Messages in this thread | | | Subject | Re: [PATCH v3 1/2] remoteproc: Add remoteproc character device interface | From | Siddharth Gupta <> | Date | Tue, 30 Jun 2020 15:02:38 -0700 |
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On 6/30/2020 12:43 AM, Arnaud POULIQUEN wrote: > > On 6/30/20 7:38 AM, Siddharth Gupta wrote: >> On 6/17/2020 1:44 AM, Arnaud POULIQUEN wrote: >>> On 6/16/20 9:56 PM, rishabhb@codeaurora.org wrote: >>>> 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) ? >> I think EPERM would indicate the operation is not permitted on the >> device, and >> EINVAL would indicate that the command/string they wrote to the char device >> is not a valid command/string. I guess even ENXIO may not be appropriate? >> >> In that case we could use EHOSTDOWN or ESHUTDOWN, thoughts? > Regarding remoteproc_sysfs.c[1], seems that the -EINVAL return would be coherent. Okay sure. > It would probably also be better to replace your condition with > if (rproc->state != RPROC_RUNNING) Will do. > > > [1] https://elixir.bootlin.com/linux/latest/source/drivers/remoteproc/remoteproc_sysfs.c#L104 > > Regards, > Arnaud > >> Thanks, >> Sid >> >>>>>> + >>>>>> + 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(¶m, 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? >>> Could you add in this file comments that describe >>> the IOCTL usage and associated parameter? >>> >>> Regards, >>> Arnaud
I don't see any for of comments that describe in detail the IOCTL usage, i.e., input parameters, etc. Could you provide an example so I can follow it?
If not, should I instead put them in Documentation/remoteproc.txt?
Thanks, Sid
>>> >>>>> Thanks, >>>>> Arnaud
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