Re: [PATCH v8 2/3] firmware: scm: Modify only the download bits in TCSR register

[Mukesh Ojha]

On 10/26/2023 5:23 AM, Elliot Berman wrote:
> On 10/25/2023 5:05 AM, Mukesh Ojha wrote:
> > Crashdump collection is done based on DLOAD bits of TCSR register.
> > To retain other bits, scm driver need to read the register and
> > modify only the DLOAD bits, as other bits in TCSR may have their
> > own significance.
> >
> > Co-developed-by: Poovendhan Selvaraj <quic_poovendh@xxxxxxxxxxx>
> > Signed-off-by: Poovendhan Selvaraj <quic_poovendh@xxxxxxxxxxx>
> > Signed-off-by: Mukesh Ojha <quic_mojha@xxxxxxxxxxx>
> > Tested-by: Kathiravan Thirumoorthy <quic_kathirav@xxxxxxxxxxx> # IPQ9574 and IPQ5332
> > Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> > ---
> >   drivers/firmware/qcom/qcom_scm.c | 12 ++++++++++--
> >   1 file changed, 10 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
> > index 25549178a30f..f1c4a9f9a53f 100644
> > --- a/drivers/firmware/qcom/qcom_scm.c
> > +++ b/drivers/firmware/qcom/qcom_scm.c
> > @@ -4,6 +4,8 @@
> >    */
> >   
> >   #include <linux/arm-smccc.h>
> > +#include <linux/bitfield.h>
> > +#include <linux/bits.h>
> >   #include <linux/clk.h>
> >   #include <linux/completion.h>
> >   #include <linux/cpumask.h>
> > @@ -117,6 +119,10 @@ static const u8 qcom_scm_cpu_warm_bits[QCOM_SCM_BOOT_MAX_CPUS] = {
> >   #define QCOM_SMC_WAITQ_FLAG_WAKE_ONE	BIT(0)
> >   #define QCOM_SMC_WAITQ_FLAG_WAKE_ALL	BIT(1)
> >   
> > +#define QCOM_DLOAD_MASK		GENMASK(5, 4)
> > +#define QCOM_DLOAD_FULLDUMP	0x1
> > +#define QCOM_DLOAD_NODUMP	0x0
> > +
>
>
> Enum would be better here for related constants.
>
> diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
> index f1c4a9f9a53f..95f73a8c51d7 100644
> --- a/drivers/firmware/qcom/qcom_scm.c
> +++ b/drivers/firmware/qcom/qcom_scm.c
> @@ -122,4 +122,6 @@ static const u8 qcom_scm_cpu_warm_bits[QCOM_SCM_BOOT_MAX_CPUS] = {
>   #define QCOM_DLOAD_MASK                GENMASK(5, 4)
> -#define QCOM_DLOAD_FULLDUMP    0x1
> -#define QCOM_DLOAD_NODUMP      0x0
> +enum qcom_dload_mode {
> +       QCOM_DLOAD_NODUMP       = 0,
> +       QCOM_DLOAD_FULLDUMP     = 1,
> +};

Would it be fine, if i do it during when i add some more modes with
minidump ?

Please ack, otherwise, will send another version.

-Mukesh

>   
>
>
> >   static const char * const qcom_scm_convention_names[] = {
> >   	[SMC_CONVENTION_UNKNOWN] = "unknown",
> >   	[SMC_CONVENTION_ARM_32] = "smc arm 32",
> > @@ -523,6 +529,7 @@ static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
> >   
> >   static void qcom_scm_set_download_mode(bool enable)
> >   {
> > +	u32 val = enable ? QCOM_DLOAD_FULLDUMP : QCOM_DLOAD_NODUMP;
> >   	bool avail;
> >   	int ret = 0;
> >   
> > @@ -532,8 +539,9 @@ static void qcom_scm_set_download_mode(bool enable)
> >   	if (avail) {
> >   		ret = __qcom_scm_set_dload_mode(__scm->dev, enable);
> >   	} 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_rmw(__scm->dload_mode_addr,
> > +					       QCOM_DLOAD_MASK,
> > +					       FIELD_PREP(QCOM_DLOAD_MASK, val));
> >   	} else {
> >   		dev_err(__scm->dev,
> >   			"No available mechanism for setting download mode\n");
>
> - Elliot