On Wed, 15 Apr 2020 at 09:41, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: > > On Tue, 14 Apr 2020 at 20:40, Michał Mirosław <mirq-linux@xxxxxxxxxxxx> wrote: > > > > On Tue, Apr 14, 2020 at 06:14:00PM +0200, Ulf Hansson wrote: > > > Some commands uses R1B responses, which means the card may assert the DAT0 > > > line to signal busy for a period of time, after it has received the > > > command. The mmc core normally specifies the busy period for the command in > > > the cmd->busy_timeout. Ideally the driver should respect it, but that > > > requires quite some update of the code, so let's defer that to someone with > > > the HW at hand. > > > > > > Instead, let's inform the mmc core about the maximum supported busy timeout > > > in ->max_busy_timeout during ->probe(). This value corresponds to the fixed > > > ~2s timeout of the polling loop, implemented in cb710_wait_for_event(). In > > > this way, we let the mmc core validate the needed timeout, which may lead > > > to that it converts from a R1B into a R1 response and then use CMD13 to > > > poll for busy completion. > > > > > > In other words, this change enables support for commands with longer busy > > > periods than 2s, like erase (CMD38) for example. > > [...] > > > + /* > > > + * In cb710_wait_for_event() we use a fixed timeout of ~2s, hence let's > > > + * inform the core about it. A future improvement should instead make > > > + * use of the cmd->busy_timeout. > > > + */ > > [...] > > > > I'm not sure whether the controller limits busy signalling time. > > Since this is rare HW now, I would just pass the timeout to > > cb710_wait_for_event() and see if someone reports a bug. > > Alright, let me try something like that. Thanks for your suggestion. I looked a bit more closely at your suggestion, but unfortunately it requires quite some changes to the code. To pass a timeout and need to move cb710_wait_for_event() from using a fixed number of polling loops into using "timeout_ms" value instead. Although, rather than open coding yet another new polling loop and perhaps introduce new errors, I prefer moving to readx_poll_timeout(). However, to do that, even more changes are needed around cb710_check_event(). Once that is done, we also have cb710_wait_while_busy(), that uses a similar polling loop as cb710_wait_for_event(). So then it seems reasonable to convert this one too. To conclude, for now, I am going to apply $subject patch as is. Then we can always do the above conversion later on, if we see that there is a need for it. Kind regards Uffe
