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Re: [PATCH v3 1/2] remoteproc: Add a sysfs interface for firmware and state

Started byWendy Liang <sunnyliangjy@gmail.com>
First post2016-11-04 00:50 +0100
Last post2016-11-07 19:20 +0100
Articles 3 — 2 participants

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  Re: [PATCH v3 1/2] remoteproc: Add a sysfs interface for firmware and state Wendy Liang <sunnyliangjy@gmail.com> - 2016-11-04 00:50 +0100
    Re: [PATCH v3 1/2] remoteproc: Add a sysfs interface for firmware and  state Matt Redfearn <matt.redfearn@imgtec.com> - 2016-11-04 10:20 +0100
      Re: [PATCH v3 1/2] remoteproc: Add a sysfs interface for firmware and state Wendy Liang <sunnyliangjy@gmail.com> - 2016-11-07 19:20 +0100

#1514939 — Re: [PATCH v3 1/2] remoteproc: Add a sysfs interface for firmware and state

FromWendy Liang <sunnyliangjy@gmail.com>
Date2016-11-04 00:50 +0100
SubjectRe: [PATCH v3 1/2] remoteproc: Add a sysfs interface for firmware and state
Message-ID<szzVD-2d3-7@gated-at.bofh.it>
HI Matt,

Thanks for your patch. I am trying it.

Please see my questions inline.

Thanks,
Wendy

On Wed, Oct 19, 2016 at 5:05 AM, Matt Redfearn <matt.redfearn@imgtec.com> wrote:
> This patch adds a sysfs interface to rproc allowing the firmware name
> and processor state to be changed dynamically.
>
> State was previously available in debugfs, and is replicated here. The
> firmware file allows retrieval of the running firmware name, and a new
> one to be specified at run time, so long as the remote processor has
> been stopped.
>
> Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
>
> ---
>
> Changes in v3:
> Drop call to rproc_add_virtio_devices from sysfs firmware_store
> Use strcspn to find firmware name length
> Explicit indexes for state strings
>
> Changes in v2:
> Have firmware_store perform the necessary steps inline.
> Use sysfs_streq when dealing with writes to sysfs files
>
>  Documentation/ABI/testing/sysfs-class-remoteproc |  50 ++++++++
>  drivers/remoteproc/Makefile                      |   1 +
>  drivers/remoteproc/remoteproc_core.c             |   3 +
>  drivers/remoteproc/remoteproc_internal.h         |   5 +
>  drivers/remoteproc/remoteproc_sysfs.c            | 151 +++++++++++++++++++++++
>  5 files changed, 210 insertions(+)
>  create mode 100644 Documentation/ABI/testing/sysfs-class-remoteproc
>  create mode 100644 drivers/remoteproc/remoteproc_sysfs.c
>
> diff --git a/Documentation/ABI/testing/sysfs-class-remoteproc b/Documentation/ABI/testing/sysfs-class-remoteproc
> new file mode 100644
> index 000000000000..d188afebc8ba
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-remoteproc
> @@ -0,0 +1,50 @@
> +What:          /sys/class/remoteproc/.../firmware
> +Date:          October 2016
> +Contact:       Matt Redfearn <matt.redfearn@imgtec.com>
> +Description:   Remote processor firmware
> +
> +               Reports the name of the firmware currently loaded to the
> +               remote processor.
> +
> +               To change the running firmware, ensure the remote processor is
> +               stopped (using /sys/class/remoteproc/.../state) and write a new filename.
> +
> +What:          /sys/class/remoteproc/.../state
> +Date:          October 2016
> +Contact:       Matt Redfearn <matt.redfearn@imgtec.com>
> +Description:   Remote processor state
> +
> +               Reports the state of the remote processor, which will be one of:
> +
> +               "offline"
> +               "suspended"
> +               "running"
> +               "crashed"
> +               "invalid"
> +
> +               "offline" means the remote processor is powered off.
> +
> +               "suspended" means that the remote processor is suspended and
> +               must be woken to receive messages.
> +
> +               "running" is the normal state of an available remote processor
> +
> +               "crashed" indicates that a problem/crash has been detected on
> +               the remote processor.
> +
> +               "invalid" is returned if the remote processor is in an
> +               unknown state.
> +
> +               Writing this file controls the state of the remote processor.
> +               The following states can be written:
> +
> +               "start"
> +               "stop"
> +
> +               Writing "start" will attempt to start the processor running the
> +               firmware indicated by, or written to,
> +               /sys/class/remoteproc/.../firmware. The remote processor should
> +               transition to "running" state.
> +
> +               Writing "stop" will attempt to halt the remote processor and
> +               return it to the "offline" state.
> diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile
> index 6dfb62ed643f..6da9b12f9798 100644
> --- a/drivers/remoteproc/Makefile
> +++ b/drivers/remoteproc/Makefile
> @@ -5,6 +5,7 @@
>  obj-$(CONFIG_REMOTEPROC)               += remoteproc.o
>  remoteproc-y                           := remoteproc_core.o
>  remoteproc-y                           += remoteproc_debugfs.o
> +remoteproc-y                           += remoteproc_sysfs.o
>  remoteproc-y                           += remoteproc_virtio.o
>  remoteproc-y                           += remoteproc_elf_loader.o
>  obj-$(CONFIG_OMAP_REMOTEPROC)          += omap_remoteproc.o
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index ccc2a73e94dd..b1860949d106 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -1347,6 +1347,7 @@ struct rproc *rproc_alloc(struct device *dev, const char *name,
>         device_initialize(&rproc->dev);
>         rproc->dev.parent = dev;
>         rproc->dev.type = &rproc_type;
> +       rproc->dev.class = &rproc_class;
>
>         /* Assign a unique device index and name */
>         rproc->index = ida_simple_get(&rproc_dev_index, 0, 0, GFP_KERNEL);
> @@ -1485,6 +1486,7 @@ EXPORT_SYMBOL(rproc_report_crash);
>
>  static int __init remoteproc_init(void)
>  {
> +       rproc_init_sysfs();
>         rproc_init_debugfs();
>
>         return 0;
> @@ -1496,6 +1498,7 @@ static void __exit remoteproc_exit(void)
>         ida_destroy(&rproc_dev_index);
>
>         rproc_exit_debugfs();
> +       rproc_exit_sysfs();
>  }
>  module_exit(remoteproc_exit);
>
> diff --git a/drivers/remoteproc/remoteproc_internal.h b/drivers/remoteproc/remoteproc_internal.h
> index 4cf93ca2816e..c2c3e4762b90 100644
> --- a/drivers/remoteproc/remoteproc_internal.h
> +++ b/drivers/remoteproc/remoteproc_internal.h
> @@ -63,6 +63,11 @@ void rproc_create_debug_dir(struct rproc *rproc);
>  void rproc_init_debugfs(void);
>  void rproc_exit_debugfs(void);
>
> +/* from remoteproc_sysfs.c */
> +extern struct class rproc_class;
> +int rproc_init_sysfs(void);
> +void rproc_exit_sysfs(void);
> +
>  void rproc_free_vring(struct rproc_vring *rvring);
>  int rproc_alloc_vring(struct rproc_vdev *rvdev, int i);
>
> diff --git a/drivers/remoteproc/remoteproc_sysfs.c b/drivers/remoteproc/remoteproc_sysfs.c
> new file mode 100644
> index 000000000000..bc5b0e00efb1
> --- /dev/null
> +++ b/drivers/remoteproc/remoteproc_sysfs.c
> @@ -0,0 +1,151 @@
> +/*
> + * Remote Processor Framework
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * version 2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/remoteproc.h>
> +
> +#include "remoteproc_internal.h"
> +
> +#define to_rproc(d) container_of(d, struct rproc, dev)
> +
> +/* Expose the loaded / running firmware name via sysfs */
> +static ssize_t firmware_show(struct device *dev, struct device_attribute *attr,
> +                         char *buf)
> +{
> +       struct rproc *rproc = to_rproc(dev);
> +
> +       return sprintf(buf, "%s\n", rproc->firmware);
> +}
> +
> +/* Change firmware name via sysfs */
> +static ssize_t firmware_store(struct device *dev,
> +                             struct device_attribute *attr,
> +                             const char *buf, size_t count)
> +{
> +       struct rproc *rproc = to_rproc(dev);
> +       char *p;
> +       int err, len = count;
> +
> +       err = mutex_lock_interruptible(&rproc->lock);
> +       if (err) {
> +               dev_err(dev, "can't lock rproc %s: %d\n", rproc->name, err);
> +               return -EINVAL;
> +       }
> +
> +       if (rproc->state != RPROC_OFFLINE) {
> +               dev_err(dev, "can't change firmware while running\n");
> +               err = -EBUSY;
> +               goto out;
> +       }
> +
> +       len = strcspn(buf, "\n");
> +
> +       p = kstrndup(buf, len, GFP_KERNEL);
> +       if (!p) {
> +               err = -ENOMEM;
> +               goto out;
> +       }
> +
> +       kfree(rproc->firmware);
it gives me kernel panic if the initial firmware name is passed from
my remoteproc driver to rproc_alloc()
and it is a const string.
It is better to have another modification to the remoteproc_core.c as
follows in the rproc_alloc().

-       if (!firmware)
+       if (!firmware) {
                /*
                 * Make room for default firmware name (minus %s plus '\0').
                 * If the caller didn't pass in a firmware name then
@@ -1332,17 +1346,29 @@ struct rproc *rproc_alloc(struct device *dev,
const char *name,
                 * the caller doesn't pass one).
                 */
                name_len = strlen(name) + strlen(template) - 2 + 1;
+               p = kmalloc_track_caller(name_len, GFP_KERNEL);
+               if (!p)
+                       return NULL;
+               snprintf(p, name_len, template, name);
+       } else {
+               p = kstrndup(firmware, strlen(firmware), GFP_KERNEL);
+               if (!p) {
+                       return NULL;
+               }
+       }

-       rproc = kzalloc(sizeof(*rproc) + len + name_len, GFP_KERNEL);
+       rproc = kzalloc(sizeof(*rproc) + len, GFP_KERNEL);

> +       rproc->firmware = p;
> +out:
> +       mutex_unlock(&rproc->lock);
> +
> +       return err ? err : count;
> +}
> +static DEVICE_ATTR_RW(firmware);
> +
> +/*
> + * A state-to-string lookup table, for exposing a human readable state
> + * via sysfs. Always keep in sync with enum rproc_state
> + */
> +static const char * const rproc_state_string[] = {
> +       [RPROC_OFFLINE]         = "offline",
> +       [RPROC_SUSPENDED]       = "suspended",
> +       [RPROC_RUNNING]         = "running",
> +       [RPROC_CRASHED]         = "crashed",
> +       [RPROC_LAST]            = "invalid",
> +};
> +
> +/* Expose the state of the remote processor via sysfs */
> +static ssize_t state_show(struct device *dev, struct device_attribute *attr,
> +                         char *buf)
> +{
> +       struct rproc *rproc = to_rproc(dev);
> +       unsigned int state;
> +
> +       state = rproc->state > RPROC_LAST ? RPROC_LAST : rproc->state;
> +       return sprintf(buf, "%s\n", rproc_state_string[state]);
> +}
> +
> +/* Change remote processor state via sysfs */
> +static ssize_t state_store(struct device *dev,
> +                             struct device_attribute *attr,
> +                             const char *buf, size_t count)
> +{
> +       struct rproc *rproc = to_rproc(dev);
> +       int ret = 0;
> +
> +       if (sysfs_streq(buf, "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(buf, "stop")) {
> +               if (rproc->state != RPROC_RUNNING)
> +                       return -EINVAL;
> +
> +               rproc_shutdown(rproc);
The kernel hanged when it was trying to unregister the virtio device
after I tried"stop".
It doesn't look like related to this sysfs API. But just wonder have you seen
similar issue?

> +       } else {
> +               dev_err(&rproc->dev, "Unrecognised option: %s\n", buf);
> +               ret = -EINVAL;
> +       }
> +       return ret ? ret : count;
> +}
> +static DEVICE_ATTR_RW(state);
> +
> +static struct attribute *rproc_attrs[] = {
> +       &dev_attr_firmware.attr,
> +       &dev_attr_state.attr,
> +       NULL
> +};
> +
> +static const struct attribute_group rproc_devgroup = {
> +       .attrs = rproc_attrs
> +};
> +
> +static const struct attribute_group *rproc_devgroups[] = {
> +       &rproc_devgroup,
> +       NULL
> +};
> +
> +struct class rproc_class = {
> +       .name           = "remoteproc",
> +       .dev_groups     = rproc_devgroups,
> +};
> +
> +int __init rproc_init_sysfs(void)
> +{
> +       /* create remoteproc device class for sysfs */
> +       int err = class_register(&rproc_class);
> +
> +       if (err)
> +               pr_err("remoteproc: unable to register class\n");
> +       return err;
> +}
> +
> +void __exit rproc_exit_sysfs(void)
> +{
> +       class_unregister(&rproc_class);
> +}
> --
> 2.7.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-remoteproc" in
> the body of a message to majordomo@vger.kernel.org
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#1515084 — Re: [PATCH v3 1/2] remoteproc: Add a sysfs interface for firmware and state

FromMatt Redfearn <matt.redfearn@imgtec.com>
Date2016-11-04 10:20 +0100
SubjectRe: [PATCH v3 1/2] remoteproc: Add a sysfs interface for firmware and state
Message-ID<szIPg-8bj-9@gated-at.bofh.it>
In reply to#1514939
Hi Wendy,

Replies inline


On 03/11/16 23:40, Wendy Liang wrote:
> HI Matt,
>
> Thanks for your patch. I am trying it.
>
> Please see my questions inline.
>
> Thanks,
> Wendy
>
> On Wed, Oct 19, 2016 at 5:05 AM, Matt Redfearn <matt.redfearn@imgtec.com> wrote:
>> This patch adds a sysfs interface to rproc allowing the firmware name
>> and processor state to be changed dynamically.
>>
>> State was previously available in debugfs, and is replicated here. The
>> firmware file allows retrieval of the running firmware name, and a new
>> one to be specified at run time, so long as the remote processor has
>> been stopped.
>>
>> Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
>>
>> ---
>>
>> Changes in v3:
>> Drop call to rproc_add_virtio_devices from sysfs firmware_store
>> Use strcspn to find firmware name length
>> Explicit indexes for state strings
>>
>> Changes in v2:
>> Have firmware_store perform the necessary steps inline.
>> Use sysfs_streq when dealing with writes to sysfs files
>>
>>   Documentation/ABI/testing/sysfs-class-remoteproc |  50 ++++++++
>>   drivers/remoteproc/Makefile                      |   1 +
>>   drivers/remoteproc/remoteproc_core.c             |   3 +
>>   drivers/remoteproc/remoteproc_internal.h         |   5 +
>>   drivers/remoteproc/remoteproc_sysfs.c            | 151 +++++++++++++++++++++++
>>   5 files changed, 210 insertions(+)
>>   create mode 100644 Documentation/ABI/testing/sysfs-class-remoteproc
>>   create mode 100644 drivers/remoteproc/remoteproc_sysfs.c
>>
>> diff --git a/Documentation/ABI/testing/sysfs-class-remoteproc b/Documentation/ABI/testing/sysfs-class-remoteproc
>> new file mode 100644
>> index 000000000000..d188afebc8ba
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/sysfs-class-remoteproc
>> @@ -0,0 +1,50 @@
>> +What:          /sys/class/remoteproc/.../firmware
>> +Date:          October 2016
>> +Contact:       Matt Redfearn <matt.redfearn@imgtec.com>
>> +Description:   Remote processor firmware
>> +
>> +               Reports the name of the firmware currently loaded to the
>> +               remote processor.
>> +
>> +               To change the running firmware, ensure the remote processor is
>> +               stopped (using /sys/class/remoteproc/.../state) and write a new filename.
>> +
>> +What:          /sys/class/remoteproc/.../state
>> +Date:          October 2016
>> +Contact:       Matt Redfearn <matt.redfearn@imgtec.com>
>> +Description:   Remote processor state
>> +
>> +               Reports the state of the remote processor, which will be one of:
>> +
>> +               "offline"
>> +               "suspended"
>> +               "running"
>> +               "crashed"
>> +               "invalid"
>> +
>> +               "offline" means the remote processor is powered off.
>> +
>> +               "suspended" means that the remote processor is suspended and
>> +               must be woken to receive messages.
>> +
>> +               "running" is the normal state of an available remote processor
>> +
>> +               "crashed" indicates that a problem/crash has been detected on
>> +               the remote processor.
>> +
>> +               "invalid" is returned if the remote processor is in an
>> +               unknown state.
>> +
>> +               Writing this file controls the state of the remote processor.
>> +               The following states can be written:
>> +
>> +               "start"
>> +               "stop"
>> +
>> +               Writing "start" will attempt to start the processor running the
>> +               firmware indicated by, or written to,
>> +               /sys/class/remoteproc/.../firmware. The remote processor should
>> +               transition to "running" state.
>> +
>> +               Writing "stop" will attempt to halt the remote processor and
>> +               return it to the "offline" state.
>> diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile
>> index 6dfb62ed643f..6da9b12f9798 100644
>> --- a/drivers/remoteproc/Makefile
>> +++ b/drivers/remoteproc/Makefile
>> @@ -5,6 +5,7 @@
>>   obj-$(CONFIG_REMOTEPROC)               += remoteproc.o
>>   remoteproc-y                           := remoteproc_core.o
>>   remoteproc-y                           += remoteproc_debugfs.o
>> +remoteproc-y                           += remoteproc_sysfs.o
>>   remoteproc-y                           += remoteproc_virtio.o
>>   remoteproc-y                           += remoteproc_elf_loader.o
>>   obj-$(CONFIG_OMAP_REMOTEPROC)          += omap_remoteproc.o
>> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
>> index ccc2a73e94dd..b1860949d106 100644
>> --- a/drivers/remoteproc/remoteproc_core.c
>> +++ b/drivers/remoteproc/remoteproc_core.c
>> @@ -1347,6 +1347,7 @@ struct rproc *rproc_alloc(struct device *dev, const char *name,
>>          device_initialize(&rproc->dev);
>>          rproc->dev.parent = dev;
>>          rproc->dev.type = &rproc_type;
>> +       rproc->dev.class = &rproc_class;
>>
>>          /* Assign a unique device index and name */
>>          rproc->index = ida_simple_get(&rproc_dev_index, 0, 0, GFP_KERNEL);
>> @@ -1485,6 +1486,7 @@ EXPORT_SYMBOL(rproc_report_crash);
>>
>>   static int __init remoteproc_init(void)
>>   {
>> +       rproc_init_sysfs();
>>          rproc_init_debugfs();
>>
>>          return 0;
>> @@ -1496,6 +1498,7 @@ static void __exit remoteproc_exit(void)
>>          ida_destroy(&rproc_dev_index);
>>
>>          rproc_exit_debugfs();
>> +       rproc_exit_sysfs();
>>   }
>>   module_exit(remoteproc_exit);
>>
>> diff --git a/drivers/remoteproc/remoteproc_internal.h b/drivers/remoteproc/remoteproc_internal.h
>> index 4cf93ca2816e..c2c3e4762b90 100644
>> --- a/drivers/remoteproc/remoteproc_internal.h
>> +++ b/drivers/remoteproc/remoteproc_internal.h
>> @@ -63,6 +63,11 @@ void rproc_create_debug_dir(struct rproc *rproc);
>>   void rproc_init_debugfs(void);
>>   void rproc_exit_debugfs(void);
>>
>> +/* from remoteproc_sysfs.c */
>> +extern struct class rproc_class;
>> +int rproc_init_sysfs(void);
>> +void rproc_exit_sysfs(void);
>> +
>>   void rproc_free_vring(struct rproc_vring *rvring);
>>   int rproc_alloc_vring(struct rproc_vdev *rvdev, int i);
>>
>> diff --git a/drivers/remoteproc/remoteproc_sysfs.c b/drivers/remoteproc/remoteproc_sysfs.c
>> new file mode 100644
>> index 000000000000..bc5b0e00efb1
>> --- /dev/null
>> +++ b/drivers/remoteproc/remoteproc_sysfs.c
>> @@ -0,0 +1,151 @@
>> +/*
>> + * Remote Processor Framework
>> + *
>> + * This program is free software; you can redistribute it and/or
>> + * modify it under the terms of the GNU General Public License
>> + * version 2 as published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + */
>> +
>> +#include <linux/remoteproc.h>
>> +
>> +#include "remoteproc_internal.h"
>> +
>> +#define to_rproc(d) container_of(d, struct rproc, dev)
>> +
>> +/* Expose the loaded / running firmware name via sysfs */
>> +static ssize_t firmware_show(struct device *dev, struct device_attribute *attr,
>> +                         char *buf)
>> +{
>> +       struct rproc *rproc = to_rproc(dev);
>> +
>> +       return sprintf(buf, "%s\n", rproc->firmware);
>> +}
>> +
>> +/* Change firmware name via sysfs */
>> +static ssize_t firmware_store(struct device *dev,
>> +                             struct device_attribute *attr,
>> +                             const char *buf, size_t count)
>> +{
>> +       struct rproc *rproc = to_rproc(dev);
>> +       char *p;
>> +       int err, len = count;
>> +
>> +       err = mutex_lock_interruptible(&rproc->lock);
>> +       if (err) {
>> +               dev_err(dev, "can't lock rproc %s: %d\n", rproc->name, err);
>> +               return -EINVAL;
>> +       }
>> +
>> +       if (rproc->state != RPROC_OFFLINE) {
>> +               dev_err(dev, "can't change firmware while running\n");
>> +               err = -EBUSY;
>> +               goto out;
>> +       }
>> +
>> +       len = strcspn(buf, "\n");
>> +
>> +       p = kstrndup(buf, len, GFP_KERNEL);
>> +       if (!p) {
>> +               err = -ENOMEM;
>> +               goto out;
>> +       }
>> +
>> +       kfree(rproc->firmware);
> it gives me kernel panic if the initial firmware name is passed from
> my remoteproc driver to rproc_alloc()
> and it is a const string.
> It is better to have another modification to the remoteproc_core.c as
> follows in the rproc_alloc().
>
> -       if (!firmware)
> +       if (!firmware) {
>                  /*
>                   * Make room for default firmware name (minus %s plus '\0').
>                   * If the caller didn't pass in a firmware name then
> @@ -1332,17 +1346,29 @@ struct rproc *rproc_alloc(struct device *dev,
> const char *name,
>                   * the caller doesn't pass one).
>                   */
>                  name_len = strlen(name) + strlen(template) - 2 + 1;
> +               p = kmalloc_track_caller(name_len, GFP_KERNEL);
> +               if (!p)
> +                       return NULL;
> +               snprintf(p, name_len, template, name);
> +       } else {
> +               p = kstrndup(firmware, strlen(firmware), GFP_KERNEL);
> +               if (!p) {
> +                       return NULL;
> +               }
> +       }
>
> -       rproc = kzalloc(sizeof(*rproc) + len + name_len, GFP_KERNEL);
> +       rproc = kzalloc(sizeof(*rproc) + len, GFP_KERNEL);

Yes - to address this a very similar change was already introduced into 
Bjorn's tree in
https://github.com/andersson/remoteproc/commit/0f57dc6ae1ff0c702450083176b657ba37c07363


>
>> +       rproc->firmware = p;
>> +out:
>> +       mutex_unlock(&rproc->lock);
>> +
>> +       return err ? err : count;
>> +}
>> +static DEVICE_ATTR_RW(firmware);
>> +
>> +/*
>> + * A state-to-string lookup table, for exposing a human readable state
>> + * via sysfs. Always keep in sync with enum rproc_state
>> + */
>> +static const char * const rproc_state_string[] = {
>> +       [RPROC_OFFLINE]         = "offline",
>> +       [RPROC_SUSPENDED]       = "suspended",
>> +       [RPROC_RUNNING]         = "running",
>> +       [RPROC_CRASHED]         = "crashed",
>> +       [RPROC_LAST]            = "invalid",
>> +};
>> +
>> +/* Expose the state of the remote processor via sysfs */
>> +static ssize_t state_show(struct device *dev, struct device_attribute *attr,
>> +                         char *buf)
>> +{
>> +       struct rproc *rproc = to_rproc(dev);
>> +       unsigned int state;
>> +
>> +       state = rproc->state > RPROC_LAST ? RPROC_LAST : rproc->state;
>> +       return sprintf(buf, "%s\n", rproc_state_string[state]);
>> +}
>> +
>> +/* Change remote processor state via sysfs */
>> +static ssize_t state_store(struct device *dev,
>> +                             struct device_attribute *attr,
>> +                             const char *buf, size_t count)
>> +{
>> +       struct rproc *rproc = to_rproc(dev);
>> +       int ret = 0;
>> +
>> +       if (sysfs_streq(buf, "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(buf, "stop")) {
>> +               if (rproc->state != RPROC_RUNNING)
>> +                       return -EINVAL;
>> +
>> +               rproc_shutdown(rproc);
> The kernel hanged when it was trying to unregister the virtio device
> after I tried"stop".
> It doesn't look like related to this sysfs API. But just wonder have you seen
> similar issue?

I have not seen that in my testing - but I did run into things such as 
virtio_console giving warnings when the device was removed from a 
remoteproc device (which I submitted a fix for). I guess that the 
removal of remoteproc devices at runtime has previously not been as easy 
and therefore not as well tested so there may well be a few issues 
lurking as new code paths are tested, depending on which virtio devices 
your firmware implements.

Thanks,
Matt

>
>> +       } else {
>> +               dev_err(&rproc->dev, "Unrecognised option: %s\n", buf);
>> +               ret = -EINVAL;
>> +       }
>> +       return ret ? ret : count;
>> +}
>> +static DEVICE_ATTR_RW(state);
>> +
>> +static struct attribute *rproc_attrs[] = {
>> +       &dev_attr_firmware.attr,
>> +       &dev_attr_state.attr,
>> +       NULL
>> +};
>> +
>> +static const struct attribute_group rproc_devgroup = {
>> +       .attrs = rproc_attrs
>> +};
>> +
>> +static const struct attribute_group *rproc_devgroups[] = {
>> +       &rproc_devgroup,
>> +       NULL
>> +};
>> +
>> +struct class rproc_class = {
>> +       .name           = "remoteproc",
>> +       .dev_groups     = rproc_devgroups,
>> +};
>> +
>> +int __init rproc_init_sysfs(void)
>> +{
>> +       /* create remoteproc device class for sysfs */
>> +       int err = class_register(&rproc_class);
>> +
>> +       if (err)
>> +               pr_err("remoteproc: unable to register class\n");
>> +       return err;
>> +}
>> +
>> +void __exit rproc_exit_sysfs(void)
>> +{
>> +       class_unregister(&rproc_class);
>> +}
>> --
>> 2.7.4
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-remoteproc" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html

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#1516414

FromWendy Liang <sunnyliangjy@gmail.com>
Date2016-11-07 19:20 +0100
Message-ID<sAWGu-6RG-13@gated-at.bofh.it>
In reply to#1515084
Hi Matt,

On Fri, Nov 4, 2016 at 2:13 AM, Matt Redfearn <matt.redfearn@imgtec.com> wrote:
> Hi Wendy,
>
> Replies inline
>
>
>
> On 03/11/16 23:40, Wendy Liang wrote:
>>
>> HI Matt,
>>
>> Thanks for your patch. I am trying it.
>>
>> Please see my questions inline.
>>
>> Thanks,
>> Wendy
>>
>> On Wed, Oct 19, 2016 at 5:05 AM, Matt Redfearn <matt.redfearn@imgtec.com>
>> wrote:
>>>
>>> This patch adds a sysfs interface to rproc allowing the firmware name
>>> and processor state to be changed dynamically.
>>>
>>> State was previously available in debugfs, and is replicated here. The
>>> firmware file allows retrieval of the running firmware name, and a new
>>> one to be specified at run time, so long as the remote processor has
>>> been stopped.
>>>
>>> Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
>>>
>>> ---
>>>
>>> Changes in v3:
>>> Drop call to rproc_add_virtio_devices from sysfs firmware_store
>>> Use strcspn to find firmware name length
>>> Explicit indexes for state strings
>>>
>>> Changes in v2:
>>> Have firmware_store perform the necessary steps inline.
>>> Use sysfs_streq when dealing with writes to sysfs files
>>>
>>>   Documentation/ABI/testing/sysfs-class-remoteproc |  50 ++++++++
>>>   drivers/remoteproc/Makefile                      |   1 +
>>>   drivers/remoteproc/remoteproc_core.c             |   3 +
>>>   drivers/remoteproc/remoteproc_internal.h         |   5 +
>>>   drivers/remoteproc/remoteproc_sysfs.c            | 151
>>> +++++++++++++++++++++++
>>>   5 files changed, 210 insertions(+)
>>>   create mode 100644 Documentation/ABI/testing/sysfs-class-remoteproc
>>>   create mode 100644 drivers/remoteproc/remoteproc_sysfs.c
>>>
>>> diff --git a/Documentation/ABI/testing/sysfs-class-remoteproc
>>> b/Documentation/ABI/testing/sysfs-class-remoteproc
>>> new file mode 100644
>>> index 000000000000..d188afebc8ba
>>> --- /dev/null
>>> +++ b/Documentation/ABI/testing/sysfs-class-remoteproc
>>> @@ -0,0 +1,50 @@
>>> +What:          /sys/class/remoteproc/.../firmware
>>> +Date:          October 2016
>>> +Contact:       Matt Redfearn <matt.redfearn@imgtec.com>
>>> +Description:   Remote processor firmware
>>> +
>>> +               Reports the name of the firmware currently loaded to the
>>> +               remote processor.
>>> +
>>> +               To change the running firmware, ensure the remote
>>> processor is
>>> +               stopped (using /sys/class/remoteproc/.../state) and write
>>> a new filename.
>>> +
>>> +What:          /sys/class/remoteproc/.../state
>>> +Date:          October 2016
>>> +Contact:       Matt Redfearn <matt.redfearn@imgtec.com>
>>> +Description:   Remote processor state
>>> +
>>> +               Reports the state of the remote processor, which will be
>>> one of:
>>> +
>>> +               "offline"
>>> +               "suspended"
>>> +               "running"
>>> +               "crashed"
>>> +               "invalid"
>>> +
>>> +               "offline" means the remote processor is powered off.
>>> +
>>> +               "suspended" means that the remote processor is suspended
>>> and
>>> +               must be woken to receive messages.
>>> +
>>> +               "running" is the normal state of an available remote
>>> processor
>>> +
>>> +               "crashed" indicates that a problem/crash has been
>>> detected on
>>> +               the remote processor.
>>> +
>>> +               "invalid" is returned if the remote processor is in an
>>> +               unknown state.
>>> +
>>> +               Writing this file controls the state of the remote
>>> processor.
>>> +               The following states can be written:
>>> +
>>> +               "start"
>>> +               "stop"
>>> +
>>> +               Writing "start" will attempt to start the processor
>>> running the
>>> +               firmware indicated by, or written to,
>>> +               /sys/class/remoteproc/.../firmware. The remote processor
>>> should
>>> +               transition to "running" state.
>>> +
>>> +               Writing "stop" will attempt to halt the remote processor
>>> and
>>> +               return it to the "offline" state.
>>> diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile
>>> index 6dfb62ed643f..6da9b12f9798 100644
>>> --- a/drivers/remoteproc/Makefile
>>> +++ b/drivers/remoteproc/Makefile
>>> @@ -5,6 +5,7 @@
>>>   obj-$(CONFIG_REMOTEPROC)               += remoteproc.o
>>>   remoteproc-y                           := remoteproc_core.o
>>>   remoteproc-y                           += remoteproc_debugfs.o
>>> +remoteproc-y                           += remoteproc_sysfs.o
>>>   remoteproc-y                           += remoteproc_virtio.o
>>>   remoteproc-y                           += remoteproc_elf_loader.o
>>>   obj-$(CONFIG_OMAP_REMOTEPROC)          += omap_remoteproc.o
>>> diff --git a/drivers/remoteproc/remoteproc_core.c
>>> b/drivers/remoteproc/remoteproc_core.c
>>> index ccc2a73e94dd..b1860949d106 100644
>>> --- a/drivers/remoteproc/remoteproc_core.c
>>> +++ b/drivers/remoteproc/remoteproc_core.c
>>> @@ -1347,6 +1347,7 @@ struct rproc *rproc_alloc(struct device *dev, const
>>> char *name,
>>>          device_initialize(&rproc->dev);
>>>          rproc->dev.parent = dev;
>>>          rproc->dev.type = &rproc_type;
>>> +       rproc->dev.class = &rproc_class;
>>>
>>>          /* Assign a unique device index and name */
>>>          rproc->index = ida_simple_get(&rproc_dev_index, 0, 0,
>>> GFP_KERNEL);
>>> @@ -1485,6 +1486,7 @@ EXPORT_SYMBOL(rproc_report_crash);
>>>
>>>   static int __init remoteproc_init(void)
>>>   {
>>> +       rproc_init_sysfs();
>>>          rproc_init_debugfs();
>>>
>>>          return 0;
>>> @@ -1496,6 +1498,7 @@ static void __exit remoteproc_exit(void)
>>>          ida_destroy(&rproc_dev_index);
>>>
>>>          rproc_exit_debugfs();
>>> +       rproc_exit_sysfs();
>>>   }
>>>   module_exit(remoteproc_exit);
>>>
>>> diff --git a/drivers/remoteproc/remoteproc_internal.h
>>> b/drivers/remoteproc/remoteproc_internal.h
>>> index 4cf93ca2816e..c2c3e4762b90 100644
>>> --- a/drivers/remoteproc/remoteproc_internal.h
>>> +++ b/drivers/remoteproc/remoteproc_internal.h
>>> @@ -63,6 +63,11 @@ void rproc_create_debug_dir(struct rproc *rproc);
>>>   void rproc_init_debugfs(void);
>>>   void rproc_exit_debugfs(void);
>>>
>>> +/* from remoteproc_sysfs.c */
>>> +extern struct class rproc_class;
>>> +int rproc_init_sysfs(void);
>>> +void rproc_exit_sysfs(void);
>>> +
>>>   void rproc_free_vring(struct rproc_vring *rvring);
>>>   int rproc_alloc_vring(struct rproc_vdev *rvdev, int i);
>>>
>>> diff --git a/drivers/remoteproc/remoteproc_sysfs.c
>>> b/drivers/remoteproc/remoteproc_sysfs.c
>>> new file mode 100644
>>> index 000000000000..bc5b0e00efb1
>>> --- /dev/null
>>> +++ b/drivers/remoteproc/remoteproc_sysfs.c
>>> @@ -0,0 +1,151 @@
>>> +/*
>>> + * Remote Processor Framework
>>> + *
>>> + * This program is free software; you can redistribute it and/or
>>> + * modify it under the terms of the GNU General Public License
>>> + * version 2 as published by the Free Software Foundation.
>>> + *
>>> + * This program is distributed in the hope that it will be useful,
>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>>> + * GNU General Public License for more details.
>>> + */
>>> +
>>> +#include <linux/remoteproc.h>
>>> +
>>> +#include "remoteproc_internal.h"
>>> +
>>> +#define to_rproc(d) container_of(d, struct rproc, dev)
>>> +
>>> +/* Expose the loaded / running firmware name via sysfs */
>>> +static ssize_t firmware_show(struct device *dev, struct device_attribute
>>> *attr,
>>> +                         char *buf)
>>> +{
>>> +       struct rproc *rproc = to_rproc(dev);
>>> +
>>> +       return sprintf(buf, "%s\n", rproc->firmware);
>>> +}
>>> +
>>> +/* Change firmware name via sysfs */
>>> +static ssize_t firmware_store(struct device *dev,
>>> +                             struct device_attribute *attr,
>>> +                             const char *buf, size_t count)
>>> +{
>>> +       struct rproc *rproc = to_rproc(dev);
>>> +       char *p;
>>> +       int err, len = count;
>>> +
>>> +       err = mutex_lock_interruptible(&rproc->lock);
>>> +       if (err) {
>>> +               dev_err(dev, "can't lock rproc %s: %d\n", rproc->name,
>>> err);
>>> +               return -EINVAL;
>>> +       }
>>> +
>>> +       if (rproc->state != RPROC_OFFLINE) {
>>> +               dev_err(dev, "can't change firmware while running\n");
>>> +               err = -EBUSY;
>>> +               goto out;
>>> +       }
>>> +
>>> +       len = strcspn(buf, "\n");
>>> +
>>> +       p = kstrndup(buf, len, GFP_KERNEL);
>>> +       if (!p) {
>>> +               err = -ENOMEM;
>>> +               goto out;
>>> +       }
>>> +
>>> +       kfree(rproc->firmware);
>>
>> it gives me kernel panic if the initial firmware name is passed from
>> my remoteproc driver to rproc_alloc()
>> and it is a const string.
>> It is better to have another modification to the remoteproc_core.c as
>> follows in the rproc_alloc().
>>
>> -       if (!firmware)
>> +       if (!firmware) {
>>                  /*
>>                   * Make room for default firmware name (minus %s plus
>> '\0').
>>                   * If the caller didn't pass in a firmware name then
>> @@ -1332,17 +1346,29 @@ struct rproc *rproc_alloc(struct device *dev,
>> const char *name,
>>                   * the caller doesn't pass one).
>>                   */
>>                  name_len = strlen(name) + strlen(template) - 2 + 1;
>> +               p = kmalloc_track_caller(name_len, GFP_KERNEL);
>> +               if (!p)
>> +                       return NULL;
>> +               snprintf(p, name_len, template, name);
>> +       } else {
>> +               p = kstrndup(firmware, strlen(firmware), GFP_KERNEL);
>> +               if (!p) {
>> +                       return NULL;
>> +               }
>> +       }
>>
>> -       rproc = kzalloc(sizeof(*rproc) + len + name_len, GFP_KERNEL);
>> +       rproc = kzalloc(sizeof(*rproc) + len, GFP_KERNEL);
>
>
> Yes - to address this a very similar change was already introduced into
> Bjorn's tree in
> https://github.com/andersson/remoteproc/commit/0f57dc6ae1ff0c702450083176b657ba37c07363
Great. I didn't know that.

>
>
>
>>
>>> +       rproc->firmware = p;
>>> +out:
>>> +       mutex_unlock(&rproc->lock);
>>> +
>>> +       return err ? err : count;
>>> +}
>>> +static DEVICE_ATTR_RW(firmware);
>>> +
>>> +/*
>>> + * A state-to-string lookup table, for exposing a human readable state
>>> + * via sysfs. Always keep in sync with enum rproc_state
>>> + */
>>> +static const char * const rproc_state_string[] = {
>>> +       [RPROC_OFFLINE]         = "offline",
>>> +       [RPROC_SUSPENDED]       = "suspended",
>>> +       [RPROC_RUNNING]         = "running",
>>> +       [RPROC_CRASHED]         = "crashed",
>>> +       [RPROC_LAST]            = "invalid",
>>> +};
>>> +
>>> +/* Expose the state of the remote processor via sysfs */
>>> +static ssize_t state_show(struct device *dev, struct device_attribute
>>> *attr,
>>> +                         char *buf)
>>> +{
>>> +       struct rproc *rproc = to_rproc(dev);
>>> +       unsigned int state;
>>> +
>>> +       state = rproc->state > RPROC_LAST ? RPROC_LAST : rproc->state;
>>> +       return sprintf(buf, "%s\n", rproc_state_string[state]);
>>> +}
>>> +
>>> +/* Change remote processor state via sysfs */
>>> +static ssize_t state_store(struct device *dev,
>>> +                             struct device_attribute *attr,
>>> +                             const char *buf, size_t count)
>>> +{
>>> +       struct rproc *rproc = to_rproc(dev);
>>> +       int ret = 0;
>>> +
>>> +       if (sysfs_streq(buf, "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(buf, "stop")) {
>>> +               if (rproc->state != RPROC_RUNNING)
>>> +                       return -EINVAL;
>>> +
>>> +               rproc_shutdown(rproc);
>>
>> The kernel hanged when it was trying to unregister the virtio device
>> after I tried"stop".
>> It doesn't look like related to this sysfs API. But just wonder have you
>> seen
>> similar issue?
>
>
> I have not seen that in my testing - but I did run into things such as
> virtio_console giving warnings when the device was removed from a remoteproc
> device (which I submitted a fix for). I guess that the removal of remoteproc
> devices at runtime has previously not been as easy and therefore not as well
> tested so there may well be a few issues lurking as new code paths are
> tested, depending on which virtio devices your firmware implements.
It is just a vring deivce, I am still checking why it hanged at
device_unregister() in the unregister_virtio_device().

>
> Thanks,
> Matt
>
>
>>
>>> +       } else {
>>> +               dev_err(&rproc->dev, "Unrecognised option: %s\n", buf);
>>> +               ret = -EINVAL;
>>> +       }
>>> +       return ret ? ret : count;
>>> +}
>>> +static DEVICE_ATTR_RW(state);
>>> +
>>> +static struct attribute *rproc_attrs[] = {
>>> +       &dev_attr_firmware.attr,
>>> +       &dev_attr_state.attr,
>>> +       NULL
>>> +};
>>> +
>>> +static const struct attribute_group rproc_devgroup = {
>>> +       .attrs = rproc_attrs
>>> +};
>>> +
>>> +static const struct attribute_group *rproc_devgroups[] = {
>>> +       &rproc_devgroup,
>>> +       NULL
>>> +};
>>> +
>>> +struct class rproc_class = {
>>> +       .name           = "remoteproc",
>>> +       .dev_groups     = rproc_devgroups,
>>> +};
>>> +
>>> +int __init rproc_init_sysfs(void)
>>> +{
>>> +       /* create remoteproc device class for sysfs */
>>> +       int err = class_register(&rproc_class);
>>> +
>>> +       if (err)
>>> +               pr_err("remoteproc: unable to register class\n");
>>> +       return err;
>>> +}
>>> +
>>> +void __exit rproc_exit_sysfs(void)
>>> +{
>>> +       class_unregister(&rproc_class);
>>> +}
>>> --
>>> 2.7.4
>>>
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe
>>> linux-remoteproc" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
>

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