Re: [PATCH v2 15/19] drm/msm/dp: enable SDP and SDE periph flush update

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On 2/10/2024 2:11 PM, Dmitry Baryshkov wrote:
On Sat, 10 Feb 2024 at 23:49, Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx> wrote:



On 2/10/2024 2:16 AM, Dmitry Baryshkov wrote:
On Sat, 10 Feb 2024 at 03:52, Paloma Arellano <quic_parellan@xxxxxxxxxxx> wrote:

DP controller can be setup to operate in either SDP update flush mode or
peripheral flush mode based on the DP controller hardware version.

Starting in DP v1.2, the hardware documents require the use of
peripheral flush mode for SDP packets such as PPS OR VSC SDP packets.

In-line with this guidance, lets program the DP controller to use
peripheral flush mode starting DP v1.2

Changes in v2:
          - Use the original dp_catalog_hw_revision() function to
            correctly check the DP HW version

Signed-off-by: Paloma Arellano <quic_parellan@xxxxxxxxxxx>
---
   drivers/gpu/drm/msm/dp/dp_catalog.c | 17 +++++++++++++++++
   drivers/gpu/drm/msm/dp/dp_catalog.h |  1 +
   drivers/gpu/drm/msm/dp/dp_ctrl.c    |  1 +
   drivers/gpu/drm/msm/dp/dp_reg.h     |  2 ++
   4 files changed, 21 insertions(+)


<Snip>


diff --git a/drivers/gpu/drm/msm/dp/dp_reg.h b/drivers/gpu/drm/msm/dp/dp_reg.h
index 2983756c125cd..6ac66532b47a4 100644
--- a/drivers/gpu/drm/msm/dp/dp_reg.h
+++ b/drivers/gpu/drm/msm/dp/dp_reg.h
@@ -102,6 +102,8 @@
   #define DP_MAINLINK_CTRL_ENABLE                        (0x00000001)
   #define DP_MAINLINK_CTRL_RESET                 (0x00000002)
   #define DP_MAINLINK_CTRL_SW_BYPASS_SCRAMBLER   (0x00000010)
+#define DP_MAINLINK_FLUSH_MODE_UPDATE_SDP      (0x00800000)
+#define DP_MAINLINK_FLUSH_MODE_SDE_PERIPH_UPDATE       (0x01800000)

Just one bit here, please.


hmm .... so the periph flush bits are 24:23 and we need a value of 3 to
select peripheral flush which translates to 0x01800000.

How do you suggest to break this up?

Then FIELD_PREP(something_mask, 3). Otherwise it is too easy to
consider it to be DP_MAINLINK_FLUSH_MODE_UPDATE_SDP | BIT(24)


Sure, FIELD_PREP() works. I was confused when you said one bit :)


   #define DP_MAINLINK_FB_BOUNDARY_SEL            (0x02000000)

   #define REG_DP_STATE_CTRL                      (0x00000004)
--
2.39.2









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