From: Pierre-Louis Bossart pierre-louis.bossart@linux.intel.com
Combining hardware reset with the multi-link mode leads to a shortened hardware reset pattern observed on the bus.
The updated hardware programming sequence is to first enable the clock with the sync_arm/sync_go pattern, and only in a second step to issue the hardware reset sequence. Since there is no longer a dependency between sync_arm/sync_go and hw_reset, the behavior of sdw_cdns_exit_reset() is changed to wait for the self-clearing CONFIG_UPDATE to go back to zero,
Link: https://github.com/thesofproject/linux/issues/4170 Signed-off-by: Pierre-Louis Bossart pierre-louis.bossart@linux.intel.com Reviewed-by: Rander Wang rander.wang@intel.com Signed-off-by: Bard Liao yung-chuan.liao@linux.intel.com --- drivers/soundwire/cadence_master.c | 31 ++++++++++++++++++------ drivers/soundwire/cadence_master.h | 3 +++ drivers/soundwire/intel_bus_common.c | 36 ++++++++++++++++++++-------- 3 files changed, 53 insertions(+), 17 deletions(-)
diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c index 39502bc75712..58686ae50bbf 100644 --- a/drivers/soundwire/cadence_master.c +++ b/drivers/soundwire/cadence_master.c @@ -283,6 +283,29 @@ static int cdns_config_update(struct sdw_cdns *cdns) return ret; }
+/** + * sdw_cdns_config_update() - Update configurations + * @cdns: Cadence instance + */ +void sdw_cdns_config_update(struct sdw_cdns *cdns) +{ + /* commit changes */ + cdns_writel(cdns, CDNS_MCP_CONFIG_UPDATE, CDNS_MCP_CONFIG_UPDATE_BIT); +} +EXPORT_SYMBOL(sdw_cdns_config_update); + +/** + * sdw_cdns_config_update_set_wait() - wait until configuration update bit is self-cleared + * @cdns: Cadence instance + */ +int sdw_cdns_config_update_set_wait(struct sdw_cdns *cdns) +{ + /* the hardware recommendation is to wait at least 300us */ + return cdns_set_wait(cdns, CDNS_MCP_CONFIG_UPDATE, + CDNS_MCP_CONFIG_UPDATE_BIT, 0); +} +EXPORT_SYMBOL(sdw_cdns_config_update_set_wait); + /* * debugfs */ @@ -1116,13 +1139,7 @@ int sdw_cdns_exit_reset(struct sdw_cdns *cdns) CDNS_MCP_CONTROL_HW_RST);
/* commit changes */ - cdns_updatel(cdns, CDNS_MCP_CONFIG_UPDATE, - CDNS_MCP_CONFIG_UPDATE_BIT, - CDNS_MCP_CONFIG_UPDATE_BIT); - - /* don't wait here */ - return 0; - + return cdns_config_update(cdns); } EXPORT_SYMBOL(sdw_cdns_exit_reset);
diff --git a/drivers/soundwire/cadence_master.h b/drivers/soundwire/cadence_master.h index 27c56274217f..8e328ba01c0a 100644 --- a/drivers/soundwire/cadence_master.h +++ b/drivers/soundwire/cadence_master.h @@ -197,4 +197,7 @@ int cdns_set_sdw_stream(struct snd_soc_dai *dai, void sdw_cdns_check_self_clearing_bits(struct sdw_cdns *cdns, const char *string, bool initial_delay, int reset_iterations);
+void sdw_cdns_config_update(struct sdw_cdns *cdns); +int sdw_cdns_config_update_set_wait(struct sdw_cdns *cdns); + #endif /* __SDW_CADENCE_H */ diff --git a/drivers/soundwire/intel_bus_common.c b/drivers/soundwire/intel_bus_common.c index 901d4f5736c1..be0c93106fc8 100644 --- a/drivers/soundwire/intel_bus_common.c +++ b/drivers/soundwire/intel_bus_common.c @@ -29,11 +29,7 @@ int intel_start_bus(struct sdw_intel *sdw) return ret; }
- ret = sdw_cdns_exit_reset(cdns); - if (ret < 0) { - dev_err(dev, "%s: unable to exit bus reset sequence: %d\n", __func__, ret); - return ret; - } + sdw_cdns_config_update(cdns);
if (bus->multi_link) { ret = sdw_intel_sync_go(sdw); @@ -43,6 +39,18 @@ int intel_start_bus(struct sdw_intel *sdw) } }
+ ret = sdw_cdns_config_update_set_wait(cdns); + if (ret < 0) { + dev_err(dev, "%s: CONFIG_UPDATE BIT still set\n", __func__); + return ret; + } + + ret = sdw_cdns_exit_reset(cdns); + if (ret < 0) { + dev_err(dev, "%s: unable to exit bus reset sequence: %d\n", __func__, ret); + return ret; + } + ret = sdw_cdns_enable_interrupt(cdns, true); if (ret < 0) { dev_err(dev, "%s: cannot enable interrupts: %d\n", __func__, ret); @@ -112,11 +120,7 @@ int intel_start_bus_after_reset(struct sdw_intel *sdw) }
if (!clock_stop0) { - ret = sdw_cdns_exit_reset(cdns); - if (ret < 0) { - dev_err(dev, "unable to exit bus reset sequence during resume\n"); - return ret; - } + sdw_cdns_config_update(cdns);
if (bus->multi_link) { ret = sdw_intel_sync_go(sdw); @@ -126,6 +130,18 @@ int intel_start_bus_after_reset(struct sdw_intel *sdw) } }
+ ret = sdw_cdns_config_update_set_wait(cdns); + if (ret < 0) { + dev_err(dev, "%s: CONFIG_UPDATE BIT still set\n", __func__); + return ret; + } + + ret = sdw_cdns_exit_reset(cdns); + if (ret < 0) { + dev_err(dev, "unable to exit bus reset sequence during resume\n"); + return ret; + } + ret = sdw_cdns_enable_interrupt(cdns, true); if (ret < 0) { dev_err(dev, "cannot enable interrupts during resume\n");