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Subject[PATCH 1/6] soundwire: cadence_master: filter out bad interrupts
Date
If somehow we read the interrupt status while the IP is not powered
the result is probably undefined or 0xffffffff. We do know that some
of the bits are reserved and read as zero, so use as a filter to
discard invalid configurations.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
drivers/soundwire/cadence_master.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index fed21e2b2277..a0ec21b64d42 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -74,6 +74,7 @@ MODULE_PARM_DESC(cdns_mcp_int_mask, "Cadence MCP IntMask");
#define CDNS_MCP_INTMASK 0x48

#define CDNS_MCP_INT_IRQ BIT(31)
+#define CDNS_MCP_INT_RESERVED1 GENMASK(30, 17)
#define CDNS_MCP_INT_WAKEUP BIT(16)
#define CDNS_MCP_INT_SLAVE_RSVD BIT(15)
#define CDNS_MCP_INT_SLAVE_ALERT BIT(14)
@@ -85,10 +86,12 @@ MODULE_PARM_DESC(cdns_mcp_int_mask, "Cadence MCP IntMask");
#define CDNS_MCP_INT_DATA_CLASH BIT(9)
#define CDNS_MCP_INT_PARITY BIT(8)
#define CDNS_MCP_INT_CMD_ERR BIT(7)
+#define CDNS_MCP_INT_RESERVED2 GENMASK(6, 4)
#define CDNS_MCP_INT_RX_NE BIT(3)
#define CDNS_MCP_INT_RX_WL BIT(2)
#define CDNS_MCP_INT_TXE BIT(1)
#define CDNS_MCP_INT_TXF BIT(0)
+#define CDNS_MCP_INT_RESERVED (CDNS_MCP_INT_RESERVED1 | CDNS_MCP_INT_RESERVED2)

#define CDNS_MCP_INTSET 0x4C

@@ -705,6 +708,10 @@ irqreturn_t sdw_cdns_irq(int irq, void *dev_id)

int_status = cdns_readl(cdns, CDNS_MCP_INTSTAT);

+ /* check for reserved values read as zero */
+ if (int_status & CDNS_MCP_INT_RESERVED)
+ return IRQ_NONE;
+
if (!(int_status & CDNS_MCP_INT_IRQ))
return IRQ_NONE;

--
2.20.1
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