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linux/sound/hda/hdac_regmap.c
Takashi Iwai 3194ed4979 ALSA: hda - Fix possible race on regmap bypass flip 
HD-audio driver uses regmap cache bypass feature for reading a raw
value without the cache.  But this is racy since both the cached and
the uncached reads may occur concurrently.  The former is done via the
normal control API access while the latter comes from the proc file
read.

Even though the regmap itself has the protection against the
concurrent accesses, the flag set/reset is done without the
protection, so it may lead to inconsistent state of bypass flag that
doesn't match with the current read and occasionally result in a
kernel WARNING like:
  WARNING: CPU: 3 PID: 2731 at drivers/base/regmap/regcache.c:499 regcache_cache_only+0x78/0x93

One way to work around such a problem is to wrap with a mutex.  But in
this case, the solution is simpler: for the uncached read, we just
skip the regmap and directly calls its accessor.  The verb execution
there is protected by itself, so basically it's safe to call
individually.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=116171
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2016-04-21 17:59:17 +02:00

532 lines
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/*
* Regmap support for HD-audio verbs
*
* A virtual register is translated to one or more hda verbs for write,
* vice versa for read.
*
* A few limitations:
* - Provided for not all verbs but only subset standard non-volatile verbs.
* - For reading, only AC_VERB_GET_* variants can be used.
* - For writing, mapped to the *corresponding* AC_VERB_SET_* variants,
* so can't handle asymmetric verbs for read and write
*/
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/regmap.h>
#include <linux/export.h>
#include <linux/pm.h>
#include <linux/pm_runtime.h>
#include <sound/core.h>
#include <sound/hdaudio.h>
#include <sound/hda_regmap.h>
static int codec_pm_lock(struct hdac_device *codec)
{
return snd_hdac_keep_power_up(codec);
}
static void codec_pm_unlock(struct hdac_device *codec, int lock)
{
if (lock == 1)
snd_hdac_power_down_pm(codec);
}
#define get_verb(reg) (((reg) >> 8) & 0xfff)
static bool hda_volatile_reg(struct device *dev, unsigned int reg)
{
struct hdac_device *codec = dev_to_hdac_dev(dev);
unsigned int verb = get_verb(reg);
switch (verb) {
case AC_VERB_GET_PROC_COEF:
return !codec->cache_coef;
case AC_VERB_GET_COEF_INDEX:
case AC_VERB_GET_PROC_STATE:
case AC_VERB_GET_POWER_STATE:
case AC_VERB_GET_PIN_SENSE:
case AC_VERB_GET_HDMI_DIP_SIZE:
case AC_VERB_GET_HDMI_ELDD:
case AC_VERB_GET_HDMI_DIP_INDEX:
case AC_VERB_GET_HDMI_DIP_DATA:
case AC_VERB_GET_HDMI_DIP_XMIT:
case AC_VERB_GET_HDMI_CP_CTRL:
case AC_VERB_GET_HDMI_CHAN_SLOT:
case AC_VERB_GET_DEVICE_SEL:
case AC_VERB_GET_DEVICE_LIST: /* read-only volatile */
return true;
}
return false;
}
static bool hda_writeable_reg(struct device *dev, unsigned int reg)
{
struct hdac_device *codec = dev_to_hdac_dev(dev);
unsigned int verb = get_verb(reg);
int i;
for (i = 0; i < codec->vendor_verbs.used; i++) {
unsigned int *v = snd_array_elem(&codec->vendor_verbs, i);
if (verb == *v)
return true;
}
if (codec->caps_overwriting)
return true;
switch (verb & 0xf00) {
case AC_VERB_GET_STREAM_FORMAT:
case AC_VERB_GET_AMP_GAIN_MUTE:
return true;
case AC_VERB_GET_PROC_COEF:
return codec->cache_coef;
case 0xf00:
break;
default:
return false;
}
switch (verb) {
case AC_VERB_GET_CONNECT_SEL:
case AC_VERB_GET_SDI_SELECT:
case AC_VERB_GET_PIN_WIDGET_CONTROL:
case AC_VERB_GET_UNSOLICITED_RESPONSE: /* only as SET_UNSOLICITED_ENABLE */
case AC_VERB_GET_BEEP_CONTROL:
case AC_VERB_GET_EAPD_BTLENABLE:
case AC_VERB_GET_DIGI_CONVERT_1:
case AC_VERB_GET_DIGI_CONVERT_2: /* only for beep control */
case AC_VERB_GET_VOLUME_KNOB_CONTROL:
case AC_VERB_GET_GPIO_MASK:
case AC_VERB_GET_GPIO_DIRECTION:
case AC_VERB_GET_GPIO_DATA: /* not for volatile read */
case AC_VERB_GET_GPIO_WAKE_MASK:
case AC_VERB_GET_GPIO_UNSOLICITED_RSP_MASK:
case AC_VERB_GET_GPIO_STICKY_MASK:
return true;
}
return false;
}
static bool hda_readable_reg(struct device *dev, unsigned int reg)
{
struct hdac_device *codec = dev_to_hdac_dev(dev);
unsigned int verb = get_verb(reg);
if (codec->caps_overwriting)
return true;
switch (verb) {
case AC_VERB_PARAMETERS:
case AC_VERB_GET_CONNECT_LIST:
case AC_VERB_GET_SUBSYSTEM_ID:
return true;
/* below are basically writable, but disabled for reducing unnecessary
* writes at sync
*/
case AC_VERB_GET_CONFIG_DEFAULT: /* usually just read */
case AC_VERB_GET_CONV: /* managed in PCM code */
case AC_VERB_GET_CVT_CHAN_COUNT: /* managed in HDMI CA code */
return true;
}
return hda_writeable_reg(dev, reg);
}
/*
* Stereo amp pseudo register:
* for making easier to handle the stereo volume control, we provide a
* fake register to deal both left and right channels by a single
* (pseudo) register access. A verb consisting of SET_AMP_GAIN with
* *both* SET_LEFT and SET_RIGHT bits takes a 16bit value, the lower 8bit
* for the left and the upper 8bit for the right channel.
*/
static bool is_stereo_amp_verb(unsigned int reg)
{
if (((reg >> 8) & 0x700) != AC_VERB_SET_AMP_GAIN_MUTE)
return false;
return (reg & (AC_AMP_SET_LEFT | AC_AMP_SET_RIGHT)) ==
(AC_AMP_SET_LEFT | AC_AMP_SET_RIGHT);
}
/* read a pseudo stereo amp register (16bit left+right) */
static int hda_reg_read_stereo_amp(struct hdac_device *codec,
unsigned int reg, unsigned int *val)
{
unsigned int left, right;
int err;
reg &= ~(AC_AMP_SET_LEFT | AC_AMP_SET_RIGHT);
err = snd_hdac_exec_verb(codec, reg | AC_AMP_GET_LEFT, 0, &left);
if (err < 0)
return err;
err = snd_hdac_exec_verb(codec, reg | AC_AMP_GET_RIGHT, 0, &right);
if (err < 0)
return err;
*val = left | (right << 8);
return 0;
}
/* write a pseudo stereo amp register (16bit left+right) */
static int hda_reg_write_stereo_amp(struct hdac_device *codec,
unsigned int reg, unsigned int val)
{
int err;
unsigned int verb, left, right;
verb = AC_VERB_SET_AMP_GAIN_MUTE << 8;
if (reg & AC_AMP_GET_OUTPUT)
verb |= AC_AMP_SET_OUTPUT;
else
verb |= AC_AMP_SET_INPUT | ((reg & 0xf) << 8);
reg = (reg & ~0xfffff) | verb;
left = val & 0xff;
right = (val >> 8) & 0xff;
if (left == right) {
reg |= AC_AMP_SET_LEFT | AC_AMP_SET_RIGHT;
return snd_hdac_exec_verb(codec, reg | left, 0, NULL);
}
err = snd_hdac_exec_verb(codec, reg | AC_AMP_SET_LEFT | left, 0, NULL);
if (err < 0)
return err;
err = snd_hdac_exec_verb(codec, reg | AC_AMP_SET_RIGHT | right, 0, NULL);
if (err < 0)
return err;
return 0;
}
/* read a pseudo coef register (16bit) */
static int hda_reg_read_coef(struct hdac_device *codec, unsigned int reg,
unsigned int *val)
{
unsigned int verb;
int err;
if (!codec->cache_coef)
return -EINVAL;
/* LSB 8bit = coef index */
verb = (reg & ~0xfff00) | (AC_VERB_SET_COEF_INDEX << 8);
err = snd_hdac_exec_verb(codec, verb, 0, NULL);
if (err < 0)
return err;
verb = (reg & ~0xfffff) | (AC_VERB_GET_COEF_INDEX << 8);
return snd_hdac_exec_verb(codec, verb, 0, val);
}
/* write a pseudo coef register (16bit) */
static int hda_reg_write_coef(struct hdac_device *codec, unsigned int reg,
unsigned int val)
{
unsigned int verb;
int err;
if (!codec->cache_coef)
return -EINVAL;
/* LSB 8bit = coef index */
verb = (reg & ~0xfff00) | (AC_VERB_SET_COEF_INDEX << 8);
err = snd_hdac_exec_verb(codec, verb, 0, NULL);
if (err < 0)
return err;
verb = (reg & ~0xfffff) | (AC_VERB_GET_COEF_INDEX << 8) |
(val & 0xffff);
return snd_hdac_exec_verb(codec, verb, 0, NULL);
}
static int hda_reg_read(void *context, unsigned int reg, unsigned int *val)
{
struct hdac_device *codec = context;
int verb = get_verb(reg);
int err;
int pm_lock = 0;
if (verb != AC_VERB_GET_POWER_STATE) {
pm_lock = codec_pm_lock(codec);
if (pm_lock < 0)
return -EAGAIN;
}
reg |= (codec->addr << 28);
if (is_stereo_amp_verb(reg)) {
err = hda_reg_read_stereo_amp(codec, reg, val);
goto out;
}
if (verb == AC_VERB_GET_PROC_COEF) {
err = hda_reg_read_coef(codec, reg, val);
goto out;
}
if ((verb & 0x700) == AC_VERB_SET_AMP_GAIN_MUTE)
reg &= ~AC_AMP_FAKE_MUTE;
err = snd_hdac_exec_verb(codec, reg, 0, val);
if (err < 0)
goto out;
/* special handling for asymmetric reads */
if (verb == AC_VERB_GET_POWER_STATE) {
if (*val & AC_PWRST_ERROR)
*val = -1;
else /* take only the actual state */
*val = (*val >> 4) & 0x0f;
}
out:
codec_pm_unlock(codec, pm_lock);
return err;
}
static int hda_reg_write(void *context, unsigned int reg, unsigned int val)
{
struct hdac_device *codec = context;
unsigned int verb;
int i, bytes, err;
int pm_lock = 0;
if (codec->caps_overwriting)
return 0;
reg &= ~0x00080000U; /* drop GET bit */
reg |= (codec->addr << 28);
verb = get_verb(reg);
if (verb != AC_VERB_SET_POWER_STATE) {
pm_lock = codec_pm_lock(codec);
if (pm_lock < 0)
return codec->lazy_cache ? 0 : -EAGAIN;
}
if (is_stereo_amp_verb(reg)) {
err = hda_reg_write_stereo_amp(codec, reg, val);
goto out;
}
if (verb == AC_VERB_SET_PROC_COEF) {
err = hda_reg_write_coef(codec, reg, val);
goto out;
}
switch (verb & 0xf00) {
case AC_VERB_SET_AMP_GAIN_MUTE:
if ((reg & AC_AMP_FAKE_MUTE) && (val & AC_AMP_MUTE))
val = 0;
verb = AC_VERB_SET_AMP_GAIN_MUTE;
if (reg & AC_AMP_GET_LEFT)
verb |= AC_AMP_SET_LEFT >> 8;
else
verb |= AC_AMP_SET_RIGHT >> 8;
if (reg & AC_AMP_GET_OUTPUT) {
verb |= AC_AMP_SET_OUTPUT >> 8;
} else {
verb |= AC_AMP_SET_INPUT >> 8;
verb |= reg & 0xf;
}
break;
}
switch (verb) {
case AC_VERB_SET_DIGI_CONVERT_1:
bytes = 2;
break;
case AC_VERB_SET_CONFIG_DEFAULT_BYTES_0:
bytes = 4;
break;
default:
bytes = 1;
break;
}
for (i = 0; i < bytes; i++) {
reg &= ~0xfffff;
reg |= (verb + i) << 8 | ((val >> (8 * i)) & 0xff);
err = snd_hdac_exec_verb(codec, reg, 0, NULL);
if (err < 0)
goto out;
}
out:
codec_pm_unlock(codec, pm_lock);
return err;
}
static const struct regmap_config hda_regmap_cfg = {
.name = "hdaudio",
.reg_bits = 32,
.val_bits = 32,
.max_register = 0xfffffff,
.writeable_reg = hda_writeable_reg,
.readable_reg = hda_readable_reg,
.volatile_reg = hda_volatile_reg,
.cache_type = REGCACHE_RBTREE,
.reg_read = hda_reg_read,
.reg_write = hda_reg_write,
.use_single_rw = true,
};
/**
* snd_hdac_regmap_init - Initialize regmap for HDA register accesses
* @codec: the codec object
*
* Returns zero for success or a negative error code.
*/
int snd_hdac_regmap_init(struct hdac_device *codec)
{
struct regmap *regmap;
regmap = regmap_init(&codec->dev, NULL, codec, &hda_regmap_cfg);
if (IS_ERR(regmap))
return PTR_ERR(regmap);
codec->regmap = regmap;
snd_array_init(&codec->vendor_verbs, sizeof(unsigned int), 8);
return 0;
}
EXPORT_SYMBOL_GPL(snd_hdac_regmap_init);
/**
* snd_hdac_regmap_init - Release the regmap from HDA codec
* @codec: the codec object
*/
void snd_hdac_regmap_exit(struct hdac_device *codec)
{
if (codec->regmap) {
regmap_exit(codec->regmap);
codec->regmap = NULL;
snd_array_free(&codec->vendor_verbs);
}
}
EXPORT_SYMBOL_GPL(snd_hdac_regmap_exit);
/**
* snd_hdac_regmap_add_vendor_verb - add a vendor-specific verb to regmap
* @codec: the codec object
* @verb: verb to allow accessing via regmap
*
* Returns zero for success or a negative error code.
*/
int snd_hdac_regmap_add_vendor_verb(struct hdac_device *codec,
unsigned int verb)
{
unsigned int *p = snd_array_new(&codec->vendor_verbs);
if (!p)
return -ENOMEM;
*p = verb | 0x800; /* set GET bit */
return 0;
}
EXPORT_SYMBOL_GPL(snd_hdac_regmap_add_vendor_verb);
/*
* helper functions
*/
/* write a pseudo-register value (w/o power sequence) */
static int reg_raw_write(struct hdac_device *codec, unsigned int reg,
unsigned int val)
{
if (!codec->regmap)
return hda_reg_write(codec, reg, val);
else
return regmap_write(codec->regmap, reg, val);
}
/**
* snd_hdac_regmap_write_raw - write a pseudo register with power mgmt
* @codec: the codec object
* @reg: pseudo register
* @val: value to write
*
* Returns zero if successful or a negative error code.
*/
int snd_hdac_regmap_write_raw(struct hdac_device *codec, unsigned int reg,
unsigned int val)
{
int err;
err = reg_raw_write(codec, reg, val);
if (err == -EAGAIN) {
err = snd_hdac_power_up_pm(codec);
if (!err)
err = reg_raw_write(codec, reg, val);
snd_hdac_power_down_pm(codec);
}
return err;
}
EXPORT_SYMBOL_GPL(snd_hdac_regmap_write_raw);
static int reg_raw_read(struct hdac_device *codec, unsigned int reg,
unsigned int *val, bool uncached)
{
if (uncached || !codec->regmap)
return hda_reg_read(codec, reg, val);
else
return regmap_read(codec->regmap, reg, val);
}
static int __snd_hdac_regmap_read_raw(struct hdac_device *codec,
unsigned int reg, unsigned int *val,
bool uncached)
{
int err;
err = reg_raw_read(codec, reg, val, uncached);
if (err == -EAGAIN) {
err = snd_hdac_power_up_pm(codec);
if (!err)
err = reg_raw_read(codec, reg, val, uncached);
snd_hdac_power_down_pm(codec);
}
return err;
}
/**
* snd_hdac_regmap_read_raw - read a pseudo register with power mgmt
* @codec: the codec object
* @reg: pseudo register
* @val: pointer to store the read value
*
* Returns zero if successful or a negative error code.
*/
int snd_hdac_regmap_read_raw(struct hdac_device *codec, unsigned int reg,
unsigned int *val)
{
return __snd_hdac_regmap_read_raw(codec, reg, val, false);
}
EXPORT_SYMBOL_GPL(snd_hdac_regmap_read_raw);
/* Works like snd_hdac_regmap_read_raw(), but this doesn't read from the
* cache but always via hda verbs.
*/
int snd_hdac_regmap_read_raw_uncached(struct hdac_device *codec,
unsigned int reg, unsigned int *val)
{
return __snd_hdac_regmap_read_raw(codec, reg, val, true);
}
/**
* snd_hdac_regmap_update_raw - update a pseudo register with power mgmt
* @codec: the codec object
* @reg: pseudo register
* @mask: bit mask to udpate
* @val: value to update
*
* Returns zero if successful or a negative error code.
*/
int snd_hdac_regmap_update_raw(struct hdac_device *codec, unsigned int reg,
unsigned int mask, unsigned int val)
{
unsigned int orig;
int err;
val &= mask;
err = snd_hdac_regmap_read_raw(codec, reg, &orig);
if (err < 0)
return err;
val |= orig & ~mask;
if (val == orig)
return 0;
err = snd_hdac_regmap_write_raw(codec, reg, val);
if (err < 0)
return err;
return 1;
}
EXPORT_SYMBOL_GPL(snd_hdac_regmap_update_raw);
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