Re: [PATCH] i2c: cadence: Increase timeout per message if necessary

[Michal Simek]

On 3/23/22 11:07, tanureal@xxxxxxxxxxxxxxxxxxxxx wrote:
> On 3/22/22 5:18 PM, Michal Simek <michal.simek@xxxxxxxxxx> wrote:
> > On 3/22/22 16:34, tanureal@xxxxxxxxxxxxxxxxxxxxx wrote:
> > > On 3/21/22 3:57 PM, Michal Simek <michal.simek@xxxxxxxxxx> wrote:
> > >> +Shubhrajyoti
> > >>
> > >> On 3/9/22 10:31, Lucas Tanure wrote:
> > >> > Timeout as 1 second sets a upper limit on the length of
> > >> > the transfer executed, but there is no maximum length of
> > >> > a write or read message set in i2c_adapter_quirks for this
> > >> > controller.
> > >>
> > >> nit: I would expect that you have run any test and you reached an issue.
> > >> Would be good to describe what exactly you have tried on which >> 
> > configuration to make it super clear.
> > >>
> > >> >
> > >> > To remove that limitation calculate the minimal time
> > >> > necessary, plus some wiggle room, for every message
> > >> > and use it instead of the default one second, if
> > >> > more than one second.
> > >> >
> > >> > Signed-off-by: Lucas Tanure <tanureal@xxxxxxxxxxxxxxxxxxxxx>
> > >> > ---
> > >> >   drivers/i2c/busses/i2c-cadence.c | 12 ++++++++++--
> > >> >   1 file changed, 10 insertions(+), 2 deletions(-)
> > >> >
> > >> > diff --git a/drivers/i2c/busses/i2c-cadence.c > >> 
> > b/drivers/i2c/busses/i2c-cadence.c
> > >> > index 805c77143a0f..b4c1ad19cdae 100644
> > >> > --- a/drivers/i2c/busses/i2c-cadence.c
> > >> > +++ b/drivers/i2c/busses/i2c-cadence.c
> > >> > @@ -760,7 +760,7 @@ static void cdns_i2c_master_reset(struct > >> 
> > i2c_adapter *adap)
> > >> >   static int cdns_i2c_process_msg(struct cdns_i2c *id, struct >> i2c_msg 
> > > *msg,
> > >> >           struct i2c_adapter *adap)
> > >> >   {
> > >> > -    unsigned long time_left;
> > >> > +    unsigned long time_left, msg_timeout;
> > >> >       u32 reg;
> > >> >       id->p_msg = msg;
> > >> > @@ -785,8 +785,16 @@ static int cdns_i2c_process_msg(struct >> cdns_i2c > 
> > *id, struct i2c_msg *msg,
> > >> >       else
> > >> >           cdns_i2c_msend(id);
> > >> > +    /* Minimal time to execute this message */
> > >> > +    msg_timeout = msecs_to_jiffies((1000 * msg->len * >> BITS_PER_BYTE) 
> > > / id->i2c_clk);
> > >> > +    /* Plus some wiggle room */
> > >> > +    msg_timeout += msecs_to_jiffies(500);
> > >> > +
> > >> > +    if (msg_timeout < adap->timeout)
> > >> > +        msg_timeout = adap->timeout;
> > >> > +
> > >> >       /* Wait for the signal of completion */
> > >> > -    time_left = wait_for_completion_timeout(&id->xfer_done, > >> 
> > adap->timeout);
> > >> > +    time_left = wait_for_completion_timeout(&id->xfer_done, > >> 
> > msg_timeout);
> > >> >       if (time_left == 0) {
> > >> >           cdns_i2c_master_reset(adap);
> > >> >           dev_err(id->adap.dev.parent,
> > >>
> > >>
> > >> If my assumption is right and there is any actual issue you had >> please 
> > send v2 and feel free to add there my:
> > >> Acked-by: Michal Simek <michal.simek@xxxxxxxxxx>
> > >>
> > >> Thanks,
> > >> Michal
> > >>
> > >>
> > >>
> > > The issue happens for I2C devices that have firmware, which will send > a 
> > big I2C message, but the I2C controller will timeout on it.
> > > That happened for CS35L41 DSP firmware tests, so no particular > 
> > configuration, just a driver sending firmware blob over I2C.
> >
> > How big is it?
> >
> > M
> The firmware has 33868 bytes, and it is split in a few writes. The first one to 
> time out has 20240 bytes:
>
> [   53.398444] cs35l41 0-0040: DSP1: Firmware version: 3
> [   53.403522] cs35l41 0-0040: DSP1: cs35l41-dsp1-spk-prot.wmfw: Fri 04 Feb 2022 
> 12:01:42 W. Europe Standard Time
> [   55.331688] cdns-i2c e0004000.i2c: timeout waiting on completion
> [   55.336721] cs35l41 0-0040: DSP1: cs35l41-dsp1-spk-prot.wmfw.5: Failed to 
> write 20240 bytes at 0 in PM_PACKED: -110
>
> 20240 bytes at 100k clock should take 1.6192 seconds, which is more than the 
> current timeout of one second.

ok.

thanks,
Michal