Re: [PATCH] soundwire: qcom: update status from device id 1

[Srinivas Kandagatla]

On 15/09/2022 14:10, Pierre-Louis Bossart wrote:
> On 9/15/22 14:42, Srinivas Kandagatla wrote:
> > By default autoenumeration is enabled on QCom SoundWire controller
> > which means the core should not be dealing with device 0 w.r.t enumeration.
> > Currently device 0 status is also shared with SoundWire core which confuses
> > the core sometimes and we endup adding 0:0:0:0 slave device.
>
> The change looks fine, but the description of the issue is surprising.

Thanks Pierre,

> Whether autoenumeration is enabled or not is irrelevant, by spec the
> device0 cannot be in ALERT status and throw in-band interrupts to the
> host with this mechanism.

This issue is more of around enumeration stage in specific during device 
status change interrupt from controller. Sharing the device 0 status 
with core makes it think that there is a device with 0:0:0:0 address and 
it tries to park device to group 13.


--srini

> > Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
> > ---
> >   drivers/soundwire/qcom.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c
> > index e21a3306bf01..871e4d8b32c7 100644
> > --- a/drivers/soundwire/qcom.c
> > +++ b/drivers/soundwire/qcom.c
> > @@ -428,7 +428,7 @@ static int qcom_swrm_get_alert_slave_dev_num(struct qcom_swrm_ctrl *ctrl)
> >   
> >   	ctrl->reg_read(ctrl, SWRM_MCP_SLV_STATUS, &val);
> >   
> > -	for (dev_num = 0; dev_num <= SDW_MAX_DEVICES; dev_num++) {
> > +	for (dev_num = 1; dev_num <= SDW_MAX_DEVICES; dev_num++) {
> >   		status = (val >> (dev_num * SWRM_MCP_SLV_STATUS_SZ));
> >   
> >   		if ((status & SWRM_MCP_SLV_STATUS_MASK) == SDW_SLAVE_ALERT) {
> > @@ -448,7 +448,7 @@ static void qcom_swrm_get_device_status(struct qcom_swrm_ctrl *ctrl)
> >   	ctrl->reg_read(ctrl, SWRM_MCP_SLV_STATUS, &val);
> >   	ctrl->slave_status = val;
> >   
> > -	for (i = 0; i <= SDW_MAX_DEVICES; i++) {
> > +	for (i = 1; i <= SDW_MAX_DEVICES; i++) {
> >   		u32 s;
> >   
> >   		s = (val >> (i * 2));