linux/drivers/mmc/core/sdio_bus.c
Ulf Hansson 2ac55d5e5e mmc: core: Re-work HW reset for SDIO cards
It have turned out that it's not a good idea to unconditionally do a power
cycle and then to re-initialize the SDIO card, as currently done through
mmc_hw_reset() -> mmc_sdio_hw_reset(). This because there may be multiple
SDIO func drivers probed, who also shares the same SDIO card.

To address these scenarios, one may be tempted to use a notification
mechanism, as to allow the core to inform each of the probed func drivers,
about an ongoing HW reset. However, supporting such an operation from the
func driver point of view, may not be entirely trivial.

Therefore, let's use a more simplistic approach to solve the problem, by
instead forcing the card to be removed and re-detected, via scheduling a
rescan-work. In this way, we can rely on existing infrastructure, as the
func driver's ->remove() and ->probe() callbacks, becomes invoked to deal
with the cleanup and the re-initialization.

This solution may be considered as rather heavy, especially if a func
driver doesn't share its card with other func drivers. To address this,
let's keep the current immediate HW reset option as well, but run it only
when there is one func driver probed for the card.

Finally, to allow the caller of mmc_hw_reset(), to understand if the reset
is being asynchronously managed from a scheduled work, it returns 1
(propagated from mmc_sdio_hw_reset()). If the HW reset is executed
successfully and synchronously it returns 0, which maintains the existing
behaviour.

Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
2019-11-14 16:28:56 +01:00

362 lines
8.2 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* linux/drivers/mmc/core/sdio_bus.c
*
* Copyright 2007 Pierre Ossman
*
* SDIO function driver model
*/
#include <linux/device.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/pm_runtime.h>
#include <linux/pm_domain.h>
#include <linux/acpi.h>
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
#include <linux/mmc/sdio_func.h>
#include <linux/of.h>
#include "core.h"
#include "card.h"
#include "sdio_cis.h"
#include "sdio_bus.h"
#define to_sdio_driver(d) container_of(d, struct sdio_driver, drv)
/* show configuration fields */
#define sdio_config_attr(field, format_string) \
static ssize_t \
field##_show(struct device *dev, struct device_attribute *attr, char *buf) \
{ \
struct sdio_func *func; \
\
func = dev_to_sdio_func (dev); \
return sprintf (buf, format_string, func->field); \
} \
static DEVICE_ATTR_RO(field)
sdio_config_attr(class, "0x%02x\n");
sdio_config_attr(vendor, "0x%04x\n");
sdio_config_attr(device, "0x%04x\n");
static ssize_t modalias_show(struct device *dev, struct device_attribute *attr, char *buf)
{
struct sdio_func *func = dev_to_sdio_func (dev);
return sprintf(buf, "sdio:c%02Xv%04Xd%04X\n",
func->class, func->vendor, func->device);
}
static DEVICE_ATTR_RO(modalias);
static struct attribute *sdio_dev_attrs[] = {
&dev_attr_class.attr,
&dev_attr_vendor.attr,
&dev_attr_device.attr,
&dev_attr_modalias.attr,
NULL,
};
ATTRIBUTE_GROUPS(sdio_dev);
static const struct sdio_device_id *sdio_match_one(struct sdio_func *func,
const struct sdio_device_id *id)
{
if (id->class != (__u8)SDIO_ANY_ID && id->class != func->class)
return NULL;
if (id->vendor != (__u16)SDIO_ANY_ID && id->vendor != func->vendor)
return NULL;
if (id->device != (__u16)SDIO_ANY_ID && id->device != func->device)
return NULL;
return id;
}
static const struct sdio_device_id *sdio_match_device(struct sdio_func *func,
struct sdio_driver *sdrv)
{
const struct sdio_device_id *ids;
ids = sdrv->id_table;
if (ids) {
while (ids->class || ids->vendor || ids->device) {
if (sdio_match_one(func, ids))
return ids;
ids++;
}
}
return NULL;
}
static int sdio_bus_match(struct device *dev, struct device_driver *drv)
{
struct sdio_func *func = dev_to_sdio_func(dev);
struct sdio_driver *sdrv = to_sdio_driver(drv);
if (sdio_match_device(func, sdrv))
return 1;
return 0;
}
static int
sdio_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
{
struct sdio_func *func = dev_to_sdio_func(dev);
if (add_uevent_var(env,
"SDIO_CLASS=%02X", func->class))
return -ENOMEM;
if (add_uevent_var(env,
"SDIO_ID=%04X:%04X", func->vendor, func->device))
return -ENOMEM;
if (add_uevent_var(env,
"MODALIAS=sdio:c%02Xv%04Xd%04X",
func->class, func->vendor, func->device))
return -ENOMEM;
return 0;
}
static int sdio_bus_probe(struct device *dev)
{
struct sdio_driver *drv = to_sdio_driver(dev->driver);
struct sdio_func *func = dev_to_sdio_func(dev);
const struct sdio_device_id *id;
int ret;
id = sdio_match_device(func, drv);
if (!id)
return -ENODEV;
ret = dev_pm_domain_attach(dev, false);
if (ret)
return ret;
atomic_inc(&func->card->sdio_funcs_probed);
/* Unbound SDIO functions are always suspended.
* During probe, the function is set active and the usage count
* is incremented. If the driver supports runtime PM,
* it should call pm_runtime_put_noidle() in its probe routine and
* pm_runtime_get_noresume() in its remove routine.
*/
if (func->card->host->caps & MMC_CAP_POWER_OFF_CARD) {
ret = pm_runtime_get_sync(dev);
if (ret < 0)
goto disable_runtimepm;
}
/* Set the default block size so the driver is sure it's something
* sensible. */
sdio_claim_host(func);
if (mmc_card_removed(func->card))
ret = -ENOMEDIUM;
else
ret = sdio_set_block_size(func, 0);
sdio_release_host(func);
if (ret)
goto disable_runtimepm;
ret = drv->probe(func, id);
if (ret)
goto disable_runtimepm;
return 0;
disable_runtimepm:
atomic_dec(&func->card->sdio_funcs_probed);
if (func->card->host->caps & MMC_CAP_POWER_OFF_CARD)
pm_runtime_put_noidle(dev);
dev_pm_domain_detach(dev, false);
return ret;
}
static int sdio_bus_remove(struct device *dev)
{
struct sdio_driver *drv = to_sdio_driver(dev->driver);
struct sdio_func *func = dev_to_sdio_func(dev);
/* Make sure card is powered before invoking ->remove() */
if (func->card->host->caps & MMC_CAP_POWER_OFF_CARD)
pm_runtime_get_sync(dev);
drv->remove(func);
atomic_dec(&func->card->sdio_funcs_probed);
if (func->irq_handler) {
pr_warn("WARNING: driver %s did not remove its interrupt handler!\n",
drv->name);
sdio_claim_host(func);
sdio_release_irq(func);
sdio_release_host(func);
}
/* First, undo the increment made directly above */
if (func->card->host->caps & MMC_CAP_POWER_OFF_CARD)
pm_runtime_put_noidle(dev);
/* Then undo the runtime PM settings in sdio_bus_probe() */
if (func->card->host->caps & MMC_CAP_POWER_OFF_CARD)
pm_runtime_put_sync(dev);
dev_pm_domain_detach(dev, false);
return 0;
}
static const struct dev_pm_ops sdio_bus_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(pm_generic_suspend, pm_generic_resume)
SET_RUNTIME_PM_OPS(
pm_generic_runtime_suspend,
pm_generic_runtime_resume,
NULL
)
};
static struct bus_type sdio_bus_type = {
.name = "sdio",
.dev_groups = sdio_dev_groups,
.match = sdio_bus_match,
.uevent = sdio_bus_uevent,
.probe = sdio_bus_probe,
.remove = sdio_bus_remove,
.pm = &sdio_bus_pm_ops,
};
int sdio_register_bus(void)
{
return bus_register(&sdio_bus_type);
}
void sdio_unregister_bus(void)
{
bus_unregister(&sdio_bus_type);
}
/**
* sdio_register_driver - register a function driver
* @drv: SDIO function driver
*/
int sdio_register_driver(struct sdio_driver *drv)
{
drv->drv.name = drv->name;
drv->drv.bus = &sdio_bus_type;
return driver_register(&drv->drv);
}
EXPORT_SYMBOL_GPL(sdio_register_driver);
/**
* sdio_unregister_driver - unregister a function driver
* @drv: SDIO function driver
*/
void sdio_unregister_driver(struct sdio_driver *drv)
{
drv->drv.bus = &sdio_bus_type;
driver_unregister(&drv->drv);
}
EXPORT_SYMBOL_GPL(sdio_unregister_driver);
static void sdio_release_func(struct device *dev)
{
struct sdio_func *func = dev_to_sdio_func(dev);
sdio_free_func_cis(func);
kfree(func->info);
kfree(func->tmpbuf);
kfree(func);
}
/*
* Allocate and initialise a new SDIO function structure.
*/
struct sdio_func *sdio_alloc_func(struct mmc_card *card)
{
struct sdio_func *func;
func = kzalloc(sizeof(struct sdio_func), GFP_KERNEL);
if (!func)
return ERR_PTR(-ENOMEM);
/*
* allocate buffer separately to make sure it's properly aligned for
* DMA usage (incl. 64 bit DMA)
*/
func->tmpbuf = kmalloc(4, GFP_KERNEL);
if (!func->tmpbuf) {
kfree(func);
return ERR_PTR(-ENOMEM);
}
func->card = card;
device_initialize(&func->dev);
func->dev.parent = &card->dev;
func->dev.bus = &sdio_bus_type;
func->dev.release = sdio_release_func;
return func;
}
#ifdef CONFIG_ACPI
static void sdio_acpi_set_handle(struct sdio_func *func)
{
struct mmc_host *host = func->card->host;
u64 addr = ((u64)host->slotno << 16) | func->num;
acpi_preset_companion(&func->dev, ACPI_COMPANION(host->parent), addr);
}
#else
static inline void sdio_acpi_set_handle(struct sdio_func *func) {}
#endif
static void sdio_set_of_node(struct sdio_func *func)
{
struct mmc_host *host = func->card->host;
func->dev.of_node = mmc_of_find_child_device(host, func->num);
}
/*
* Register a new SDIO function with the driver model.
*/
int sdio_add_func(struct sdio_func *func)
{
int ret;
dev_set_name(&func->dev, "%s:%d", mmc_card_id(func->card), func->num);
sdio_set_of_node(func);
sdio_acpi_set_handle(func);
device_enable_async_suspend(&func->dev);
ret = device_add(&func->dev);
if (ret == 0)
sdio_func_set_present(func);
return ret;
}
/*
* Unregister a SDIO function with the driver model, and
* (eventually) free it.
* This function can be called through error paths where sdio_add_func() was
* never executed (because a failure occurred at an earlier point).
*/
void sdio_remove_func(struct sdio_func *func)
{
if (!sdio_func_present(func))
return;
device_del(&func->dev);
of_node_put(func->dev.of_node);
put_device(&func->dev);
}