Messages in this thread | | | Date | Mon, 12 Sep 2022 16:36:09 +0100 | Subject | Re: [PATCH 5/7] soundwire: intel: Don't disable interrupt until children are removed | From | Richard Fitzgerald <> |
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On 12/09/2022 11:53, Pierre-Louis Bossart wrote: > > > On 9/7/22 12:14, Richard Fitzgerald wrote: >> The cadence_master code needs the interrupt to complete message transfers. >> When the bus driver is being removed child drivers are removed, and their >> remove actions might need bus transactions. >> >> Use the sdw_master_ops.remove callback to disable the interrupt handling >> only after the child drivers have been removed. >> >> Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com> >> --- >> drivers/soundwire/intel.c | 9 ++++++++- >> 1 file changed, 8 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c >> index 01be62fa6c83..d5e723a9c80b 100644 >> --- a/drivers/soundwire/intel.c >> +++ b/drivers/soundwire/intel.c >> @@ -1255,6 +1255,13 @@ static int intel_prop_read(struct sdw_bus *bus) >> return 0; >> } >> >> +static void intel_bus_remove(struct sdw_bus *bus) >> +{ >> + struct sdw_cdns *cdns = bus_to_cdns(bus); >> + >> + sdw_cdns_enable_interrupt(cdns, false); > > don't you need to check for any on-going transactions on the bus? >
As all the child drivers have removed, I think the only other place that can generate bus transactions is the PING handler but sdw_cdns_enable_interrupt(false) calls cancel_work_sync() to cancel the cdns->work and it sets a flag so that it will not be re-queued.
> I wonder if there could be a corner case where there are no child > devices but still a device physically attached to the bus. I am not sure > if the 'no devices left' is a good-enough indication of no activity on > the bus. >
As above - yes there could, but sdw_cdns_enable_interrupt(false) will cancel the work and stop it being re-queued.
>> +} >> + >> static struct sdw_master_ops sdw_intel_ops = { >> .read_prop = sdw_master_read_prop, >> .override_adr = sdw_dmi_override_adr, >> @@ -1264,6 +1271,7 @@ static struct sdw_master_ops sdw_intel_ops = { >> .set_bus_conf = cdns_bus_conf, >> .pre_bank_switch = intel_pre_bank_switch, >> .post_bank_switch = intel_post_bank_switch, >> + .remove = intel_bus_remove, >> }; >> >> static int intel_init(struct sdw_intel *sdw) >> @@ -1502,7 +1510,6 @@ static void intel_link_remove(struct auxiliary_device *auxdev) >> */ >> if (!bus->prop.hw_disabled) { >> intel_debugfs_exit(sdw); >> - sdw_cdns_enable_interrupt(cdns, false); >> snd_soc_unregister_component(dev); >> } >> sdw_bus_master_delete(bus);
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