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drm/amd/display: Add debugfs dpcd interface

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[Why]
We need arbitrary read/write over DP AUX DPCD
for debugging

[How]
Three debugfs entries

Set the target address by writing to
"aux_dpcd_address"
(The first four bytes written are used)

Set the transaction size in bytes by writing to
"aux_dpcd_size"
(The first four bytes written are used)

Start a transaction by reading/writing
"aux_dpcd_data"

Do note: there is no concerrency protection at all
Accessing these entries in quick succession can lead
to strange behaviour

Signed-off-by: David Francis <David.Francis@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
David Francis
2019-03-05 10:04:15 -05:00
committed by Alex Deucher
parent c7ba3653e9
commit f258fee6c3
3 changed files with 112 additions and 1 deletions
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4
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
View File

@@ -238,6 +238,10 @@ struct amdgpu_dm_connector {
struct mutex hpd_lock;
bool fake_enable;
#ifdef CONFIG_DEBUG_FS
uint32_t debugfs_dpcd_address;
uint32_t debugfs_dpcd_size;
#endif
};
#define to_amdgpu_dm_connector(x) container_of(x, struct amdgpu_dm_connector, base)