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linux_dsm_epyc7002/sound/hda/hdac_regmap.c
Takashi Iwai 1a462be52f ALSA: hda: Manage concurrent reg access more properly 
In the commit 8e85def572 ("ALSA: hda: enable regmap internal
locking"), we re-enabled the regmap lock due to the reported
regression that showed the possible concurrent accesses.  It was a
temporary workaround, and there are still a few opened races even
after the revert.  In this patch, we cover those still opened windows
with a proper mutex lock and disable the regmap internal lock again.

First off, the patch introduces a new snd_hdac_device.regmap_lock
mutex that is applied for each snd_hdac_regmap_*() call, including
read, write and update helpers.  The mutex is applied carefully so
that it won't block the self-power-up procedure in the helper
function.  Also, this assures the protection for the accesses without
regmap, too.

The snd_hdac_regmap_update_raw() is refactored to use the standard
regmap_update_bits_check() function instead of the open-code.  The
non-regmap case is still open-coded but it's an easy part.  The all
read and write operations are in the single mutex protection, so it's
now race-free.

In addition, a couple of new helper functions are added:
snd_hdac_regmap_update_raw_once() and snd_hdac_regmap_sync().  Both
are called from HD-audio legacy driver.  The former is to initialize
the given verb bits but only once when it's not initialized yet.  Due
to this condition, the function invokes regcache_cache_only(), and
it's now performed inside the regmap_lock (formerly it was racy) too.
The latter function is for simply invoking regcache_sync() inside the
regmap_lock, which is called from the codec resume call path.
Along with that, the HD-audio codec driver code is slightly modified /
simplified to adapt those new functions.

And finally, snd_hdac_regmap_read_raw(), *_write_raw(), etc are
rewritten with the helper macro.  It's just for simplification because
the code logic is identical among all those functions.

Tested-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Link: https://lore.kernel.org/r/20200109090104.26073-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2020-01-13 13:40:41 +01:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* 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>
#include "local.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);
const unsigned int *v;
int i;
snd_array_for_each(&codec->vendor_verbs, i, v) {
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_read = true,
.use_single_write = true,
.disable_locking = 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)
{
int err;
mutex_lock(&codec->regmap_lock);
if (!codec->regmap)
err = hda_reg_write(codec, reg, val);
else
err = regmap_write(codec->regmap, reg, val);
mutex_unlock(&codec->regmap_lock);
return err;
}
/* a helper macro to call @func_call; retry with power-up if failed */
#define CALL_RAW_FUNC(codec, func_call) \
({ \
int _err = func_call; \
if (_err == -EAGAIN) { \
_err = snd_hdac_power_up_pm(codec); \
if (_err >= 0) \
_err = func_call; \
snd_hdac_power_down_pm(codec); \
} \
_err;})
/**
* 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)
{
return CALL_RAW_FUNC(codec, reg_raw_write(codec, reg, val));
}
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)
{
int err;
mutex_lock(&codec->regmap_lock);
if (uncached || !codec->regmap)
err = hda_reg_read(codec, reg, val);
else
err = regmap_read(codec->regmap, reg, val);
mutex_unlock(&codec->regmap_lock);
return err;
}
static int __snd_hdac_regmap_read_raw(struct hdac_device *codec,
unsigned int reg, unsigned int *val,
bool uncached)
{
return CALL_RAW_FUNC(codec, reg_raw_read(codec, reg, val, uncached));
}
/**
* 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);
}
static int reg_raw_update(struct hdac_device *codec, unsigned int reg,
unsigned int mask, unsigned int val)
{
unsigned int orig;
bool change;
int err;
mutex_lock(&codec->regmap_lock);
if (codec->regmap) {
err = regmap_update_bits_check(codec->regmap, reg, mask, val,
&change);
if (!err)
err = change ? 1 : 0;
} else {
err = hda_reg_read(codec, reg, &orig);
if (!err) {
val &= mask;
val |= orig & ~mask;
if (val != orig) {
err = hda_reg_write(codec, reg, val);
if (!err)
err = 1;
}
}
}
mutex_unlock(&codec->regmap_lock);
return err;
}
/**
* snd_hdac_regmap_update_raw - update a pseudo register with power mgmt
* @codec: the codec object
* @reg: pseudo register
* @mask: bit mask to update
* @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)
{
return CALL_RAW_FUNC(codec, reg_raw_update(codec, reg, mask, val));
}
EXPORT_SYMBOL_GPL(snd_hdac_regmap_update_raw);
static int reg_raw_update_once(struct hdac_device *codec, unsigned int reg,
unsigned int mask, unsigned int val)
{
unsigned int orig;
int err;
if (!codec->regmap)
return reg_raw_update(codec, reg, mask, val);
mutex_lock(&codec->regmap_lock);
regcache_cache_only(codec->regmap, true);
err = regmap_read(codec->regmap, reg, &orig);
regcache_cache_only(codec->regmap, false);
if (err < 0)
err = regmap_update_bits(codec->regmap, reg, mask, val);
mutex_unlock(&codec->regmap_lock);
return err;
}
/**
* snd_hdac_regmap_update_raw_once - initialize the register value only once
* @codec: the codec object
* @reg: pseudo register
* @mask: bit mask to update
* @val: value to update
*
* Performs the update of the register bits only once when the register
* hasn't been initialized yet. Used in HD-audio legacy driver.
* Returns zero if successful or a negative error code
*/
int snd_hdac_regmap_update_raw_once(struct hdac_device *codec, unsigned int reg,
unsigned int mask, unsigned int val)
{
return CALL_RAW_FUNC(codec, reg_raw_update_once(codec, reg, mask, val));
}
EXPORT_SYMBOL_GPL(snd_hdac_regmap_update_raw_once);
/**
* snd_hdac_regmap_sync - sync out the cached values for PM resume
* @codec: the codec object
*/
void snd_hdac_regmap_sync(struct hdac_device *codec)
{
if (codec->regmap) {
mutex_lock(&codec->regmap_lock);
regcache_sync(codec->regmap);
mutex_unlock(&codec->regmap_lock);
}
}
EXPORT_SYMBOL_GPL(snd_hdac_regmap_sync);
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