Re: [PATCH v6 06/10] drivers: qcom: rpmh-rsc: allow invalidation of sleep/wake TCS

From: Matthias Kaehlcke
Date: Fri Apr 27 2018 - 12:54:19 EST


On Fri, Apr 27, 2018 at 10:44:21AM -0600, Lina Iyer wrote:
> On Wed, Apr 25 2018 at 16:11 -0600, Matthias Kaehlcke wrote:
> > On Thu, Apr 19, 2018 at 04:16:31PM -0600, Lina Iyer wrote:
> > > Allow sleep and wake commands to be cleared from the respective TCSes,
> > > so that they can be re-populated.
> > >
> > > Signed-off-by: Lina Iyer <ilina@xxxxxxxxxxxxxx>
> > > ---
> > >
> > > Changes in v6:
> > > - remove unnecessary locks around __tcs_invalidate
> > > - rename function to tcs_invaldiate
> > >
> > > Changes in v4:
> > > - refactored the rphm_rsc_invalidate()
> > > ---
> > > drivers/soc/qcom/rpmh-rsc.c | 45 +++++++++++++++++++++++++++++++++++++
> > > 1 file changed, 45 insertions(+)
> > >
> > > diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
> > > index d169f7da5422..170d4a10275d 100644
> > > --- a/drivers/soc/qcom/rpmh-rsc.c
> > > +++ b/drivers/soc/qcom/rpmh-rsc.c
> > > @@ -101,6 +101,51 @@ static struct tcs_group *get_tcs_of_type(struct rsc_drv *drv, int type)
> > > return &drv->tcs[type];
> > > }
> > >
> > > +static int tcs_invalidate(struct rsc_drv *drv, int type)
> > > +{
> > > + int m;
> > > + struct tcs_group *tcs;
> > > +
> > > + tcs = get_tcs_of_type(drv, type);
> > > + if (IS_ERR(tcs))
> > > + return PTR_ERR(tcs);
> > > +
> > > + spin_lock(&tcs->lock);
> > > + if (bitmap_empty(tcs->slots, MAX_TCS_SLOTS)) {
> > > + spin_unlock(&tcs->lock);
> > > + return 0;
> > > + }
> > > +
> > > + for (m = tcs->offset; m < tcs->offset + tcs->num_tcs; m++) {
> > > + if (!tcs_is_free(drv, m)) {
> > > + spin_unlock(&tcs->lock);
> > > + return -EAGAIN;
> > > + }
> > > + write_tcs_reg_sync(drv, RSC_DRV_CMD_ENABLE, m, 0);
> > > + bitmap_zero(tcs->slots, MAX_TCS_SLOTS);
> >
> > Shouldn't this only clear the slots corresponding to 'm'?
> >
> > If resetting the entire bitmap is really intended it could be done
> > once after the loop, though the bitmap might be left in an
> > inconsistent state if a TCS is still in use.
> The TCS will not be in use, the check tcs_is_free() will ensure that. I
> will move the bitmap_zero() outside the for().

Sure, but it could occur that one or more TCSes are disabled, then
tcs_is_free() returns false for the next TCS and the function returns
without having updated tcs->slots for the TCSes that have been
disabled.