the PMU Firmware
> + *		       and initialize debugfs interface
> + *
> + * @pdev:	Pointer to the platform_device structure
> + *
> + * Return: Returns 0 on success, negative error code otherwise
> + */

Again, huge 8-line comment that provide no value.

If anyone wants to know what a platform driver probe() does, he
or she better check the primary references at:

    - Documentation/driver-model/platform.txt
    - include/linux/platform_device.h

and not the comment above..

> +static int zynqmp_pm_probe(struct platform_device *pdev)
> +{
> +	int ret, irq;
> +	u32 pm_api_version;
> +
> +	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
> +
> +	if (!eemi_ops || !eemi_ops->get_api_version || !eemi_ops->init_finalize)
> +		return -ENXIO;
> +
> +	eemi_ops->init_finalize();
> +	eemi_ops->get_api_version(&pm_api_version);
> +
> +	/* Check PM API version number */
> +	if (pm_api_version < ZYNQMP_PM_VERSION)
> +		return -ENODEV;
> +
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq <= 0)
> +		return -ENXIO;
> +
> +	ret = devm_request_irq(&pdev->dev, irq, zynqmp_pm_isr, IRQF_SHARED,
> +			       dev_name(&pdev->dev), pdev);
> +	if (ret) {
> +		dev_err(&pdev->dev, "request_irq '%d' failed with %d\n",
> +			irq, ret);
> +		return ret;
> +	}
> +
> +	zynqmp_pm_init_suspend_work =
> +		devm_kzalloc(&pdev->dev, sizeof(struct zynqmp_pm_work_struct),
> +			     GFP_KERNEL);
> +	if (!zynqmp_pm_init_suspend_work)
> +		return -ENOMEM;
> +
> +	INIT_WORK(&zynqmp_pm_init_suspend_work->callback_work,
> +		  zynqmp_pm_init_suspend_work_fn);
> +

Let's use devm_request_threaded_irq(). Then we can completely
remove the work_struct, INIT_WORK(), and queuue_work() bits.

> +	ret = zynqmp_pm_sysfs_init(&pdev->dev);
> +	if (ret) {
> +		dev_err(&pdev->dev, "unable to initialize sysfs interface\n");
> +		return ret;
> +	}
> +
> +	return ret;

Just return 0 please. BTW ret was declared without initialization.

> +}
> +
> +static const struct of_device_id pm_of_match[] = {
> +	{ .compatible = "xlnx,zynqmp-power", },
> +	{ /* end of table */ },
> +};
> +MODULE_DEVICE_TABLE(of, pm_of_match);
> +
> +static struct platform_driver zynqmp_pm_platform_driver = {
> +	.probe = zynqmp_pm_probe,
> +	.driver = {
> +		.name = "zynqmp_power",
> +		.of_match_table = pm_of_match,
> +	},
> +};

.remove with a basic sysfs_remove_file() is needed.

Thanks,

--
Darwi
http://darwish.chasingpointers.com

RE: [PATCH v3 3/3] drivers: soc: xilinx: Add ZynqMP PM driver

[Jolly Shah]

Hi Ahmed,

Thanks for the review. I will take care of suggested changes in next version.

Thanks,
Jolly Shah


> -----Original Message-----
> From: Ahmed S. Darwish [mailto:darwish.07@gmail.com]
> Sent: Tuesday, September 11, 2018 6:10 PM
> To: Jolly Shah <JOLLYS@xilinx.com>
> Cc: matthias.bgg@gmail.com; andy.gross@linaro.org; shawnguo@kernel.org;
> geert+renesas@glider.be; bjorn.andersson@linaro.org;
> sean.wang@mediatek.com; m.szyprowski@samsung.com; Michal Simek
> <michals@xilinx.com>; robh+dt@kernel.org; mark.rutland@arm.com; Rajan
> Vaja <RAJANV@xilinx.com>; devicetree@vger.kernel.org; linux-arm-
> kernel@lists.infradead.org; linux-kernel@vger.kernel.org; Rajan Vaja
> <RAJANV@xilinx.com>; Jolly Shah <JOLLYS@xilinx.com>
> Subject: Re: [PATCH v3 3/3] drivers: soc: xilinx: Add ZynqMP PM driver
> 
> Hi!
> 
> [ Thanks a lot for upstreaming this.. ]
> 
> On Tue, Sep 11, 2018 at 02:34:57PM -0700, Jolly Shah wrote:
> > From: Rajan Vaja <rajan.vaja@xilinx.com>
> >
> > Add ZynqMP PM driver. PM driver provides power management support for
> > ZynqMP.
> >
> > Signed-off-by: Rajan Vaja <rajan.vaja@xilinx.com>
> > Signed-off-by: Jolly Shah <jollys@xilinx.com>
> > ---
> 
> [...]
> 
> > +static irqreturn_t zynqmp_pm_isr(int irq, void *data) {
> > +	u32 payload[CB_PAYLOAD_SIZE];
> > +
> > +	zynqmp_pm_get_callback_data(payload);
> > +
> > +	/* First element is callback API ID, others are callback arguments */
> > +	if (payload[0] == PM_INIT_SUSPEND_CB) {
> > +		if (work_pending(&zynqmp_pm_init_suspend_work-
> >callback_work))
> > +			goto done;
> > +
> > +		/* Copy callback arguments into work's structure */
> > +		memcpy(zynqmp_pm_init_suspend_work->args, &payload[1],
> > +		       sizeof(zynqmp_pm_init_suspend_work->args));
> > +
> > +		queue_work(system_unbound_wq,
> > +			   &zynqmp_pm_init_suspend_work->callback_work);
> 
> We already have devm_request_threaded_irq() which can does this
> automatically for us.
> 
> Use that method to register the ISR instead, then if there's more work to do, just
> do the memcpy and return IRQ_WAKE_THREAD.
> 
> > +	}
> > +
> > +done:
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +/**
> > + * zynqmp_pm_init_suspend_work_fn() - Initialize suspend
> > + * @work:	Pointer to work_struct
> > + *
> > + * Bottom-half of PM callback IRQ handler.
> > + */
> > +static void zynqmp_pm_init_suspend_work_fn(struct work_struct *work)
> > +{
> > +	struct zynqmp_pm_work_struct *pm_work =
> > +		container_of(work, struct zynqmp_pm_work_struct,
> callback_work);
> > +
> > +	if (pm_work->args[0] ==
> ZYNQMP_PM_SUSPEND_REASON_SYSTEM_SHUTDOWN) {
> 
> we_really_seem_to_love_long_40_col_names_for_some_reason
> 
> > +		orderly_poweroff(true);
> > +	} else if (pm_work->args[0] ==
> > +		   ZYNQMP_PM_SUSPEND_REASON_POWER_UNIT_REQUEST) {
> 
> Ditto
> 
> [...]
> 
> > +/**
> > + * zynqmp_pm_sysfs_init() - Initialize PM driver sysfs interface
> > + * @dev:	Pointer to device structure
> > + *
> > + * Return: 0 on success, negative error code otherwise  */ static int
> > +zynqmp_pm_sysfs_init(struct device *dev) {
> > +	return sysfs_create_file(&dev->kobj, &dev_attr_suspend_mode.attr); }
> > +
> 
> Sysfs file is created in platform driver's probe(), but is not removed anywhere in
> the code.
> 
> What happens if this is built as a module? Am I missing something obvious?
> 
> Moreover, what's the wisdom of creating a one-liner function with a huge six-
> line comment that:
> 
>     a) _purely_ wraps sysfs_create_file(); no extra logic
>     b) is called only once
>     c) and not passed as a function pointer anywhere
> 
> IMO Such one-liner translators obfuscate the code and review process with no
> apparent gain..
> 
> > +/**
> > + * zynqmp_pm_probe() - Probe existence of the PMU Firmware
> > + *		       and initialize debugfs interface
> > + *
> > + * @pdev:	Pointer to the platform_device structure
> > + *
> > + * Return: Returns 0 on success, negative error code otherwise  */
> 
> Again, huge 8-line comment that provide no value.
> 
> If anyone wants to know what a platform driver probe() does, he or she better
> check the primary references at:
> 
>     - Documentation/driver-model/platform.txt
>     - include/linux/platform_device.h
> 
> and not the comment above..
> 
> > +static int zynqmp_pm_probe(struct platform_device *pdev) {
> > +	int ret, irq;
> > +	u32 pm_api_version;
> > +
> > +	const struct zynqmp_eemi_ops *eemi_ops =
> zynqmp_pm_get_eemi_ops();
> > +
> > +	if (!eemi_ops || !eemi_ops->get_api_version || !eemi_ops-
> >init_finalize)
> > +		return -ENXIO;
> > +
> > +	eemi_ops->init_finalize();
> > +	eemi_ops->get_api_version(&pm_api_version);
> > +
> > +	/* Check PM API version number */
> > +	if (pm_api_version < ZYNQMP_PM_VERSION)
> > +		return -ENODEV;
> > +
> > +	irq = platform_get_irq(pdev, 0);
> > +	if (irq <= 0)
> > +		return -ENXIO;
> > +
> > +	ret = devm_request_irq(&pdev->dev, irq, zynqmp_pm_isr,
> IRQF_SHARED,
> > +			       dev_name(&pdev->dev), pdev);
> > +	if (ret) {
> > +		dev_err(&pdev->dev, "request_irq '%d' failed with %d\n",
> > +			irq, ret);
> > +		return ret;
> > +	}
> > +
> > +	zynqmp_pm_init_suspend_work =
> > +		devm_kzalloc(&pdev->dev, sizeof(struct
> zynqmp_pm_work_struct),
> > +			     GFP_KERNEL);
> > +	if (!zynqmp_pm_init_suspend_work)
> > +		return -ENOMEM;
> > +
> > +	INIT_WORK(&zynqmp_pm_init_suspend_work->callback_work,
> > +		  zynqmp_pm_init_suspend_work_fn);
> > +
> 
> Let's use devm_request_threaded_irq(). Then we can completely remove the
> work_struct, INIT_WORK(), and queuue_work() bits.
> 
> > +	ret = zynqmp_pm_sysfs_init(&pdev->dev);
> > +	if (ret) {
> > +		dev_err(&pdev->dev, "unable to initialize sysfs interface\n");
> > +		return ret;
> > +	}
> > +
> > +	return ret;
> 
> Just return 0 please. BTW ret was declared without initialization.
> 
> > +}
> > +
> > +static const struct of_device_id pm_of_match[] = {
> > +	{ .compatible = "xlnx,zynqmp-power", },
> > +	{ /* end of table */ },
> > +};
> > +MODULE_DEVICE_TABLE(of, pm_of_match);
> > +
> > +static struct platform_driver zynqmp_pm_platform_driver = {
> > +	.probe = zynqmp_pm_probe,
> > +	.driver = {
> > +		.name = "zynqmp_power",
> > +		.of_match_table = pm_of_match,
> > +	},
> > +};
> 
> .remove with a basic sysfs_remove_file() is needed.
> 
> Thanks,
> 
> --
> Darwi
> http://darwish.chasingpointers.com