On 16/09/2022 10:39, Pierre-Louis Bossart wrote:
On 9/16/22 11:12, Srinivas Kandagatla wrote:
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.
Still not clear, sorry, see my comment below.
--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) {
can this really happen?
I have not see this happening, I had to change this line for consistency
reasons due to other changes in the patch.
Only case the issue was seen is during enumeration.
Device0 cannot be in alert status, can it? The only this it can do is
assert PREQ and set the Device0 status to 1 (ATTACHED). I don't get how
a device status could be 2.
So even if the status is shared somehow,I don't see how this could be
related to parking the device as suggested above. If the condition is
always false then changing the loop counter from 0 to 1 would not have
an effect?
The reason why core tries to park this device is because it sees
status[0] as SDW_SLAVE_ATTACHED and start programming the device id,
however reading DEVID registers return zeros which does not match to any
of the slaves in the list and the core attempts to park this device to
Group 13.
--srini
@@ -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));
