* [PATCH v4] i2c: virtio: add a virtio i2c frontend driver
@ 2020-10-12 1:55 Jie Deng
2020-10-12 5:45 ` kernel test robot
` (2 more replies)
0 siblings, 3 replies; 8+ messages in thread
From: Jie Deng @ 2020-10-12 1:55 UTC (permalink / raw)
To: linux-i2c, virtualization, linux-kernel
Cc: mst, jasowang, wsa+renesas, wsa, andriy.shevchenko,
jarkko.nikula, jdelvare, Sergey.Semin, krzk, rppt, jie.deng,
loic.poulain, tali.perry1, bjorn.andersson, shuo.a.liu,
conghui.chen, yu1.wang
Add an I2C bus driver for virtio para-virtualization.
The controller can be emulated by the backend driver in
any device model software by following the virtio protocol.
This driver communicates with the backend driver through a
virtio I2C message structure which includes following parts:
- Header: i2c_msg addr, flags, len.
- Data buffer: the pointer to the I2C msg data.
- Status: the processing result from the backend.
People may implement different backend drivers to emulate
different controllers according to their needs. A backend
example can be found in the device model of the open source
project ACRN. For more information, please refer to
https://projectacrn.org.
The virtio device ID 34 is used for this I2C adpter since IDs
before 34 have been reserved by other virtio devices.
Co-developed-by: Conghui Chen <conghui.chen@intel.com>
Signed-off-by: Conghui Chen <conghui.chen@intel.com>
Signed-off-by: Jie Deng <jie.deng@intel.com>
Reviewed-by: Shuo Liu <shuo.a.liu@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
The device ID request:
https://github.com/oasis-tcs/virtio-spec/issues/85
The specification:
https://lists.oasis-open.org/archives/virtio-comment/202009/msg00021.html
Changes in v4:
- Use (!(vmsg && vmsg == &vi->vmsg)) instead of ((!vmsg) || (vmsg != &vi->vmsg))
Changes in v3:
- Move the interface into uAPI according to Jason.
- Fix issues reported by Dan Carpenter.
- Fix typo reported by Randy.
Changes in v2:
- Addressed comments received from Michael, Andy and Jason.
drivers/i2c/busses/Kconfig | 11 ++
drivers/i2c/busses/Makefile | 3 +
drivers/i2c/busses/i2c-virtio.c | 256 ++++++++++++++++++++++++++++++++++++++++
include/uapi/linux/virtio_i2c.h | 31 +++++
include/uapi/linux/virtio_ids.h | 1 +
5 files changed, 302 insertions(+)
create mode 100644 drivers/i2c/busses/i2c-virtio.c
create mode 100644 include/uapi/linux/virtio_i2c.h
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 293e7a0..f2f6543 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -21,6 +21,17 @@ config I2C_ALI1535
This driver can also be built as a module. If so, the module
will be called i2c-ali1535.
+config I2C_VIRTIO
+ tristate "Virtio I2C Adapter"
+ depends on VIRTIO
+ help
+ If you say yes to this option, support will be included for the virtio
+ I2C adapter driver. The hardware can be emulated by any device model
+ software according to the virtio protocol.
+
+ This driver can also be built as a module. If so, the module
+ will be called i2c-virtio.
+
config I2C_ALI1563
tristate "ALI 1563"
depends on PCI
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 19aff0e..821acfa 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -6,6 +6,9 @@
# ACPI drivers
obj-$(CONFIG_I2C_SCMI) += i2c-scmi.o
+# VIRTIO I2C host controller driver
+obj-$(CONFIG_I2C_VIRTIO) += i2c-virtio.o
+
# PC SMBus host controller drivers
obj-$(CONFIG_I2C_ALI1535) += i2c-ali1535.o
obj-$(CONFIG_I2C_ALI1563) += i2c-ali1563.o
diff --git a/drivers/i2c/busses/i2c-virtio.c b/drivers/i2c/busses/i2c-virtio.c
new file mode 100644
index 0000000..36d8c68
--- /dev/null
+++ b/drivers/i2c/busses/i2c-virtio.c
@@ -0,0 +1,256 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Virtio I2C Bus Driver
+ *
+ * Copyright (c) 2020 Intel Corporation. All rights reserved.
+ */
+
+#include <linux/acpi.h>
+#include <linux/completion.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/io.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/wait.h>
+
+#include <linux/virtio.h>
+#include <linux/virtio_i2c.h>
+
+/**
+ * struct virtio_i2c_msg - the virtio I2C message structure
+ * @hdr: the virtio I2C message header
+ * @buf: virtio I2C message data buffer
+ * @status: the processing result from the backend
+ */
+struct virtio_i2c_msg {
+ struct virtio_i2c_hdr hdr;
+ u8 *buf;
+ u8 status;
+};
+
+/**
+ * struct virtio_i2c - virtio I2C data
+ * @vdev: virtio device for this controller
+ * @completion: completion of virtio I2C message
+ * @vmsg: the virtio I2C message for communication
+ * @adap: I2C adapter for this controller
+ * @i2c_lock: lock for virtqueue processing
+ * @vq: the virtio virtqueue for communication
+ */
+struct virtio_i2c {
+ struct virtio_device *vdev;
+ struct completion completion;
+ struct virtio_i2c_msg vmsg;
+ struct i2c_adapter adap;
+ struct mutex i2c_lock;
+ struct virtqueue *vq;
+};
+
+static void virtio_i2c_msg_done(struct virtqueue *vq)
+{
+ struct virtio_i2c *vi = vq->vdev->priv;
+
+ complete(&vi->completion);
+}
+
+static int virtio_i2c_add_msg(struct virtqueue *vq,
+ struct virtio_i2c_msg *vmsg,
+ struct i2c_msg *msg)
+{
+ struct scatterlist *sgs[3], hdr, bout, bin, status;
+ int outcnt = 0, incnt = 0;
+
+ if (!msg->len)
+ return -EINVAL;
+
+ vmsg->hdr.addr = cpu_to_le16(msg->addr);
+ vmsg->hdr.flags = cpu_to_le16(msg->flags);
+ vmsg->hdr.len = cpu_to_le16(msg->len);
+
+ vmsg->buf = kzalloc(msg->len, GFP_KERNEL);
+ if (!vmsg->buf)
+ return -ENOMEM;
+
+ sg_init_one(&hdr, &vmsg->hdr, sizeof(struct virtio_i2c_hdr));
+ sgs[outcnt++] = &hdr;
+ if (msg->flags & I2C_M_RD) {
+ sg_init_one(&bin, vmsg->buf, msg->len);
+ sgs[outcnt + incnt++] = &bin;
+ } else {
+ memcpy(vmsg->buf, msg->buf, msg->len);
+ sg_init_one(&bout, vmsg->buf, msg->len);
+ sgs[outcnt++] = &bout;
+ }
+ sg_init_one(&status, &vmsg->status, sizeof(vmsg->status));
+ sgs[outcnt + incnt++] = &status;
+
+ return virtqueue_add_sgs(vq, sgs, outcnt, incnt, vmsg, GFP_KERNEL);
+}
+
+static int virtio_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
+{
+ struct virtio_i2c *vi = i2c_get_adapdata(adap);
+ struct virtqueue *vq = vi->vq;
+ struct virtio_i2c_msg *vmsg;
+ unsigned long time_left;
+ int len, i, ret = 0;
+
+ mutex_lock(&vi->i2c_lock);
+ vmsg = &vi->vmsg;
+ vmsg->buf = NULL;
+
+ for (i = 0; i < num; i++) {
+ ret = virtio_i2c_add_msg(vq, vmsg, &msgs[i]);
+ if (ret) {
+ dev_err(&adap->dev, "failed to add msg[%d] to virtqueue.\n", i);
+ break;
+ }
+
+ virtqueue_kick(vq);
+
+ time_left = wait_for_completion_timeout(&vi->completion, adap->timeout);
+ if (!time_left) {
+ dev_err(&adap->dev, "msg[%d]: addr=0x%x timeout.\n", i, msgs[i].addr);
+ break;
+ }
+
+ vmsg = (struct virtio_i2c_msg *)virtqueue_get_buf(vq, &len);
+ /* vmsg should point to the same address with &vi->vmsg */
+ if (!(vmsg && vmsg == &vi->vmsg)) {
+ dev_err(&adap->dev, "msg[%d]: addr=0x%x virtqueue error.\n",
+ i, msgs[i].addr);
+ break;
+ }
+
+ if (vmsg->status != VIRTIO_I2C_MSG_OK) {
+ dev_err(&adap->dev, "msg[%d]: addr=0x%x error=%d.\n",
+ i, msgs[i].addr, vmsg->status);
+ break;
+ }
+
+ if ((msgs[i].flags & I2C_M_RD) && msgs[i].len)
+ memcpy(msgs[i].buf, vmsg->buf, msgs[i].len);
+
+ kfree(vmsg->buf);
+ vmsg->buf = NULL;
+
+ reinit_completion(&vi->completion);
+ }
+
+ mutex_unlock(&vi->i2c_lock);
+ kfree(vi->vmsg.buf);
+ vi->vmsg.buf = NULL;
+ return ((ret < 0) ? ret : i);
+}
+
+static void virtio_i2c_del_vqs(struct virtio_device *vdev)
+{
+ vdev->config->reset(vdev);
+ vdev->config->del_vqs(vdev);
+}
+
+static int virtio_i2c_setup_vqs(struct virtio_i2c *vi)
+{
+ struct virtio_device *vdev = vi->vdev;
+
+ vi->vq = virtio_find_single_vq(vdev, virtio_i2c_msg_done, "msg");
+ return PTR_ERR_OR_ZERO(vi->vq);
+}
+
+static u32 virtio_i2c_func(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static struct i2c_algorithm virtio_algorithm = {
+ .master_xfer = virtio_i2c_xfer,
+ .functionality = virtio_i2c_func,
+};
+
+static struct i2c_adapter virtio_adapter = {
+ .owner = THIS_MODULE,
+ .name = "Virtio I2C Adapter",
+ .class = I2C_CLASS_DEPRECATED,
+ .algo = &virtio_algorithm,
+};
+
+static int virtio_i2c_probe(struct virtio_device *vdev)
+{
+ struct device *pdev = vdev->dev.parent;
+ struct virtio_i2c *vi;
+ int ret;
+
+ vi = devm_kzalloc(&vdev->dev, sizeof(*vi), GFP_KERNEL);
+ if (!vi)
+ return -ENOMEM;
+
+ vdev->priv = vi;
+ vi->vdev = vdev;
+
+ mutex_init(&vi->i2c_lock);
+ init_completion(&vi->completion);
+
+ ret = virtio_i2c_setup_vqs(vi);
+ if (ret)
+ return ret;
+
+ vi->adap = virtio_adapter;
+ i2c_set_adapdata(&vi->adap, vi);
+ vi->adap.dev.parent = &vdev->dev;
+ /* Setup ACPI node for slave devices which will be probed through ACPI */
+ ACPI_COMPANION_SET(&vi->adap.dev, ACPI_COMPANION(pdev));
+ vi->adap.timeout = HZ / 10;
+
+ ret = i2c_add_adapter(&vi->adap);
+ if (ret) {
+ virtio_i2c_del_vqs(vdev);
+ dev_err(&vdev->dev, "failed to add virtio-i2c adapter.\n");
+ }
+
+ return ret;
+}
+
+static void virtio_i2c_remove(struct virtio_device *vdev)
+{
+ struct virtio_i2c *vi = vdev->priv;
+
+ i2c_del_adapter(&vi->adap);
+ virtio_i2c_del_vqs(vdev);
+}
+
+static struct virtio_device_id id_table[] = {
+ { VIRTIO_ID_I2C_ADPTER, VIRTIO_DEV_ANY_ID },
+ {}
+};
+MODULE_DEVICE_TABLE(virtio, id_table);
+
+static int __maybe_unused virtio_i2c_freeze(struct virtio_device *vdev)
+{
+ virtio_i2c_del_vqs(vdev);
+ return 0;
+}
+
+static int __maybe_unused virtio_i2c_restore(struct virtio_device *vdev)
+{
+ return virtio_i2c_setup_vqs(vdev->priv);
+}
+
+static struct virtio_driver virtio_i2c_driver = {
+ .id_table = id_table,
+ .probe = virtio_i2c_probe,
+ .remove = virtio_i2c_remove,
+ .driver = {
+ .name = "i2c_virtio",
+ },
+#ifdef CONFIG_PM_SLEEP
+ .freeze = virtio_i2c_freeze,
+ .restore = virtio_i2c_restore,
+#endif
+};
+module_virtio_driver(virtio_i2c_driver);
+
+MODULE_DESCRIPTION("Virtio i2c bus driver");
+MODULE_LICENSE("GPL");
diff --git a/include/uapi/linux/virtio_i2c.h b/include/uapi/linux/virtio_i2c.h
new file mode 100644
index 0000000..7413e45
--- /dev/null
+++ b/include/uapi/linux/virtio_i2c.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later OR BSD-3-Clause */
+/*
+ * Definitions for virtio I2C Adpter
+ *
+ * Copyright (c) 2020 Intel Corporation. All rights reserved.
+ */
+
+#ifndef _UAPI_LINUX_VIRTIO_I2C_H
+#define _UAPI_LINUX_VIRTIO_I2C_H
+
+#include <linux/types.h>
+#include <linux/virtio_ids.h>
+#include <linux/virtio_config.h>
+
+/**
+ * struct virtio_i2c_hdr - the virtio I2C message header structure
+ * @addr: i2c_msg addr, the slave address
+ * @flags: i2c_msg flags
+ * @len: i2c_msg len
+ */
+struct virtio_i2c_hdr {
+ __le16 addr;
+ __le16 flags;
+ __le16 len;
+};
+
+/* The final status written by the device */
+#define VIRTIO_I2C_MSG_OK 0
+#define VIRTIO_I2C_MSG_ERR 1
+
+#endif /* _UAPI_LINUX_VIRTIO_I2C_H */
diff --git a/include/uapi/linux/virtio_ids.h b/include/uapi/linux/virtio_ids.h
index b052355..398ef2d 100644
--- a/include/uapi/linux/virtio_ids.h
+++ b/include/uapi/linux/virtio_ids.h
@@ -48,5 +48,6 @@
#define VIRTIO_ID_FS 26 /* virtio filesystem */
#define VIRTIO_ID_PMEM 27 /* virtio pmem */
#define VIRTIO_ID_MAC80211_HWSIM 29 /* virtio mac80211-hwsim */
+#define VIRTIO_ID_I2C_ADPTER 34 /* virtio i2c adpter */
#endif /* _LINUX_VIRTIO_IDS_H */
--
2.7.4
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH v4] i2c: virtio: add a virtio i2c frontend driver
2020-10-12 1:55 [PATCH v4] i2c: virtio: add a virtio i2c frontend driver Jie Deng
@ 2020-10-12 5:45 ` kernel test robot
2020-11-25 9:35 ` Michael S. Tsirkin
2021-02-25 7:21 ` Viresh Kumar
2 siblings, 0 replies; 8+ messages in thread
From: kernel test robot @ 2020-10-12 5:45 UTC (permalink / raw)
To: Jie Deng, linux-i2c, virtualization, linux-kernel
Cc: kbuild-all, clang-built-linux, mst, jasowang, wsa+renesas, wsa,
andriy.shevchenko, jarkko.nikula, jdelvare
[-- Attachment #1: Type: text/plain, Size: 2242 bytes --]
Hi Jie,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on wsa/i2c/for-next]
[also build test ERROR on vhost/linux-next linus/master linux/master v5.9 next-20201009]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Jie-Deng/i2c-virtio-add-a-virtio-i2c-frontend-driver/20201012-095821
base: https://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux.git i2c/for-next
config: x86_64-randconfig-a004-20201012 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 9e72d3eaf38f217698f72cb8fdc969a6e72dad3a)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install x86_64 cross compiling tool for clang build
# apt-get install binutils-x86-64-linux-gnu
# https://github.com/0day-ci/linux/commit/152ef3f6057acca49f276933274b09df8880243d
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Jie-Deng/i2c-virtio-add-a-virtio-i2c-frontend-driver/20201012-095821
git checkout 152ef3f6057acca49f276933274b09df8880243d
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
>> error: include/uapi/linux/virtio_i2c.h: missing "WITH Linux-syscall-note" for SPDX-License-Identifier
make[2]: *** [scripts/Makefile.headersinst:63: usr/include/linux/virtio_i2c.h] Error 1
make[2]: Target '__headers' not remade because of errors.
make[1]: *** [Makefile:1286: headers] Error 2
make[1]: Target 'prepare' not remade because of errors.
make: *** [Makefile:185: __sub-make] Error 2
make: Target 'prepare' not remade because of errors.
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 33014 bytes --]
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v4] i2c: virtio: add a virtio i2c frontend driver
2020-10-12 1:55 [PATCH v4] i2c: virtio: add a virtio i2c frontend driver Jie Deng
2020-10-12 5:45 ` kernel test robot
@ 2020-11-25 9:35 ` Michael S. Tsirkin
2020-11-26 2:00 ` Jie Deng
2021-02-25 7:21 ` Viresh Kumar
2 siblings, 1 reply; 8+ messages in thread
From: Michael S. Tsirkin @ 2020-11-25 9:35 UTC (permalink / raw)
To: Jie Deng
Cc: linux-i2c, virtualization, linux-kernel, jasowang, wsa+renesas,
wsa, andriy.shevchenko, jarkko.nikula, jdelvare, Sergey.Semin,
krzk, rppt, loic.poulain, tali.perry1, bjorn.andersson,
shuo.a.liu, conghui.chen, yu1.wang
On Mon, Oct 12, 2020 at 09:55:55AM +0800, Jie Deng wrote:
> Add an I2C bus driver for virtio para-virtualization.
>
> The controller can be emulated by the backend driver in
> any device model software by following the virtio protocol.
>
> This driver communicates with the backend driver through a
> virtio I2C message structure which includes following parts:
>
> - Header: i2c_msg addr, flags, len.
> - Data buffer: the pointer to the I2C msg data.
> - Status: the processing result from the backend.
>
> People may implement different backend drivers to emulate
> different controllers according to their needs. A backend
> example can be found in the device model of the open source
> project ACRN. For more information, please refer to
> https://projectacrn.org.
>
> The virtio device ID 34 is used for this I2C adpter since IDs
> before 34 have been reserved by other virtio devices.
>
> Co-developed-by: Conghui Chen <conghui.chen@intel.com>
> Signed-off-by: Conghui Chen <conghui.chen@intel.com>
> Signed-off-by: Jie Deng <jie.deng@intel.com>
> Reviewed-by: Shuo Liu <shuo.a.liu@intel.com>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
I assume this will be updated once the specification is acked
by the virtio tc. Holding off on this one for now since
we know there will be host/guest ABI changes.
> ---
> The device ID request:
> https://github.com/oasis-tcs/virtio-spec/issues/85
>
> The specification:
> https://lists.oasis-open.org/archives/virtio-comment/202009/msg00021.html
>
> Changes in v4:
> - Use (!(vmsg && vmsg == &vi->vmsg)) instead of ((!vmsg) || (vmsg != &vi->vmsg))
>
> Changes in v3:
> - Move the interface into uAPI according to Jason.
> - Fix issues reported by Dan Carpenter.
> - Fix typo reported by Randy.
>
> Changes in v2:
> - Addressed comments received from Michael, Andy and Jason.
>
> drivers/i2c/busses/Kconfig | 11 ++
> drivers/i2c/busses/Makefile | 3 +
> drivers/i2c/busses/i2c-virtio.c | 256 ++++++++++++++++++++++++++++++++++++++++
> include/uapi/linux/virtio_i2c.h | 31 +++++
> include/uapi/linux/virtio_ids.h | 1 +
> 5 files changed, 302 insertions(+)
> create mode 100644 drivers/i2c/busses/i2c-virtio.c
> create mode 100644 include/uapi/linux/virtio_i2c.h
>
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index 293e7a0..f2f6543 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -21,6 +21,17 @@ config I2C_ALI1535
> This driver can also be built as a module. If so, the module
> will be called i2c-ali1535.
>
> +config I2C_VIRTIO
> + tristate "Virtio I2C Adapter"
> + depends on VIRTIO
> + help
> + If you say yes to this option, support will be included for the virtio
> + I2C adapter driver. The hardware can be emulated by any device model
> + software according to the virtio protocol.
> +
> + This driver can also be built as a module. If so, the module
> + will be called i2c-virtio.
> +
> config I2C_ALI1563
> tristate "ALI 1563"
> depends on PCI
> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> index 19aff0e..821acfa 100644
> --- a/drivers/i2c/busses/Makefile
> +++ b/drivers/i2c/busses/Makefile
> @@ -6,6 +6,9 @@
> # ACPI drivers
> obj-$(CONFIG_I2C_SCMI) += i2c-scmi.o
>
> +# VIRTIO I2C host controller driver
> +obj-$(CONFIG_I2C_VIRTIO) += i2c-virtio.o
> +
> # PC SMBus host controller drivers
> obj-$(CONFIG_I2C_ALI1535) += i2c-ali1535.o
> obj-$(CONFIG_I2C_ALI1563) += i2c-ali1563.o
> diff --git a/drivers/i2c/busses/i2c-virtio.c b/drivers/i2c/busses/i2c-virtio.c
> new file mode 100644
> index 0000000..36d8c68
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-virtio.c
> @@ -0,0 +1,256 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Virtio I2C Bus Driver
> + *
> + * Copyright (c) 2020 Intel Corporation. All rights reserved.
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/completion.h>
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/io.h>
> +#include <linux/jiffies.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/wait.h>
> +
> +#include <linux/virtio.h>
> +#include <linux/virtio_i2c.h>
> +
> +/**
> + * struct virtio_i2c_msg - the virtio I2C message structure
> + * @hdr: the virtio I2C message header
> + * @buf: virtio I2C message data buffer
> + * @status: the processing result from the backend
> + */
> +struct virtio_i2c_msg {
> + struct virtio_i2c_hdr hdr;
> + u8 *buf;
> + u8 status;
> +};
> +
> +/**
> + * struct virtio_i2c - virtio I2C data
> + * @vdev: virtio device for this controller
> + * @completion: completion of virtio I2C message
> + * @vmsg: the virtio I2C message for communication
> + * @adap: I2C adapter for this controller
> + * @i2c_lock: lock for virtqueue processing
> + * @vq: the virtio virtqueue for communication
> + */
> +struct virtio_i2c {
> + struct virtio_device *vdev;
> + struct completion completion;
> + struct virtio_i2c_msg vmsg;
> + struct i2c_adapter adap;
> + struct mutex i2c_lock;
> + struct virtqueue *vq;
> +};
> +
> +static void virtio_i2c_msg_done(struct virtqueue *vq)
> +{
> + struct virtio_i2c *vi = vq->vdev->priv;
> +
> + complete(&vi->completion);
> +}
> +
> +static int virtio_i2c_add_msg(struct virtqueue *vq,
> + struct virtio_i2c_msg *vmsg,
> + struct i2c_msg *msg)
> +{
> + struct scatterlist *sgs[3], hdr, bout, bin, status;
> + int outcnt = 0, incnt = 0;
> +
> + if (!msg->len)
> + return -EINVAL;
> +
> + vmsg->hdr.addr = cpu_to_le16(msg->addr);
> + vmsg->hdr.flags = cpu_to_le16(msg->flags);
> + vmsg->hdr.len = cpu_to_le16(msg->len);
> +
> + vmsg->buf = kzalloc(msg->len, GFP_KERNEL);
> + if (!vmsg->buf)
> + return -ENOMEM;
> +
> + sg_init_one(&hdr, &vmsg->hdr, sizeof(struct virtio_i2c_hdr));
> + sgs[outcnt++] = &hdr;
> + if (msg->flags & I2C_M_RD) {
> + sg_init_one(&bin, vmsg->buf, msg->len);
> + sgs[outcnt + incnt++] = &bin;
> + } else {
> + memcpy(vmsg->buf, msg->buf, msg->len);
> + sg_init_one(&bout, vmsg->buf, msg->len);
> + sgs[outcnt++] = &bout;
> + }
> + sg_init_one(&status, &vmsg->status, sizeof(vmsg->status));
> + sgs[outcnt + incnt++] = &status;
> +
> + return virtqueue_add_sgs(vq, sgs, outcnt, incnt, vmsg, GFP_KERNEL);
> +}
> +
> +static int virtio_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
> +{
> + struct virtio_i2c *vi = i2c_get_adapdata(adap);
> + struct virtqueue *vq = vi->vq;
> + struct virtio_i2c_msg *vmsg;
> + unsigned long time_left;
> + int len, i, ret = 0;
> +
> + mutex_lock(&vi->i2c_lock);
> + vmsg = &vi->vmsg;
> + vmsg->buf = NULL;
> +
> + for (i = 0; i < num; i++) {
> + ret = virtio_i2c_add_msg(vq, vmsg, &msgs[i]);
> + if (ret) {
> + dev_err(&adap->dev, "failed to add msg[%d] to virtqueue.\n", i);
> + break;
> + }
> +
> + virtqueue_kick(vq);
> +
> + time_left = wait_for_completion_timeout(&vi->completion, adap->timeout);
> + if (!time_left) {
> + dev_err(&adap->dev, "msg[%d]: addr=0x%x timeout.\n", i, msgs[i].addr);
> + break;
> + }
> +
> + vmsg = (struct virtio_i2c_msg *)virtqueue_get_buf(vq, &len);
> + /* vmsg should point to the same address with &vi->vmsg */
> + if (!(vmsg && vmsg == &vi->vmsg)) {
> + dev_err(&adap->dev, "msg[%d]: addr=0x%x virtqueue error.\n",
> + i, msgs[i].addr);
> + break;
> + }
> +
> + if (vmsg->status != VIRTIO_I2C_MSG_OK) {
> + dev_err(&adap->dev, "msg[%d]: addr=0x%x error=%d.\n",
> + i, msgs[i].addr, vmsg->status);
> + break;
> + }
> +
> + if ((msgs[i].flags & I2C_M_RD) && msgs[i].len)
> + memcpy(msgs[i].buf, vmsg->buf, msgs[i].len);
> +
> + kfree(vmsg->buf);
> + vmsg->buf = NULL;
> +
> + reinit_completion(&vi->completion);
> + }
> +
> + mutex_unlock(&vi->i2c_lock);
> + kfree(vi->vmsg.buf);
> + vi->vmsg.buf = NULL;
> + return ((ret < 0) ? ret : i);
> +}
> +
> +static void virtio_i2c_del_vqs(struct virtio_device *vdev)
> +{
> + vdev->config->reset(vdev);
> + vdev->config->del_vqs(vdev);
> +}
> +
> +static int virtio_i2c_setup_vqs(struct virtio_i2c *vi)
> +{
> + struct virtio_device *vdev = vi->vdev;
> +
> + vi->vq = virtio_find_single_vq(vdev, virtio_i2c_msg_done, "msg");
> + return PTR_ERR_OR_ZERO(vi->vq);
> +}
> +
> +static u32 virtio_i2c_func(struct i2c_adapter *adap)
> +{
> + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
> +}
> +
> +static struct i2c_algorithm virtio_algorithm = {
> + .master_xfer = virtio_i2c_xfer,
> + .functionality = virtio_i2c_func,
> +};
> +
> +static struct i2c_adapter virtio_adapter = {
> + .owner = THIS_MODULE,
> + .name = "Virtio I2C Adapter",
> + .class = I2C_CLASS_DEPRECATED,
> + .algo = &virtio_algorithm,
> +};
> +
> +static int virtio_i2c_probe(struct virtio_device *vdev)
> +{
> + struct device *pdev = vdev->dev.parent;
> + struct virtio_i2c *vi;
> + int ret;
> +
> + vi = devm_kzalloc(&vdev->dev, sizeof(*vi), GFP_KERNEL);
> + if (!vi)
> + return -ENOMEM;
> +
> + vdev->priv = vi;
> + vi->vdev = vdev;
> +
> + mutex_init(&vi->i2c_lock);
> + init_completion(&vi->completion);
> +
> + ret = virtio_i2c_setup_vqs(vi);
> + if (ret)
> + return ret;
> +
> + vi->adap = virtio_adapter;
> + i2c_set_adapdata(&vi->adap, vi);
> + vi->adap.dev.parent = &vdev->dev;
> + /* Setup ACPI node for slave devices which will be probed through ACPI */
> + ACPI_COMPANION_SET(&vi->adap.dev, ACPI_COMPANION(pdev));
> + vi->adap.timeout = HZ / 10;
> +
> + ret = i2c_add_adapter(&vi->adap);
> + if (ret) {
> + virtio_i2c_del_vqs(vdev);
> + dev_err(&vdev->dev, "failed to add virtio-i2c adapter.\n");
> + }
> +
> + return ret;
> +}
> +
> +static void virtio_i2c_remove(struct virtio_device *vdev)
> +{
> + struct virtio_i2c *vi = vdev->priv;
> +
> + i2c_del_adapter(&vi->adap);
> + virtio_i2c_del_vqs(vdev);
> +}
> +
> +static struct virtio_device_id id_table[] = {
> + { VIRTIO_ID_I2C_ADPTER, VIRTIO_DEV_ANY_ID },
> + {}
> +};
> +MODULE_DEVICE_TABLE(virtio, id_table);
> +
> +static int __maybe_unused virtio_i2c_freeze(struct virtio_device *vdev)
> +{
> + virtio_i2c_del_vqs(vdev);
> + return 0;
> +}
> +
> +static int __maybe_unused virtio_i2c_restore(struct virtio_device *vdev)
> +{
> + return virtio_i2c_setup_vqs(vdev->priv);
> +}
> +
> +static struct virtio_driver virtio_i2c_driver = {
> + .id_table = id_table,
> + .probe = virtio_i2c_probe,
> + .remove = virtio_i2c_remove,
> + .driver = {
> + .name = "i2c_virtio",
> + },
> +#ifdef CONFIG_PM_SLEEP
> + .freeze = virtio_i2c_freeze,
> + .restore = virtio_i2c_restore,
> +#endif
> +};
> +module_virtio_driver(virtio_i2c_driver);
> +
> +MODULE_DESCRIPTION("Virtio i2c bus driver");
> +MODULE_LICENSE("GPL");
> diff --git a/include/uapi/linux/virtio_i2c.h b/include/uapi/linux/virtio_i2c.h
> new file mode 100644
> index 0000000..7413e45
> --- /dev/null
> +++ b/include/uapi/linux/virtio_i2c.h
> @@ -0,0 +1,31 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later OR BSD-3-Clause */
> +/*
> + * Definitions for virtio I2C Adpter
> + *
> + * Copyright (c) 2020 Intel Corporation. All rights reserved.
> + */
> +
> +#ifndef _UAPI_LINUX_VIRTIO_I2C_H
> +#define _UAPI_LINUX_VIRTIO_I2C_H
> +
> +#include <linux/types.h>
> +#include <linux/virtio_ids.h>
> +#include <linux/virtio_config.h>
> +
> +/**
> + * struct virtio_i2c_hdr - the virtio I2C message header structure
> + * @addr: i2c_msg addr, the slave address
> + * @flags: i2c_msg flags
> + * @len: i2c_msg len
> + */
> +struct virtio_i2c_hdr {
> + __le16 addr;
> + __le16 flags;
> + __le16 len;
> +};
> +
> +/* The final status written by the device */
> +#define VIRTIO_I2C_MSG_OK 0
> +#define VIRTIO_I2C_MSG_ERR 1
> +
> +#endif /* _UAPI_LINUX_VIRTIO_I2C_H */
> diff --git a/include/uapi/linux/virtio_ids.h b/include/uapi/linux/virtio_ids.h
> index b052355..398ef2d 100644
> --- a/include/uapi/linux/virtio_ids.h
> +++ b/include/uapi/linux/virtio_ids.h
> @@ -48,5 +48,6 @@
> #define VIRTIO_ID_FS 26 /* virtio filesystem */
> #define VIRTIO_ID_PMEM 27 /* virtio pmem */
> #define VIRTIO_ID_MAC80211_HWSIM 29 /* virtio mac80211-hwsim */
> +#define VIRTIO_ID_I2C_ADPTER 34 /* virtio i2c adpter */
>
> #endif /* _LINUX_VIRTIO_IDS_H */
> --
> 2.7.4
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v4] i2c: virtio: add a virtio i2c frontend driver
2020-11-25 9:35 ` Michael S. Tsirkin
@ 2020-11-26 2:00 ` Jie Deng
0 siblings, 0 replies; 8+ messages in thread
From: Jie Deng @ 2020-11-26 2:00 UTC (permalink / raw)
To: Michael S. Tsirkin
Cc: linux-i2c, virtualization, linux-kernel, jasowang, wsa+renesas,
wsa, andriy.shevchenko, jarkko.nikula, jdelvare, Sergey.Semin,
krzk, rppt, loic.poulain, tali.perry1, bjorn.andersson,
shuo.a.liu, conghui.chen, yu1.wang
On 2020/11/25 17:35, Michael S. Tsirkin wrote:
> On Mon, Oct 12, 2020 at 09:55:55AM +0800, Jie Deng wrote:
>> Add an I2C bus driver for virtio para-virtualization.
>>
>> The controller can be emulated by the backend driver in
>> any device model software by following the virtio protocol.
>>
>> This driver communicates with the backend driver through a
>> virtio I2C message structure which includes following parts:
>>
>> - Header: i2c_msg addr, flags, len.
>> - Data buffer: the pointer to the I2C msg data.
>> - Status: the processing result from the backend.
>>
>> People may implement different backend drivers to emulate
>> different controllers according to their needs. A backend
>> example can be found in the device model of the open source
>> project ACRN. For more information, please refer to
>> https://projectacrn.org.
>>
>> The virtio device ID 34 is used for this I2C adpter since IDs
>> before 34 have been reserved by other virtio devices.
>>
>> Co-developed-by: Conghui Chen <conghui.chen@intel.com>
>> Signed-off-by: Conghui Chen <conghui.chen@intel.com>
>> Signed-off-by: Jie Deng <jie.deng@intel.com>
>> Reviewed-by: Shuo Liu <shuo.a.liu@intel.com>
>> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> I assume this will be updated once the specification is acked
> by the virtio tc. Holding off on this one for now since
> we know there will be host/guest ABI changes.
Yeah. I will update this driver once the specification is acked by the
virtio tc.
Thanks.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v4] i2c: virtio: add a virtio i2c frontend driver
2020-10-12 1:55 [PATCH v4] i2c: virtio: add a virtio i2c frontend driver Jie Deng
2020-10-12 5:45 ` kernel test robot
2020-11-25 9:35 ` Michael S. Tsirkin
@ 2021-02-25 7:21 ` Viresh Kumar
2021-02-26 2:46 ` Jie Deng
2 siblings, 1 reply; 8+ messages in thread
From: Viresh Kumar @ 2021-02-25 7:21 UTC (permalink / raw)
To: Jie Deng
Cc: linux-i2c, virtualization, linux-kernel, mst, jasowang,
wsa+renesas, wsa, andriy.shevchenko, jarkko.nikula, jdelvare,
Sergey.Semin, krzk, rppt, loic.poulain, tali.perry1,
bjorn.andersson, shuo.a.liu, conghui.chen, yu1.wang,
Alex Bennée, Vincent Guittot
On 12-10-20, 09:55, Jie Deng wrote:
> Add an I2C bus driver for virtio para-virtualization.
>
> The controller can be emulated by the backend driver in
> any device model software by following the virtio protocol.
>
> This driver communicates with the backend driver through a
> virtio I2C message structure which includes following parts:
>
> - Header: i2c_msg addr, flags, len.
> - Data buffer: the pointer to the I2C msg data.
> - Status: the processing result from the backend.
>
> People may implement different backend drivers to emulate
> different controllers according to their needs. A backend
> example can be found in the device model of the open source
> project ACRN. For more information, please refer to
> https://projectacrn.org.
> diff --git a/include/uapi/linux/virtio_i2c.h b/include/uapi/linux/virtio_i2c.h
> new file mode 100644
> index 0000000..7413e45
> --- /dev/null
> +++ b/include/uapi/linux/virtio_i2c.h
> @@ -0,0 +1,31 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later OR BSD-3-Clause */
> +/*
> + * Definitions for virtio I2C Adpter
> + *
> + * Copyright (c) 2020 Intel Corporation. All rights reserved.
> + */
> +
> +#ifndef _UAPI_LINUX_VIRTIO_I2C_H
> +#define _UAPI_LINUX_VIRTIO_I2C_H
> +
> +#include <linux/types.h>
> +#include <linux/virtio_ids.h>
> +#include <linux/virtio_config.h>
> +
> +/**
> + * struct virtio_i2c_hdr - the virtio I2C message header structure
> + * @addr: i2c_msg addr, the slave address
> + * @flags: i2c_msg flags
> + * @len: i2c_msg len
> + */
> +struct virtio_i2c_hdr {
> + __le16 addr;
> + __le16 flags;
> + __le16 len;
> +};
Hi Jie,
I am a bit confused about the header and the format in which data is being
processed here. When I look at the specification present here:
https://lists.oasis-open.org/archives/virtio-comment/202009/msg00021.html
it talks about
struct virtio_i2c_out_hdr {
le16 addr;
le16 padding;
le32 flags;
};
struct virtio_i2c_in_hdr {
u8 status;
};
struct virtio_i2c_req {
struct virtio_i2c_out_hdr out_hdr;
u8 write_buf [];
u8 read_buf [];
struct virtio_i2c_in_hdr in_hdr;
};
while what we have above is completely different. What am I missing ?
--
viresh
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v4] i2c: virtio: add a virtio i2c frontend driver
2021-02-25 7:21 ` Viresh Kumar
@ 2021-02-26 2:46 ` Jie Deng
2021-02-26 4:21 ` Viresh Kumar
0 siblings, 1 reply; 8+ messages in thread
From: Jie Deng @ 2021-02-26 2:46 UTC (permalink / raw)
To: Viresh Kumar
Cc: linux-i2c, virtualization, linux-kernel, mst, jasowang,
wsa+renesas, wsa, andriy.shevchenko, jarkko.nikula, jdelvare,
Sergey.Semin, krzk, rppt, loic.poulain, tali.perry1,
bjorn.andersson, shuo.a.liu, conghui.chen, yu1.wang,
Alex Bennée, Vincent Guittot
On 2021/2/25 15:21, Viresh Kumar wrote:
> On 12-10-20, 09:55, Jie Deng wrote:
>> Add an I2C bus driver for virtio para-virtualization.
>>
>> The controller can be emulated by the backend driver in
>> any device model software by following the virtio protocol.
>>
>> This driver communicates with the backend driver through a
>> virtio I2C message structure which includes following parts:
>>
>> - Header: i2c_msg addr, flags, len.
>> - Data buffer: the pointer to the I2C msg data.
>> - Status: the processing result from the backend.
>>
>> People may implement different backend drivers to emulate
>> different controllers according to their needs. A backend
>> example can be found in the device model of the open source
>> project ACRN. For more information, please refer to
>> https://projectacrn.org.
>> diff --git a/include/uapi/linux/virtio_i2c.h b/include/uapi/linux/virtio_i2c.h
>> new file mode 100644
>> index 0000000..7413e45
>> --- /dev/null
>> +++ b/include/uapi/linux/virtio_i2c.h
>> @@ -0,0 +1,31 @@
>> +/* SPDX-License-Identifier: GPL-2.0-or-later OR BSD-3-Clause */
>> +/*
>> + * Definitions for virtio I2C Adpter
>> + *
>> + * Copyright (c) 2020 Intel Corporation. All rights reserved.
>> + */
>> +
>> +#ifndef _UAPI_LINUX_VIRTIO_I2C_H
>> +#define _UAPI_LINUX_VIRTIO_I2C_H
>> +
>> +#include <linux/types.h>
>> +#include <linux/virtio_ids.h>
>> +#include <linux/virtio_config.h>
>> +
>> +/**
>> + * struct virtio_i2c_hdr - the virtio I2C message header structure
>> + * @addr: i2c_msg addr, the slave address
>> + * @flags: i2c_msg flags
>> + * @len: i2c_msg len
>> + */
>> +struct virtio_i2c_hdr {
>> + __le16 addr;
>> + __le16 flags;
>> + __le16 len;
>> +};
> Hi Jie,
>
> I am a bit confused about the header and the format in which data is being
> processed here. When I look at the specification present here:
>
> https://lists.oasis-open.org/archives/virtio-comment/202009/msg00021.html
>
> it talks about
>
> struct virtio_i2c_out_hdr {
> le16 addr;
> le16 padding;
> le32 flags;
> };
> struct virtio_i2c_in_hdr {
> u8 status;
> };
>
> struct virtio_i2c_req {
> struct virtio_i2c_out_hdr out_hdr;
> u8 write_buf [];
> u8 read_buf [];
> struct virtio_i2c_in_hdr in_hdr;
> };
>
> while what we have above is completely different. What am I missing ?
This v4 was the old version before the specification was acked by the
virtio tc.
Following is the latest specification.
https://raw.githubusercontent.com/oasis-tcs/virtio-spec/master/virtio-i2c.tex
I will send the v5 since the host/guest ABI changes.
Thanks.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v4] i2c: virtio: add a virtio i2c frontend driver
2021-02-26 2:46 ` Jie Deng
@ 2021-02-26 4:21 ` Viresh Kumar
2021-02-26 6:36 ` Jie Deng
0 siblings, 1 reply; 8+ messages in thread
From: Viresh Kumar @ 2021-02-26 4:21 UTC (permalink / raw)
To: Jie Deng
Cc: linux-i2c, virtualization, linux-kernel, mst, jasowang,
wsa+renesas, wsa, andriy.shevchenko, jarkko.nikula, jdelvare,
Sergey.Semin, krzk, rppt, loic.poulain, tali.perry1,
bjorn.andersson, shuo.a.liu, conghui.chen, yu1.wang,
Alex Bennée, Vincent Guittot
On 26-02-21, 10:46, Jie Deng wrote:
> This v4 was the old version before the specification was acked by the virtio
> tc.
>
> Following is the latest specification.
>
> https://raw.githubusercontent.com/oasis-tcs/virtio-spec/master/virtio-i2c.tex
>
> I will send the v5 since the host/guest ABI changes.
Okay, now it makes some sense :)
I am interested in this stuff, if possible please keep me Cc'd for following
versions, thanks.
--
viresh
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v4] i2c: virtio: add a virtio i2c frontend driver
2021-02-26 4:21 ` Viresh Kumar
@ 2021-02-26 6:36 ` Jie Deng
0 siblings, 0 replies; 8+ messages in thread
From: Jie Deng @ 2021-02-26 6:36 UTC (permalink / raw)
To: Viresh Kumar
Cc: linux-i2c, virtualization, linux-kernel, mst, jasowang,
wsa+renesas, wsa, andriy.shevchenko, jarkko.nikula, jdelvare,
Sergey.Semin, krzk, rppt, loic.poulain, tali.perry1,
bjorn.andersson, shuo.a.liu, conghui.chen, yu1.wang,
Alex Bennée, Vincent Guittot
On 2021/2/26 12:21, Viresh Kumar wrote:
> On 26-02-21, 10:46, Jie Deng wrote:
>> This v4 was the old version before the specification was acked by the virtio
>> tc.
>>
>> Following is the latest specification.
>>
>> https://raw.githubusercontent.com/oasis-tcs/virtio-spec/master/virtio-i2c.tex
>>
>> I will send the v5 since the host/guest ABI changes.
> Okay, now it makes some sense :)
>
> I am interested in this stuff, if possible please keep me Cc'd for following
> versions, thanks.
Sure. I will add you to the Cc list.
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2021-02-26 6:37 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-10-12 1:55 [PATCH v4] i2c: virtio: add a virtio i2c frontend driver Jie Deng
2020-10-12 5:45 ` kernel test robot
2020-11-25 9:35 ` Michael S. Tsirkin
2020-11-26 2:00 ` Jie Deng
2021-02-25 7:21 ` Viresh Kumar
2021-02-26 2:46 ` Jie Deng
2021-02-26 4:21 ` Viresh Kumar
2021-02-26 6:36 ` Jie Deng
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