From: Bard Liao <yung-chuan.liao@linux.intel.com> To: alsa-devel@alsa-project.org, vkoul@kernel.org Cc: vinod.koul@linaro.org, linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org, jank@cadence.com, srinivas.kandagatla@linaro.org, rander.wang@linux.intel.com, ranjani.sridharan@linux.intel.com, hui.wang@canonical.com, pierre-louis.bossart@linux.intel.com, sanyog.r.kale@intel.com, mengdong.lin@intel.com, bard.liao@intel.com Subject: [PATCH 1/5] soundwire: bus: add comments to explain interrupt loop filter Date: Tue, 24 Nov 2020 09:33:14 +0800 [thread overview] Message-ID: <20201124013318.8963-2-yung-chuan.liao@linux.intel.com> (raw) In-Reply-To: <20201124013318.8963-1-yung-chuan.liao@linux.intel.com> 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]; -- 2.17.1
WARNING: multiple messages have this Message-ID (diff)
From: Bard Liao <yung-chuan.liao@linux.intel.com> To: alsa-devel@alsa-project.org, vkoul@kernel.org Cc: pierre-louis.bossart@linux.intel.com, vinod.koul@linaro.org, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, ranjani.sridharan@linux.intel.com, hui.wang@canonical.com, srinivas.kandagatla@linaro.org, jank@cadence.com, mengdong.lin@intel.com, sanyog.r.kale@intel.com, rander.wang@linux.intel.com, bard.liao@intel.com Subject: [PATCH 1/5] soundwire: bus: add comments to explain interrupt loop filter Date: Tue, 24 Nov 2020 09:33:14 +0800 [thread overview] Message-ID: <20201124013318.8963-2-yung-chuan.liao@linux.intel.com> (raw) In-Reply-To: <20201124013318.8963-1-yung-chuan.liao@linux.intel.com> 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]; -- 2.17.1
next prev parent reply other threads:[~2020-11-24 13:26 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-11-24 1:33 [PATCH 0/5] soundwire: only clear valid interrupts Bard Liao 2020-11-24 1:33 ` Bard Liao 2020-11-24 1:33 ` Bard Liao [this message] 2020-11-24 1:33 ` [PATCH 1/5] soundwire: bus: add comments to explain interrupt loop filter Bard Liao 2020-11-24 1:33 ` [PATCH 2/5] soundwire: bus: reset slave_notify status at each loop Bard Liao 2020-11-24 1:33 ` Bard Liao 2020-11-24 1:33 ` [PATCH 3/5] soundwire: registers: add definitions for clearable interrupt fields Bard Liao 2020-11-24 1:33 ` Bard Liao 2020-11-24 1:33 ` [PATCH 4/5] soundwire: bus: only clear valid DP0 interrupts Bard Liao 2020-11-24 1:33 ` Bard Liao 2020-11-24 1:33 ` [PATCH 5/5] soundwire: bus: only clear valid DPN interrupts Bard Liao 2020-11-24 1:33 ` Bard Liao 2020-11-25 5:02 ` [PATCH 0/5] soundwire: only clear valid interrupts Vinod Koul 2020-11-25 5:02 ` Vinod Koul
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