soundwire: cadence: mask Slave interrupt before stopping clock (af4cc917) · Commits · 戴 / test

Intel QA reported a very rare case, possibly hardware-dependent, where a Slave can become UNATTACHED during a clock stop sequence, which leads to timeouts and failed suspend sequences. This patch suppresses the handling of all Slave events while this transition happens. The two cases that matter are: a) alerts: if the Slave wants to signal an alert condition, it can do so using the in-band wake, so there's almost no impact with this patch. b) sync loss or imp-def reset: in those cases, bringing back the Slave to functional state requires a complete re-enumeration. It's better to just ignore this case and restart cleanly, rather than attempt a 'clean' suspend. Validation results show the timeouts no longer visible with this patch. GitHub issue: https://github.com/thesofproject/linux/issues/1678 Signed-off-by:

Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> Link: https://lore.kernel.org/r/20200317163329.25501-8-pierre-louis.bossart@linux.intel.com Signed-off-by:

Vinod Koul <vkoul@kernel.org>

drivers/soundwire/cadence_master.c

+28 −0

Original line number	Diff line number	Diff line
		@@ -865,6 +865,24 @@ int sdw_cdns_exit_reset(struct sdw_cdns *cdns)
		}
		EXPORT_SYMBOL(sdw_cdns_exit_reset);

		/**
		* sdw_cdns_enable_slave_interrupt() - Enable SDW slave interrupts
		* @cdns: Cadence instance
		* @state: boolean for true/false
		*/
		static void cdns_enable_slave_interrupts(struct sdw_cdns *cdns, bool state)
		{
		u32 mask;

		mask = cdns_readl(cdns, CDNS_MCP_INTMASK);
		if (state)
		mask \|= CDNS_MCP_INT_SLAVE_MASK;
		else
		mask &= ~CDNS_MCP_INT_SLAVE_MASK;

		cdns_writel(cdns, CDNS_MCP_INTMASK, mask);
		}

		/**
		* sdw_cdns_enable_interrupt() - Enable SDW interrupts
		* @cdns: Cadence instance
		@@ -1262,6 +1280,13 @@ int sdw_cdns_clock_stop(struct sdw_cdns *cdns, bool block_wake)
		return 0;
		}

		/*
		* Before entering clock stop we mask the Slave
		* interrupts. This helps avoid having to deal with e.g. a
		* Slave becoming UNATTACHED while the clock is being stopped
		*/
		cdns_enable_slave_interrupts(cdns, false);

		/*
		* For specific platforms, it is required to be able to put
		* master into a state in which it ignores wake-up trials
		@@ -1339,6 +1364,9 @@ int sdw_cdns_clock_restart(struct sdw_cdns *cdns, bool bus_reset)
		{
		int ret;

		/* unmask Slave interrupts that were masked when stopping the clock */
		cdns_enable_slave_interrupts(cdns, true);

		ret = cdns_clear_bit(cdns, CDNS_MCP_CONTROL,
		CDNS_MCP_CONTROL_CLK_STOP_CLR);
		if (ret < 0) {

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