[PATCH 4/8] drm/amd/display: filter out invalid bits in pipe_fuses

[Alan Liu]

From: Samson Tam <samson....@amd.com>

[Why]
Reading pipe_fuses from register may have invalid bits set, which may
 affect the num_pipes erroneously.

[How]
Add read_pipes_fuses() call and filter bits based on expected number
 of pipes.

Reviewed-by: Alvin Lee <alvin.l...@amd.com>
Acked-by: Alan Liu <haoping....@amd.com>
Signed-off-by: Samson Tam <samson....@amd.com>
---
 drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c  | 10 +++++++++-
 .../gpu/drm/amd/display/dc/dcn321/dcn321_resource.c    | 10 +++++++++-
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c 
b/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c
index 7feeba78c0c9..a49323885874 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c
@@ -2082,6 +2082,14 @@ static struct resource_funcs dcn32_res_pool_funcs = {
        .restore_mall_state = dcn32_restore_mall_state,
 };
 
+static uint32_t read_pipe_fuses(struct dc_context *ctx)
+{
+       uint32_t value = REG_READ(CC_DC_PIPE_DIS);
+       /* DCN32 support max 4 pipes */
+       value = value & 0xf;
+       return value;
+}
+
 
 static bool dcn32_resource_construct(
        uint8_t num_virtual_links,
@@ -2125,7 +2133,7 @@ static bool dcn32_resource_construct(
        pool->base.res_cap = &res_cap_dcn32;
        /* max number of pipes for ASIC before checking for pipe fuses */
        num_pipes  = pool->base.res_cap->num_timing_generator;
-       pipe_fuses = REG_READ(CC_DC_PIPE_DIS);
+       pipe_fuses = read_pipe_fuses(ctx);
 
        for (i = 0; i < pool->base.res_cap->num_timing_generator; i++)
                if (pipe_fuses & 1 << i)
diff --git a/drivers/gpu/drm/amd/display/dc/dcn321/dcn321_resource.c 
b/drivers/gpu/drm/amd/display/dc/dcn321/dcn321_resource.c
index 63bd6928c82f..4c1e0f5a5f09 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn321/dcn321_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn321/dcn321_resource.c
@@ -1633,6 +1633,14 @@ static struct resource_funcs dcn321_res_pool_funcs = {
        .restore_mall_state = dcn32_restore_mall_state,
 };
 
+static uint32_t read_pipe_fuses(struct dc_context *ctx)
+{
+       uint32_t value = REG_READ(CC_DC_PIPE_DIS);
+       /* DCN321 support max 4 pipes */
+       value = value & 0xf;
+       return value;
+}
+
 
 static bool dcn321_resource_construct(
        uint8_t num_virtual_links,
@@ -1675,7 +1683,7 @@ static bool dcn321_resource_construct(
        pool->base.res_cap = &res_cap_dcn321;
        /* max number of pipes for ASIC before checking for pipe fuses */
        num_pipes  = pool->base.res_cap->num_timing_generator;
-       pipe_fuses = REG_READ(CC_DC_PIPE_DIS);
+       pipe_fuses = read_pipe_fuses(ctx);
 
        for (i = 0; i < pool->base.res_cap->num_timing_generator; i++)
                if (pipe_fuses & 1 << i)
-- 
2.34.1