6 декабря 2022 г. 02:08:13 GMT+03:00, Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx> пишет:
>Add capability to parser and retrieve max DP link supported rate from
>link-frequencies property of dp_out endpoint.
>
>Changes in v6:
>-- second patch after split parser patch into two patches
>
>Changes in v7:
>-- without checking cnt against DP_MAX_NUM_DP_LANES to retrieve link rate
>
>Changes in v9:
>-- separate parser link-frequencies out of data-lanes
>
>Signed-off-by: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx>
>---
> drivers/gpu/drm/msm/dp/dp_parser.c | 20 ++++++++++++++++++--
> drivers/gpu/drm/msm/dp/dp_parser.h | 2 ++
> 2 files changed, 20 insertions(+), 2 deletions(-)
>
>diff --git a/drivers/gpu/drm/msm/dp/dp_parser.c b/drivers/gpu/drm/msm/dp/dp_parser.c
>index b5f7e70..fdea843 100644
>--- a/drivers/gpu/drm/msm/dp/dp_parser.c
>+++ b/drivers/gpu/drm/msm/dp/dp_parser.c
>@@ -94,15 +94,17 @@ static int dp_parser_ctrl_res(struct dp_parser *parser)
> static int dp_parser_misc(struct dp_parser *parser)
> {
> struct device_node *of_node = parser->pdev->dev.of_node;
>+ struct device_node *endpoint;
>+ u64 frequency;
> int cnt;
>
> /*
> * data-lanes is the property of dp_out endpoint
> */
> cnt = drm_of_get_data_lanes_count_ep(of_node, 1, 0, 1, DP_MAX_NUM_DP_LANES);
>- if (cnt > 0)
>+ if (cnt > 0) {
> parser->max_dp_lanes = cnt;
>- else {
>+ } else {
This belongs to the previous patch
> /*
> * legacy code, data-lanes is the property of mdss_dp node
> */
>@@ -113,6 +115,20 @@ static int dp_parser_misc(struct dp_parser *parser)
> parser->max_dp_lanes = DP_MAX_NUM_DP_LANES; /* 4 lanes */
> }
>
>+ cnt = 0;
>+ endpoint = of_graph_get_endpoint_by_regs(of_node, 1, 0); /* port@1 */
>+ if (endpoint)
>+ cnt = of_property_count_u64_elems(endpoint, "link-frequencies");
>+ of_node_put(endpoint);
>+ if (cnt > 0) {
>+ of_property_read_u64_index(endpoint, "link-frequencies",
And this is use after free.
I still think than an additional function would make code simpler. You can return an error code at any point. And then handle it in the calling code.
>+ cnt - 1, &frequency);
>+ frequency /= 10; /* from symbol rate to link rate */
>+ parser->max_dp_link_rate = (frequency / 1000); /* kbits */
>+ } else {
>+ parser->max_dp_link_rate = DP_LINK_RATE_HBR2; /* 540000 khz */
>+ }
>+
> return 0;
> }
>
>diff --git a/drivers/gpu/drm/msm/dp/dp_parser.h b/drivers/gpu/drm/msm/dp/dp_parser.h
>index 866c1a8..3ddf639 100644
>--- a/drivers/gpu/drm/msm/dp/dp_parser.h
>+++ b/drivers/gpu/drm/msm/dp/dp_parser.h
>@@ -15,6 +15,7 @@
> #define DP_LABEL "MDSS DP DISPLAY"
> #define DP_MAX_PIXEL_CLK_KHZ 675000
> #define DP_MAX_NUM_DP_LANES 4
>+#define DP_LINK_RATE_HBR2 540000
>
> enum dp_pm_type {
> DP_CORE_PM,
>@@ -119,6 +120,7 @@ struct dp_parser {
> struct dp_io io;
> struct dp_display_data disp_data;
> u32 max_dp_lanes;
>+ u32 max_dp_link_rate;
> struct drm_bridge *next_bridge;
>
> int (*parse)(struct dp_parser *parser);
