soundwire: bus: only clear valid DP0 interrupts

We should only access the fields that are relevant for DP0, and never
write to reserved or read-only SDCA_CASCADE fields.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20201124013318.8963-5-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index d6e6465..f66a804 100644 (file)
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -1280,7 +1280,7 @@ static int sdw_initialize_slave(struct sdw_slave *slave)
 
 static int sdw_handle_dp0_interrupt(struct sdw_slave *slave, u8 *slave_status)
 {
-       u8 clear = 0, impl_int_mask;
+       u8 clear, impl_int_mask;
        int status, status2, ret, count = 0;
 
        status = sdw_read(slave, SDW_DP0_INT);
@@ -1291,6 +1291,8 @@ static int sdw_handle_dp0_interrupt(struct sdw_slave *slave, u8 *slave_status)
        }
 
        do {
+               clear = status & ~SDW_DP0_INTERRUPTS;
+
                if (status & SDW_DP0_INT_TEST_FAIL) {
                        dev_err(&slave->dev, "Test fail for port 0\n");
                        clear |= SDW_DP0_INT_TEST_FAIL;
@@ -1319,7 +1321,7 @@ static int sdw_handle_dp0_interrupt(struct sdw_slave *slave, u8 *slave_status)
                        *slave_status = clear;
                }
 
-               /* clear the interrupt */
+               /* clear the interrupts but don't touch reserved and SDCA_CASCADE fields */
                ret = sdw_write(slave, SDW_DP0_INT, clear);
                if (ret < 0) {
                        dev_err(slave->bus->dev,
@@ -1340,7 +1342,7 @@ static int sdw_handle_dp0_interrupt(struct sdw_slave *slave, u8 *slave_status)
                count++;
 
                /* we can get alerts while processing so keep retrying */
-       } while (status != 0 && count < SDW_READ_INTR_CLEAR_RETRY);
+       } while ((status & SDW_DP0_INTERRUPTS) && (count < SDW_READ_INTR_CLEAR_RETRY));
 
        if (count == SDW_READ_INTR_CLEAR_RETRY)
                dev_warn(slave->bus->dev, "Reached MAX_RETRY on DP0 read\n");