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SubjectRe: [PATCH v3 1/2] remoteproc: Add remoteproc character device interface
On 2020-04-30 01:30, Arnaud POULIQUEN wrote:
> Hi Rishabh,
>
>
> On 4/21/20 8:10 PM, Rishabh Bhatnagar wrote:
>> Add the character device interface into remoteproc framework.
>> This interface can be used in order to boot/shutdown remote
>> subsystems and provides a basic ioctl based interface to implement
>> supplementary functionality. An ioctl call is implemented to enable
>> the shutdown on release feature which will allow remote processors to
>> be shutdown when the controlling userpsace application crashes or
>> hangs.
>>
>
> Thanks for intruducing Ioctl, this will help for future evolutions.
>
>> Signed-off-by: Rishabh Bhatnagar <rishabhb@codeaurora.org>
>> ---
>> Documentation/userspace-api/ioctl/ioctl-number.rst | 1 +
>> drivers/remoteproc/Kconfig | 9 ++
>> drivers/remoteproc/Makefile | 1 +
>> drivers/remoteproc/remoteproc_cdev.c | 143
>> +++++++++++++++++++++
>> drivers/remoteproc/remoteproc_internal.h | 21 +++
>> include/linux/remoteproc.h | 3 +
>> include/uapi/linux/remoteproc_cdev.h | 20 +++
>> 7 files changed, 198 insertions(+)
>> create mode 100644 drivers/remoteproc/remoteproc_cdev.c
>> create mode 100644 include/uapi/linux/remoteproc_cdev.h
>>
>> diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst
>> b/Documentation/userspace-api/ioctl/ioctl-number.rst
>> index 2e91370..412b2a0 100644
>> --- a/Documentation/userspace-api/ioctl/ioctl-number.rst
>> +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
>> @@ -337,6 +337,7 @@ Code Seq# Include File
>> Comments
>> 0xB4 00-0F linux/gpio.h
>> <mailto:linux-gpio@vger.kernel.org>
>> 0xB5 00-0F uapi/linux/rpmsg.h
>> <mailto:linux-remoteproc@vger.kernel.org>
>> 0xB6 all linux/fpga-dfl.h
>> +0xB7 all uapi/linux/remoteproc_cdev.h
>> <mailto:linux-remoteproc@vger.kernel.org>
>> 0xC0 00-0F linux/usb/iowarrior.h
>> 0xCA 00-0F uapi/misc/cxl.h
>> 0xCA 10-2F uapi/misc/ocxl.h
>> diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
>> index de3862c..6374b79 100644
>> --- a/drivers/remoteproc/Kconfig
>> +++ b/drivers/remoteproc/Kconfig
>> @@ -14,6 +14,15 @@ config REMOTEPROC
>>
>> if REMOTEPROC
>>
>> +config REMOTEPROC_CDEV
>> + bool "Remoteproc character device interface"
>> + help
>> + Say y here to have a character device interface for Remoteproc
>> + framework. Userspace can boot/shutdown remote processors through
>> + this interface.
>> +
>> + It's safe to say N if you don't want to use this interface.
>> +
>> config IMX_REMOTEPROC
>> tristate "IMX6/7 remoteproc support"
>> depends on ARCH_MXC
>> diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile
>> index e30a1b1..b7d4f77 100644
>> --- a/drivers/remoteproc/Makefile
>> +++ b/drivers/remoteproc/Makefile
>> @@ -9,6 +9,7 @@ remoteproc-y += remoteproc_debugfs.o
>> remoteproc-y += remoteproc_sysfs.o
>> remoteproc-y += remoteproc_virtio.o
>> remoteproc-y += remoteproc_elf_loader.o
>> +obj-$(CONFIG_REMOTEPROC_CDEV) += remoteproc_cdev.o
>> obj-$(CONFIG_IMX_REMOTEPROC) += imx_rproc.o
>> obj-$(CONFIG_MTK_SCP) += mtk_scp.o mtk_scp_ipi.o
>> obj-$(CONFIG_OMAP_REMOTEPROC) += omap_remoteproc.o
>> diff --git a/drivers/remoteproc/remoteproc_cdev.c
>> b/drivers/remoteproc/remoteproc_cdev.c
>> new file mode 100644
>> index 0000000..65142ec
>> --- /dev/null
>> +++ b/drivers/remoteproc/remoteproc_cdev.c
>> @@ -0,0 +1,143 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * Character device interface driver for Remoteproc framework.
>> + *
>> + * Copyright (c) 2020, The Linux Foundation. All rights reserved.
>> + */
>> +
>> +#include <linux/cdev.h>
>> +#include <linux/fs.h>
>> +#include <linux/module.h>
>> +#include <linux/mutex.h>
>> +#include <linux/remoteproc.h>
>> +#include <uapi/linux/remoteproc_cdev.h>
>> +#include <linux/uaccess.h>
>> +
>> +#include "remoteproc_internal.h"
>> +
>> +#define NUM_RPROC_DEVICES 64
>> +static dev_t rproc_major;
>> +
>> +static ssize_t rproc_cdev_write(struct file *filp, const char __user
>> *buf,
>> + size_t len, loff_t *pos)
>> +{
>> + struct rproc *rproc = container_of(filp->f_inode->i_cdev,
>> + struct rproc, char_dev);
>> + int ret = 0;
>> + char cmd[10];
>> +
>> + if (!len || len > sizeof(cmd))
>> + return -EINVAL;
>> +
>> + ret = copy_from_user(cmd, buf, sizeof(cmd));
>> + if (ret)
>> + return -EFAULT;
>> +
>> + if (sysfs_streq(cmd, "start")) {
>> + if (rproc->state == RPROC_RUNNING)
>> + return -EBUSY;
>> +
>> + ret = rproc_boot(rproc);
>> + if (ret)
>> + dev_err(&rproc->dev, "Boot failed:%d\n", ret);
>> + } else if (sysfs_streq(cmd, "stop")) {
>> + if (rproc->state == RPROC_OFFLINE)
>> + return -ENXIO;
>
> returning ENXIO in this case seems to me no appropriate , what about
> EPERM or
> EINVAL (rproc_sysfs) ?
>
>> +
>> + rproc_shutdown(rproc);
>> + } else {
>> + dev_err(&rproc->dev, "Unrecognized option\n");
>> + ret = -EINVAL;
>> + }
>> +
>> + return ret ? ret : len;
>> +}
>> +
>> +static long rproc_device_ioctl(struct file *filp, unsigned int ioctl,
>> + unsigned long arg)
>> +{
>> + struct rproc *rproc = container_of(filp->f_inode->i_cdev,
>> + struct rproc, char_dev);
>> + void __user *argp = (void __user *)arg;
>> + int ret;
>> + bool param;
>> +
>> + switch (ioctl) {
>> + case RPROC_SET_SHUTDOWN_ON_RELEASE:
>> + ret = copy_from_user(&param, argp, sizeof(bool));
>> + if (ret) {
>> + dev_err(&rproc->dev, "Data copy from userspace failed\n");
>> + return -EINVAL;
>> + }
>> + rproc->cdev_put_on_release = param;
>
> argp is an void value, where cdev_put_on_release is a bool a check or
> a conversion seems
> missing
>
>> + break;
>> + case RPROC_GET_SHUTDOWN_ON_RELEASE:
>> + ret = copy_to_user(argp, &rproc->cdev_put_on_release,
>> + sizeof(bool));
>> + if (ret) {
>> + dev_err(&rproc->dev, "Data copy to userspace failed\n");
>> + return -EINVAL;
>> + }
>> + break;
>> + default:
>> + dev_err(&rproc->dev, "Unsupported ioctl\n");
>> + return -EINVAL;
>> + }
>> + return 0;
>> +}
>> +
>> +static int rproc_cdev_release(struct inode *inode, struct file *filp)
>> +{
>> + struct rproc *rproc = container_of(inode->i_cdev, struct rproc,
>> + char_dev);
>> +
>> + if (rproc->cdev_put_on_release && rproc->state != RPROC_OFFLINE)
>> + rproc_shutdown(rproc);
>> +
>> + return 0;
>> +}
>> +
>> +
>> +static const struct file_operations rproc_fops = {
>> + .write = rproc_cdev_write,
>> + .unlocked_ioctl = rproc_device_ioctl,
>> + .release = rproc_cdev_release,
>> +};
>> +
>> +int rproc_char_device_add(struct rproc *rproc)
>> +{
>> + int ret;
>> + dev_t cdevt;
>> +
>> + cdev_init(&rproc->char_dev, &rproc_fops);
>> + rproc->char_dev.owner = THIS_MODULE;
>> +
>> + cdevt = MKDEV(MAJOR(rproc_major), rproc->index);
>> + ret = cdev_add(&rproc->char_dev, cdevt, 1);
>> + if (ret < 0)
>> + goto out;
>> +
>> + rproc->dev.devt = cdevt;
>> +out:
>> + return ret;
>> +}
>> +
>> +void rproc_char_device_remove(struct rproc *rproc)
>> +{
>> + __unregister_chrdev(MAJOR(rproc->dev.devt), rproc->index, 1,
>> "rproc");
>> +}
>> +
>> +void __init rproc_init_cdev(void)
>> +{
>> + int ret;
>> +
>> + ret = alloc_chrdev_region(&rproc_major, 0, NUM_RPROC_DEVICES,
>> "rproc");
>
> "remoteproc"instead of "rproc" (in line with sysfs and debugfs naming)
> .
>
>> + if (ret < 0)
>> + pr_err("Failed to alloc rproc_cdev region, err %d\n", ret);
>> +}
>> +
>> +void __exit rproc_exit_cdev(void)
>> +{
>> + unregister_chrdev_region(MKDEV(MAJOR(rproc_major), 0),
>> + NUM_RPROC_DEVICES);
>> +}
>> diff --git a/drivers/remoteproc/remoteproc_internal.h
>> b/drivers/remoteproc/remoteproc_internal.h
>> index 493ef92..fb9d891 100644
>> --- a/drivers/remoteproc/remoteproc_internal.h
>> +++ b/drivers/remoteproc/remoteproc_internal.h
>> @@ -47,6 +47,27 @@ struct dentry *rproc_create_trace_file(const char
>> *name, struct rproc *rproc,
>> int rproc_init_sysfs(void);
>> void rproc_exit_sysfs(void);
>>
>> +#ifdef CONFIG_REMOTEPROC_CDEV
>> +void rproc_init_cdev(void);
>> +void rproc_exit_cdev(void);
>> +int rproc_char_device_add(struct rproc *rproc);
>> +void rproc_char_device_remove(struct rproc *rproc);
>> +#else
>> +static inline void rproc_init_cdev(void)
>> +{
>> +}
>> +static inline void rproc_exit_cdev(void)
>> +{
>> +}
>> +static inline int rproc_char_device_add(struct rproc *rproc)
>> +{
>> + return 0;
>> +}
>> +static inline void rproc_char_device_remove(struct rproc *rproc)
>> +{
>> +}
>> +#endif
>> +
>> void rproc_free_vring(struct rproc_vring *rvring);
>> int rproc_alloc_vring(struct rproc_vdev *rvdev, int i);
>>
>> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
>> index 16ad666..9bd2ff5 100644
>> --- a/include/linux/remoteproc.h
>> +++ b/include/linux/remoteproc.h
>> @@ -40,6 +40,7 @@
>> #include <linux/virtio.h>
>> #include <linux/completion.h>
>> #include <linux/idr.h>
>> +#include <linux/cdev.h>
>> #include <linux/of.h>
>>
>> /**
>> @@ -514,6 +515,8 @@ struct rproc {
>> bool auto_boot;
>> struct list_head dump_segments;
>> int nb_vdev;
>> + struct cdev char_dev;
>> + bool cdev_put_on_release;
>> };
>
> These parameters are local variables of rproc_cdev. Could be defined
> in a separate structure.
> with a pointer in rproc to this structure.
>
>>
>> /**
>> diff --git a/include/uapi/linux/remoteproc_cdev.h
>> b/include/uapi/linux/remoteproc_cdev.h
>> new file mode 100644
>> index 0000000..3975120
>> --- /dev/null
>> +++ b/include/uapi/linux/remoteproc_cdev.h
>> @@ -0,0 +1,20 @@
>> +/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */
>> +/*
>> + * IOCTLs for Remoteproc's character device interface.
>> + *
>> + * Copyright (c) 2020, The Linux Foundation. All rights reserved.
>> + */
>> +
>> +
>> +#ifndef _UAPI_REMOTEPROC_CDEV_H_
>> +#define _UAPI_REMOTEPROC_CDEV_H_
>> +
>> +#include <linux/ioctl.h>
>> +#include <linux/types.h>
>> +
>> +#define RPROC_MAGIC 0xB7
>> +
>> +#define RPROC_SET_SHUTDOWN_ON_RELEASE _IOW(RPROC_MAGIC, 1, int)
>> +#define RPROC_GET_SHUTDOWN_ON_RELEASE _IOR(RPROC_MAGIC, 2, int)
>> +
>> +#endif
>>
> IOCTLs should probaly be documented.
I have added documentation to
Documentation/userspace-api/ioctl/ioctl-number.rst
Is there another place where I need to add documentation for this?
>
> Thanks,
> Arnaud

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