soundwire: intel: add CLK_STOP_BUS_RESET support

Move existing pm_runtime suspend under the CLK_STOP_TEARDOWN case.

In this mode the Master IP will lose all context but in-band wakes are
supported.

On pm_runtime resume a complete re-enumeration will be performed after
a bus reset.

Signed-off-by: Rander Wang <rander.wang@intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20200817152923.3259-9-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c
index 68c1cdfb799949c04422e4dd15a4d51bc3aa597a..ad476e9e4d252bc74c872ec6a0fde0c151022eb3 100644 (file)
--- a/drivers/soundwire/intel.c
+++ b/drivers/soundwire/intel.c
@@ -1575,6 +1575,26 @@ static int intel_suspend_runtime(struct device *dev)
 
                intel_shim_wake(sdw, false);
 
+       } else if (clock_stop_quirks & SDW_INTEL_CLK_STOP_BUS_RESET) {
+               ret = sdw_cdns_clock_stop(cdns, true);
+               if (ret < 0) {
+                       dev_err(dev, "cannot enable clock stop on suspend\n");
+                       return ret;
+               }
+
+               ret = sdw_cdns_enable_interrupt(cdns, false);
+               if (ret < 0) {
+                       dev_err(dev, "cannot disable interrupts on suspend\n");
+                       return ret;
+               }
+
+               ret = intel_link_power_down(sdw);
+               if (ret) {
+                       dev_err(dev, "Link power down failed: %d", ret);
+                       return ret;
+               }
+
+               intel_shim_wake(sdw, true);
        } else {
                dev_err(dev, "%s clock_stop_quirks %x unsupported\n",
                        __func__, clock_stop_quirks);
@@ -1691,6 +1711,30 @@ static int intel_resume_runtime(struct device *dev)
                        dev_err(dev, "unable to exit bus reset sequence during resume\n");
                        return ret;
                }
+       } else if (clock_stop_quirks & SDW_INTEL_CLK_STOP_BUS_RESET) {
+               ret = intel_init(sdw);
+               if (ret) {
+                       dev_err(dev, "%s failed: %d", __func__, ret);
+                       return ret;
+               }
+
+               /*
+                * make sure all Slaves are tagged as UNATTACHED and
+                * provide reason for reinitialization
+                */
+               sdw_clear_slave_status(bus, SDW_UNATTACH_REQUEST_MASTER_RESET);
+
+               ret = sdw_cdns_enable_interrupt(cdns, true);
+               if (ret < 0) {
+                       dev_err(dev, "cannot enable interrupts during resume\n");
+                       return ret;
+               }
+
+               ret = sdw_cdns_clock_restart(cdns, true);
+               if (ret < 0) {
+                       dev_err(dev, "unable to restart clock during resume\n");
+                       return ret;
+               }
        } else {
                dev_err(dev, "%s clock_stop_quirks %x unsupported\n",
                        __func__, clock_stop_quirks);