On Tue, Mar 31, 2020 at 11:24:57AM -0700, Matthias Kaehlcke wrote:
> Hi Akash,
>
> On Tue, Mar 31, 2020 at 04:39:31PM +0530, Akash Asthana wrote:
> > QUP core clock is shared among all the SE drivers present on particular
> > QUP wrapper, the system will reset(unclocked access) if earlycon used after
> > QUP core clock is put to 0 from other SE drivers before real console comes
> > up.
> >
> > As earlycon can't vote for it's QUP core need, to fix this add ICC
> > support to common/QUP wrapper driver and put vote for QUP core from
> > probe on behalf of earlycon and remove vote during earlycon exit call.
> >
> > Signed-off-by: Akash Asthana <akashast@xxxxxxxxxxxxxx>
> > Reported-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
> > ---
> > Change is V3:
> > - Add geni_remove_earlycon_icc_vote API that will be used by earlycon
> > exit function to remove ICC vote for earlyconsole.
> > - Remove suspend/resume hook for geni-se driver as we are no longer
> > removing earlyconsole ICC vote from system suspend, we are removing
> > from earlycon exit.
> >
> > drivers/soc/qcom/qcom-geni-se.c | 51 +++++++++++++++++++++++++++++++++++
> > drivers/tty/serial/qcom_geni_serial.c | 7 +++++
> > include/linux/qcom-geni-se.h | 2 ++
> > 3 files changed, 60 insertions(+)
> >
> > diff --git a/drivers/soc/qcom/qcom-geni-se.c b/drivers/soc/qcom/qcom-geni-se.c
> > index 9344c14..d30c282 100644
> > --- a/drivers/soc/qcom/qcom-geni-se.c
> > +++ b/drivers/soc/qcom/qcom-geni-se.c
> > @@ -90,8 +90,11 @@ struct geni_wrapper {
> > struct device *dev;
> > void __iomem *base;
> > struct clk_bulk_data ahb_clks[NUM_AHB_CLKS];
> > + struct geni_icc_path to_core;
> > };
> >
> > +struct geni_wrapper *earlycon_wrapper;
>
> should be static
>
> > +
> > #define QUP_HW_VER_REG 0x4
> >
> > /* Common SE registers */
> > @@ -818,6 +821,26 @@ int geni_icc_vote_off(struct geni_se *se)
> > }
> > EXPORT_SYMBOL(geni_icc_vote_off);
> >
> > +void geni_remove_earlycon_icc_vote(void)
> > +{
> > + struct geni_wrapper *wrapper = earlycon_wrapper;
> > + struct device_node *parent = of_get_next_parent(wrapper->dev->of_node);
> > + struct device_node *child;
> > +
> > + for_each_child_of_node(parent, child) {
> > + if (of_device_is_compatible(child, "qcom,geni-se-qup")) {
> > + wrapper = platform_get_drvdata(of_find_device_by_node(
> > + child));
> > + icc_put(wrapper->to_core.path);
> > + wrapper->to_core.path = NULL;
> > + }
> > + }
> > + of_node_put(parent);
> > +
> > + earlycon_wrapper = NULL;
> > +}
> > +EXPORT_SYMBOL(geni_remove_earlycon_icc_vote);
>
> I didn't know that consoles have an exit handler, this is way nicer than
> the miscellaneous triggers we discussed earlier :)
No wonder I 'missed' this when looking at the console code for possible
triggers, it is brand new and as of now only exists in -next:
commit ed31685c96e18f773ca11dd1a637974d62130673
Author: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Date: Mon Feb 3 15:31:30 2020 +0200
console: Introduce ->exit() callback
sharp timing!
