Add a regmap_read_bypassed() to allow reads from the hardware registers while the regmap is in cache-only mode.

This patch is a prerequisite for a bugfix to the ASoC cs35l56 driver.

A typical use for this is to keep the cache in cache-only mode until the hardware has reached a valid state, but one or more status registers must be polled to determine when this state is reached.

For example, firmware download on the cs35l56 can take several seconds if there are multiple amps sharing limited bus bandwidth. This is too long to block in probe() so it is done as a background task. The device must be soft-reset to reboot the firmware and during this time the registers are not accessible, so the cache should be in cache-only. But the driver must poll a register to detect when reboot has completed.

Signed-off-by: Richard Fitzgerald rf@opensource.cirrus.com Fixes: 8a731fd37f8b ("ASoC: cs35l56: Move utility functions to shared file") --- I have a kunit test case for this. But it's based on top of a chain of other changes I've made to the regmap kunit test, so I'll send it with that chain. --- drivers/base/regmap/regmap.c | 37 ++++++++++++++++++++++++++++++++++++ include/linux/regmap.h | 8 ++++++++ 2 files changed, 45 insertions(+)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c index 5cb425f6f02d..0a34dd3c4f38 100644 --- a/drivers/base/regmap/regmap.c +++ b/drivers/base/regmap/regmap.c @@ -2838,6 +2838,43 @@ int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val) } EXPORT_SYMBOL_GPL(regmap_read);

+/** + * regmap_read_bypassed() - Read a value from a single register direct + * from the device, bypassing the cache + * + * @map: Register map to read from + * @reg: Register to be read from + * @val: Pointer to store read value + * + * A value of zero will be returned on success, a negative errno will + * be returned in error cases. + */ +int regmap_read_bypassed(struct regmap *map, unsigned int reg, unsigned int *val) +{ + int ret; + bool bypass, cache_only; + + if (!IS_ALIGNED(reg, map->reg_stride)) + return -EINVAL; + + map->lock(map->lock_arg); + + bypass = map->cache_bypass; + cache_only = map->cache_only; + map->cache_bypass = true; + map->cache_only = false; + + ret = _regmap_read(map, reg, val); + + map->cache_bypass = bypass; + map->cache_only = cache_only; + + map->unlock(map->lock_arg); + + return ret; +} +EXPORT_SYMBOL_GPL(regmap_read_bypassed); + /** * regmap_raw_read() - Read raw data from the device * diff --git a/include/linux/regmap.h b/include/linux/regmap.h index b743241cfb7c..d470303b1bbb 100644 --- a/include/linux/regmap.h +++ b/include/linux/regmap.h @@ -1230,6 +1230,7 @@ int regmap_multi_reg_write_bypassed(struct regmap *map, int regmap_raw_write_async(struct regmap *map, unsigned int reg, const void *val, size_t val_len); int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val); +int regmap_read_bypassed(struct regmap *map, unsigned int reg, unsigned int *val); int regmap_raw_read(struct regmap *map, unsigned int reg, void *val, size_t val_len); int regmap_noinc_read(struct regmap *map, unsigned int reg, @@ -1739,6 +1740,13 @@ static inline int regmap_read(struct regmap *map, unsigned int reg, return -EINVAL; }

+static inline int regmap_read_bypassed(struct regmap *map, unsigned int reg, + unsigned int *val) +{ + WARN_ONCE(1, "regmap API is disabled"); + return -EINVAL; +} + static inline int regmap_raw_read(struct regmap *map, unsigned int reg, void *val, size_t val_len) {

Adds calls to disable regmap cache-only after a successful return from cs35l56_wait_for_firmware_boot().

This is to prepare for a change in the shared ASoC module that will leave regmap in cache-only mode after cs35l56_system_reset(). This is to prevent register accesses going to the hardware while it is rebooting.

Signed-off-by: Richard Fitzgerald rf@opensource.cirrus.com --- This will have to go through Mark's tree because it's necessary to make this change to the HDA driver before applying patch #3 in this series. --- sound/pci/hda/cs35l56_hda.c | 4 ++++ 1 file changed, 4 insertions(+)

diff --git a/sound/pci/hda/cs35l56_hda.c b/sound/pci/hda/cs35l56_hda.c index 1a3f84599cb5..558c1f38fe97 100644 --- a/sound/pci/hda/cs35l56_hda.c +++ b/sound/pci/hda/cs35l56_hda.c @@ -644,6 +644,8 @@ static int cs35l56_hda_fw_load(struct cs35l56_hda *cs35l56) ret = cs35l56_wait_for_firmware_boot(&cs35l56->base); if (ret) goto err_powered_up; + + regcache_cache_only(cs35l56->base.regmap, false); }

/* Disable auto-hibernate so that runtime_pm has control */ @@ -1002,6 +1004,8 @@ int cs35l56_hda_common_probe(struct cs35l56_hda *cs35l56, int hid, int id) if (ret) goto err;

+ regcache_cache_only(cs35l56->base.regmap, false); + ret = cs35l56_set_patch(&cs35l56->base); if (ret) goto err;

Only populate the ASP1 config registers in the regmap cache if the ASP DAI is used. This prevents regcache_sync() from overwriting these registers with their defaults when the firmware owns control of these registers.

On a SoundWire system the ASP could be owned by the firmware to share reference audio with the firmware on other cs35l56. Or it can be used as a normal codec-codec interface owned by the driver. The driver must not overwrite the registers if the firmware has control of them.

The original implementation for this in commit 07f7d6e7a124 ("ASoC: cs35l56: Fix for initializing ASP1 mixer registers") was to still provide defaults for these registers, assuming that if they were never reconfigured from defaults then regcache_sync() would not write them out because they are not dirty. Unfortunately regcache_sync() is not that smart. If the chip has not reset (so the driver has not called regcache_mark_dirty()) a regcache_sync() could write out registers that are not dirty.

To avoid accidental overwriting of the ASP registers, they are removed from the table of defaults and instead are populated with defaults only if one of the ASP DAI configuration functions is called. So if the DAI has never been configured, the firmware is assumed to have ownership of these registers, and the regmap cache will not contain any entries for them.

Signed-off-by: Richard Fitzgerald rf@opensource.cirrus.com Fixes: 07f7d6e7a124 ("ASoC: cs35l56: Fix for initializing ASP1 mixer registers") --- include/sound/cs35l56.h | 2 + sound/soc/codecs/cs35l56-shared.c | 63 ++++++++++++++++++++----------- sound/soc/codecs/cs35l56.c | 24 +++++++++++- 3 files changed, 67 insertions(+), 22 deletions(-)

diff --git a/include/sound/cs35l56.h b/include/sound/cs35l56.h index e0629699b563..1a3c6f66f620 100644 --- a/include/sound/cs35l56.h +++ b/include/sound/cs35l56.h @@ -267,6 +267,7 @@ struct cs35l56_base { bool fw_patched; bool secured; bool can_hibernate; + bool fw_owns_asp1; bool cal_data_valid; s8 cal_index; struct cirrus_amp_cal_data cal_data; @@ -283,6 +284,7 @@ extern const char * const cs35l56_tx_input_texts[CS35L56_NUM_INPUT_SRC]; extern const unsigned int cs35l56_tx_input_values[CS35L56_NUM_INPUT_SRC];

int cs35l56_set_patch(struct cs35l56_base *cs35l56_base); +int cs35l56_init_asp1_regs_for_driver_control(struct cs35l56_base *cs35l56_base); int cs35l56_force_sync_asp1_registers_from_cache(struct cs35l56_base *cs35l56_base); int cs35l56_mbox_send(struct cs35l56_base *cs35l56_base, unsigned int command); int cs35l56_firmware_shutdown(struct cs35l56_base *cs35l56_base); diff --git a/sound/soc/codecs/cs35l56-shared.c b/sound/soc/codecs/cs35l56-shared.c index a83317db75ed..ec1d95e57061 100644 --- a/sound/soc/codecs/cs35l56-shared.c +++ b/sound/soc/codecs/cs35l56-shared.c @@ -40,16 +40,11 @@ EXPORT_SYMBOL_NS_GPL(cs35l56_set_patch, SND_SOC_CS35L56_SHARED); static const struct reg_default cs35l56_reg_defaults[] = { /* no defaults for OTP_MEM - first read populates cache */

- { CS35L56_ASP1_ENABLES1, 0x00000000 }, - { CS35L56_ASP1_CONTROL1, 0x00000028 }, - { CS35L56_ASP1_CONTROL2, 0x18180200 }, - { CS35L56_ASP1_CONTROL3, 0x00000002 }, - { CS35L56_ASP1_FRAME_CONTROL1, 0x03020100 }, - { CS35L56_ASP1_FRAME_CONTROL5, 0x00020100 }, - { CS35L56_ASP1_DATA_CONTROL1, 0x00000018 }, - { CS35L56_ASP1_DATA_CONTROL5, 0x00000018 }, - - /* no defaults for ASP1TX mixer */ + /* + * No defaults for ASP1 control or ASP1TX mixer. See + * cs35l56_populate_asp1_register_defaults() and + * cs35l56_sync_asp1_mixer_widgets_with_firmware(). + */

{ CS35L56_SWIRE_DP3_CH1_INPUT, 0x00000018 }, { CS35L56_SWIRE_DP3_CH2_INPUT, 0x00000019 }, @@ -210,6 +205,36 @@ static bool cs35l56_volatile_reg(struct device *dev, unsigned int reg) } }

+static const struct reg_sequence cs35l56_asp1_defaults[] = { + REG_SEQ0(CS35L56_ASP1_ENABLES1, 0x00000000), + REG_SEQ0(CS35L56_ASP1_CONTROL1, 0x00000028), + REG_SEQ0(CS35L56_ASP1_CONTROL2, 0x18180200), + REG_SEQ0(CS35L56_ASP1_CONTROL3, 0x00000002), + REG_SEQ0(CS35L56_ASP1_FRAME_CONTROL1, 0x03020100), + REG_SEQ0(CS35L56_ASP1_FRAME_CONTROL5, 0x00020100), + REG_SEQ0(CS35L56_ASP1_DATA_CONTROL1, 0x00000018), + REG_SEQ0(CS35L56_ASP1_DATA_CONTROL5, 0x00000018), +}; + +/* + * The firmware can have control of the ASP so we don't provide regmap + * with defaults for these registers, to prevent a regcache_sync() from + * overwriting the firmware settings. But if the machine driver hooks up + * the ASP it means the driver is taking control of the ASP, so then the + * registers are populated with the defaults. + */ +int cs35l56_init_asp1_regs_for_driver_control(struct cs35l56_base *cs35l56_base) +{ + if (!cs35l56_base->fw_owns_asp1) + return 0; + + cs35l56_base->fw_owns_asp1 = false; + + return regmap_multi_reg_write(cs35l56_base->regmap, cs35l56_asp1_defaults, + ARRAY_SIZE(cs35l56_asp1_defaults)); +} +EXPORT_SYMBOL_NS_GPL(cs35l56_init_asp1_regs_for_driver_control, SND_SOC_CS35L56_SHARED); + /* * The firmware boot sequence can overwrite the ASP1 config registers so that * they don't match regmap's view of their values. Rewrite the values from the @@ -217,19 +242,15 @@ static bool cs35l56_volatile_reg(struct device *dev, unsigned int reg) */ int cs35l56_force_sync_asp1_registers_from_cache(struct cs35l56_base *cs35l56_base) { - struct reg_sequence asp1_regs[] = { - { .reg = CS35L56_ASP1_ENABLES1 }, - { .reg = CS35L56_ASP1_CONTROL1 }, - { .reg = CS35L56_ASP1_CONTROL2 }, - { .reg = CS35L56_ASP1_CONTROL3 }, - { .reg = CS35L56_ASP1_FRAME_CONTROL1 }, - { .reg = CS35L56_ASP1_FRAME_CONTROL5 }, - { .reg = CS35L56_ASP1_DATA_CONTROL1 }, - { .reg = CS35L56_ASP1_DATA_CONTROL5 }, - }; + struct reg_sequence asp1_regs[ARRAY_SIZE(cs35l56_asp1_defaults)]; int i, ret;

- /* Read values from regmap cache into a write sequence */ + if (cs35l56_base->fw_owns_asp1) + return 0; + + memcpy(asp1_regs, cs35l56_asp1_defaults, sizeof(asp1_regs)); + + /* Read current values from regmap cache into the write sequence */ for (i = 0; i < ARRAY_SIZE(asp1_regs); ++i) { ret = regmap_read(cs35l56_base->regmap, asp1_regs[i].reg, &asp1_regs[i].def); if (ret) diff --git a/sound/soc/codecs/cs35l56.c b/sound/soc/codecs/cs35l56.c index 5a4e0e479414..6331b8c6136e 100644 --- a/sound/soc/codecs/cs35l56.c +++ b/sound/soc/codecs/cs35l56.c @@ -454,9 +454,14 @@ static int cs35l56_asp_dai_set_fmt(struct snd_soc_dai *codec_dai, unsigned int f { struct cs35l56_private *cs35l56 = snd_soc_component_get_drvdata(codec_dai->component); unsigned int val; + int ret;

dev_dbg(cs35l56->base.dev, "%s: %#x\n", __func__, fmt);

+ ret = cs35l56_init_asp1_regs_for_driver_control(&cs35l56->base); + if (ret) + return ret; + switch (fmt & SND_SOC_DAIFMT_CLOCK_PROVIDER_MASK) { case SND_SOC_DAIFMT_CBC_CFC: break; @@ -530,6 +535,11 @@ static int cs35l56_asp_dai_set_tdm_slot(struct snd_soc_dai *dai, unsigned int tx unsigned int rx_mask, int slots, int slot_width) { struct cs35l56_private *cs35l56 = snd_soc_component_get_drvdata(dai->component); + int ret; + + ret = cs35l56_init_asp1_regs_for_driver_control(&cs35l56->base); + if (ret) + return ret;

if ((slots == 0) || (slot_width == 0)) { dev_dbg(cs35l56->base.dev, "tdm config cleared\n"); @@ -578,6 +588,11 @@ static int cs35l56_asp_dai_hw_params(struct snd_pcm_substream *substream, struct cs35l56_private *cs35l56 = snd_soc_component_get_drvdata(dai->component); unsigned int rate = params_rate(params); u8 asp_width, asp_wl; + int ret; + + ret = cs35l56_init_asp1_regs_for_driver_control(&cs35l56->base); + if (ret) + return ret;

asp_wl = params_width(params); if (cs35l56->asp_slot_width) @@ -634,7 +649,11 @@ static int cs35l56_asp_dai_set_sysclk(struct snd_soc_dai *dai, int clk_id, unsigned int freq, int dir) { struct cs35l56_private *cs35l56 = snd_soc_component_get_drvdata(dai->component); - int freq_id; + int freq_id, ret; + + ret = cs35l56_init_asp1_regs_for_driver_control(&cs35l56->base); + if (ret) + return ret;

if (freq == 0) { cs35l56->sysclk_set = false; @@ -1403,6 +1422,9 @@ int cs35l56_common_probe(struct cs35l56_private *cs35l56) cs35l56->base.cal_index = -1; cs35l56->speaker_id = -ENOENT;

+ /* Assume that the firmware owns ASP1 until we know different */ + cs35l56->base.fw_owns_asp1 = true; + dev_set_drvdata(cs35l56->base.dev, cs35l56);

cs35l56_fill_supply_names(cs35l56->supplies);