From: Pierre-Louis Bossart pierre-louis.bossart@linux.intel.com

The interrupt handling in SoundWire requires software to re-read the interrupt status after clearing an interrupt. In case the interrupt is still outstanding, the code in bus.c will loop a number of times, however that loop is limited to the interrupts detected in the first read. This strategy helps meet SoundWire requirements without remaining forever in an interrupt handler.

Add a couple of comments to document this design.

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 --- drivers/soundwire/bus.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c index ffe4600fd95b..45131b9f5080 100644 --- a/drivers/soundwire/bus.c +++ b/drivers/soundwire/bus.c @@ -1334,6 +1334,7 @@ static int sdw_handle_dp0_interrupt(struct sdw_slave *slave, u8 *slave_status) "SDW_DP0_INT read failed:%d\n", status2); return status2; } + /* filter to limit loop to interrupts identified in the first status read */ status &= status2;

count++; @@ -1404,6 +1405,7 @@ static int sdw_handle_port_interrupt(struct sdw_slave *slave, "SDW_DPN_INT read failed:%d\n", status2); return status2; } + /* filter to limit loop to interrupts identified in the first status read */ status &= status2;

count++; @@ -1589,7 +1591,10 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave) sdca_cascade = ret & SDW_DP0_SDCA_CASCADE; }

- /* Make sure no interrupts are pending */ + /* + * Make sure no interrupts are pending, but filter to limit loop + * to interrupts identified in the first status read + */ buf &= _buf; buf2[0] &= _buf2[0]; buf2[1] &= _buf2[1];

From: Pierre-Louis Bossart pierre-louis.bossart@linux.intel.com

DP0 has reserved fields and the read-only SDCA_CASCADE bit. We should not try to write values in these fields, so add a formal definition for clearable interrupts to be used in DP0 interrupt handling.

DPN also has reserved fields so add definitions for clearable interrupts as well.

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 --- include/linux/soundwire/sdw_registers.h | 11 +++++++++++ 1 file changed, 11 insertions(+)

diff --git a/include/linux/soundwire/sdw_registers.h b/include/linux/soundwire/sdw_registers.h index f420e8059779..0cb1a22685b8 100644 --- a/include/linux/soundwire/sdw_registers.h +++ b/include/linux/soundwire/sdw_registers.h @@ -41,6 +41,12 @@ #define SDW_DP0_INT_IMPDEF1 BIT(5) #define SDW_DP0_INT_IMPDEF2 BIT(6) #define SDW_DP0_INT_IMPDEF3 BIT(7) +#define SDW_DP0_INTERRUPTS (SDW_DP0_INT_TEST_FAIL | \ + SDW_DP0_INT_PORT_READY | \ + SDW_DP0_INT_BRA_FAILURE | \ + SDW_DP0_INT_IMPDEF1 | \ + SDW_DP0_INT_IMPDEF2 | \ + SDW_DP0_INT_IMPDEF3)

#define SDW_DP0_PORTCTRL_DATAMODE GENMASK(3, 2) #define SDW_DP0_PORTCTRL_NXTINVBANK BIT(4) @@ -241,6 +247,11 @@ #define SDW_DPN_INT_IMPDEF1 BIT(5) #define SDW_DPN_INT_IMPDEF2 BIT(6) #define SDW_DPN_INT_IMPDEF3 BIT(7) +#define SDW_DPN_INTERRUPTS (SDW_DPN_INT_TEST_FAIL | \ + SDW_DPN_INT_PORT_READY | \ + SDW_DPN_INT_IMPDEF1 | \ + SDW_DPN_INT_IMPDEF2 | \ + SDW_DPN_INT_IMPDEF3)

#define SDW_DPN_PORTCTRL_FLOWMODE GENMASK(1, 0) #define SDW_DPN_PORTCTRL_DATAMODE GENMASK(3, 2)

From: Pierre-Louis Bossart pierre-louis.bossart@linux.intel.com

Mirror the changes made for DP0 and don't modify reserved 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 --- drivers/soundwire/bus.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c index f66a804f9b74..d1e8c3a54976 100644 --- a/drivers/soundwire/bus.c +++ b/drivers/soundwire/bus.c @@ -1353,7 +1353,7 @@ static int sdw_handle_dp0_interrupt(struct sdw_slave *slave, u8 *slave_status) static int sdw_handle_port_interrupt(struct sdw_slave *slave, int port, u8 *slave_status) { - u8 clear = 0, impl_int_mask; + u8 clear, impl_int_mask; int status, status2, ret, count = 0; u32 addr;

@@ -1370,6 +1370,8 @@ static int sdw_handle_port_interrupt(struct sdw_slave *slave, }

do { + clear = status & ~SDW_DPN_INTERRUPTS; + if (status & SDW_DPN_INT_TEST_FAIL) { dev_err(&slave->dev, "Test fail for port:%d\n", port); clear |= SDW_DPN_INT_TEST_FAIL; @@ -1392,7 +1394,7 @@ static int sdw_handle_port_interrupt(struct sdw_slave *slave, *slave_status = clear; }

- /* clear the interrupt */ + /* clear the interrupt but don't touch reserved fields */ ret = sdw_write(slave, addr, clear); if (ret < 0) { dev_err(slave->bus->dev, @@ -1413,7 +1415,7 @@ static int sdw_handle_port_interrupt(struct sdw_slave *slave, count++;

/* we can get alerts while processing so keep retrying */ - } while (status != 0 && count < SDW_READ_INTR_CLEAR_RETRY); + } while ((status & SDW_DPN_INTERRUPTS) && (count < SDW_READ_INTR_CLEAR_RETRY));

if (count == SDW_READ_INTR_CLEAR_RETRY) dev_warn(slave->bus->dev, "Reached MAX_RETRY on port read");