From: Simon Trimmer simont@opensource.cirrus.com
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 --- drivers/soundwire/cadence_master.c | 57 +++++++++++++----------------- 1 file changed, 25 insertions(+), 32 deletions(-)
diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c index 4fbb19557f5e..245191d22ccd 100644 --- 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 & CDNS_MCP_SLAVE_INTSTAT_ATTACHED) { - status[i] = SDW_SLAVE_ATTACHED; - set_status++; - } + if (mask) { + is_slave = true;
- 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]); - } }