soundwire: cadence: fix updating slave status when a bus has multiple peripherals

The cadence IP explicitly reports slave status changes with bits for
each possible change. The function cdns_update_slave_status() attempts
to translate this into the current status of each of the slaves.

However when there are multiple peripherals on a bus any slave that did
not have a status change when the work function ran would not have it's
status updated - the array is initialised to a value that equates to
UNATTACHED and this can cause spurious reports that slaves had dropped
off the bus.

In the case where a slave has no status change or has multiple status
changes the value from the last PING command is used.

Signed-off-by: Simon Trimmer <simont@opensource.cirrus.com>
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20220914160248.1047627-2-rf@opensource.cirrus.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index 4fbb195..245191d 100644 (file)
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -782,6 +782,7 @@ static int cdns_update_slave_status(struct sdw_cdns *cdns,
        enum sdw_slave_status status[SDW_MAX_DEVICES + 1];
        bool is_slave = false;
        u32 mask;
+       u32 val;
        int i, set_status;
 
        memset(status, 0, sizeof(status));
@@ -789,41 +790,38 @@ static int cdns_update_slave_status(struct sdw_cdns *cdns,
        for (i = 0; i <= SDW_MAX_DEVICES; i++) {
                mask = (slave_intstat >> (i * CDNS_MCP_SLAVE_STATUS_NUM)) &
                        CDNS_MCP_SLAVE_STATUS_BITS;
-               if (!mask)
-                       continue;
 
-               is_slave = true;
                set_status = 0;
 
-               if (mask & CDNS_MCP_SLAVE_INTSTAT_RESERVED) {
-                       status[i] = SDW_SLAVE_RESERVED;
-                       set_status++;
-               }
+               if (mask) {
+                       is_slave = true;
 
-               if (mask & CDNS_MCP_SLAVE_INTSTAT_ATTACHED) {
-                       status[i] = SDW_SLAVE_ATTACHED;
-                       set_status++;
-               }
-
-               if (mask & CDNS_MCP_SLAVE_INTSTAT_ALERT) {
-                       status[i] = SDW_SLAVE_ALERT;
-                       set_status++;
-               }
+                       if (mask & CDNS_MCP_SLAVE_INTSTAT_RESERVED) {
+                               status[i] = SDW_SLAVE_RESERVED;
+                               set_status++;
+                       }
 
-               if (mask & CDNS_MCP_SLAVE_INTSTAT_NPRESENT) {
-                       status[i] = SDW_SLAVE_UNATTACHED;
-                       set_status++;
-               }
+                       if (mask & CDNS_MCP_SLAVE_INTSTAT_ATTACHED) {
+                               status[i] = SDW_SLAVE_ATTACHED;
+                               set_status++;
+                       }
 
-               /* first check if Slave reported multiple status */
-               if (set_status > 1) {
-                       u32 val;
+                       if (mask & CDNS_MCP_SLAVE_INTSTAT_ALERT) {
+                               status[i] = SDW_SLAVE_ALERT;
+                               set_status++;
+                       }
 
-                       dev_warn_ratelimited(cdns->dev,
-                                            "Slave %d reported multiple Status: %d\n",
-                                            i, mask);
+                       if (mask & CDNS_MCP_SLAVE_INTSTAT_NPRESENT) {
+                               status[i] = SDW_SLAVE_UNATTACHED;
+                               set_status++;
+                       }
+               }
 
-                       /* check latest status extracted from PING commands */
+               /*
+                * check that there was a single reported Slave status and when
+                * there is not use the latest status extracted from PING commands
+                */
+               if (set_status != 1) {
                        val = cdns_readl(cdns, CDNS_MCP_SLAVE_STAT);
                        val >>= (i * 2);
 
@@ -842,11 +840,6 @@ static int cdns_update_slave_status(struct sdw_cdns *cdns,
                                status[i] = SDW_SLAVE_RESERVED;
                                break;
                        }
-
-                       dev_warn_ratelimited(cdns->dev,
-                                            "Slave %d status updated to %d\n",
-                                            i, status[i]);
-
                }
        }