Re: [PATCH v4 7/8] drm/mediatek: Add programming flow for unsupported subsys ID hardware

[AngeloGioacchino Del Regno]

Il 18/02/25 06:41, Jason-JH Lin ha scritto:
To support hardware without subsys IDs on new SoCs, add a programming
flow that checks whether the subsys ID is valid. If the subsys ID is
invalid, the flow will call 2 alternative CMDQ APIs:
cmdq_pkt_assign() and cmdq_pkt_write_s_value() to achieve the same
functionality.
Signed-off-by: Jason-JH Lin <jason-jh....@mediatek.com>
Reviewed-by: CK Hu <ck...@mediatek.com>
---
  drivers/gpu/drm/mediatek/mtk_ddp_comp.c | 33 ++++++++++++++++++++-----
  1 file changed, 27 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_ddp_comp.c 
b/drivers/gpu/drm/mediatek/mtk_ddp_comp.c
index edc6417639e6..219d67735a54 100644
--- a/drivers/gpu/drm/mediatek/mtk_ddp_comp.c
+++ b/drivers/gpu/drm/mediatek/mtk_ddp_comp.c
@@ -66,14 +66,37 @@ struct mtk_ddp_comp_dev {
        struct cmdq_client_reg cmdq_reg;
  };
  
+#if IS_REACHABLE(CONFIG_MTK_CMDQ)
+static void mtk_ddp_write_cmdq_pkt(struct cmdq_pkt *cmdq_pkt, struct 
cmdq_client_reg *cmdq_reg,
+                                  unsigned int offset, unsigned int value, 
unsigned int mask)
+{
+       offset += cmdq_reg->offset;
+
+       if (cmdq_reg->subsys != CMDQ_SUBSYS_INVALID) {
+               if (mask == GENMASK(31, 0))
+                       cmdq_pkt_write(cmdq_pkt, cmdq_reg->subsys, offset, 
value);
+               else
+                       cmdq_pkt_write_mask(cmdq_pkt, cmdq_reg->subsys, offset, 
value, mask);

Sorry but this is pointless, really...

Function cmdq_pkt_write_mask() in mtk-cmdq-helper is doing:

        if (mask != GENMASK(31, 0)) {
                err = cmdq_pkt_mask(pkt, mask);
                if (err < 0)
                        return err;

                offset_mask |= CMDQ_WRITE_ENABLE_MASK;
        }
        return cmdq_pkt_write(pkt, subsys, offset_mask, value);

here you're doing the exact inverse check.

At this point you can just do:

static int mtk_ddp_write_cmdq_pkt(struct cmdq_pkt *cmdq_pkt, struct cmdq_client_reg 
*cmdq_reg,
                                  u16 offset, u32 value, u32 mask)
{
        u16 gce_offset = cmdq_reg->offset + offset;

        if (cmdq_reg->subsys != CMDQ_SUBSYS_INVALID)
                return cmdq_pkt_write_mask(pkt, cmdq_reg->subsys, gce_offset, 
value, mask);

        return cmdq_pkt_write_mask_pa(cmdq_pkt, cmdq_reg->pa_base, gce_offset, 
value, mask);
}

Cheers,
Angelo

+       } else {
+               /* only MMIO access, no need to check mminfro_offset */
+               cmdq_pkt_assign(cmdq_pkt, 0, CMDQ_ADDR_HIGH(cmdq_reg->pa_base));
+               if (mask == GENMASK(31, 0))
+                       cmdq_pkt_write_s_value(cmdq_pkt, CMDQ_THR_SPR_IDX0,
+                                              CMDQ_ADDR_LOW(offset), value);
+               else
+                       cmdq_pkt_write_s_mask_value(cmdq_pkt, CMDQ_THR_SPR_IDX0,
+                                                   CMDQ_ADDR_LOW(offset), 
value, mask);
+       }
+}
+#endif
+
  void mtk_ddp_write(struct cmdq_pkt *cmdq_pkt, unsigned int value,
                   struct cmdq_client_reg *cmdq_reg, void __iomem *regs,
                   unsigned int offset)
  {
  #if IS_REACHABLE(CONFIG_MTK_CMDQ)
        if (cmdq_pkt)
-               cmdq_pkt_write(cmdq_pkt, cmdq_reg->subsys,
-                              cmdq_reg->offset + offset, value);
+               mtk_ddp_write_cmdq_pkt(cmdq_pkt, cmdq_reg, offset, value, 
GENMASK(31, 0));
        else
  #endif
                writel(value, regs + offset);
@@ -85,8 +108,7 @@ void mtk_ddp_write_relaxed(struct cmdq_pkt *cmdq_pkt, 
unsigned int value,
  {
  #if IS_REACHABLE(CONFIG_MTK_CMDQ)
        if (cmdq_pkt)
-               cmdq_pkt_write(cmdq_pkt, cmdq_reg->subsys,
-                              cmdq_reg->offset + offset, value);
+               mtk_ddp_write_cmdq_pkt(cmdq_pkt, cmdq_reg, offset, value, 
GENMASK(31, 0));
        else
  #endif
                writel_relaxed(value, regs + offset);
@@ -98,8 +120,7 @@ void mtk_ddp_write_mask(struct cmdq_pkt *cmdq_pkt, unsigned 
int value,
  {
  #if IS_REACHABLE(CONFIG_MTK_CMDQ)
        if (cmdq_pkt) {
-               cmdq_pkt_write_mask(cmdq_pkt, cmdq_reg->subsys,
-                                   cmdq_reg->offset + offset, value, mask);
+               mtk_ddp_write_cmdq_pkt(cmdq_pkt, cmdq_reg, offset, value, mask);
        } else {
  #endif
                u32 tmp = readl(regs + offset);