drm/amd/display: filter out invalid bits in pipe_fuses

commit 682439f upstream.

[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.Lee2@amd.com>
Acked-by: Alan Liu <HaoPing.Liu@amd.com>
Signed-off-by: Samson Tam <Samson.Tam@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org # 6.1.x
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c

@@ -2037,6 +2037,14 @@ static struct resource_funcs dcn32_res_pool_funcs = {
 	.remove_phantom_pipes = dcn32_remove_phantom_pipes,
 };
 
+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,
@@ -2079,7 +2087,7 @@ 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)

drivers/gpu/drm/amd/display/dc/dcn321/dcn321_resource.c

@@ -1621,6 +1621,14 @@ static struct resource_funcs dcn321_res_pool_funcs = {
 	.remove_phantom_pipes = dcn32_remove_phantom_pipes,
 };
 
+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,
@@ -1663,7 +1671,7 @@ 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)