On Tue 11 Oct 06:39 PDT 2016, Matt Redfearn 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.redfe...@imgtec.com>
>
> ---
>
> 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 | 132
> +++++++++++++++++++++++
> 5 files changed, 191 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.redfe...@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.redfe...@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 92d3758bd15c..666258bd80aa 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 2152b484f314..642c5b58fec5 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -1455,6 +1455,7 @@ 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);
> @@ -1580,6 +1581,7 @@ EXPORT_SYMBOL(rproc_report_crash);
>
> static int __init remoteproc_init(void)
> {
> + rproc_init_sysfs();
> rproc_init_debugfs();
>
> return 0;
> @@ -1591,6 +1593,7 @@ 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 837faf2677a6..2beb86ddfacc 100644
> --- a/drivers/remoteproc/remoteproc_internal.h
> +++ b/drivers/remoteproc/remoteproc_internal.h
> @@ -64,6 +64,11 @@ 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..892599863ca6
> --- /dev/null
> +++ b/drivers/remoteproc/remoteproc_sysfs.c
> @@ -0,0 +1,132 @@
> +/*
> + * 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);
> +
> + if (rproc->firmware)
> + return sprintf(buf, "%s\n", rproc->firmware);
> + else
> + return sprintf(buf, "unknown");
Per current and future logic, rproc->firmware can't be NULL.
> +}
> +
> +/* 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);
> + int err;
> +
> + err = rproc_change_firmware(rproc, buf);
Rather than introducing rproc_set_firmware_name() and
rproc_change_firmware() - which does not have a use case beyond this
caller you should be able to keep rproc_alloc() more or less as is, and
then inline a simplified version (as we don't have to deal with the
templated case here).
> + return err ? err : count;
> +}
> +static DEVICE_ATTR_RW(firmware);
> +
Extra newline...
> +
> +/*
> + * 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[] = {
> + "offline",
> + "suspended",
> + "running",
> + "crashed",
> + "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 scnprintf(buf, 30, "%.28s (%d)\n",
> + rproc_state_string[state], rproc->state);
The documentation above does not describe the "($state)" part, which I'm
fine leaving out. We know the strings are below PAGE_SIZE, so you can
use sprintf().
> +}
> +
> +/* 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;
> + int len = count;
> +
> + if (buf[len - 1] == '\n')
> + len--;
> +
> + if (!strncmp(buf, "start", len)) {
Please use sysfs_streq() instead, it will handle the \n for you.
> + if (rproc->state == RPROC_RUNNING)
> + return -EBUSY;
> +
> + ret = rproc_boot(rproc);
> + if (ret)
> + dev_err(&rproc->dev, "Boot failed: %d\n", ret);
> + } else if (!strncmp(buf, "stop", len)) {
> + rproc_shutdown(rproc);
> + } else {
> + dev_err(&rproc->dev, "Unrecognised option: %s\n", buf);
> + ret = -EINVAL;
> + }
> + return ret ? ret : count;
> +}
> +static DEVICE_ATTR_RW(state);
> +
> +static const 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);
> +}
Besides these nits, I think this looks good.
Thanks,
Bjorn
