Re: [PATCH v7 09/20] soc: mediatek: mtk-cmdq: Add pa_base parsing for hardware without subsys ID support

["Jason-JH Lin (林睿祥)" <Jason-JH.Lin@mediatek.com>]

On Thu, 2025-10-09 at 13:35 +0200, AngeloGioacchino Del Regno wrote:
> 
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
> 
> 
> Il 27/08/25 13:37, Jason-JH Lin ha scritto:
> > When GCE executes instructions, it typically locates the
> > corresponding
> > hardware register using the subsys ID. For hardware that does not
> > support subsys ID, the subsys ID is set to an invalid value, and
> > the
> > physical address must be used to generate GCE instructions.
> > 
> > The main advantage of using subsys ID is to reduce the number of
> > instructions. Without subsys ID, an additional `ASSIGN` instruction
> > is needed to assign the high bytes of the physical address, which
> > can
> > impact performance if too many instructions are required. However,
> > if
> > the hardware does not support subsys ID, using the physical address
> > is the only option to achieve the same functionality.
> > 
> > This commit adds a pa_base parsing flow to the cmdq_client_reg
> > structure
> > to handle hardware without subsys ID support.
> > 
> > Signed-off-by: Jason-JH Lin <jason-jh.lin@mediatek.com>
> > ---
> >   drivers/soc/mediatek/mtk-cmdq-helper.c | 15 +++++++++++++--
> >   include/linux/soc/mediatek/mtk-cmdq.h  |  3 +++
> >   2 files changed, 16 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/soc/mediatek/mtk-cmdq-helper.c
> > b/drivers/soc/mediatek/mtk-cmdq-helper.c
> > index 4b1591e5b1ae..41e1997cdd53 100644
> > --- a/drivers/soc/mediatek/mtk-cmdq-helper.c
> > +++ b/drivers/soc/mediatek/mtk-cmdq-helper.c
> > @@ -8,6 +8,7 @@
> >   #include <linux/module.h>
> >   #include <linux/mailbox_controller.h>
> >   #include <linux/of.h>
> > +#include <linux/of_address.h>
> >   #include <linux/soc/mediatek/mtk-cmdq.h>
> > 
> >   #define CMDQ_WRITE_ENABLE_MASK      BIT(0)
> > @@ -60,20 +61,30 @@ int cmdq_dev_get_client_reg(struct device *dev,
> >                           struct cmdq_client_reg *client_reg, int
> > idx)
> >   {
> >       struct of_phandle_args spec;
> > +     struct resource res;
> >       int err;
> > 
> >       if (!client_reg)
> >               return -ENOENT;
> > 
> 
>         err = of_address_to_resource( ... )
>         if (err) {
>                 dev_err(....)
>                 return;
>         }
> 
> after which:
> 
> Reviewed-by: AngeloGioacchino Del Regno
> <angelogioacchino.delregno@collabora.com>
> 
> > +     if (of_address_to_resource(dev->of_node, 0, &res) != 0) {
> > +             dev_err(dev, "Missing reg in %s node\n", dev-
> > >of_node->full_name);
> > +             return -EINVAL;
> > +     }

OK, I'll refine this.
Thanks for the reviews.

Regards,
Jason-JH Lin

> > +     client_reg->pa_base = res.start;
> > +
> >       err = of_parse_phandle_with_fixed_args(dev->of_node,
> >                                              "mediatek,gce-client-
> > reg",
> >                                              3, idx, &spec);
> >       if (err < 0) {
> > -             dev_warn(dev,
> > +             dev_dbg(dev,
> >                       "error %d can't parse gce-client-reg property
> > (%d)",
> >                       err, idx);
> > 
> > -             return err;
> > +             /* make subsys invalid */
> > +             client_reg->subsys = CMDQ_SUBSYS_INVALID;
> > +
> > +             return 0;
> >       }
> > 
> >       client_reg->subsys = (u8)spec.args[0];
> > diff --git a/include/linux/soc/mediatek/mtk-cmdq.h
> > b/include/linux/soc/mediatek/mtk-cmdq.h
> > index 5e3a0e807980..3699229a7375 100644
> > --- a/include/linux/soc/mediatek/mtk-cmdq.h
> > +++ b/include/linux/soc/mediatek/mtk-cmdq.h
> > @@ -23,6 +23,8 @@
> >   #define CMDQ_THR_SPR_IDX2   (2)
> >   #define CMDQ_THR_SPR_IDX3   (3)
> > 
> > +#define CMDQ_SUBSYS_INVALID  (U8_MAX)
> > +
> >   struct cmdq_pkt;
> > 
> >   enum cmdq_logic_op {
> > @@ -52,6 +54,7 @@ struct cmdq_operand {
> > 
> >   struct cmdq_client_reg {
> >       u8 subsys;
> > +     phys_addr_t pa_base;
> >       u16 offset;
> >       u16 size;
> >   };
> 
>