Re: [PATCH 5/7] soundwire: intel: Don't disable interrupt until children are removed

Pierre-Louis Bossart
2022-09-12T12:00:04Z

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?

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.

> +}
> +
> 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);