On 2021-10-05 10:15, Harry Wentland wrote:
>
>
> On 2021-10-05 03:51, Wayne Lin wrote:
>> From: Jimmy Kizito <Jimmy.Kizito@xxxxxxx>
>>
>> [Why & How]
>> Add codes for commit "e1f4328f22c0 drm/amd/display: Update link
>> encoder object creation" to support USB4 DP tunneling feature
>>
>
> It looks like all of Jimmy's patches refer to porting code from some other
> patches. Do those patches have a patch description?
>
> Basically, above "Why & How" description doesn't describe why this
> change is made and how it is done. Please provide that description.
>
> Same with other patches in this set that talk about "Add codes..."
> without providing an actual description.
>
A decent description for this would be something like this (note
that I'm not a USB4 expert, so keeping this purposely high-level):
"USB4 endpoints are dynamically mapped. We create additional link
encoders for USB4 use when DC is created and destroy them when DC
is destructed."
Harry
> Harry
>
>> Reviewed-by: Jun Lei <Jun.Lei@xxxxxxx>
>> Acked-by: Wayne Lin <Wayne.Lin@xxxxxxx>
>> Acked-by: Nicholas Kazlauskas <nicholas.kazlauskas@xxxxxxx>
>> Signed-off-by: Jimmy Kizito <Jimmy.Kizito@xxxxxxx>
>> ---
>> drivers/gpu/drm/amd/display/dc/core/dc.c | 77 +++++++++++++++++++
>> .../gpu/drm/amd/display/dc/inc/core_types.h | 2 +
>> drivers/gpu/drm/amd/display/dc/inc/resource.h | 1 +
>> 3 files changed, 80 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/amd/display/dc/core/dc.c b/drivers/gpu/drm/amd/display/dc/core/dc.c
>> index 8e0bcd4fd000..673fb0ef7a89 100644
>> --- a/drivers/gpu/drm/amd/display/dc/core/dc.c
>> +++ b/drivers/gpu/drm/amd/display/dc/core/dc.c
>> @@ -296,6 +296,75 @@ static bool create_links(
>> return false;
>> }
>>
>> +/* Create additional DIG link encoder objects if fewer than the platform
>> + * supports were created during link construction. This can happen if the
>> + * number of physical connectors is less than the number of DIGs.
>> + */
>> +static bool create_link_encoders(struct dc *dc)
>> +{
>> + bool res = true;
>> + unsigned int num_usb4_dpia = dc->res_pool->res_cap->num_usb4_dpia;
>> + unsigned int num_dig_link_enc = dc->res_pool->res_cap->num_dig_link_enc;
>> + int i;
>> +
>> + /* A platform without USB4 DPIA endpoints has a fixed mapping between DIG
>> + * link encoders and physical display endpoints and does not require
>> + * additional link encoder objects.
>> + */
>> + if (num_usb4_dpia == 0)
>> + return res;
>> +
>> + /* Create as many link encoder objects as the platform supports. DPIA
>> + * endpoints can be programmably mapped to any DIG.
>> + */
>> + if (num_dig_link_enc > dc->res_pool->dig_link_enc_count) {
>> + for (i = 0; i < num_dig_link_enc; i++) {
>> + struct link_encoder *link_enc = dc->res_pool->link_encoders[i];
>> +
>> + if (!link_enc && dc->res_pool->funcs->link_enc_create_minimal) {
>> + link_enc = dc->res_pool->funcs->link_enc_create_minimal(dc->ctx,
>> + (enum engine_id)(ENGINE_ID_DIGA + i));
>> + if (link_enc) {
>> + dc->res_pool->link_encoders[i] = link_enc;
>> + dc->res_pool->dig_link_enc_count++;
>> + } else {
>> + res = false;
>> + }
>> + }
>> + }
>> + }
>> +
>> + return res;
>> +}
>> +
>> +/* Destroy any additional DIG link encoder objects created by
>> + * create_link_encoders().
>> + * NB: Must only be called after destroy_links().
>> + */
>> +static void destroy_link_encoders(struct dc *dc)
>> +{
>> + unsigned int num_usb4_dpia = dc->res_pool->res_cap->num_usb4_dpia;
>> + unsigned int num_dig_link_enc = dc->res_pool->res_cap->num_dig_link_enc;
>> + int i;
>> +
>> + /* A platform without USB4 DPIA endpoints has a fixed mapping between DIG
>> + * link encoders and physical display endpoints and does not require
>> + * additional link encoder objects.
>> + */
>> + if (num_usb4_dpia == 0)
>> + return;
>> +
>> + for (i = 0; i < num_dig_link_enc; i++) {
>> + struct link_encoder *link_enc = dc->res_pool->link_encoders[i];
>> +
>> + if (link_enc) {
>> + link_enc->funcs->destroy(&link_enc);
>> + dc->res_pool->link_encoders[i] = NULL;
>> + dc->res_pool->dig_link_enc_count--;
>> + }
>> + }
>> +}
>> +
>> static struct dc_perf_trace *dc_perf_trace_create(void)
>> {
>> return kzalloc(sizeof(struct dc_perf_trace), GFP_KERNEL);
>> @@ -729,6 +798,8 @@ static void dc_destruct(struct dc *dc)
>>
>> destroy_links(dc);
>>
>> + destroy_link_encoders(dc);
>> +
>> if (dc->clk_mgr) {
>> dc_destroy_clk_mgr(dc->clk_mgr);
>> dc->clk_mgr = NULL;
>> @@ -933,6 +1004,12 @@ static bool dc_construct(struct dc *dc,
>> if (!create_links(dc, init_params->num_virtual_links))
>> goto fail;
>>
>> + /* Create additional DIG link encoder objects if fewer than the platform
>> + * supports were created during link construction.
>> + */
>> + if (!create_link_encoders(dc))
>> + goto fail;
>> +
>> /* Initialise DIG link encoder resource tracking variables. */
>> link_enc_cfg_init(dc, dc->current_state);
>>
>> diff --git a/drivers/gpu/drm/amd/display/dc/inc/core_types.h b/drivers/gpu/drm/amd/display/dc/inc/core_types.h
>> index 0fea258c6db3..ed09af238911 100644
>> --- a/drivers/gpu/drm/amd/display/dc/inc/core_types.h
>> +++ b/drivers/gpu/drm/amd/display/dc/inc/core_types.h
>> @@ -245,6 +245,8 @@ struct resource_pool {
>> * entries in link_encoders array.
>> */
>> unsigned int dig_link_enc_count;
>> + /* Number of USB4 DPIA (DisplayPort Input Adapter) link objects created.*/
>> + unsigned int usb4_dpia_count;
>>
>> #if defined(CONFIG_DRM_AMD_DC_DCN)
>> unsigned int hpo_dp_stream_enc_count;
>> diff --git a/drivers/gpu/drm/amd/display/dc/inc/resource.h b/drivers/gpu/drm/amd/display/dc/inc/resource.h
>> index 3fbda9d7e257..372c0898facd 100644
>> --- a/drivers/gpu/drm/amd/display/dc/inc/resource.h
>> +++ b/drivers/gpu/drm/amd/display/dc/inc/resource.h
>> @@ -49,6 +49,7 @@ struct resource_caps {
>> int num_vmid;
>> int num_dsc;
>> unsigned int num_dig_link_enc; // Total number of DIGs (digital encoders) in DIO (Display Input/Output).
>> + unsigned int num_usb4_dpia; // Total number of USB4 DPIA (DisplayPort Input Adapters).
>> #if defined(CONFIG_DRM_AMD_DC_DCN)
>> int num_hpo_dp_stream_encoder;
>> int num_hpo_dp_link_encoder;
>>
>
