Message ID | 20200311184128.4212-8-pierre-louis.bossart@linux.intel.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | SoundWire: cadence: add clock stop and fix programming sequences | expand |
On 11-03-20, 13:41, Pierre-Louis Bossart wrote: > 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> > --- > drivers/soundwire/cadence_master.c | 28 ++++++++++++++++++++++++++++ > 1 file changed, 28 insertions(+) > > diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c > index 02f18ce6b7e7..a4ba57f44c1f 100644 > --- a/drivers/soundwire/cadence_master.c > +++ b/drivers/soundwire/cadence_master.c > @@ -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) Do you want to rename this as cdns_configure_slave_interrupts, with argument as enable/disable... ?
>> +/** >> + * 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) > > Do you want to rename this as cdns_configure_slave_interrupts, with > argument as enable/disable... ? this follows the convention we already have with: int sdw_cdns_enable_interrupt(struct sdw_cdns *cdns, bool state); but it just deals with slave interrupts only.
diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c index 02f18ce6b7e7..a4ba57f44c1f 100644 --- a/drivers/soundwire/cadence_master.c +++ b/drivers/soundwire/cadence_master.c @@ -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 @@ -1272,6 +1290,13 @@ int sdw_cdns_clock_stop(struct sdw_cdns *cdns, bool block_wake) return 1; } + /* + * 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 @@ -1349,6 +1374,9 @@ 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) {
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> --- drivers/soundwire/cadence_master.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+)