Re: [PATCH v4 5/5] remoteproc: qcom: Always assert and deassert reset signals in SDM845

[Sibi S]

Hi Bjorn,
Thanks for the review. Will make all the required changes in v5.

On 05/19/2018 03:17 AM, Bjorn Andersson wrote:
> On Wed 25 Apr 08:08 PDT 2018, Sibi Sankar wrote:
>
> > SDM845 brings a new reset signal ALT_RESET which is a part of the MSS
> > subsystem hence requires some of the active clks to be enabled before
> > assert/deassert
> >
> > Reset the modem if the BOOT FSM does timeout
> >
> > Reset assert/deassert sequence vary across SoCs adding reset, adding
> > start/stop helper functions to handle SoC specific reset sequences
> >
> > Signed-off-by: Sibi Sankar <sibis@xxxxxxxxxxxxxx>
> > ---
> >   drivers/remoteproc/qcom_q6v5_pil.c | 81 ++++++++++++++++++++++++++++--
> >   1 file changed, 76 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/remoteproc/qcom_q6v5_pil.c b/drivers/remoteproc/qcom_q6v5_pil.c
> [..]
> > @@ -349,6 +356,32 @@ static int q6v5_load(struct rproc *rproc, const struct firmware *fw)
> >   	return 0;
> >   }
> >   
> > +static int q6v5_reset_assert(struct q6v5 *qproc)
> > +{
> > +	return reset_control_assert(qproc->mss_restart);
> > +}
> > +
> > +static int q6v5_reset_deassert(struct q6v5 *qproc)
> > +{
> > +	return reset_control_deassert(qproc->mss_restart);
> > +}
> > +
> > +static int q6v5_alt_reset_assert(struct q6v5 *qproc)
> > +{
> > +	return reset_control_reset(qproc->mss_restart);
> > +}
> > +
> > +static int q6v5_alt_reset_deassert(struct q6v5 *qproc)
> > +{
> > +	/* Ensure alt reset is written before restart reg */
> > +	writel(1, qproc->rmb_base + RMB_MBA_ALT_RESET);
> > +
> > +	reset_control_reset(qproc->mss_restart);
> > +
> > +	writel(0, qproc->rmb_base + RMB_MBA_ALT_RESET);
> > +	return 0;
> > +}
> > +
>
> Rather than having these four functions and scattering jumps to some
> function pointer in the code I think it will be shorter and cleaner to
> just have the q6v5_reset_{asert,deassert}() functions and in there check
> if has_alt_reset and take appropriate action.

yes this seems simpler

> >   static int q6v5_rmb_pbl_wait(struct q6v5 *qproc, int ms)
> >   {
> >   	unsigned long timeout;
> > @@ -424,6 +457,8 @@ static int q6v5proc_reset(struct q6v5 *qproc)
> >   				val, (val & BIT(0)) != 0, 10, BOOT_FSM_TIMEOUT);
> >   		if (ret) {
> >   			dev_err(qproc->dev, "Boot FSM failed to complete.\n");
> > +			/* Reset the modem so that boot FSM is in reset state */
> > +			qproc->reset_deassert(qproc);
>
>
> A thing like this typically should go into it's own patch, to keep a
> clear record of why it was changed, but as this is simply amending the
> previous patch it indicates that that one wasn't complete.
>
> So if you reorder the two patches you can just put this directly into
> the sdm845 patch, making it "complete".
>
> (This also means that I want to merge the handover vs ready interrupt
> patch before that one, so please include it in the next revision of the
> series).

Will re-order them.


> >   			return ret;
> >   		}
> >   
> > @@ -792,12 +827,20 @@ static int q6v5_start(struct rproc *rproc)
> >   		dev_err(qproc->dev, "failed to enable supplies\n");
> >   		goto disable_proxy_clk;
> >   	}
> > -	ret = reset_control_deassert(qproc->mss_restart);
> > +
> > +	ret = q6v5_clk_enable(qproc->dev, qproc->reset_clks,
> > +			      qproc->reset_clk_count);
>
> Remind me, why can't you always enable the active clock before
> deasserting reset? That way we wouldn't have to split out the iface
> clock handling to be just slightly longer than the active clocks.

Have to introduce reset clks for backward compatibility, both msm8916
and msm8996 require the mss_reset to be deasserted before enabling
the active clks.

> >   	if (ret) {
> > -		dev_err(qproc->dev, "failed to deassert mss restart\n");
> > +		dev_err(qproc->dev, "failed to enable reset clocks\n");
> >   		goto disable_vdd;
> >   	}
> >   
> > +	ret = qproc->reset_deassert(qproc);
> > +	if (ret) {
> > +		dev_err(qproc->dev, "failed to deassert mss restart\n");
> > +		goto disable_reset_clks;
> > +	}
> > +
> [..]
> > @@ -1335,8 +1399,11 @@ static const struct rproc_hexagon_res sdm845_mss = {
> >   			"prng",
> >   			NULL
> >   	},
> > -	.active_clk_names = (char*[]){
> > +	.reset_clk_names = (char*[]){
> >   			"iface",
> > +			NULL
> > +	},
> > +	.active_clk_names = (char*[]){
>
> Again, if you reorder your patches to first add the support for
> alt_reset and then introduce sdm845 you don't need to modify the
> previous patch directly to make it work.

yeah I'll re-order them

> >   			"bus",
> >   			"mem",
> >   			"gpll0_mss",
>
> Regards,
> Bjorn

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