Re: [PATCH 1/4] remoteproc: k3-r5: Fix IPC-only mode detection

Mathieu Poirier
2024-06-28T19:58:44Z

Nishanth, Vignesh, Hari and Andrew - please have a look at this patch.

Thanks,
Mathieu

On Fri, 28 Jun 2024 at 13:53, Mathieu Poirier
<mathieu.poirier@linaro.org> wrote:
>
> Good day,
>
> On Fri, Jun 21, 2024 at 05:00:55PM +0200, Richard Genoud wrote:
> > ret variable was used to test reset status, get from
> > reset_control_status() call. But this variable was overwritten by
> > ti_sci_proc_get_status() a few lines bellow.
> > And as ti_sci_proc_get_status() returns 0 or a negative value (in this
> > latter case, followed by a return), the expression !ret was always true,
> >
> > Clearly, this was not what was intended:
> > In the comment above it's said that "requires both local and module
> > resets to be deasserted"; if reset_control_status() returns 0 it means
> > that the reset line is deasserted.
> > So, it's pretty clear that the return value of reset_control_status()
> > was intended to be used instead of ti_sci_proc_get_status() return
> > value.
> >
> > This could lead in an incorrect IPC-only mode detection if reset line is
> > asserted (so reset_control_status() return > 0) and c_state != 0 and
> > halted == 0.
> > In this case, the old code would have detected an IPC-only mode instead
> > of a mismatched mode.
> >
>
> Your assessment seems to be correct. That said I'd like to have an RB or a TB
> from someone in the TI delegation - guys please have a look.
>
> Thanks,
> Mathieu
>
> > Fixes: 1168af40b1ad ("remoteproc: k3-r5: Add support for IPC-only mode for all R5Fs")
> > Signed-off-by: Richard Genoud <richard.genoud@bootlin.com>
> > ---
> > drivers/remoteproc/ti_k3_r5_remoteproc.c | 13 +++++++------
> > 1 file changed, 7 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c b/drivers/remoteproc/ti_k3_r5_remoteproc.c
> > index 50e486bcfa10..39a47540c590 100644
> > --- a/drivers/remoteproc/ti_k3_r5_remoteproc.c
> > +++ b/drivers/remoteproc/ti_k3_r5_remoteproc.c
> > @@ -1144,6 +1144,7 @@ static int k3_r5_rproc_configure_mode(struct k3_r5_rproc *kproc)
> > u32 atcm_enable, btcm_enable, loczrama;
> > struct k3_r5_core *core0;
> > enum cluster_mode mode = cluster->mode;
> > + int reset_ctrl_status;
> > int ret;
> >
> > core0 = list_first_entry(&cluster->cores, struct k3_r5_core, elem);
> > @@ -1160,11 +1161,11 @@ static int k3_r5_rproc_configure_mode(struct k3_r5_rproc *kproc)
> > r_state, c_state);
> > }
> >
> > - ret = reset_control_status(core->reset);
> > - if (ret < 0) {
> > + reset_ctrl_status = reset_control_status(core->reset);
> > + if (reset_ctrl_status < 0) {
> > dev_err(cdev, "failed to get initial local reset status, ret = %d\n",
> > - ret);
> > - return ret;
> > + reset_ctrl_status);
> > + return reset_ctrl_status;
> > }
> >
> > /*
> > @@ -1199,7 +1200,7 @@ static int k3_r5_rproc_configure_mode(struct k3_r5_rproc *kproc)
> > * irrelevant if module reset is asserted (POR value has local reset
> > * deasserted), and is deemed as remoteproc mode
> > */
> > - if (c_state && !ret && !halted) {
> > + if (c_state && !reset_ctrl_status && !halted) {
> > dev_info(cdev, "configured R5F for IPC-only mode\n");
> > kproc->rproc->state = RPROC_DETACHED;
> > ret = 1;
> > @@ -1217,7 +1218,7 @@ static int k3_r5_rproc_configure_mode(struct k3_r5_rproc *kproc)
> > ret = 0;
> > } else {
> > dev_err(cdev, "mismatched mode: local_reset = %s, module_reset = %s, core_state = %s\n",
> > - !ret ? "deasserted" : "asserted",
> > + !reset_ctrl_status ? "deasserted" : "asserted",
> > c_state ? "deasserted" : "asserted",
> > halted ? "halted" : "unhalted");
> > ret = -EINVAL;