On Wed, 7 Feb 2024 at 20:25, Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx> wrote:
>
>
>
> On 1/5/2024 3:34 PM, Dmitry Baryshkov wrote:
> > Older (mdp5) platforms do not use per-SoC compatible strings. Instead
> > they use a single compat entry 'qcom,mdss'. To facilitate migrating
> > these platforms to the DPU driver provide a way to generate the MDSS /
> > UBWC data at runtime, when the DPU driver asks for it.
> >
> > It is not possible to generate this data structure at the probe time,
> > since some platforms might not have MDP_CLK enabled, which makes reading
> > HW_REV register return 0.
> >
>
> I would have expected a crash if clock was not enabled and we tried to
> access the hw_rev register.
No, for all the platforms I tested it returns 0 instead.
However this doesn't make any difference, we don't read the register
in MDP5 case until all clocks are enabled.
>
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> > ---
> > drivers/gpu/drm/msm/msm_mdss.c | 51 ++++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 51 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/msm/msm_mdss.c b/drivers/gpu/drm/msm/msm_mdss.c
> > index 455b2e3a0cdd..566a5dd5b8e8 100644
> > --- a/drivers/gpu/drm/msm/msm_mdss.c
> > +++ b/drivers/gpu/drm/msm/msm_mdss.c
> > @@ -3,6 +3,7 @@
> > * Copyright (c) 2018, The Linux Foundation
> > */
> >
> > +#include <linux/bitfield.h>
> > #include <linux/clk.h>
> > #include <linux/delay.h>
> > #include <linux/interconnect.h>
> > @@ -213,6 +214,49 @@ static void msm_mdss_setup_ubwc_dec_40(struct msm_mdss *msm_mdss)
> > }
> > }
> >
> > +#define MDSS_HW_MAJ_MIN GENMASK(31, 16)
> > +
> > +#define MDSS_HW_MSM8996 0x1007
> > +#define MDSS_HW_MSM8937 0x100e
> > +#define MDSS_HW_MSM8956 0x1010
>
> This should be 0x100B in the docs I see.
Yes, I mixed MSM8956 and MSM8953 here. The code support the latter one.
>
> > +#define MDSS_HW_MSM8998 0x3000
> > +#define MDSS_HW_SDM660 0x3002
> > +#define MDSS_HW_SDM630 0x3003
> > +
> > +/*
> > + * MDP5 platforms use generic qcom,mdp5 compat string, so we have to generate this data
> > + */
> > +static const struct msm_mdss_data *msm_mdss_generate_mdp5_mdss_data(struct msm_mdss *mdss)
> > +{
> > + struct msm_mdss_data *data;
> > + u32 hw_rev;
> > +
> > + data = devm_kzalloc(mdss->dev, sizeof(*data), GFP_KERNEL);
> > + if (!data)
> > + return NULL;
> > +
> > + hw_rev = readl_relaxed(mdss->mmio + HW_REV);
> > + hw_rev = FIELD_GET(MDSS_HW_MAJ_MIN, hw_rev);
> > +
> > + if (hw_rev == MDSS_HW_MSM8996 ||
> > + hw_rev == MDSS_HW_MSM8937 ||
> > + hw_rev == MDSS_HW_MSM8956 ||
> > + hw_rev == MDSS_HW_MSM8998 ||
> > + hw_rev == MDSS_HW_SDM660 ||
> > + hw_rev == MDSS_HW_SDM630) {
> > + data->ubwc_dec_version = UBWC_1_0;
> > + data->ubwc_enc_version = UBWC_1_0;
> > + }
> > +
> > + if (hw_rev == MDSS_HW_MSM8996 ||
> > + hw_rev == MDSS_HW_MSM8998)
> > + data->highest_bank_bit = 2;
> > + else
> > + data->highest_bank_bit = 1;
> > +
> > + return data;
> > +}
> > +
> > const struct msm_mdss_data *msm_mdss_get_mdss_data(struct device *dev)
> > {
> > struct msm_mdss *mdss;
> > @@ -222,6 +266,13 @@ const struct msm_mdss_data *msm_mdss_get_mdss_data(struct device *dev)
> >
> > mdss = dev_get_drvdata(dev);
> >
> > + /*
> > + * We could not do it at the probe time, since hw revision register was
> > + * not readable. Fill data structure now for the MDP5 platforms.
> > + */
> > + if (!mdss->mdss_data && mdss->is_mdp5)
> > + mdss->mdss_data = msm_mdss_generate_mdp5_mdss_data(mdss);
> > +
> > return mdss->mdss_data;
> > }
> >
> >
--
With best wishes
Dmitry
