Hi Uli, On Tue, Sep 22, 2020 at 5:49 PM Ulrich Hecht <uli+renesas@xxxxxxxx> wrote: > Implements atomic transfers to fix reboot/shutdown on r8a7790 Lager and > similar boards. > > Signed-off-by: Ulrich Hecht <uli+renesas@xxxxxxxx> > Tested-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx> > Tested-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> > > This is a rebased version of v2 with a minor issue fixed. It does not > resolve the runtime PM issue that may arise (see "watchdog: da9063: wake up > parent ahead of reboot", https://patchwork.kernel.org/patch/11749121/ ), but > in practice it works, and our understanding so far is that this will have to > be resolved outside this driver and should IMO not block this patch. See my comment below. > Changes since v2: > - rebase > - make sure time_left is updated Thanks for the update! > --- a/drivers/i2c/busses/i2c-sh_mobile.c > +++ b/drivers/i2c/busses/i2c-sh_mobile.c > @@ -429,7 +432,8 @@ static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id) > > if (wakeup) { > pd->sr |= SW_DONE; > - wake_up(&pd->wait); > + if (!pd->atomic_xfer) > + wake_up(&pd->wait); > } > > /* defeat write posting to avoid spurious WAIT interrupts */ > @@ -581,12 +585,14 @@ static void start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg, > pd->pos = -1; > pd->sr = 0; > if (pd->atomic_xfer) return; and be done with it? > - pd->dma_buf = i2c_get_dma_safe_msg_buf(pd->msg, 8); > - if (pd->dma_buf) > - sh_mobile_i2c_xfer_dma(pd); > - > - /* Enable all interrupts to begin with */ > - iic_wr(pd, ICIC, ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE); > + if (!pd->atomic_xfer) { > + pd->dma_buf = i2c_get_dma_safe_msg_buf(pd->msg, 8); > + if (pd->dma_buf) > + sh_mobile_i2c_xfer_dma(pd); > + /* Enable all interrupts to begin with */ > + iic_wr(pd, ICIC, > + ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE); > + } > } > > @@ -696,14 +721,35 @@ static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter, > return err ?: num; > } > > +static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter, > + struct i2c_msg *msgs, > + int num) > +{ > + struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter); > + > + pd->atomic_xfer = false; > + return sh_mobile_xfer(pd, msgs, num); > +} > + > +static int sh_mobile_i2c_xfer_atomic(struct i2c_adapter *adapter, > + struct i2c_msg *msgs, > + int num) > +{ > + struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter); > + To make sure external conditions are satisfied, and we never deadlock: if (pd->dev->power.is_suspended) return -EPERM; /* any other suitable error code? */ Perhaps this can even be done in the i2c core instead? > + pd->atomic_xfer = true; > + return sh_mobile_xfer(pd, msgs, num); > +} Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
