soundwire: intel: add CLK_STOP_NOT_ALLOWED support

In case the clock needs to keep running, we need to prevent the Master
from entering pm_runtime suspend.

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/20200817152923.3259-10-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 ad476e9e4d252bc74c872ec6a0fde0c151022eb3..95b14c034ea73dcf6199fcbe363e0c6583e71fb9 100644 (file)
--- a/drivers/soundwire/intel.c
+++ b/drivers/soundwire/intel.c
@@ -1367,6 +1367,7 @@ int intel_master_startup(struct platform_device *pdev)
        struct sdw_intel *sdw = cdns_to_intel(cdns);
        struct sdw_bus *bus = &cdns->bus;
        int link_flags;
+       u32 clock_stop_quirks;
        int ret;
 
        if (bus->prop.hw_disabled) {
@@ -1423,6 +1424,20 @@ int intel_master_startup(struct platform_device *pdev)
                pm_runtime_enable(dev);
        }
 
+       clock_stop_quirks = sdw->link_res->clock_stop_quirks;
+       if (clock_stop_quirks & SDW_INTEL_CLK_STOP_NOT_ALLOWED) {
+               /*
+                * To keep the clock running we need to prevent
+                * pm_runtime suspend from happening by increasing the
+                * reference count.
+                * This quirk is specified by the parent PCI device in
+                * case of specific latency requirements. It will have
+                * no effect if pm_runtime is disabled by the user via
+                * a module parameter for testing purposes.
+                */
+               pm_runtime_get_noresume(dev);
+       }
+
        /*
         * The runtime PM status of Slave devices is "Unsupported"
         * until they report as ATTACHED. If they don't, e.g. because
@@ -1454,6 +1469,11 @@ static int intel_master_remove(struct platform_device *pdev)
        struct sdw_intel *sdw = cdns_to_intel(cdns);
        struct sdw_bus *bus = &cdns->bus;
 
+       /*
+        * Since pm_runtime is already disabled, we don't decrease
+        * the refcount when the clock_stop_quirk is
+        * SDW_INTEL_CLK_STOP_NOT_ALLOWED
+        */
        if (!bus->prop.hw_disabled) {
                intel_debugfs_exit(sdw);
                sdw_cdns_enable_interrupt(cdns, false);