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linux/drivers/mmc/core/host.c
Ulf Hansson 682696605c mmc: sdio: Add API to manage SDIO IRQs from a workqueue 
For hosts not supporting MMC_CAP2_SDIO_IRQ_NOTHREAD but MMC_CAP_SDIO_IRQ,
the SDIO IRQs are processed from a dedicated kernel thread. For these
cases, the host calls mmc_signal_sdio_irq() from its ISR to signal a new
SDIO IRQ.

Signaling an SDIO IRQ makes the host's ->enable_sdio_irq() callback to be
invoked to temporary disable the IRQs, before the kernel thread is woken up
to process it. When processing of the IRQs are completed, they are
re-enabled by the kernel thread, again via invoking the host's
->enable_sdio_irq().

The observation from this, is that the execution path is being unnecessary
complex, as the host driver already knows that it needs to temporary
disable the IRQs before signaling a new one. Moreover, replacing the kernel
thread with a work/workqueue would not only greatly simplify the code, but
also make it more robust.

To address the above problems, let's continue to build upon the support for
MMC_CAP2_SDIO_IRQ_NOTHREAD, as it already implements SDIO IRQs to be
processed without using the clumsy kernel thread and without the ping-pong
calls of the host's ->enable_sdio_irq() callback for each processed IRQ.

Therefore, let's add new API sdio_signal_irq(), which enables hosts to
signal/process SDIO IRQs by using a work/workqueue, rather than using the
kernel thread.

Add also a new host callback ->ack_sdio_irq(), which the work invokes when
the SDIO IRQs have been processed. This informs the host about when it
shall re-enable the SDIO IRQs. Potentially, we could re-use the existing
->enable_sdio_irq() callback instead of adding a new one, however it has
turned out that it's more convenient for hosts to get this information via
a separate callback.

Hosts that wants to use this new method to signal/process SDIO IRQs, must
enable MMC_CAP2_SDIO_IRQ_NOTHREAD and implement the ->ack_sdio_irq()
callback.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
2017-06-20 10:30:11 +02:00

472 lines
12 KiB
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/*
* linux/drivers/mmc/core/host.c
*
* Copyright (C) 2003 Russell King, All Rights Reserved.
* Copyright (C) 2007-2008 Pierre Ossman
* Copyright (C) 2010 Linus Walleij
*
* 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.
*
* MMC host class device management
*/
#include <linux/device.h>
#include <linux/err.h>
#include <linux/idr.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/pagemap.h>
#include <linux/export.h>
#include <linux/leds.h>
#include <linux/slab.h>
#include <linux/mmc/host.h>
#include <linux/mmc/card.h>
#include <linux/mmc/slot-gpio.h>
#include "core.h"
#include "host.h"
#include "slot-gpio.h"
#include "pwrseq.h"
#include "sdio_ops.h"
#define cls_dev_to_mmc_host(d) container_of(d, struct mmc_host, class_dev)
static DEFINE_IDA(mmc_host_ida);
static void mmc_host_classdev_release(struct device *dev)
{
struct mmc_host *host = cls_dev_to_mmc_host(dev);
ida_simple_remove(&mmc_host_ida, host->index);
kfree(host);
}
static struct class mmc_host_class = {
.name = "mmc_host",
.dev_release = mmc_host_classdev_release,
};
int mmc_register_host_class(void)
{
return class_register(&mmc_host_class);
}
void mmc_unregister_host_class(void)
{
class_unregister(&mmc_host_class);
}
void mmc_retune_enable(struct mmc_host *host)
{
host->can_retune = 1;
if (host->retune_period)
mod_timer(&host->retune_timer,
jiffies + host->retune_period * HZ);
}
/*
* Pause re-tuning for a small set of operations. The pause begins after the
* next command and after first doing re-tuning.
*/
void mmc_retune_pause(struct mmc_host *host)
{
if (!host->retune_paused) {
host->retune_paused = 1;
mmc_retune_needed(host);
mmc_retune_hold(host);
}
}
EXPORT_SYMBOL(mmc_retune_pause);
void mmc_retune_unpause(struct mmc_host *host)
{
if (host->retune_paused) {
host->retune_paused = 0;
mmc_retune_release(host);
}
}
EXPORT_SYMBOL(mmc_retune_unpause);
void mmc_retune_disable(struct mmc_host *host)
{
mmc_retune_unpause(host);
host->can_retune = 0;
del_timer_sync(&host->retune_timer);
host->retune_now = 0;
host->need_retune = 0;
}
void mmc_retune_timer_stop(struct mmc_host *host)
{
del_timer_sync(&host->retune_timer);
}
EXPORT_SYMBOL(mmc_retune_timer_stop);
void mmc_retune_hold(struct mmc_host *host)
{
if (!host->hold_retune)
host->retune_now = 1;
host->hold_retune += 1;
}
void mmc_retune_release(struct mmc_host *host)
{
if (host->hold_retune)
host->hold_retune -= 1;
else
WARN_ON(1);
}
int mmc_retune(struct mmc_host *host)
{
bool return_to_hs400 = false;
int err;
if (host->retune_now)
host->retune_now = 0;
else
return 0;
if (!host->need_retune || host->doing_retune || !host->card)
return 0;
host->need_retune = 0;
host->doing_retune = 1;
if (host->ios.timing == MMC_TIMING_MMC_HS400) {
err = mmc_hs400_to_hs200(host->card);
if (err)
goto out;
return_to_hs400 = true;
if (host->ops->prepare_hs400_tuning)
host->ops->prepare_hs400_tuning(host, &host->ios);
}
err = mmc_execute_tuning(host->card);
if (err)
goto out;
if (return_to_hs400)
err = mmc_hs200_to_hs400(host->card);
out:
host->doing_retune = 0;
return err;
}
static void mmc_retune_timer(unsigned long data)
{
struct mmc_host *host = (struct mmc_host *)data;
mmc_retune_needed(host);
}
/**
* mmc_of_parse() - parse host's device-tree node
* @host: host whose node should be parsed.
*
* To keep the rest of the MMC subsystem unaware of whether DT has been
* used to to instantiate and configure this host instance or not, we
* parse the properties and set respective generic mmc-host flags and
* parameters.
*/
int mmc_of_parse(struct mmc_host *host)
{
struct device_node *np;
u32 bus_width;
int ret;
bool cd_cap_invert, cd_gpio_invert = false;
bool ro_cap_invert, ro_gpio_invert = false;
if (!host->parent || !host->parent->of_node)
return 0;
np = host->parent->of_node;
/* "bus-width" is translated to MMC_CAP_*_BIT_DATA flags */
if (of_property_read_u32(np, "bus-width", &bus_width) < 0) {
dev_dbg(host->parent,
"\"bus-width\" property is missing, assuming 1 bit.\n");
bus_width = 1;
}
switch (bus_width) {
case 8:
host->caps |= MMC_CAP_8_BIT_DATA;
/* Hosts capable of 8-bit transfers can also do 4 bits */
case 4:
host->caps |= MMC_CAP_4_BIT_DATA;
break;
case 1:
break;
default:
dev_err(host->parent,
"Invalid \"bus-width\" value %u!\n", bus_width);
return -EINVAL;
}
/* f_max is obtained from the optional "max-frequency" property */
of_property_read_u32(np, "max-frequency", &host->f_max);
/*
* Configure CD and WP pins. They are both by default active low to
* match the SDHCI spec. If GPIOs are provided for CD and / or WP, the
* mmc-gpio helpers are used to attach, configure and use them. If
* polarity inversion is specified in DT, one of MMC_CAP2_CD_ACTIVE_HIGH
* and MMC_CAP2_RO_ACTIVE_HIGH capability-2 flags is set. If the
* "broken-cd" property is provided, the MMC_CAP_NEEDS_POLL capability
* is set. If the "non-removable" property is found, the
* MMC_CAP_NONREMOVABLE capability is set and no card-detection
* configuration is performed.
*/
/* Parse Card Detection */
if (of_property_read_bool(np, "non-removable")) {
host->caps |= MMC_CAP_NONREMOVABLE;
} else {
cd_cap_invert = of_property_read_bool(np, "cd-inverted");
if (of_property_read_bool(np, "broken-cd"))
host->caps |= MMC_CAP_NEEDS_POLL;
ret = mmc_gpiod_request_cd(host, "cd", 0, true,
0, &cd_gpio_invert);
if (!ret)
dev_info(host->parent, "Got CD GPIO\n");
else if (ret != -ENOENT && ret != -ENOSYS)
return ret;
/*
* There are two ways to flag that the CD line is inverted:
* through the cd-inverted flag and by the GPIO line itself
* being inverted from the GPIO subsystem. This is a leftover
* from the times when the GPIO subsystem did not make it
* possible to flag a line as inverted.
*
* If the capability on the host AND the GPIO line are
* both inverted, the end result is that the CD line is
* not inverted.
*/
if (cd_cap_invert ^ cd_gpio_invert)
host->caps2 |= MMC_CAP2_CD_ACTIVE_HIGH;
}
/* Parse Write Protection */
ro_cap_invert = of_property_read_bool(np, "wp-inverted");
ret = mmc_gpiod_request_ro(host, "wp", 0, false, 0, &ro_gpio_invert);
if (!ret)
dev_info(host->parent, "Got WP GPIO\n");
else if (ret != -ENOENT && ret != -ENOSYS)
return ret;
if (of_property_read_bool(np, "disable-wp"))
host->caps2 |= MMC_CAP2_NO_WRITE_PROTECT;
/* See the comment on CD inversion above */
if (ro_cap_invert ^ ro_gpio_invert)
host->caps2 |= MMC_CAP2_RO_ACTIVE_HIGH;
if (of_property_read_bool(np, "cap-sd-highspeed"))
host->caps |= MMC_CAP_SD_HIGHSPEED;
if (of_property_read_bool(np, "cap-mmc-highspeed"))
host->caps |= MMC_CAP_MMC_HIGHSPEED;
if (of_property_read_bool(np, "sd-uhs-sdr12"))
host->caps |= MMC_CAP_UHS_SDR12;
if (of_property_read_bool(np, "sd-uhs-sdr25"))
host->caps |= MMC_CAP_UHS_SDR25;
if (of_property_read_bool(np, "sd-uhs-sdr50"))
host->caps |= MMC_CAP_UHS_SDR50;
if (of_property_read_bool(np, "sd-uhs-sdr104"))
host->caps |= MMC_CAP_UHS_SDR104;
if (of_property_read_bool(np, "sd-uhs-ddr50"))
host->caps |= MMC_CAP_UHS_DDR50;
if (of_property_read_bool(np, "cap-power-off-card"))
host->caps |= MMC_CAP_POWER_OFF_CARD;
if (of_property_read_bool(np, "cap-mmc-hw-reset"))
host->caps |= MMC_CAP_HW_RESET;
if (of_property_read_bool(np, "cap-sdio-irq"))
host->caps |= MMC_CAP_SDIO_IRQ;
if (of_property_read_bool(np, "full-pwr-cycle"))
host->caps2 |= MMC_CAP2_FULL_PWR_CYCLE;
if (of_property_read_bool(np, "keep-power-in-suspend"))
host->pm_caps |= MMC_PM_KEEP_POWER;
if (of_property_read_bool(np, "wakeup-source") ||
of_property_read_bool(np, "enable-sdio-wakeup")) /* legacy */
host->pm_caps |= MMC_PM_WAKE_SDIO_IRQ;
if (of_property_read_bool(np, "mmc-ddr-3_3v"))
host->caps |= MMC_CAP_3_3V_DDR;
if (of_property_read_bool(np, "mmc-ddr-1_8v"))
host->caps |= MMC_CAP_1_8V_DDR;
if (of_property_read_bool(np, "mmc-ddr-1_2v"))
host->caps |= MMC_CAP_1_2V_DDR;
if (of_property_read_bool(np, "mmc-hs200-1_8v"))
host->caps2 |= MMC_CAP2_HS200_1_8V_SDR;
if (of_property_read_bool(np, "mmc-hs200-1_2v"))
host->caps2 |= MMC_CAP2_HS200_1_2V_SDR;
if (of_property_read_bool(np, "mmc-hs400-1_8v"))
host->caps2 |= MMC_CAP2_HS400_1_8V | MMC_CAP2_HS200_1_8V_SDR;
if (of_property_read_bool(np, "mmc-hs400-1_2v"))
host->caps2 |= MMC_CAP2_HS400_1_2V | MMC_CAP2_HS200_1_2V_SDR;
if (of_property_read_bool(np, "mmc-hs400-enhanced-strobe"))
host->caps2 |= MMC_CAP2_HS400_ES;
if (of_property_read_bool(np, "no-sdio"))
host->caps2 |= MMC_CAP2_NO_SDIO;
if (of_property_read_bool(np, "no-sd"))
host->caps2 |= MMC_CAP2_NO_SD;
if (of_property_read_bool(np, "no-mmc"))
host->caps2 |= MMC_CAP2_NO_MMC;
host->dsr_req = !of_property_read_u32(np, "dsr", &host->dsr);
if (host->dsr_req && (host->dsr & ~0xffff)) {
dev_err(host->parent,
"device tree specified broken value for DSR: 0x%x, ignoring\n",
host->dsr);
host->dsr_req = 0;
}
return mmc_pwrseq_alloc(host);
}
EXPORT_SYMBOL(mmc_of_parse);
/**
* mmc_alloc_host - initialise the per-host structure.
* @extra: sizeof private data structure
* @dev: pointer to host device model structure
*
* Initialise the per-host structure.
*/
struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
{
int err;
struct mmc_host *host;
host = kzalloc(sizeof(struct mmc_host) + extra, GFP_KERNEL);
if (!host)
return NULL;
/* scanning will be enabled when we're ready */
host->rescan_disable = 1;
err = ida_simple_get(&mmc_host_ida, 0, 0, GFP_KERNEL);
if (err < 0) {
kfree(host);
return NULL;
}
host->index = err;
dev_set_name(&host->class_dev, "mmc%d", host->index);
host->parent = dev;
host->class_dev.parent = dev;
host->class_dev.class = &mmc_host_class;
device_initialize(&host->class_dev);
device_enable_async_suspend(&host->class_dev);
if (mmc_gpio_alloc(host)) {
put_device(&host->class_dev);
ida_simple_remove(&mmc_host_ida, host->index);
kfree(host);
return NULL;
}
spin_lock_init(&host->lock);
init_waitqueue_head(&host->wq);
INIT_DELAYED_WORK(&host->detect, mmc_rescan);
INIT_DELAYED_WORK(&host->sdio_irq_work, sdio_irq_work);
setup_timer(&host->retune_timer, mmc_retune_timer, (unsigned long)host);
/*
* By default, hosts do not support SGIO or large requests.
* They have to set these according to their abilities.
*/
host->max_segs = 1;
host->max_seg_size = PAGE_SIZE;
host->max_req_size = PAGE_SIZE;
host->max_blk_size = 512;
host->max_blk_count = PAGE_SIZE / 512;
return host;
}
EXPORT_SYMBOL(mmc_alloc_host);
/**
* mmc_add_host - initialise host hardware
* @host: mmc host
*
* Register the host with the driver model. The host must be
* prepared to start servicing requests before this function
* completes.
*/
int mmc_add_host(struct mmc_host *host)
{
int err;
WARN_ON((host->caps & MMC_CAP_SDIO_IRQ) &&
!host->ops->enable_sdio_irq);
err = device_add(&host->class_dev);
if (err)
return err;
led_trigger_register_simple(dev_name(&host->class_dev), &host->led);
#ifdef CONFIG_DEBUG_FS
mmc_add_host_debugfs(host);
#endif
mmc_start_host(host);
mmc_register_pm_notifier(host);
return 0;
}
EXPORT_SYMBOL(mmc_add_host);
/**
* mmc_remove_host - remove host hardware
* @host: mmc host
*
* Unregister and remove all cards associated with this host,
* and power down the MMC bus. No new requests will be issued
* after this function has returned.
*/
void mmc_remove_host(struct mmc_host *host)
{
mmc_unregister_pm_notifier(host);
mmc_stop_host(host);
#ifdef CONFIG_DEBUG_FS
mmc_remove_host_debugfs(host);
#endif
device_del(&host->class_dev);
led_trigger_unregister_simple(host->led);
}
EXPORT_SYMBOL(mmc_remove_host);
/**
* mmc_free_host - free the host structure
* @host: mmc host
*
* Free the host once all references to it have been dropped.
*/
void mmc_free_host(struct mmc_host *host)
{
mmc_pwrseq_free(host);
put_device(&host->class_dev);
}
EXPORT_SYMBOL(mmc_free_host);
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