Hi,
Mathias Nyman <mathias.ny...@linux.intel.com> writes:
> [ text/plain ]
> On 26.01.2016 14:58, Lu Baolu wrote:
>> In case of endpoint stall, software is able to detect the situation
>> by reading DCCTRL.HIT or DCCTRL.HOT bits. DbC follows the normal USB
>> framework to handle endpoint stall. When software detects endpoint
>> stall situation, it should wait until endpoint is recovered before
>> read or write oprations.
>>
>> Signed-off-by: Lu Baolu <baolu...@linux.intel.com>
>> ---
>> drivers/usb/early/xhci-dbc.c | 36 ++++++++++++++++++++++++++++++++++++
>> 1 file changed, 36 insertions(+)
>>
>> diff --git a/drivers/usb/early/xhci-dbc.c b/drivers/usb/early/xhci-dbc.c
>> index c81df40..344d93e 100644
>> --- a/drivers/usb/early/xhci-dbc.c
>> +++ b/drivers/usb/early/xhci-dbc.c
>> @@ -1163,6 +1163,37 @@ static int xdbc_wait_until_dbc_configured(void)
>> return -ETIMEDOUT;
>> }
>>
>> +static int xdbc_wait_until_epstall_cleared(bool read)
>> +{
>> + int timeout = 0;
>> +
>> + if (read) {
>> + do {
>> + if (!(readl(&xdbcp->xdbc_reg->control) & CTRL_HIT)) {
>> + xdbcp->in_ep_state = EP_RUNNING;
>> +
>> + return 0;
>> + }
>> +
>> + xdbcp->in_ep_state = EP_HALTED;
>> + xdbc_udelay(10);
>> + } while (timeout++ < XDBC_LOOPS);
>> + } else {
>> + do {
>> + if (!(readl(&xdbcp->xdbc_reg->control) & CTRL_HOT)) {
>> + xdbcp->out_ep_state = EP_RUNNING;
>> +
>> + return 0;
>> + }
>> +
>> + xdbcp->out_ep_state = EP_HALTED;
>> + xdbc_udelay(10);
>> + } while (timeout++ < XDBC_LOOPS);
>> + }
>> +
>> + return -ETIMEDOUT;
>> +}
>>
>
> how about something like:
>
> enum xdbc_ep_state *ep_state;
> u32 halt_bit;
>
> if (read) {
> ep_state = &xdbcp->in_ep_state
> halt_bit = CTRL_HIT
> } else {
> ep_state = &xdbcp->out_ep_state
> halt_bit = CTRL_HOT
> }
> do {
> if (!(readl(..) & halt_bit)) {
> *ep_state = EP_RUNNING;
> return 0;
> }
> *ep_state = EP_HALTED;
> delay()
> } while (..)
I'll agree, this looks better. Might also want to refactor the handshake
loop to its own function:
static int xdbg_ep_state_handshake(enum xdbc_ep_state *ep_state, u32 halt_bit)
{
do {
if (!(readl(...) & halt_bit)) {
...
}
*ep_state = EP_HALTED;
delay(...);
} while (...)
>> @@ -1182,6 +1213,11 @@ static int xdbc_bulk_transfer(void *data, int size,
>> int loops, bool read)
>> return -EPERM;
>> }
>>
>> + if (xdbc_wait_until_epstall_cleared(read)) {
>> + xdbc_trace("%s: endpoint not ready\n", __func__);
>> + return -EPERM;
>
> Is -EPERM appropriate here?
>
> Not sure about what error codes the device side is using, but usually
> HALT is set due to some Data buffer/transmission/TRB error.
EIO perhaps ?
> In this case the failure is that debug host failed to send a
> clearFeature(EP_HALT) request in time.
I haven't read the spec, but does it define a maximum time for this to
happen ?
--
balbi
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