Re: [PATCH v2] firmware: qcom_scm: modify qcom_scm_set_download_mode()

[Mukesh Ojha]

On 2/3/2023 8:21 PM, Srinivas Kandagatla wrote:
> On 03/02/2023 10:17, Mukesh Ojha wrote:
> > Modify qcom_scm_set_download_mode() such that it can support
> > multiple modes. There is no functional change with this change.
> >
> > Signed-off-by: Mukesh Ojha <quic_mojha@xxxxxxxxxxx>
> > ---
> > Changes in v2:
> >    - Stop changing legacy scm id for dload mode.
> >
> >   drivers/firmware/qcom_scm.c | 15 +++++++--------
> >   include/linux/qcom_scm.h    |  5 +++++
> >   2 files changed, 12 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
> > index cdbfe54..6245b97 100644
> > --- a/drivers/firmware/qcom_scm.c
> > +++ b/drivers/firmware/qcom_scm.c
> > @@ -400,7 +400,7 @@ int qcom_scm_set_remote_state(u32 state, u32 id)
> >   }
> >   EXPORT_SYMBOL(qcom_scm_set_remote_state);
> > -static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
> > +static int __qcom_scm_set_dload_mode(struct device *dev, enum 
> > qcom_download_mode mode)
> >   {
> >       struct qcom_scm_desc desc = {
> >           .svc = QCOM_SCM_SVC_BOOT,
> > @@ -410,12 +410,12 @@ static int __qcom_scm_set_dload_mode(struct 
> > device *dev, bool enable)
> >           .owner = ARM_SMCCC_OWNER_SIP,
> >       };
> > -    desc.args[1] = enable ? QCOM_SCM_BOOT_SET_DLOAD_MODE : 0;
> > +    desc.args[1] = mode ? QCOM_SCM_BOOT_SET_DLOAD_MODE : 0;
>
> I think this line should be:
>
>      desc.args[1] = mode;

Should be fine..for backward compatibility as we want to avoid what is 
passed to trust zone without check and since this is legacy code, i 
would like to avoid.

-Mukesh
> --srini
>
> >       return qcom_scm_call_atomic(__scm->dev, &desc, NULL);
> >   }
> > -static void qcom_scm_set_download_mode(bool enable)
> > +static void qcom_scm_set_download_mode(enum qcom_download_mode mode)
> >   {
> >       bool avail;
> >       int ret = 0;
> > @@ -424,10 +424,9 @@ static void qcom_scm_set_download_mode(bool enable)
> >                            QCOM_SCM_SVC_BOOT,
> >                            QCOM_SCM_BOOT_SET_DLOAD_MODE);
> >       if (avail) {
> > -        ret = __qcom_scm_set_dload_mode(__scm->dev, enable);
> > +        ret = __qcom_scm_set_dload_mode(__scm->dev, mode);
> >       } else if (__scm->dload_mode_addr) {
> > -        ret = qcom_scm_io_writel(__scm->dload_mode_addr,
> > -                enable ? QCOM_SCM_BOOT_SET_DLOAD_MODE : 0);
> > +        ret = qcom_scm_io_writel(__scm->dload_mode_addr, mode);
> >       } else {
> >           dev_err(__scm->dev,
> >               "No available mechanism for setting download mode\n");
> > @@ -1410,7 +1409,7 @@ static int qcom_scm_probe(struct platform_device 
> > *pdev)
> >        * disabled below by a clean shutdown/reboot.
> >        */
> >       if (download_mode)
> > -        qcom_scm_set_download_mode(true);
> > +        qcom_scm_set_download_mode(QCOM_DOWNLOAD_FULLDUMP);
> >       return 0;
> >   }
> > @@ -1419,7 +1418,7 @@ static void qcom_scm_shutdown(struct 
> > platform_device *pdev)
> >   {
> >       /* Clean shutdown, disable download mode to allow normal restart */
> >       if (download_mode)
> > -        qcom_scm_set_download_mode(false);
> > +        qcom_scm_set_download_mode(QCOM_DOWNLOAD_NODUMP);
> >   }
> >   static const struct of_device_id qcom_scm_dt_match[] = {
> > diff --git a/include/linux/qcom_scm.h b/include/linux/qcom_scm.h
> > index f833564..f9bc84e 100644
> > --- a/include/linux/qcom_scm.h
> > +++ b/include/linux/qcom_scm.h
> > @@ -14,6 +14,11 @@
> >   #define QCOM_SCM_CPU_PWR_DOWN_L2_OFF    0x1
> >   #define QCOM_SCM_HDCP_MAX_REQ_CNT    5
> > +enum qcom_download_mode {
> > +    QCOM_DOWNLOAD_NODUMP    = 0x00,
> > +    QCOM_DOWNLOAD_FULLDUMP  = 0x10,
> > +};
> > +
> >   struct qcom_scm_hdcp_req {
> >       u32 addr;
> >       u32 val;