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Commit 9eadcc05 authored by Ulf Hansson's avatar Ulf Hansson

mmc: core: Remove MMC_CLKGATE

MMC_CLKGATE was once invented to save power by gating the bus clock at
request inactivity. At that time it served its purpose. The modern way to
deal with power saving for these scenarios, is by using runtime PM.

Nowadays, several host drivers have deployed runtime PM, but for those
that haven't and which still cares power saving at request inactivity,
it's certainly time to deploy runtime PM as it has been around for several
years now.

To simplify code to mmc core and thus decrease maintenance efforts, this
patch removes all code related to MMC_CLKGATE.
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent a22950c8
......@@ -72,13 +72,3 @@ Note on raw_rpmb_size_mult:
"raw_rpmb_size_mult" is a mutliple of 128kB block.
RPMB size in byte is calculated by using the following equation:
RPMB partition size = 128kB x raw_rpmb_size_mult
SD/MMC/SDIO Clock Gating Attribute
==================================
Read and write access is provided to following attribute.
This attribute appears only if CONFIG_MMC_CLKGATE is enabled.
clkgate_delay Tune the clock gating delay with desired value in milliseconds.
echo <desired delay> > /sys/class/mmc_host/mmcX/clkgate_delay
#
# MMC core configuration
#
config MMC_CLKGATE
bool "MMC host clock gating"
help
This will attempt to aggressively gate the clock to the MMC card.
This is done to save power due to gating off the logic and bus
noise when the MMC card is not in use. Your host driver has to
support handling this in order for it to be of any use.
If unsure, say N.
......@@ -187,8 +187,6 @@ void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)
if (mrq->done)
mrq->done(mrq);
mmc_host_clk_release(host);
}
}
......@@ -292,7 +290,6 @@ static int mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
mrq->stop->mrq = mrq;
}
}
mmc_host_clk_hold(host);
led_trigger_event(host->led, LED_FULL);
__mmc_start_request(host, mrq);
......@@ -542,11 +539,8 @@ static void mmc_wait_for_req_done(struct mmc_host *host,
static void mmc_pre_req(struct mmc_host *host, struct mmc_request *mrq,
bool is_first_req)
{
if (host->ops->pre_req) {
mmc_host_clk_hold(host);
if (host->ops->pre_req)
host->ops->pre_req(host, mrq, is_first_req);
mmc_host_clk_release(host);
}
}
/**
......@@ -561,11 +555,8 @@ static void mmc_pre_req(struct mmc_host *host, struct mmc_request *mrq,
static void mmc_post_req(struct mmc_host *host, struct mmc_request *mrq,
int err)
{
if (host->ops->post_req) {
mmc_host_clk_hold(host);
if (host->ops->post_req)
host->ops->post_req(host, mrq, err);
mmc_host_clk_release(host);
}
}
/**
......@@ -850,9 +841,9 @@ void mmc_set_data_timeout(struct mmc_data *data, const struct mmc_card *card)
unsigned int timeout_us, limit_us;
timeout_us = data->timeout_ns / 1000;
if (mmc_host_clk_rate(card->host))
if (card->host->ios.clock)
timeout_us += data->timeout_clks * 1000 /
(mmc_host_clk_rate(card->host) / 1000);
(card->host->ios.clock / 1000);
if (data->flags & MMC_DATA_WRITE)
/*
......@@ -1050,8 +1041,6 @@ static inline void mmc_set_ios(struct mmc_host *host)
ios->power_mode, ios->chip_select, ios->vdd,
ios->bus_width, ios->timing);
if (ios->clock > 0)
mmc_set_ungated(host);
host->ops->set_ios(host, ios);
}
......@@ -1060,17 +1049,15 @@ static inline void mmc_set_ios(struct mmc_host *host)
*/
void mmc_set_chip_select(struct mmc_host *host, int mode)
{
mmc_host_clk_hold(host);
host->ios.chip_select = mode;
mmc_set_ios(host);
mmc_host_clk_release(host);
}
/*
* Sets the host clock to the highest possible frequency that
* is below "hz".
*/
static void __mmc_set_clock(struct mmc_host *host, unsigned int hz)
void mmc_set_clock(struct mmc_host *host, unsigned int hz)
{
WARN_ON(hz && hz < host->f_min);
......@@ -1081,68 +1068,6 @@ static void __mmc_set_clock(struct mmc_host *host, unsigned int hz)
mmc_set_ios(host);
}
void mmc_set_clock(struct mmc_host *host, unsigned int hz)
{
mmc_host_clk_hold(host);
__mmc_set_clock(host, hz);
mmc_host_clk_release(host);
}
#ifdef CONFIG_MMC_CLKGATE
/*
* This gates the clock by setting it to 0 Hz.
*/
void mmc_gate_clock(struct mmc_host *host)
{
unsigned long flags;
spin_lock_irqsave(&host->clk_lock, flags);
host->clk_old = host->ios.clock;
host->ios.clock = 0;
host->clk_gated = true;
spin_unlock_irqrestore(&host->clk_lock, flags);
mmc_set_ios(host);
}
/*
* This restores the clock from gating by using the cached
* clock value.
*/
void mmc_ungate_clock(struct mmc_host *host)
{
/*
* We should previously have gated the clock, so the clock shall
* be 0 here! The clock may however be 0 during initialization,
* when some request operations are performed before setting
* the frequency. When ungate is requested in that situation
* we just ignore the call.
*/
if (host->clk_old) {
BUG_ON(host->ios.clock);
/* This call will also set host->clk_gated to false */
__mmc_set_clock(host, host->clk_old);
}
}
void mmc_set_ungated(struct mmc_host *host)
{
unsigned long flags;
/*
* We've been given a new frequency while the clock is gated,
* so make sure we regard this as ungating it.
*/
spin_lock_irqsave(&host->clk_lock, flags);
host->clk_gated = false;
spin_unlock_irqrestore(&host->clk_lock, flags);
}
#else
void mmc_set_ungated(struct mmc_host *host)
{
}
#endif
int mmc_execute_tuning(struct mmc_card *card)
{
struct mmc_host *host = card->host;
......@@ -1157,9 +1082,7 @@ int mmc_execute_tuning(struct mmc_card *card)
else
opcode = MMC_SEND_TUNING_BLOCK;
mmc_host_clk_hold(host);
err = host->ops->execute_tuning(host, opcode);
mmc_host_clk_release(host);
if (err)
pr_err("%s: tuning execution failed\n", mmc_hostname(host));
......@@ -1174,10 +1097,8 @@ int mmc_execute_tuning(struct mmc_card *card)
*/
void mmc_set_bus_mode(struct mmc_host *host, unsigned int mode)
{
mmc_host_clk_hold(host);
host->ios.bus_mode = mode;
mmc_set_ios(host);
mmc_host_clk_release(host);
}
/*
......@@ -1185,10 +1106,8 @@ void mmc_set_bus_mode(struct mmc_host *host, unsigned int mode)
*/
void mmc_set_bus_width(struct mmc_host *host, unsigned int width)
{
mmc_host_clk_hold(host);
host->ios.bus_width = width;
mmc_set_ios(host);
mmc_host_clk_release(host);
}
/*
......@@ -1532,11 +1451,8 @@ int __mmc_set_signal_voltage(struct mmc_host *host, int signal_voltage)
int old_signal_voltage = host->ios.signal_voltage;
host->ios.signal_voltage = signal_voltage;
if (host->ops->start_signal_voltage_switch) {
mmc_host_clk_hold(host);
if (host->ops->start_signal_voltage_switch)
err = host->ops->start_signal_voltage_switch(host, &host->ios);
mmc_host_clk_release(host);
}
if (err)
host->ios.signal_voltage = old_signal_voltage;
......@@ -1570,20 +1486,17 @@ int mmc_set_signal_voltage(struct mmc_host *host, int signal_voltage, u32 ocr)
pr_warn("%s: cannot verify signal voltage switch\n",
mmc_hostname(host));
mmc_host_clk_hold(host);
cmd.opcode = SD_SWITCH_VOLTAGE;
cmd.arg = 0;
cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
err = mmc_wait_for_cmd(host, &cmd, 0);
if (err)
goto err_command;
return err;
if (!mmc_host_is_spi(host) && (cmd.resp[0] & R1_ERROR))
return -EIO;
if (!mmc_host_is_spi(host) && (cmd.resp[0] & R1_ERROR)) {
err = -EIO;
goto err_command;
}
/*
* The card should drive cmd and dat[0:3] low immediately
* after the response of cmd11, but wait 1 ms to be sure
......@@ -1632,9 +1545,6 @@ power_cycle:
mmc_power_cycle(host, ocr);
}
err_command:
mmc_host_clk_release(host);
return err;
}
......@@ -1643,10 +1553,8 @@ err_command:
*/
void mmc_set_timing(struct mmc_host *host, unsigned int timing)
{
mmc_host_clk_hold(host);
host->ios.timing = timing;
mmc_set_ios(host);
mmc_host_clk_release(host);
}
/*
......@@ -1654,10 +1562,8 @@ void mmc_set_timing(struct mmc_host *host, unsigned int timing)
*/
void mmc_set_driver_type(struct mmc_host *host, unsigned int drv_type)
{
mmc_host_clk_hold(host);
host->ios.drv_type = drv_type;
mmc_set_ios(host);
mmc_host_clk_release(host);
}
int mmc_select_drive_strength(struct mmc_card *card, unsigned int max_dtr,
......@@ -1665,7 +1571,6 @@ int mmc_select_drive_strength(struct mmc_card *card, unsigned int max_dtr,
{
struct mmc_host *host = card->host;
int host_drv_type = SD_DRIVER_TYPE_B;
int drive_strength;
*drv_type = 0;
......@@ -1688,14 +1593,10 @@ int mmc_select_drive_strength(struct mmc_card *card, unsigned int max_dtr,
* information and let the hardware specific code
* return what is possible given the options
*/
mmc_host_clk_hold(host);
drive_strength = host->ops->select_drive_strength(card, max_dtr,
host_drv_type,
card_drv_type,
drv_type);
mmc_host_clk_release(host);
return drive_strength;
return host->ops->select_drive_strength(card, max_dtr,
host_drv_type,
card_drv_type,
drv_type);
}
/*
......@@ -1714,8 +1615,6 @@ void mmc_power_up(struct mmc_host *host, u32 ocr)
if (host->ios.power_mode == MMC_POWER_ON)
return;
mmc_host_clk_hold(host);
mmc_pwrseq_pre_power_on(host);
host->ios.vdd = fls(ocr) - 1;
......@@ -1749,8 +1648,6 @@ void mmc_power_up(struct mmc_host *host, u32 ocr)
* time required to reach a stable voltage.
*/
mmc_delay(10);
mmc_host_clk_release(host);
}
void mmc_power_off(struct mmc_host *host)
......@@ -1758,8 +1655,6 @@ void mmc_power_off(struct mmc_host *host)
if (host->ios.power_mode == MMC_POWER_OFF)
return;
mmc_host_clk_hold(host);
mmc_pwrseq_power_off(host);
host->ios.clock = 0;
......@@ -1775,8 +1670,6 @@ void mmc_power_off(struct mmc_host *host)
* can be successfully turned on again.
*/
mmc_delay(1);
mmc_host_clk_release(host);
}
void mmc_power_cycle(struct mmc_host *host, u32 ocr)
......@@ -1992,7 +1885,7 @@ static unsigned int mmc_mmc_erase_timeout(struct mmc_card *card,
*/
timeout_clks <<= 1;
timeout_us += (timeout_clks * 1000) /
(mmc_host_clk_rate(card->host) / 1000);
(card->host->ios.clock / 1000);
erase_timeout = timeout_us / 1000;
......@@ -2440,9 +2333,7 @@ static void mmc_hw_reset_for_init(struct mmc_host *host)
{
if (!(host->caps & MMC_CAP_HW_RESET) || !host->ops->hw_reset)
return;
mmc_host_clk_hold(host);
host->ops->hw_reset(host);
mmc_host_clk_release(host);
}
int mmc_hw_reset(struct mmc_host *host)
......
......@@ -40,9 +40,6 @@ void mmc_init_erase(struct mmc_card *card);
void mmc_set_chip_select(struct mmc_host *host, int mode);
void mmc_set_clock(struct mmc_host *host, unsigned int hz);
void mmc_gate_clock(struct mmc_host *host);
void mmc_ungate_clock(struct mmc_host *host);
void mmc_set_ungated(struct mmc_host *host);
void mmc_set_bus_mode(struct mmc_host *host, unsigned int mode);
void mmc_set_bus_width(struct mmc_host *host, unsigned int width);
u32 mmc_select_voltage(struct mmc_host *host, u32 ocr);
......
......@@ -255,11 +255,6 @@ void mmc_add_host_debugfs(struct mmc_host *host)
&mmc_clock_fops))
goto err_node;
#ifdef CONFIG_MMC_CLKGATE
if (!debugfs_create_u32("clk_delay", (S_IRUSR | S_IWUSR),
root, &host->clk_delay))
goto err_node;
#endif
#ifdef CONFIG_FAIL_MMC_REQUEST
if (fail_request)
setup_fault_attr(&fail_default_attr, fail_request);
......
......@@ -61,246 +61,6 @@ void mmc_unregister_host_class(void)
class_unregister(&mmc_host_class);
}
#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
void mmc_retune_enable(struct mmc_host *host)
{
host->can_retune = 1;
......@@ -583,8 +343,6 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
return NULL;
}
mmc_host_clk_init(host);
spin_lock_init(&host->lock);
init_waitqueue_head(&host->wq);
INIT_DELAYED_WORK(&host->detect, mmc_rescan);
......@@ -633,7 +391,6 @@ int mmc_add_host(struct mmc_host *host)
#ifdef CONFIG_DEBUG_FS
mmc_add_host_debugfs(host);
#endif
mmc_host_clk_sysfs_init(host);
mmc_start_host(host);
register_pm_notifier(&host->pm_notify);
......@@ -663,8 +420,6 @@ void mmc_remove_host(struct mmc_host *host)
device_del(&host->class_dev);
led_trigger_unregister_simple(host->led);
mmc_host_clk_exit(host);
}
EXPORT_SYMBOL(mmc_remove_host);
......
......@@ -1931,14 +1931,12 @@ static int mmc_reset(struct mmc_host *host)
if (!mmc_can_reset(card))
return -EOPNOTSUPP;