linux/drivers/rpmsg/rpmsg_core.c
Uwe Kleine-König fc7a6209d5 bus: Make remove callback return void
The driver core ignores the return value of this callback because there
is only little it can do when a device disappears.

This is the final bit of a long lasting cleanup quest where several
buses were converted to also return void from their remove callback.
Additionally some resource leaks were fixed that were caused by drivers
returning an error code in the expectation that the driver won't go
away.

With struct bus_type::remove returning void it's prevented that newly
implemented buses return an ignored error code and so don't anticipate
wrong expectations for driver authors.

Reviewed-by: Tom Rix <trix@redhat.com> (For fpga)
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Cornelia Huck <cohuck@redhat.com> (For drivers/s390 and drivers/vfio)
Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> (For ARM, Amba and related parts)
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Chen-Yu Tsai <wens@csie.org> (for sunxi-rsb)
Acked-by: Pali Rohár <pali@kernel.org>
Acked-by: Mauro Carvalho Chehab <mchehab@kernel.org> (for media)
Acked-by: Hans de Goede <hdegoede@redhat.com> (For drivers/platform)
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-By: Vinod Koul <vkoul@kernel.org>
Acked-by: Juergen Gross <jgross@suse.com> (For xen)
Acked-by: Lee Jones <lee.jones@linaro.org> (For mfd)
Acked-by: Johannes Thumshirn <jth@kernel.org> (For mcb)
Acked-by: Johan Hovold <johan@kernel.org>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> (For slimbus)
Acked-by: Kirti Wankhede <kwankhede@nvidia.com> (For vfio)
Acked-by: Maximilian Luz <luzmaximilian@gmail.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> (For ulpi and typec)
Acked-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com> (For ipack)
Acked-by: Geoff Levand <geoff@infradead.org> (For ps3)
Acked-by: Yehezkel Bernat <YehezkelShB@gmail.com> (For thunderbolt)
Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> (For intel_th)
Acked-by: Dominik Brodowski <linux@dominikbrodowski.net> (For pcmcia)
Acked-by: Rafael J. Wysocki <rafael@kernel.org> (For ACPI)
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org> (rpmsg and apr)
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> (For intel-ish-hid)
Acked-by: Dan Williams <dan.j.williams@intel.com> (For CXL, DAX, and NVDIMM)
Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com> (For isa)
Acked-by: Stefan Richter <stefanr@s5r6.in-berlin.de> (For firewire)
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> (For hid)
Acked-by: Thorsten Scherer <t.scherer@eckelmann.de> (For siox)
Acked-by: Sven Van Asbroeck <TheSven73@gmail.com> (For anybuss)
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> (For MMC)
Acked-by: Wolfram Sang <wsa@kernel.org> # for I2C
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Finn Thain <fthain@linux-m68k.org>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20210713193522.1770306-6-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-21 11:53:42 +02:00

648 lines
18 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* remote processor messaging bus
*
* Copyright (C) 2011 Texas Instruments, Inc.
* Copyright (C) 2011 Google, Inc.
*
* Ohad Ben-Cohen <ohad@wizery.com>
* Brian Swetland <swetland@google.com>
*/
#define pr_fmt(fmt) "%s: " fmt, __func__
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/rpmsg.h>
#include <linux/of_device.h>
#include <linux/pm_domain.h>
#include <linux/slab.h>
#include "rpmsg_internal.h"
/**
* rpmsg_create_channel() - create a new rpmsg channel
* using its name and address info.
* @rpdev: rpmsg device
* @chinfo: channel_info to bind
*
* Returns a pointer to the new rpmsg device on success, or NULL on error.
*/
struct rpmsg_device *rpmsg_create_channel(struct rpmsg_device *rpdev,
struct rpmsg_channel_info *chinfo)
{
if (WARN_ON(!rpdev))
return NULL;
if (!rpdev->ops || !rpdev->ops->create_channel) {
dev_err(&rpdev->dev, "no create_channel ops found\n");
return NULL;
}
return rpdev->ops->create_channel(rpdev, chinfo);
}
EXPORT_SYMBOL(rpmsg_create_channel);
/**
* rpmsg_release_channel() - release a rpmsg channel
* using its name and address info.
* @rpdev: rpmsg device
* @chinfo: channel_info to bind
*
* Returns 0 on success or an appropriate error value.
*/
int rpmsg_release_channel(struct rpmsg_device *rpdev,
struct rpmsg_channel_info *chinfo)
{
if (WARN_ON(!rpdev))
return -EINVAL;
if (!rpdev->ops || !rpdev->ops->release_channel) {
dev_err(&rpdev->dev, "no release_channel ops found\n");
return -ENXIO;
}
return rpdev->ops->release_channel(rpdev, chinfo);
}
EXPORT_SYMBOL(rpmsg_release_channel);
/**
* rpmsg_create_ept() - create a new rpmsg_endpoint
* @rpdev: rpmsg channel device
* @cb: rx callback handler
* @priv: private data for the driver's use
* @chinfo: channel_info with the local rpmsg address to bind with @cb
*
* Every rpmsg address in the system is bound to an rx callback (so when
* inbound messages arrive, they are dispatched by the rpmsg bus using the
* appropriate callback handler) by means of an rpmsg_endpoint struct.
*
* This function allows drivers to create such an endpoint, and by that,
* bind a callback, and possibly some private data too, to an rpmsg address
* (either one that is known in advance, or one that will be dynamically
* assigned for them).
*
* Simple rpmsg drivers need not call rpmsg_create_ept, because an endpoint
* is already created for them when they are probed by the rpmsg bus
* (using the rx callback provided when they registered to the rpmsg bus).
*
* So things should just work for simple drivers: they already have an
* endpoint, their rx callback is bound to their rpmsg address, and when
* relevant inbound messages arrive (i.e. messages which their dst address
* equals to the src address of their rpmsg channel), the driver's handler
* is invoked to process it.
*
* That said, more complicated drivers might need to allocate
* additional rpmsg addresses, and bind them to different rx callbacks.
* To accomplish that, those drivers need to call this function.
*
* Drivers should provide their @rpdev channel (so the new endpoint would belong
* to the same remote processor their channel belongs to), an rx callback
* function, an optional private data (which is provided back when the
* rx callback is invoked), and an address they want to bind with the
* callback. If @addr is RPMSG_ADDR_ANY, then rpmsg_create_ept will
* dynamically assign them an available rpmsg address (drivers should have
* a very good reason why not to always use RPMSG_ADDR_ANY here).
*
* Returns a pointer to the endpoint on success, or NULL on error.
*/
struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *rpdev,
rpmsg_rx_cb_t cb, void *priv,
struct rpmsg_channel_info chinfo)
{
if (WARN_ON(!rpdev))
return NULL;
return rpdev->ops->create_ept(rpdev, cb, priv, chinfo);
}
EXPORT_SYMBOL(rpmsg_create_ept);
/**
* rpmsg_destroy_ept() - destroy an existing rpmsg endpoint
* @ept: endpoing to destroy
*
* Should be used by drivers to destroy an rpmsg endpoint previously
* created with rpmsg_create_ept(). As with other types of "free" NULL
* is a valid parameter.
*/
void rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
{
if (ept && ept->ops)
ept->ops->destroy_ept(ept);
}
EXPORT_SYMBOL(rpmsg_destroy_ept);
/**
* rpmsg_send() - send a message across to the remote processor
* @ept: the rpmsg endpoint
* @data: payload of message
* @len: length of payload
*
* This function sends @data of length @len on the @ept endpoint.
* The message will be sent to the remote processor which the @ept
* endpoint belongs to, using @ept's address and its associated rpmsg
* device destination addresses.
* In case there are no TX buffers available, the function will block until
* one becomes available, or a timeout of 15 seconds elapses. When the latter
* happens, -ERESTARTSYS is returned.
*
* Can only be called from process context (for now).
*
* Returns 0 on success and an appropriate error value on failure.
*/
int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
{
if (WARN_ON(!ept))
return -EINVAL;
if (!ept->ops->send)
return -ENXIO;
return ept->ops->send(ept, data, len);
}
EXPORT_SYMBOL(rpmsg_send);
/**
* rpmsg_sendto() - send a message across to the remote processor, specify dst
* @ept: the rpmsg endpoint
* @data: payload of message
* @len: length of payload
* @dst: destination address
*
* This function sends @data of length @len to the remote @dst address.
* The message will be sent to the remote processor which the @ept
* endpoint belongs to, using @ept's address as source.
* In case there are no TX buffers available, the function will block until
* one becomes available, or a timeout of 15 seconds elapses. When the latter
* happens, -ERESTARTSYS is returned.
*
* Can only be called from process context (for now).
*
* Returns 0 on success and an appropriate error value on failure.
*/
int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
{
if (WARN_ON(!ept))
return -EINVAL;
if (!ept->ops->sendto)
return -ENXIO;
return ept->ops->sendto(ept, data, len, dst);
}
EXPORT_SYMBOL(rpmsg_sendto);
/**
* rpmsg_send_offchannel() - send a message using explicit src/dst addresses
* @ept: the rpmsg endpoint
* @src: source address
* @dst: destination address
* @data: payload of message
* @len: length of payload
*
* This function sends @data of length @len to the remote @dst address,
* and uses @src as the source address.
* The message will be sent to the remote processor which the @ept
* endpoint belongs to.
* In case there are no TX buffers available, the function will block until
* one becomes available, or a timeout of 15 seconds elapses. When the latter
* happens, -ERESTARTSYS is returned.
*
* Can only be called from process context (for now).
*
* Returns 0 on success and an appropriate error value on failure.
*/
int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
void *data, int len)
{
if (WARN_ON(!ept))
return -EINVAL;
if (!ept->ops->send_offchannel)
return -ENXIO;
return ept->ops->send_offchannel(ept, src, dst, data, len);
}
EXPORT_SYMBOL(rpmsg_send_offchannel);
/**
* rpmsg_trysend() - send a message across to the remote processor
* @ept: the rpmsg endpoint
* @data: payload of message
* @len: length of payload
*
* This function sends @data of length @len on the @ept endpoint.
* The message will be sent to the remote processor which the @ept
* endpoint belongs to, using @ept's address as source and its associated
* rpdev's address as destination.
* In case there are no TX buffers available, the function will immediately
* return -ENOMEM without waiting until one becomes available.
*
* Can only be called from process context (for now).
*
* Returns 0 on success and an appropriate error value on failure.
*/
int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
{
if (WARN_ON(!ept))
return -EINVAL;
if (!ept->ops->trysend)
return -ENXIO;
return ept->ops->trysend(ept, data, len);
}
EXPORT_SYMBOL(rpmsg_trysend);
/**
* rpmsg_trysendto() - send a message across to the remote processor, specify dst
* @ept: the rpmsg endpoint
* @data: payload of message
* @len: length of payload
* @dst: destination address
*
* This function sends @data of length @len to the remote @dst address.
* The message will be sent to the remote processor which the @ept
* endpoint belongs to, using @ept's address as source.
* In case there are no TX buffers available, the function will immediately
* return -ENOMEM without waiting until one becomes available.
*
* Can only be called from process context (for now).
*
* Returns 0 on success and an appropriate error value on failure.
*/
int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
{
if (WARN_ON(!ept))
return -EINVAL;
if (!ept->ops->trysendto)
return -ENXIO;
return ept->ops->trysendto(ept, data, len, dst);
}
EXPORT_SYMBOL(rpmsg_trysendto);
/**
* rpmsg_poll() - poll the endpoint's send buffers
* @ept: the rpmsg endpoint
* @filp: file for poll_wait()
* @wait: poll_table for poll_wait()
*
* Returns mask representing the current state of the endpoint's send buffers
*/
__poll_t rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp,
poll_table *wait)
{
if (WARN_ON(!ept))
return 0;
if (!ept->ops->poll)
return 0;
return ept->ops->poll(ept, filp, wait);
}
EXPORT_SYMBOL(rpmsg_poll);
/**
* rpmsg_trysend_offchannel() - send a message using explicit src/dst addresses
* @ept: the rpmsg endpoint
* @src: source address
* @dst: destination address
* @data: payload of message
* @len: length of payload
*
* This function sends @data of length @len to the remote @dst address,
* and uses @src as the source address.
* The message will be sent to the remote processor which the @ept
* endpoint belongs to.
* In case there are no TX buffers available, the function will immediately
* return -ENOMEM without waiting until one becomes available.
*
* Can only be called from process context (for now).
*
* Returns 0 on success and an appropriate error value on failure.
*/
int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
void *data, int len)
{
if (WARN_ON(!ept))
return -EINVAL;
if (!ept->ops->trysend_offchannel)
return -ENXIO;
return ept->ops->trysend_offchannel(ept, src, dst, data, len);
}
EXPORT_SYMBOL(rpmsg_trysend_offchannel);
/*
* match a rpmsg channel with a channel info struct.
* this is used to make sure we're not creating rpmsg devices for channels
* that already exist.
*/
static int rpmsg_device_match(struct device *dev, void *data)
{
struct rpmsg_channel_info *chinfo = data;
struct rpmsg_device *rpdev = to_rpmsg_device(dev);
if (chinfo->src != RPMSG_ADDR_ANY && chinfo->src != rpdev->src)
return 0;
if (chinfo->dst != RPMSG_ADDR_ANY && chinfo->dst != rpdev->dst)
return 0;
if (strncmp(chinfo->name, rpdev->id.name, RPMSG_NAME_SIZE))
return 0;
/* found a match ! */
return 1;
}
struct device *rpmsg_find_device(struct device *parent,
struct rpmsg_channel_info *chinfo)
{
return device_find_child(parent, chinfo, rpmsg_device_match);
}
EXPORT_SYMBOL(rpmsg_find_device);
/* sysfs show configuration fields */
#define rpmsg_show_attr(field, path, format_string) \
static ssize_t \
field##_show(struct device *dev, \
struct device_attribute *attr, char *buf) \
{ \
struct rpmsg_device *rpdev = to_rpmsg_device(dev); \
\
return sprintf(buf, format_string, rpdev->path); \
} \
static DEVICE_ATTR_RO(field);
#define rpmsg_string_attr(field, member) \
static ssize_t \
field##_store(struct device *dev, struct device_attribute *attr, \
const char *buf, size_t sz) \
{ \
struct rpmsg_device *rpdev = to_rpmsg_device(dev); \
char *new, *old; \
\
new = kstrndup(buf, sz, GFP_KERNEL); \
if (!new) \
return -ENOMEM; \
new[strcspn(new, "\n")] = '\0'; \
\
device_lock(dev); \
old = rpdev->member; \
if (strlen(new)) { \
rpdev->member = new; \
} else { \
kfree(new); \
rpdev->member = NULL; \
} \
device_unlock(dev); \
\
kfree(old); \
\
return sz; \
} \
static ssize_t \
field##_show(struct device *dev, \
struct device_attribute *attr, char *buf) \
{ \
struct rpmsg_device *rpdev = to_rpmsg_device(dev); \
\
return sprintf(buf, "%s\n", rpdev->member); \
} \
static DEVICE_ATTR_RW(field)
/* for more info, see Documentation/ABI/testing/sysfs-bus-rpmsg */
rpmsg_show_attr(name, id.name, "%s\n");
rpmsg_show_attr(src, src, "0x%x\n");
rpmsg_show_attr(dst, dst, "0x%x\n");
rpmsg_show_attr(announce, announce ? "true" : "false", "%s\n");
rpmsg_string_attr(driver_override, driver_override);
static ssize_t modalias_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct rpmsg_device *rpdev = to_rpmsg_device(dev);
ssize_t len;
len = of_device_modalias(dev, buf, PAGE_SIZE);
if (len != -ENODEV)
return len;
return sprintf(buf, RPMSG_DEVICE_MODALIAS_FMT "\n", rpdev->id.name);
}
static DEVICE_ATTR_RO(modalias);
static struct attribute *rpmsg_dev_attrs[] = {
&dev_attr_name.attr,
&dev_attr_modalias.attr,
&dev_attr_dst.attr,
&dev_attr_src.attr,
&dev_attr_announce.attr,
&dev_attr_driver_override.attr,
NULL,
};
ATTRIBUTE_GROUPS(rpmsg_dev);
/* rpmsg devices and drivers are matched using the service name */
static inline int rpmsg_id_match(const struct rpmsg_device *rpdev,
const struct rpmsg_device_id *id)
{
return strncmp(id->name, rpdev->id.name, RPMSG_NAME_SIZE) == 0;
}
/* match rpmsg channel and rpmsg driver */
static int rpmsg_dev_match(struct device *dev, struct device_driver *drv)
{
struct rpmsg_device *rpdev = to_rpmsg_device(dev);
struct rpmsg_driver *rpdrv = to_rpmsg_driver(drv);
const struct rpmsg_device_id *ids = rpdrv->id_table;
unsigned int i;
if (rpdev->driver_override)
return !strcmp(rpdev->driver_override, drv->name);
if (ids)
for (i = 0; ids[i].name[0]; i++)
if (rpmsg_id_match(rpdev, &ids[i])) {
rpdev->id.driver_data = ids[i].driver_data;
return 1;
}
return of_driver_match_device(dev, drv);
}
static int rpmsg_uevent(struct device *dev, struct kobj_uevent_env *env)
{
struct rpmsg_device *rpdev = to_rpmsg_device(dev);
int ret;
ret = of_device_uevent_modalias(dev, env);
if (ret != -ENODEV)
return ret;
return add_uevent_var(env, "MODALIAS=" RPMSG_DEVICE_MODALIAS_FMT,
rpdev->id.name);
}
/*
* when an rpmsg driver is probed with a channel, we seamlessly create
* it an endpoint, binding its rx callback to a unique local rpmsg
* address.
*
* if we need to, we also announce about this channel to the remote
* processor (needed in case the driver is exposing an rpmsg service).
*/
static int rpmsg_dev_probe(struct device *dev)
{
struct rpmsg_device *rpdev = to_rpmsg_device(dev);
struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
struct rpmsg_channel_info chinfo = {};
struct rpmsg_endpoint *ept = NULL;
int err;
err = dev_pm_domain_attach(dev, true);
if (err)
goto out;
if (rpdrv->callback) {
strncpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
chinfo.src = rpdev->src;
chinfo.dst = RPMSG_ADDR_ANY;
ept = rpmsg_create_ept(rpdev, rpdrv->callback, NULL, chinfo);
if (!ept) {
dev_err(dev, "failed to create endpoint\n");
err = -ENOMEM;
goto out;
}
rpdev->ept = ept;
rpdev->src = ept->addr;
}
err = rpdrv->probe(rpdev);
if (err) {
dev_err(dev, "%s: failed: %d\n", __func__, err);
if (ept)
rpmsg_destroy_ept(ept);
goto out;
}
if (ept && rpdev->ops->announce_create)
err = rpdev->ops->announce_create(rpdev);
out:
return err;
}
static void rpmsg_dev_remove(struct device *dev)
{
struct rpmsg_device *rpdev = to_rpmsg_device(dev);
struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
if (rpdev->ops->announce_destroy)
rpdev->ops->announce_destroy(rpdev);
if (rpdrv->remove)
rpdrv->remove(rpdev);
dev_pm_domain_detach(dev, true);
if (rpdev->ept)
rpmsg_destroy_ept(rpdev->ept);
}
static struct bus_type rpmsg_bus = {
.name = "rpmsg",
.match = rpmsg_dev_match,
.dev_groups = rpmsg_dev_groups,
.uevent = rpmsg_uevent,
.probe = rpmsg_dev_probe,
.remove = rpmsg_dev_remove,
};
int rpmsg_register_device(struct rpmsg_device *rpdev)
{
struct device *dev = &rpdev->dev;
int ret;
dev_set_name(&rpdev->dev, "%s.%s.%d.%d", dev_name(dev->parent),
rpdev->id.name, rpdev->src, rpdev->dst);
rpdev->dev.bus = &rpmsg_bus;
ret = device_register(&rpdev->dev);
if (ret) {
dev_err(dev, "device_register failed: %d\n", ret);
put_device(&rpdev->dev);
}
return ret;
}
EXPORT_SYMBOL(rpmsg_register_device);
/*
* find an existing channel using its name + address properties,
* and destroy it
*/
int rpmsg_unregister_device(struct device *parent,
struct rpmsg_channel_info *chinfo)
{
struct device *dev;
dev = rpmsg_find_device(parent, chinfo);
if (!dev)
return -EINVAL;
device_unregister(dev);
put_device(dev);
return 0;
}
EXPORT_SYMBOL(rpmsg_unregister_device);
/**
* __register_rpmsg_driver() - register an rpmsg driver with the rpmsg bus
* @rpdrv: pointer to a struct rpmsg_driver
* @owner: owning module/driver
*
* Returns 0 on success, and an appropriate error value on failure.
*/
int __register_rpmsg_driver(struct rpmsg_driver *rpdrv, struct module *owner)
{
rpdrv->drv.bus = &rpmsg_bus;
rpdrv->drv.owner = owner;
return driver_register(&rpdrv->drv);
}
EXPORT_SYMBOL(__register_rpmsg_driver);
/**
* unregister_rpmsg_driver() - unregister an rpmsg driver from the rpmsg bus
* @rpdrv: pointer to a struct rpmsg_driver
*
* Returns 0 on success, and an appropriate error value on failure.
*/
void unregister_rpmsg_driver(struct rpmsg_driver *rpdrv)
{
driver_unregister(&rpdrv->drv);
}
EXPORT_SYMBOL(unregister_rpmsg_driver);
static int __init rpmsg_init(void)
{
int ret;
ret = bus_register(&rpmsg_bus);
if (ret)
pr_err("failed to register rpmsg bus: %d\n", ret);
return ret;
}
postcore_initcall(rpmsg_init);
static void __exit rpmsg_fini(void)
{
bus_unregister(&rpmsg_bus);
}
module_exit(rpmsg_fini);
MODULE_DESCRIPTION("remote processor messaging bus");
MODULE_LICENSE("GPL v2");