linux/drivers/mmc/core/bus.c
Konstantin Dorfman 2220eedfd7 mmc: fix async request mechanism for sequential read scenarios
When current request is running on the bus and if next request fetched
by mmcqd is NULL, mmc context (mmcqd thread) gets blocked until the
current request completes. This means that if new request comes in while
the mmcqd thread is blocked, this new request can not be prepared in
parallel to current ongoing request. This may result in delaying the new
request execution and increase it's latency.

This change allows to wake up the MMC thread on new request arrival.
Now once the MMC thread is woken up, a new request can be fetched and
prepared in parallel to the current running request which means this new
request can be started immediately after the current running request
completes.

With this change read throughput is improved by 16%.

Signed-off-by: Konstantin Dorfman <kdorfman@codeaurora.org>
Reviewed-by: Seungwon Jeon <tgih.jun@samsung.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
2013-02-11 13:28:49 -05:00

359 lines
7.4 KiB
C

/*
* linux/drivers/mmc/core/bus.c
*
* Copyright (C) 2003 Russell King, All Rights Reserved.
* Copyright (C) 2007 Pierre Ossman
*
* 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 card bus driver model
*/
#include <linux/export.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/pm_runtime.h>
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
#include "core.h"
#include "sdio_cis.h"
#include "bus.h"
#define to_mmc_driver(d) container_of(d, struct mmc_driver, drv)
static ssize_t mmc_type_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct mmc_card *card = mmc_dev_to_card(dev);
switch (card->type) {
case MMC_TYPE_MMC:
return sprintf(buf, "MMC\n");
case MMC_TYPE_SD:
return sprintf(buf, "SD\n");
case MMC_TYPE_SDIO:
return sprintf(buf, "SDIO\n");
case MMC_TYPE_SD_COMBO:
return sprintf(buf, "SDcombo\n");
default:
return -EFAULT;
}
}
static struct device_attribute mmc_dev_attrs[] = {
__ATTR(type, S_IRUGO, mmc_type_show, NULL),
__ATTR_NULL,
};
/*
* This currently matches any MMC driver to any MMC card - drivers
* themselves make the decision whether to drive this card in their
* probe method.
*/
static int mmc_bus_match(struct device *dev, struct device_driver *drv)
{
return 1;
}
static int
mmc_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
{
struct mmc_card *card = mmc_dev_to_card(dev);
const char *type;
int retval = 0;
switch (card->type) {
case MMC_TYPE_MMC:
type = "MMC";
break;
case MMC_TYPE_SD:
type = "SD";
break;
case MMC_TYPE_SDIO:
type = "SDIO";
break;
case MMC_TYPE_SD_COMBO:
type = "SDcombo";
break;
default:
type = NULL;
}
if (type) {
retval = add_uevent_var(env, "MMC_TYPE=%s", type);
if (retval)
return retval;
}
retval = add_uevent_var(env, "MMC_NAME=%s", mmc_card_name(card));
if (retval)
return retval;
/*
* Request the mmc_block device. Note: that this is a direct request
* for the module it carries no information as to what is inserted.
*/
retval = add_uevent_var(env, "MODALIAS=mmc:block");
return retval;
}
static int mmc_bus_probe(struct device *dev)
{
struct mmc_driver *drv = to_mmc_driver(dev->driver);
struct mmc_card *card = mmc_dev_to_card(dev);
return drv->probe(card);
}
static int mmc_bus_remove(struct device *dev)
{
struct mmc_driver *drv = to_mmc_driver(dev->driver);
struct mmc_card *card = mmc_dev_to_card(dev);
drv->remove(card);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int mmc_bus_suspend(struct device *dev)
{
struct mmc_driver *drv = to_mmc_driver(dev->driver);
struct mmc_card *card = mmc_dev_to_card(dev);
int ret = 0;
if (dev->driver && drv->suspend)
ret = drv->suspend(card);
return ret;
}
static int mmc_bus_resume(struct device *dev)
{
struct mmc_driver *drv = to_mmc_driver(dev->driver);
struct mmc_card *card = mmc_dev_to_card(dev);
int ret = 0;
if (dev->driver && drv->resume)
ret = drv->resume(card);
return ret;
}
#endif
#ifdef CONFIG_PM_RUNTIME
static int mmc_runtime_suspend(struct device *dev)
{
struct mmc_card *card = mmc_dev_to_card(dev);
return mmc_power_save_host(card->host);
}
static int mmc_runtime_resume(struct device *dev)
{
struct mmc_card *card = mmc_dev_to_card(dev);
return mmc_power_restore_host(card->host);
}
static int mmc_runtime_idle(struct device *dev)
{
return pm_runtime_suspend(dev);
}
#endif /* !CONFIG_PM_RUNTIME */
static const struct dev_pm_ops mmc_bus_pm_ops = {
SET_RUNTIME_PM_OPS(mmc_runtime_suspend, mmc_runtime_resume,
mmc_runtime_idle)
SET_SYSTEM_SLEEP_PM_OPS(mmc_bus_suspend, mmc_bus_resume)
};
static struct bus_type mmc_bus_type = {
.name = "mmc",
.dev_attrs = mmc_dev_attrs,
.match = mmc_bus_match,
.uevent = mmc_bus_uevent,
.probe = mmc_bus_probe,
.remove = mmc_bus_remove,
.pm = &mmc_bus_pm_ops,
};
int mmc_register_bus(void)
{
return bus_register(&mmc_bus_type);
}
void mmc_unregister_bus(void)
{
bus_unregister(&mmc_bus_type);
}
/**
* mmc_register_driver - register a media driver
* @drv: MMC media driver
*/
int mmc_register_driver(struct mmc_driver *drv)
{
drv->drv.bus = &mmc_bus_type;
return driver_register(&drv->drv);
}
EXPORT_SYMBOL(mmc_register_driver);
/**
* mmc_unregister_driver - unregister a media driver
* @drv: MMC media driver
*/
void mmc_unregister_driver(struct mmc_driver *drv)
{
drv->drv.bus = &mmc_bus_type;
driver_unregister(&drv->drv);
}
EXPORT_SYMBOL(mmc_unregister_driver);
static void mmc_release_card(struct device *dev)
{
struct mmc_card *card = mmc_dev_to_card(dev);
sdio_free_common_cis(card);
kfree(card->info);
kfree(card);
}
/*
* Allocate and initialise a new MMC card structure.
*/
struct mmc_card *mmc_alloc_card(struct mmc_host *host, struct device_type *type)
{
struct mmc_card *card;
card = kzalloc(sizeof(struct mmc_card), GFP_KERNEL);
if (!card)
return ERR_PTR(-ENOMEM);
card->host = host;
device_initialize(&card->dev);
card->dev.parent = mmc_classdev(host);
card->dev.bus = &mmc_bus_type;
card->dev.release = mmc_release_card;
card->dev.type = type;
return card;
}
/*
* Register a new MMC card with the driver model.
*/
int mmc_add_card(struct mmc_card *card)
{
int ret;
const char *type;
const char *uhs_bus_speed_mode = "";
static const char *const uhs_speeds[] = {
[UHS_SDR12_BUS_SPEED] = "SDR12 ",
[UHS_SDR25_BUS_SPEED] = "SDR25 ",
[UHS_SDR50_BUS_SPEED] = "SDR50 ",
[UHS_SDR104_BUS_SPEED] = "SDR104 ",
[UHS_DDR50_BUS_SPEED] = "DDR50 ",
};
dev_set_name(&card->dev, "%s:%04x", mmc_hostname(card->host), card->rca);
switch (card->type) {
case MMC_TYPE_MMC:
type = "MMC";
break;
case MMC_TYPE_SD:
type = "SD";
if (mmc_card_blockaddr(card)) {
if (mmc_card_ext_capacity(card))
type = "SDXC";
else
type = "SDHC";
}
break;
case MMC_TYPE_SDIO:
type = "SDIO";
break;
case MMC_TYPE_SD_COMBO:
type = "SD-combo";
if (mmc_card_blockaddr(card))
type = "SDHC-combo";
break;
default:
type = "?";
break;
}
if (mmc_sd_card_uhs(card) &&
(card->sd_bus_speed < ARRAY_SIZE(uhs_speeds)))
uhs_bus_speed_mode = uhs_speeds[card->sd_bus_speed];
if (mmc_host_is_spi(card->host)) {
pr_info("%s: new %s%s%s card on SPI\n",
mmc_hostname(card->host),
mmc_card_highspeed(card) ? "high speed " : "",
mmc_card_ddr_mode(card) ? "DDR " : "",
type);
} else {
pr_info("%s: new %s%s%s%s%s card at address %04x\n",
mmc_hostname(card->host),
mmc_card_uhs(card) ? "ultra high speed " :
(mmc_card_highspeed(card) ? "high speed " : ""),
(mmc_card_hs200(card) ? "HS200 " : ""),
mmc_card_ddr_mode(card) ? "DDR " : "",
uhs_bus_speed_mode, type, card->rca);
}
#ifdef CONFIG_DEBUG_FS
mmc_add_card_debugfs(card);
#endif
mmc_init_context_info(card->host);
ret = device_add(&card->dev);
if (ret)
return ret;
mmc_card_set_present(card);
return 0;
}
/*
* Unregister a new MMC card with the driver model, and
* (eventually) free it.
*/
void mmc_remove_card(struct mmc_card *card)
{
#ifdef CONFIG_DEBUG_FS
mmc_remove_card_debugfs(card);
#endif
if (mmc_card_present(card)) {
if (mmc_host_is_spi(card->host)) {
pr_info("%s: SPI card removed\n",
mmc_hostname(card->host));
} else {
pr_info("%s: card %04x removed\n",
mmc_hostname(card->host), card->rca);
}
device_del(&card->dev);
}
put_device(&card->dev);
}