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core.c
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/*
* linux/drivers/mmc/core/core.c
*
* Copyright (C) 2003-2004 Russell King, All Rights Reserved.
* SD support Copyright (C) 2004 Ian Molton, All Rights Reserved.
* Copyright (C) 2005-2008 Pierre Ossman, All Rights Reserved.
* MMCv4 support Copyright (C) 2006 Philip Langdale, All Rights Reserved.
*
* 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.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/completion.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/pagemap.h>
#include <linux/err.h>
#include <linux/leds.h>
#include <linux/scatterlist.h>
#include <linux/log2.h>
#include <linux/regulator/consumer.h>
#include <linux/wakelock.h>
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
#include <linux/mmc/mmc.h>
#include <linux/mmc/sd.h>
#include "core.h"
#include "bus.h"
#include "host.h"
#include "sdio_bus.h"
#include "mmc_ops.h"
#include "sd_ops.h"
#include "sdio_ops.h"
static struct workqueue_struct *workqueue;
static struct wake_lock mmc_delayed_work_wake_lock;
/*
* Enabling software CRCs on the data blocks can be a significant (30%)
* performance cost, and for other reasons may not always be desired.
* So we allow it it to be disabled.
*/
int use_spi_crc = 1;
module_param(use_spi_crc, bool, 0);
/*
* We normally treat cards as removed during suspend if they are not
* known to be on a non-removable bus, to avoid the risk of writing
* back data to a different card after resume. Allow this to be
* overridden if necessary.
*/
#ifdef CONFIG_MMC_UNSAFE_RESUME
int mmc_assume_removable;
#else
int mmc_assume_removable = 1;
#endif
module_param_named(removable, mmc_assume_removable, bool, 0644);
MODULE_PARM_DESC(
removable,
"MMC/SD cards are removable and may be removed during suspend");
/*
* Internal function. Schedule delayed work in the MMC work queue.
*/
static int mmc_schedule_delayed_work(struct delayed_work *work,
unsigned long delay)
{
wake_lock(&mmc_delayed_work_wake_lock);
return queue_delayed_work(workqueue, work, delay);
}
/*
* Internal function. Flush all scheduled work from the MMC work queue.
*/
static void mmc_flush_scheduled_work(void)
{
flush_workqueue(workqueue);
}
/**
* mmc_request_done - finish processing an MMC request
* @host: MMC host which completed request
* @mrq: MMC request which request
*
* MMC drivers should call this function when they have completed
* their processing of a request.
*/
void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)
{
struct mmc_command *cmd = mrq->cmd;
int err = cmd->error;
if (err && cmd->retries && mmc_host_is_spi(host)) {
if (cmd->resp[0] & R1_SPI_ILLEGAL_COMMAND)
cmd->retries = 0;
}
if (err && cmd->retries) {
pr_debug("%s: req failed (CMD%u): %d, retrying...\n",
mmc_hostname(host), cmd->opcode, err);
cmd->retries--;
cmd->error = 0;
host->ops->request(host, mrq);
} else {
led_trigger_event(host->led, LED_OFF);
pr_debug("%s: req done (CMD%u): %d: %08x %08x %08x %08x\n",
mmc_hostname(host), cmd->opcode, err,
cmd->resp[0], cmd->resp[1],
cmd->resp[2], cmd->resp[3]);
if (mrq->data) {
pr_debug("%s: %d bytes transferred: %d\n",
mmc_hostname(host),
mrq->data->bytes_xfered, mrq->data->error);
}
if (mrq->stop) {
pr_debug("%s: (CMD%u): %d: %08x %08x %08x %08x\n",
mmc_hostname(host), mrq->stop->opcode,
mrq->stop->error,
mrq->stop->resp[0], mrq->stop->resp[1],
mrq->stop->resp[2], mrq->stop->resp[3]);
}
if (mrq->done)
mrq->done(mrq);
}
}
EXPORT_SYMBOL(mmc_request_done);
static void
mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
{
#ifdef CONFIG_MMC_DEBUG
unsigned int i, sz;
struct scatterlist *sg;
#endif
pr_debug("%s: starting CMD%u arg %08x flags %08x\n",
mmc_hostname(host), mrq->cmd->opcode,
mrq->cmd->arg, mrq->cmd->flags);
if (mrq->data) {
pr_debug("%s: blksz %d blocks %d flags %08x "
"tsac %d ms nsac %d\n",
mmc_hostname(host), mrq->data->blksz,
mrq->data->blocks, mrq->data->flags,
mrq->data->timeout_ns / 1000000,
mrq->data->timeout_clks);
}
if (mrq->stop) {
pr_debug("%s: CMD%u arg %08x flags %08x\n",
mmc_hostname(host), mrq->stop->opcode,
mrq->stop->arg, mrq->stop->flags);
}
WARN_ON(!host->claimed);
led_trigger_event(host->led, LED_FULL);
mrq->cmd->error = 0;
mrq->cmd->mrq = mrq;
if (mrq->data) {
BUG_ON(mrq->data->blksz > host->max_blk_size);
BUG_ON(mrq->data->blocks > host->max_blk_count);
BUG_ON(mrq->data->blocks * mrq->data->blksz >
host->max_req_size);
#ifdef CONFIG_MMC_DEBUG
sz = 0;
for_each_sg(mrq->data->sg, sg, mrq->data->sg_len, i)
sz += sg->length;
BUG_ON(sz != mrq->data->blocks * mrq->data->blksz);
#endif
mrq->cmd->data = mrq->data;
mrq->data->error = 0;
mrq->data->mrq = mrq;
if (mrq->stop) {
mrq->data->stop = mrq->stop;
mrq->stop->error = 0;
mrq->stop->mrq = mrq;
}
}
host->ops->request(host, mrq);
}
static void mmc_wait_done(struct mmc_request *mrq)
{
complete(mrq->done_data);
}
/**
* mmc_wait_for_req - start a request and wait for completion
* @host: MMC host to start command
* @mrq: MMC request to start
*
* Start a new MMC custom command request for a host, and wait
* for the command to complete. Does not attempt to parse the
* response.
*/
void mmc_wait_for_req(struct mmc_host *host, struct mmc_request *mrq)
{
DECLARE_COMPLETION_ONSTACK(complete);
mrq->done_data = &complete;
mrq->done = mmc_wait_done;
mmc_start_request(host, mrq);
wait_for_completion(&complete);
}
EXPORT_SYMBOL(mmc_wait_for_req);
/**
* mmc_wait_for_cmd - start a command and wait for completion
* @host: MMC host to start command
* @cmd: MMC command to start
* @retries: maximum number of retries
*
* Start a new MMC command for a host, and wait for the command
* to complete. Return any error that occurred while the command
* was executing. Do not attempt to parse the response.
*/
int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd, int retries)
{
struct mmc_request mrq;
WARN_ON(!host->claimed);
memset(&mrq, 0, sizeof(struct mmc_request));
memset(cmd->resp, 0, sizeof(cmd->resp));
cmd->retries = retries;
mrq.cmd = cmd;
cmd->data = NULL;
mmc_wait_for_req(host, &mrq);
return cmd->error;
}
EXPORT_SYMBOL(mmc_wait_for_cmd);
/**
* mmc_set_data_timeout - set the timeout for a data command
* @data: data phase for command
* @card: the MMC card associated with the data transfer
*
* Computes the data timeout parameters according to the
* correct algorithm given the card type.
*/
void mmc_set_data_timeout(struct mmc_data *data, const struct mmc_card *card)
{
unsigned int mult;
/*
* SDIO cards only define an upper 1 s limit on access.
*/
if (mmc_card_sdio(card)) {
data->timeout_ns = 1000000000;
data->timeout_clks = 0;
return;
}
/*
* SD cards use a 100 multiplier rather than 10
*/
mult = mmc_card_sd(card) ? 100 : 10;
/*
* Scale up the multiplier (and therefore the timeout) by
* the r2w factor for writes.
*/
if (data->flags & MMC_DATA_WRITE)
mult <<= card->csd.r2w_factor;
data->timeout_ns = card->csd.tacc_ns * mult;
data->timeout_clks = card->csd.tacc_clks * mult;
/*
* SD cards also have an upper limit on the timeout.
*/
if (mmc_card_sd(card)) {
unsigned int timeout_us, limit_us;
timeout_us = data->timeout_ns / 1000;
timeout_us += data->timeout_clks * 1000 /
(card->host->ios.clock / 1000);
if (data->flags & MMC_DATA_WRITE)
/*
* The limit is really 250 ms, but that is
* insufficient for some crappy cards.
*/
limit_us = 300000;
else
limit_us = 100000;
/*
* SDHC cards always use these fixed values.
*/
if (timeout_us > limit_us || mmc_card_blockaddr(card)) {
data->timeout_ns = limit_us * 1000;
data->timeout_clks = 0;
}
}
/*
* Some cards need very high timeouts if driven in SPI mode.
* The worst observed timeout was 900ms after writing a
* continuous stream of data until the internal logic
* overflowed.
*/
if (mmc_host_is_spi(card->host)) {
if (data->flags & MMC_DATA_WRITE) {
if (data->timeout_ns < 1000000000)
data->timeout_ns = 1000000000; /* 1s */
} else {
if (data->timeout_ns < 100000000)
data->timeout_ns = 100000000; /* 100ms */
}
}
}
EXPORT_SYMBOL(mmc_set_data_timeout);
/**
* mmc_align_data_size - pads a transfer size to a more optimal value
* @card: the MMC card associated with the data transfer
* @sz: original transfer size
*
* Pads the original data size with a number of extra bytes in
* order to avoid controller bugs and/or performance hits
* (e.g. some controllers revert to PIO for certain sizes).
*
* Returns the improved size, which might be unmodified.
*
* Note that this function is only relevant when issuing a
* single scatter gather entry.
*/
unsigned int mmc_align_data_size(struct mmc_card *card, unsigned int sz)
{
/*
* FIXME: We don't have a system for the controller to tell
* the core about its problems yet, so for now we just 32-bit
* align the size.
*/
sz = ((sz + 3) / 4) * 4;
return sz;
}
EXPORT_SYMBOL(mmc_align_data_size);
/**
* mmc_host_enable - enable a host.
* @host: mmc host to enable
*
* Hosts that support power saving can use the 'enable' and 'disable'
* methods to exit and enter power saving states. For more information
* see comments for struct mmc_host_ops.
*/
int mmc_host_enable(struct mmc_host *host)
{
if (!(host->caps & MMC_CAP_DISABLE))
return 0;
if (host->en_dis_recurs)
return 0;
if (host->nesting_cnt++)
return 0;
cancel_delayed_work_sync(&host->disable);
if (host->enabled)
return 0;
if (host->ops->enable) {
int err;
host->en_dis_recurs = 1;
err = host->ops->enable(host);
host->en_dis_recurs = 0;
if (err) {
pr_debug("%s: enable error %d\n",
mmc_hostname(host), err);
return err;
}
}
host->enabled = 1;
return 0;
}
EXPORT_SYMBOL(mmc_host_enable);
static int mmc_host_do_disable(struct mmc_host *host, int lazy)
{
if (host->ops->disable) {
int err;
host->en_dis_recurs = 1;
err = host->ops->disable(host, lazy);
host->en_dis_recurs = 0;
if (err < 0) {
pr_debug("%s: disable error %d\n",
mmc_hostname(host), err);
return err;
}
if (err > 0) {
unsigned long delay = msecs_to_jiffies(err);
mmc_schedule_delayed_work(&host->disable, delay);
}
}
host->enabled = 0;
return 0;
}
/**
* mmc_host_disable - disable a host.
* @host: mmc host to disable
*
* Hosts that support power saving can use the 'enable' and 'disable'
* methods to exit and enter power saving states. For more information
* see comments for struct mmc_host_ops.
*/
int mmc_host_disable(struct mmc_host *host)
{
int err;
if (!(host->caps & MMC_CAP_DISABLE))
return 0;
if (host->en_dis_recurs)
return 0;
if (--host->nesting_cnt)
return 0;
if (!host->enabled)
return 0;
err = mmc_host_do_disable(host, 0);
return err;
}
EXPORT_SYMBOL(mmc_host_disable);
/**
* __mmc_claim_host - exclusively claim a host
* @host: mmc host to claim
* @abort: whether or not the operation should be aborted
*
* Claim a host for a set of operations. If @abort is non null and
* dereference a non-zero value then this will return prematurely with
* that non-zero value without acquiring the lock. Returns zero
* with the lock held otherwise.
*/
int __mmc_claim_host(struct mmc_host *host, atomic_t *abort)
{
DECLARE_WAITQUEUE(wait, current);
unsigned long flags;
int stop;
might_sleep();
add_wait_queue(&host->wq, &wait);
spin_lock_irqsave(&host->lock, flags);
while (1) {
set_current_state(TASK_UNINTERRUPTIBLE);
stop = abort ? atomic_read(abort) : 0;
if (stop || !host->claimed || host->claimer == current)
break;
spin_unlock_irqrestore(&host->lock, flags);
schedule();
spin_lock_irqsave(&host->lock, flags);
}
set_current_state(TASK_RUNNING);
if (!stop) {
host->claimed = 1;
host->claimer = current;
host->claim_cnt += 1;
} else
wake_up(&host->wq);
spin_unlock_irqrestore(&host->lock, flags);
remove_wait_queue(&host->wq, &wait);
if (!stop)
mmc_host_enable(host);
return stop;
}
EXPORT_SYMBOL(__mmc_claim_host);
/**
* mmc_try_claim_host - try exclusively to claim a host
* @host: mmc host to claim
*
* Returns %1 if the host is claimed, %0 otherwise.
*/
int mmc_try_claim_host(struct mmc_host *host)
{
int claimed_host = 0;
unsigned long flags;
spin_lock_irqsave(&host->lock, flags);
if (!host->claimed || host->claimer == current) {
host->claimed = 1;
host->claimer = current;
host->claim_cnt += 1;
claimed_host = 1;
}
spin_unlock_irqrestore(&host->lock, flags);
return claimed_host;
}
EXPORT_SYMBOL(mmc_try_claim_host);
static void mmc_do_release_host(struct mmc_host *host)
{
unsigned long flags;
spin_lock_irqsave(&host->lock, flags);
if (--host->claim_cnt) {
/* Release for nested claim */
spin_unlock_irqrestore(&host->lock, flags);
} else {
host->claimed = 0;
host->claimer = NULL;
spin_unlock_irqrestore(&host->lock, flags);
wake_up(&host->wq);
}
}
void mmc_host_deeper_disable(struct work_struct *work)
{
struct mmc_host *host =
container_of(work, struct mmc_host, disable.work);
/* If the host is claimed then we do not want to disable it anymore */
if (!mmc_try_claim_host(host))
goto out;
mmc_host_do_disable(host, 1);
mmc_do_release_host(host);
out:
wake_unlock(&mmc_delayed_work_wake_lock);
}
/**
* mmc_host_lazy_disable - lazily disable a host.
* @host: mmc host to disable
*
* Hosts that support power saving can use the 'enable' and 'disable'
* methods to exit and enter power saving states. For more information
* see comments for struct mmc_host_ops.
*/
int mmc_host_lazy_disable(struct mmc_host *host)
{
if (!(host->caps & MMC_CAP_DISABLE))
return 0;
if (host->en_dis_recurs)
return 0;
if (--host->nesting_cnt)
return 0;
if (!host->enabled)
return 0;
if (host->disable_delay) {
mmc_schedule_delayed_work(&host->disable,
msecs_to_jiffies(host->disable_delay));
return 0;
} else
return mmc_host_do_disable(host, 1);
}
EXPORT_SYMBOL(mmc_host_lazy_disable);
/**
* mmc_release_host - release a host
* @host: mmc host to release
*
* Release a MMC host, allowing others to claim the host
* for their operations.
*/
void mmc_release_host(struct mmc_host *host)
{
WARN_ON(!host->claimed);
mmc_host_lazy_disable(host);
mmc_do_release_host(host);
}
EXPORT_SYMBOL(mmc_release_host);
/*
* Internal function that does the actual ios call to the host driver,
* optionally printing some debug output.
*/
static inline void mmc_set_ios(struct mmc_host *host)
{
struct mmc_ios *ios = &host->ios;
pr_debug("%s: clock %uHz busmode %u powermode %u cs %u Vdd %u "
"width %u timing %u\n",
mmc_hostname(host), ios->clock, ios->bus_mode,
ios->power_mode, ios->chip_select, ios->vdd,
ios->bus_width, ios->timing);
host->ops->set_ios(host, ios);
}
/*
* Control chip select pin on a host.
*/
void mmc_set_chip_select(struct mmc_host *host, int mode)
{
host->ios.chip_select = mode;
mmc_set_ios(host);
}
/*
* Sets the host clock to the highest possible frequency that
* is below "hz".
*/
void mmc_set_clock(struct mmc_host *host, unsigned int hz)
{
WARN_ON(hz < host->f_min);
if (hz > host->f_max)
hz = host->f_max;
host->ios.clock = hz;
mmc_set_ios(host);
}
/*
* Change the bus mode (open drain/push-pull) of a host.
*/
void mmc_set_bus_mode(struct mmc_host *host, unsigned int mode)
{
host->ios.bus_mode = mode;
mmc_set_ios(host);
}
/*
* Change data bus width of a host.
*/
void mmc_set_bus_width(struct mmc_host *host, unsigned int width)
{
host->ios.bus_width = width;
mmc_set_ios(host);
}
/**
* mmc_vdd_to_ocrbitnum - Convert a voltage to the OCR bit number
* @vdd: voltage (mV)
* @low_bits: prefer low bits in boundary cases
*
* This function returns the OCR bit number according to the provided @vdd
* value. If conversion is not possible a negative errno value returned.
*
* Depending on the @low_bits flag the function prefers low or high OCR bits
* on boundary voltages. For example,
* with @low_bits = true, 3300 mV translates to ilog2(MMC_VDD_32_33);
* with @low_bits = false, 3300 mV translates to ilog2(MMC_VDD_33_34);
*
* Any value in the [1951:1999] range translates to the ilog2(MMC_VDD_20_21).
*/
static int mmc_vdd_to_ocrbitnum(int vdd, bool low_bits)
{
const int max_bit = ilog2(MMC_VDD_35_36);
int bit;
if (vdd < 1650 || vdd > 3600)
return -EINVAL;
if (vdd >= 1650 && vdd <= 1950)
return ilog2(MMC_VDD_165_195);
if (low_bits)
vdd -= 1;
/* Base 2000 mV, step 100 mV, bit's base 8. */
bit = (vdd - 2000) / 100 + 8;
if (bit > max_bit)
return max_bit;
return bit;
}
/**
* mmc_vddrange_to_ocrmask - Convert a voltage range to the OCR mask
* @vdd_min: minimum voltage value (mV)
* @vdd_max: maximum voltage value (mV)
*
* This function returns the OCR mask bits according to the provided @vdd_min
* and @vdd_max values. If conversion is not possible the function returns 0.
*
* Notes wrt boundary cases:
* This function sets the OCR bits for all boundary voltages, for example
* [3300:3400] range is translated to MMC_VDD_32_33 | MMC_VDD_33_34 |
* MMC_VDD_34_35 mask.
*/
u32 mmc_vddrange_to_ocrmask(int vdd_min, int vdd_max)
{
u32 mask = 0;
if (vdd_max < vdd_min)
return 0;
/* Prefer high bits for the boundary vdd_max values. */
vdd_max = mmc_vdd_to_ocrbitnum(vdd_max, false);
if (vdd_max < 0)
return 0;
/* Prefer low bits for the boundary vdd_min values. */
vdd_min = mmc_vdd_to_ocrbitnum(vdd_min, true);
if (vdd_min < 0)
return 0;
/* Fill the mask, from max bit to min bit. */
while (vdd_max >= vdd_min)
mask |= 1 << vdd_max--;
return mask;
}
EXPORT_SYMBOL(mmc_vddrange_to_ocrmask);
#ifdef CONFIG_REGULATOR
/**
* mmc_regulator_get_ocrmask - return mask of supported voltages
* @supply: regulator to use
*
* This returns either a negative errno, or a mask of voltages that
* can be provided to MMC/SD/SDIO devices using the specified voltage
* regulator. This would normally be called before registering the
* MMC host adapter.
*/
int mmc_regulator_get_ocrmask(struct regulator *supply)
{
int result = 0;
int count;
int i;
count = regulator_count_voltages(supply);
if (count < 0)
return count;
for (i = 0; i < count; i++) {
int vdd_uV;
int vdd_mV;
vdd_uV = regulator_list_voltage(supply, i);
if (vdd_uV <= 0)
continue;
vdd_mV = vdd_uV / 1000;
result |= mmc_vddrange_to_ocrmask(vdd_mV, vdd_mV);
}
return result;
}
EXPORT_SYMBOL(mmc_regulator_get_ocrmask);
/**
* mmc_regulator_set_ocr - set regulator to match host->ios voltage
* @vdd_bit: zero for power off, else a bit number (host->ios.vdd)
* @supply: regulator to use
*
* Returns zero on success, else negative errno.
*
* MMC host drivers may use this to enable or disable a regulator using
* a particular supply voltage. This would normally be called from the
* set_ios() method.
*/
int mmc_regulator_set_ocr(struct regulator *supply, unsigned short vdd_bit)
{
int result = 0;
int min_uV, max_uV;
int enabled;
enabled = regulator_is_enabled(supply);
if (enabled < 0)
return enabled;
if (vdd_bit) {
int tmp;
int voltage;
/* REVISIT mmc_vddrange_to_ocrmask() may have set some
* bits this regulator doesn't quite support ... don't
* be too picky, most cards and regulators are OK with
* a 0.1V range goof (it's a small error percentage).
*/
tmp = vdd_bit - ilog2(MMC_VDD_165_195);
if (tmp == 0) {
min_uV = 1650 * 1000;
max_uV = 1950 * 1000;
} else {
min_uV = 1900 * 1000 + tmp * 100 * 1000;
max_uV = min_uV + 100 * 1000;
}
/* avoid needless changes to this voltage; the regulator
* might not allow this operation
*/
voltage = regulator_get_voltage(supply);
if (voltage < 0)
result = voltage;
else if (voltage < min_uV || voltage > max_uV)
result = regulator_set_voltage(supply, min_uV, max_uV);
else
result = 0;
if (result == 0 && !enabled)
result = regulator_enable(supply);
} else if (enabled) {
result = regulator_disable(supply);
}
return result;
}
EXPORT_SYMBOL(mmc_regulator_set_ocr);
#endif
/*
* Mask off any voltages we don't support and select
* the lowest voltage
*/
u32 mmc_select_voltage(struct mmc_host *host, u32 ocr)
{
int bit;
ocr &= host->ocr_avail;
bit = ffs(ocr);
if (bit) {
bit -= 1;
ocr &= 3 << bit;
host->ios.vdd = bit;
mmc_set_ios(host);
} else {
pr_warning("%s: host doesn't support card's voltages\n",
mmc_hostname(host));
ocr = 0;
}
return ocr;
}
/*
* Select timing parameters for host.
*/
void mmc_set_timing(struct mmc_host *host, unsigned int timing)
{
host->ios.timing = timing;
mmc_set_ios(host);
}
/*
* Apply power to the MMC stack. This is a two-stage process.
* First, we enable power to the card without the clock running.
* We then wait a bit for the power to stabilise. Finally,
* enable the bus drivers and clock to the card.
*
* We must _NOT_ enable the clock prior to power stablising.
*
* If a host does all the power sequencing itself, ignore the
* initial MMC_POWER_UP stage.
*/
static void mmc_power_up(struct mmc_host *host)
{
int bit;
/* If ocr is set, we use it */
if (host->ocr)
bit = ffs(host->ocr) - 1;
else
bit = fls(host->ocr_avail) - 1;
host->ios.vdd = bit;
if (mmc_host_is_spi(host)) {
host->ios.chip_select = MMC_CS_HIGH;
host->ios.bus_mode = MMC_BUSMODE_PUSHPULL;
} else {
host->ios.chip_select = MMC_CS_DONTCARE;
host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
}
host->ios.power_mode = MMC_POWER_UP;
host->ios.bus_width = MMC_BUS_WIDTH_1;
host->ios.timing = MMC_TIMING_LEGACY;
mmc_set_ios(host);
/*
* This delay should be sufficient to allow the power supply
* to reach the minimum voltage.
*/
mmc_delay(10);
host->ios.clock = host->f_min;
host->ios.power_mode = MMC_POWER_ON;
mmc_set_ios(host);
/*
* This delay must be at least 74 clock sizes, or 1 ms, or the
* time required to reach a stable voltage.
*/
mmc_delay(10);
}
static void mmc_power_off(struct mmc_host *host)
{
host->ios.clock = 0;
host->ios.vdd = 0;
if (!mmc_host_is_spi(host)) {
host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
host->ios.chip_select = MMC_CS_DONTCARE;
}
host->ios.power_mode = MMC_POWER_OFF;
host->ios.bus_width = MMC_BUS_WIDTH_1;
host->ios.timing = MMC_TIMING_LEGACY;
mmc_set_ios(host);
}
/*
* Cleanup when the last reference to the bus operator is dropped.
*/
static void __mmc_release_bus(struct mmc_host *host)
{
BUG_ON(!host);
BUG_ON(host->bus_refs);
BUG_ON(!host->bus_dead);
host->bus_ops = NULL;
}
/*
* Increase reference count of bus operator
*/
static inline void mmc_bus_get(struct mmc_host *host)
{
unsigned long flags;
spin_lock_irqsave(&host->lock, flags);
host->bus_refs++;
spin_unlock_irqrestore(&host->lock, flags);
}
/*
* Decrease reference count of bus operator and free it if
* it is the last reference.
*/
static inline void mmc_bus_put(struct mmc_host *host)
{
unsigned long flags;
spin_lock_irqsave(&host->lock, flags);
host->bus_refs--;
if ((host->bus_refs == 0) && host->bus_ops)
__mmc_release_bus(host);
spin_unlock_irqrestore(&host->lock, flags);
}
int mmc_resume_bus(struct mmc_host *host)
{
unsigned long flags;
if (!mmc_bus_needs_resume(host))
return -EINVAL;
printk("%s: Starting deferred resume\n", mmc_hostname(host));
spin_lock_irqsave(&host->lock, flags);
host->bus_resume_flags &= ~MMC_BUSRESUME_NEEDS_RESUME;
host->rescan_disable = 0;
spin_unlock_irqrestore(&host->lock, flags);
mmc_bus_get(host);
if (host->bus_ops && !host->bus_dead) {
mmc_power_up(host);
BUG_ON(!host->bus_ops->resume);
host->bus_ops->resume(host);
}