- 根目录:
- drivers
- mmc
- core
- host.c
/*
* 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/suspend.h>
#include <linux/mmc/host.h>
#include <linux/mmc/card.h>
#include <linux/mmc/slot-gpio.h>
#include "core.h"
#include "host.h"
#define cls_dev_to_mmc_host(d) container_of(d, struct mmc_host, class_dev)
static void mmc_host_classdev_release(struct device *dev)
{
struct mmc_host *host = cls_dev_to_mmc_host(dev);
mutex_destroy(&host->slot.lock);
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);
}
static DEFINE_IDR(mmc_host_idr);
static DEFINE_SPINLOCK(mmc_host_lock);
#ifdef CONFIG_MMC_CLKGATE
static ssize_t clkgate_delay_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct mmc_host *host = cls_dev_to_mmc_host(dev);
return snprintf(buf, PAGE_SIZE, "%lu\n", host->clkgate_delay);
}
static ssize_t clkgate_delay_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t count)
{
struct mmc_host *host = cls_dev_to_mmc_host(dev);
unsigned long flags, value;
if (kstrtoul(buf, 0, &value))
return -EINVAL;
spin_lock_irqsave(&host->clk_lock, flags);
host->clkgate_delay = value;
spin_unlock_irqrestore(&host->clk_lock, flags);
return count;
}
/*
* Enabling clock gating will make the core call out to the host
* once up and once down when it performs a request or card operation
* intermingled in any fashion. The driver will see this through
* set_ios() operations with ios.clock field set to 0 to gate (disable)
* the block clock, and to the old frequency to enable it again.
*/
static void mmc_host_clk_gate_delayed(struct mmc_host *host)
{
unsigned long tick_ns;
unsigned long freq = host->ios.clock;
unsigned long flags;
if (!freq) {
pr_debug("%s: frequency set to 0 in disable function, "
"this means the clock is already disabled.\n",
mmc_hostname(host));
return;
}
/*
* New requests may have appeared while we were scheduling,
* then there is no reason to delay the check before
* clk_disable().
*/
spin_lock_irqsave(&host->clk_lock, flags);
/*
* Delay n bus cycles (at least 8 from MMC spec) before attempting
* to disable the MCI block clock. The reference count may have
* gone up again after this delay due to rescheduling!
*/
if (!host->clk_requests) {
spin_unlock_irqrestore(&host->clk_lock, flags);
tick_ns = DIV_ROUND_UP(1000000000, freq);
ndelay(host->clk_delay * tick_ns);
} else {
/* New users appeared while waiting for this work */
spin_unlock_irqrestore(&host->clk_lock, flags);
return;
}
mutex_lock(&host->clk_gate_mutex);
spin_lock_irqsave(&host->clk_lock, flags);
if (!host->clk_requests) {
spin_unlock_irqrestore(&host->clk_lock, flags);
/* This will set host->ios.clock to 0 */
mmc_gate_clock(host);
spin_lock_irqsave(&host->clk_lock, flags);
pr_debug("%s: gated MCI clock\n", mmc_hostname(host));
}
spin_unlock_irqrestore(&host->clk_lock, flags);
mutex_unlock(&host->clk_gate_mutex);
}
/*
* Internal work. Work to disable the clock at some later point.
*/
static void mmc_host_clk_gate_work(struct work_struct *work)
{
struct mmc_host *host = container_of(work, struct mmc_host,
clk_gate_work.work);
mmc_host_clk_gate_delayed(host);
}
/**
* mmc_host_clk_hold - ungate hardware MCI clocks
* @host: host to ungate.
*
* Makes sure the host ios.clock is restored to a non-zero value
* past this call. Increase clock reference count and ungate clock
* if we're the first user.
*/
void mmc_host_clk_hold(struct mmc_host *host)
{
unsigned long flags;
/* cancel any clock gating work scheduled by mmc_host_clk_release() */
cancel_delayed_work_sync(&host->clk_gate_work);
mutex_lock(&host->clk_gate_mutex);
spin_lock_irqsave(&host->clk_lock, flags);
if (host->clk_gated) {
spin_unlock_irqrestore(&host->clk_lock, flags);
mmc_ungate_clock(host);
spin_lock_irqsave(&host->clk_lock, flags);
pr_debug("%s: ungated MCI clock\n", mmc_hostname(host));
}
host->clk_requests++;
spin_unlock_irqrestore(&host->clk_lock, flags);
mutex_unlock(&host->clk_gate_mutex);
}
/**
* mmc_host_may_gate_card - check if this card may be gated
* @card: card to check.
*/
static bool mmc_host_may_gate_card(struct mmc_card *card)
{
/* If there is no card we may gate it */
if (!card)
return true;
/*
* Don't gate SDIO cards! These need to be clocked at all times
* since they may be independent systems generating interrupts
* and other events. The clock requests counter from the core will
* go down to zero since the core does not need it, but we will not
* gate the clock, because there is somebody out there that may still
* be using it.
*/
return !(card->quirks & MMC_QUIRK_BROKEN_CLK_GATING);
}
/**
* mmc_host_clk_release - gate off hardware MCI clocks
* @host: host to gate.
*
* Calls the host driver with ios.clock set to zero as often as possible
* in order to gate off hardware MCI clocks. Decrease clock reference
* count and schedule disabling of clock.
*/
void mmc_host_clk_release(struct mmc_host *host)
{
unsigned long flags;
spin_lock_irqsave(&host->clk_lock, flags);
host->clk_requests--;
if (mmc_host_may_gate_card(host->card) &&
!host->clk_requests)
schedule_delayed_work(&host->clk_gate_work,
msecs_to_jiffies(host->clkgate_delay));
spin_unlock_irqrestore(&host->clk_lock, flags);
}
/**
* mmc_host_clk_rate - get current clock frequency setting
* @host: host to get the clock frequency for.
*
* Returns current clock frequency regardless of gating.
*/
unsigned int mmc_host_clk_rate(struct mmc_host *host)
{
unsigned long freq;
unsigned long flags;
spin_lock_irqsave(&host->clk_lock, flags);
if (host->clk_gated)
freq = host->clk_old;
else
freq = host->ios.clock;
spin_unlock_irqrestore(&host->clk_lock, flags);
return freq;
}
/**
* mmc_host_clk_init - set up clock gating code
* @host: host with potential clock to control
*/
static inline void mmc_host_clk_init(struct mmc_host *host)
{
host->clk_requests = 0;
/* Hold MCI clock for 8 cycles by default */
host->clk_delay = 8;
/*
* Default clock gating delay is 0ms to avoid wasting power.
* This value can be tuned by writing into sysfs entry.
*/
host->clkgate_delay = 0;
host->clk_gated = false;
INIT_DELAYED_WORK(&host->clk_gate_work, mmc_host_clk_gate_work);
spin_lock_init(&host->clk_lock);
mutex_init(&host->clk_gate_mutex);
}
/**
* mmc_host_clk_exit - shut down clock gating code
* @host: host with potential clock to control
*/
static inline void mmc_host_clk_exit(struct mmc_host *host)
{
/*
* Wait for any outstanding gate and then make sure we're
* ungated before exiting.
*/
if (cancel_delayed_work_sync(&host->clk_gate_work))
mmc_host_clk_gate_delayed(host);
if (host->clk_gated)
mmc_host_clk_hold(host);
/* There should be only one user now */
WARN_ON(host->clk_requests > 1);
}
static inline void mmc_host_clk_sysfs_init(struct mmc_host *host)
{
host->clkgate_delay_attr.show = clkgate_delay_show;
host->clkgate_delay_attr.store = clkgate_delay_store;
sysfs_attr_init(&host->clkgate_delay_attr.attr);
host->clkgate_delay_attr.attr.name = "clkgate_delay";
host->clkgate_delay_attr.attr.mode = S_IRUGO | S_IWUSR;
if (device_create_file(&host->class_dev, &host->clkgate_delay_attr))
pr_err("%s: Failed to create clkgate_delay sysfs entry\n",
mmc_hostname(host));
}
#else
static inline void mmc_host_clk_init(struct mmc_host *host)
{
}
static inline void mmc_host_clk_exit(struct mmc_host *host)
{
}
static inline void mmc_host_clk_sysfs_init(struct mmc_host *host)
{
}
#endif
/**
* 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;
bool explicit_inv_wp, gpio_inv_wp = false;
enum of_gpio_flags flags;
int len, ret, gpio;
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 %ud!\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_find_property(np, "non-removable", &len)) {
host->caps |= MMC_CAP_NONREMOVABLE;
} else {
bool explicit_inv_cd, gpio_inv_cd = false;
explicit_inv_cd = of_property_read_bool(np, "cd-inverted");
if (of_find_property(np, "broken-cd", &len))
host->caps |= MMC_CAP_NEEDS_POLL;
gpio = of_get_named_gpio_flags(np, "cd-gpios", 0, &flags);
if (gpio == -EPROBE_DEFER)
return gpio;
if (gpio_is_valid(gpio)) {
if (!(flags & OF_GPIO_ACTIVE_LOW))
gpio_inv_cd = true;
ret = mmc_gpio_request_cd(host, gpio, 0);
if (ret < 0) {
dev_err(host->parent,
"Failed to request CD GPIO #%d: %d!\n",
gpio, ret);
return ret;
} else {
dev_info(host->parent, "Got CD GPIO #%d.\n",
gpio);
}
}
if (explicit_inv_cd ^ gpio_inv_cd)
host->caps2 |= MMC_CAP2_CD_ACTIVE_HIGH;
}
/* Parse Write Protection */
explicit_inv_wp = of_property_read_bool(np, "wp-inverted");
gpio = of_get_named_gpio_flags(np, "wp-gpios", 0, &flags);
if (gpio == -EPROBE_DEFER) {
ret = -EPROBE_DEFER;
goto out;
}
if (gpio_is_valid(gpio)) {
if (!(flags & OF_GPIO_ACTIVE_LOW))
gpio_inv_wp = true;
ret = mmc_gpio_request_ro(host, gpio);
if (ret < 0) {
dev_err(host->parent,
"Failed to request WP GPIO: %d!\n", ret);
goto out;
} else {
dev_info(host->parent, "Got WP GPIO #%d.\n",
gpio);
}
}
if (explicit_inv_wp ^ gpio_inv_wp)
host->caps2 |= MMC_CAP2_RO_ACTIVE_HIGH;
if (of_find_property(np, "cap-sd-highspeed", &len))
host->caps |= MMC_CAP_SD_HIGHSPEED;
if (of_find_property(np, "cap-mmc-highspeed", &len))
host->caps |= MMC_CAP_MMC_HIGHSPEED;
if (of_find_property(np, "cap-power-off-card", &len))
host->caps |= MMC_CAP_POWER_OFF_CARD;
if (of_find_property(np, "cap-sdio-irq", &len))
host->caps |= MMC_CAP_SDIO_IRQ;
if (of_find_property(np, "full-pwr-cycle", &len))
host->caps2 |= MMC_CAP2_FULL_PWR_CYCLE;
if (of_find_property(np, "keep-power-in-suspend", &len))
host->pm_caps |= MMC_PM_KEEP_POWER;
if (of_find_property(np, "enable-sdio-wakeup", &len))
host->pm_caps |= MMC_PM_WAKE_SDIO_IRQ;
return 0;
out:
mmc_gpio_free_cd(host);
return ret;
}
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;
idr_preload(GFP_KERNEL);
spin_lock(&mmc_host_lock);
err = idr_alloc(&mmc_host_idr, host, 0, 0, GFP_NOWAIT);
if (err >= 0)
host->index = err;
spin_unlock(&mmc_host_lock);
idr_preload_end();
if (err < 0)
goto free;
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);
mmc_host_clk_init(host);
mutex_init(&host->slot.lock);
host->slot.cd_irq = -EINVAL;
spin_lock_init(&host->lock);
init_waitqueue_head(&host->wq);
INIT_DELAYED_WORK(&host->detect, mmc_rescan);
#ifdef CONFIG_PM
host->pm_notify.notifier_call = mmc_pm_notify;
#endif
/*
* 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_CACHE_SIZE;
host->max_req_size = PAGE_CACHE_SIZE;
host->max_blk_size = 512;
host->max_blk_count = PAGE_CACHE_SIZE / 512;
return host;
free:
kfree(host);
return NULL;
}
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_host_clk_sysfs_init(host);
mmc_start_host(host);
if (!(host->pm_flags & MMC_PM_IGNORE_PM_NOTIFY))
register_pm_notifier(&host->pm_notify);
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)
{
if (!(host->pm_flags & MMC_PM_IGNORE_PM_NOTIFY))
unregister_pm_notifier(&host->pm_notify);
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);
mmc_host_clk_exit(host);
}
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)
{
spin_lock(&mmc_host_lock);
idr_remove(&mmc_host_idr, host->index);
spin_unlock(&mmc_host_lock);
put_device(&host->class_dev);
}
EXPORT_SYMBOL(mmc_free_host);