On 7/21/2017 6:20 PM, Rafal wrote:
Again, ap6212 device on board. When the module gets unloaded and then
loaded again, sometimes the driver fails to bring up the device - it
stops with the following errors:
[ 125.668000] brcmfmac: brcmf_sdio_txfail: sdio error, abort command
and terminate frame
[ 125.676000] brcmfmac: brcmf_sdio_txfail: sdio error, abort command
and terminate frame
[ 125.680000] brcmfmac: brcmf_sdio_txfail: sdio error, abort command
and terminate frame
[ 125.684000] brcmfmac: brcmf_sdio_dpc: failed backplane access over
SDIO, halting operation
[ 125.684000] brcmfmac: brcmf_proto_bcdc_query_dcmd:
brcmf_proto_bcdc_msg failed w/status -84
[ 125.684000] brcmfmac: brcmf_c_preinit_dcmds: Retreiving cur_etheraddr
failed, -84
[ 125.684000] brcmfmac: brcmf_bus_started: failed: -84
I have made some investigations and it looks the problem is caused by
too short time between getting CM3 core out of reset and first
communication attempt with the device. It looks the device needs about
50ms to boot up. Usually the appropriate delay is introduced by function
sdio_enable_func which is called just after activation of the core to
enable F2 function on device. Usually the sdio function introduces the
needed 50ms delay and everything is OK. But sometimes the function
returns immediately. In this case the driver breaks down with the above
error. But if the additional delay is added in place of
sdio_enable_func, everything is okay.
Hi Rafal,
That is an interesting find. I took a dive into the SDIO code. After
enabling F2 there are actually three signals from the device that
indicate its readiness to handle communication with the host. However,
none of them are waited for before activating higher layer operations in
the driver. So instead of the delay it may be better to wait for the
device to come up properly and indicate its readiness. If we do need
this delay I would rather put it in sdio.c. Anyway, if I come up with a
patch for testing would you be willing to give it a spin. Thanks for
digging deeper.
Regards,
Arend
