Re: [PATCH v7 7/8] drm/tidss: Update encoder/bridge chain connect model

From: Aradhya Bhatia
Date: Mon Oct 30 2023 - 15:39:39 EST

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In reply to: Jan Kiszka: "Re: [PATCH v7 7/8] drm/tidss: Update encoder/bridge chain connect model"
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On 30-Oct-23 14:55, Jan Kiszka wrote:
> On 06.06.23 10:21, Aradhya Bhatia wrote:
>> With the new encoder/bridge chain model, the display controller driver
>> is required to create a drm_connector entity instead of asking the
>> bridge to do so during drm_bridge_attach. Moreover, the controller
>> driver should create a drm_bridge entity to negotiate bus formats and a
>> 'simple' drm_encoder entity to expose it to userspace.
>>
>> Update the encoder/bridge initialization sequence in tidss as per the
>> new model.
>>
>> Signed-off-by: Aradhya Bhatia <a-bhatia1@xxxxxx>
>> ---
>>
>> Notes:
>>
>> changes from v5:
>> * Drop patches 5 and 6 from the original series.
>> * Instead add this patch that addresses Boris Brezillon's comments
>> of creating bridge, simple encoder and connector.
>>
>> drivers/gpu/drm/tidss/tidss_encoder.c | 140 ++++++++++++++++----------
>> drivers/gpu/drm/tidss/tidss_encoder.h | 5 +-
>> drivers/gpu/drm/tidss/tidss_kms.c | 12 +--
>> 3 files changed, 94 insertions(+), 63 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/tidss/tidss_encoder.c b/drivers/gpu/drm/tidss/tidss_encoder.c
>> index 0d4865e9c03d..17a86bed8054 100644
>> --- a/drivers/gpu/drm/tidss/tidss_encoder.c
>> +++ b/drivers/gpu/drm/tidss/tidss_encoder.c
>> @@ -6,91 +6,125 @@
>>
>> #include <linux/export.h>
>>
>> +#include <drm/drm_atomic_helper.h>
>> +#include <drm/drm_bridge.h>
>> +#include <drm/drm_bridge_connector.h>
>> #include <drm/drm_crtc.h>
>> #include <drm/drm_modeset_helper_vtables.h>
>> #include <drm/drm_panel.h>
>> #include <drm/drm_of.h>
>> +#include <drm/drm_simple_kms_helper.h>
>>
>> #include "tidss_crtc.h"
>> #include "tidss_drv.h"
>> #include "tidss_encoder.h"
>>
>> -static int tidss_encoder_atomic_check(struct drm_encoder *encoder,
>> - struct drm_crtc_state *crtc_state,
>> - struct drm_connector_state *conn_state)
>> +struct tidss_encoder {
>> + struct drm_bridge bridge;
>> + struct drm_encoder encoder;
>> + struct drm_connector *connector;
>> + struct drm_bridge *next_bridge;
>> + struct tidss_device *tidss;
>> +};
>> +
>> +static inline struct tidss_encoder
>> +*bridge_to_tidss_encoder(struct drm_bridge *b)
>> +{
>> + return container_of(b, struct tidss_encoder, bridge);
>> +}
>> +
>> +static int tidss_bridge_attach(struct drm_bridge *bridge,
>> + enum drm_bridge_attach_flags flags)
>> +{
>> + struct tidss_encoder *t_enc = bridge_to_tidss_encoder(bridge);
>> +
>> + return drm_bridge_attach(bridge->encoder, t_enc->next_bridge,
>> + bridge, flags);
>> +}
>> +
>> +static int tidss_bridge_atomic_check(struct drm_bridge *bridge,
>> + struct drm_bridge_state *bridge_state,
>> + struct drm_crtc_state *crtc_state,
>> + struct drm_connector_state *conn_state)
>> {
>> - struct drm_device *ddev = encoder->dev;
>> + struct tidss_encoder *t_enc = bridge_to_tidss_encoder(bridge);
>> + struct tidss_device *tidss = t_enc->tidss;
>> struct tidss_crtc_state *tcrtc_state = to_tidss_crtc_state(crtc_state);
>> struct drm_display_info *di = &conn_state->connector->display_info;
>> - struct drm_bridge *bridge;
>> - bool bus_flags_set = false;
>> -
>> - dev_dbg(ddev->dev, "%s\n", __func__);
>> -
>> - /*
>> - * Take the bus_flags from the first bridge that defines
>> - * bridge timings, or from the connector's display_info if no
>> - * bridge defines the timings.
>> - */
>> - drm_for_each_bridge_in_chain(encoder, bridge) {
>> - if (!bridge->timings)
>> - continue;
>> -
>> - tcrtc_state->bus_flags = bridge->timings->input_bus_flags;
>> - bus_flags_set = true;
>> - break;
>> - }
>> + struct drm_bridge_state *next_bridge_state = NULL;
>> +
>> + if (t_enc->next_bridge)
>> + next_bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,
>> + t_enc->next_bridge);
>>
>> - if (!di->bus_formats || di->num_bus_formats == 0) {
>> - dev_err(ddev->dev, "%s: No bus_formats in connected display\n",
>> + if (next_bridge_state) {
>> + tcrtc_state->bus_flags = next_bridge_state->input_bus_cfg.flags;
>> + tcrtc_state->bus_format = next_bridge_state->input_bus_cfg.format;
>> + } else if (di->num_bus_formats) {
>> + tcrtc_state->bus_format = di->bus_formats[0];
>> + tcrtc_state->bus_flags = di->bus_flags;
>> + } else {
>> + dev_err(tidss->dev, "%s: No bus_formats in connected display\n",
>> __func__);
>> return -EINVAL;
>> }
>>
>> - // XXX any cleaner way to set bus format and flags?
>> - tcrtc_state->bus_format = di->bus_formats[0];
>> - if (!bus_flags_set)
>> - tcrtc_state->bus_flags = di->bus_flags;
>> -
>> return 0;
>> }
>>
>> -static void tidss_encoder_destroy(struct drm_encoder *encoder)
>> -{
>> - drm_encoder_cleanup(encoder);
>> - kfree(encoder);
>> -}
>> -
>> -static const struct drm_encoder_helper_funcs encoder_helper_funcs = {
>> - .atomic_check = tidss_encoder_atomic_check,
>> -};
>> -
>> -static const struct drm_encoder_funcs encoder_funcs = {
>> - .destroy = tidss_encoder_destroy,
>> +static const struct drm_bridge_funcs tidss_bridge_funcs = {
>> + .attach = tidss_bridge_attach,
>> + .atomic_check = tidss_bridge_atomic_check,
>> + .atomic_reset = drm_atomic_helper_bridge_reset,
>> + .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
>> + .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
>> };
>>
>> -struct drm_encoder *tidss_encoder_create(struct tidss_device *tidss,
>> - u32 encoder_type, u32 possible_crtcs)
>> +int tidss_encoder_create(struct tidss_device *tidss,
>> + struct drm_bridge *next_bridge,
>> + u32 encoder_type, u32 possible_crtcs)
>> {
>> + struct tidss_encoder *t_enc;
>> struct drm_encoder *enc;
>> + struct drm_connector *connector;
>> int ret;
>>
>> - enc = kzalloc(sizeof(*enc), GFP_KERNEL);
>> - if (!enc)
>> - return ERR_PTR(-ENOMEM);
>> + t_enc = drmm_simple_encoder_alloc(&tidss->ddev, struct tidss_encoder,
>> + encoder, encoder_type);
>> + if (IS_ERR(t_enc))
>> + return PTR_ERR(t_enc);
>> +
>> + t_enc->tidss = tidss;
>> + t_enc->next_bridge = next_bridge;
>> + t_enc->bridge.funcs = &tidss_bridge_funcs;
>>
>> + enc = &t_enc->encoder;
>> enc->possible_crtcs = possible_crtcs;
>>
>> - ret = drm_encoder_init(&tidss->ddev, enc, &encoder_funcs,
>> - encoder_type, NULL);
>> - if (ret < 0) {
>> - kfree(enc);
>> - return ERR_PTR(ret);
>> + /* Attaching first bridge to the encoder */
>> + ret = drm_bridge_attach(enc, &t_enc->bridge, NULL,
>> + DRM_BRIDGE_ATTACH_NO_CONNECTOR);
>> + if (ret) {
>> + dev_err(tidss->dev, "bridge attach failed: %d\n", ret);
>> + return ret;
>> + }
>> +
>> + /* Initializing the connector at the end of bridge-chain */
>> + connector = drm_bridge_connector_init(&tidss->ddev, enc);
>> + if (IS_ERR(connector)) {
>> + dev_err(tidss->dev, "bridge_connector create failed\n");
>> + return PTR_ERR(connector);
>> + }
>> +
>> + ret = drm_connector_attach_encoder(connector, enc);
>> + if (ret) {
>> + dev_err(tidss->dev, "attaching encoder to connector failed\n");
>> + return ret;
>> }
>>
>> - drm_encoder_helper_add(enc, &encoder_helper_funcs);
>> + t_enc->connector = connector;
>>
>> dev_dbg(tidss->dev, "Encoder create done\n");
>>
>> - return enc;
>> + return ret;
>> }
>> diff --git a/drivers/gpu/drm/tidss/tidss_encoder.h b/drivers/gpu/drm/tidss/tidss_encoder.h
>> index ace877c0e0fd..3e561d6b1e83 100644
>> --- a/drivers/gpu/drm/tidss/tidss_encoder.h
>> +++ b/drivers/gpu/drm/tidss/tidss_encoder.h
>> @@ -11,7 +11,8 @@
>>
>> struct tidss_device;
>>
>> -struct drm_encoder *tidss_encoder_create(struct tidss_device *tidss,
>> - u32 encoder_type, u32 possible_crtcs);
>> +int tidss_encoder_create(struct tidss_device *tidss,
>> + struct drm_bridge *next_bridge,
>> + u32 encoder_type, u32 possible_crtcs);
>>
>> #endif
>> diff --git a/drivers/gpu/drm/tidss/tidss_kms.c b/drivers/gpu/drm/tidss/tidss_kms.c
>> index ad2fa3c3d4a7..c979ad1af236 100644
>> --- a/drivers/gpu/drm/tidss/tidss_kms.c
>> +++ b/drivers/gpu/drm/tidss/tidss_kms.c
>> @@ -193,7 +193,6 @@ static int tidss_dispc_modeset_init(struct tidss_device *tidss)
>> for (i = 0; i < num_pipes; ++i) {
>> struct tidss_plane *tplane;
>> struct tidss_crtc *tcrtc;
>> - struct drm_encoder *enc;
>> u32 hw_plane_id = feat->vid_order[tidss->num_planes];
>> int ret;
>>
>> @@ -216,16 +215,13 @@ static int tidss_dispc_modeset_init(struct tidss_device *tidss)
>>
>> tidss->crtcs[tidss->num_crtcs++] = &tcrtc->crtc;
>>
>> - enc = tidss_encoder_create(tidss, pipes[i].enc_type,
>> + ret = tidss_encoder_create(tidss, pipes[i].bridge,
>> + pipes[i].enc_type,
>> 1 << tcrtc->crtc.index);
>> - if (IS_ERR(enc)) {
>> + if (ret) {
>> dev_err(tidss->dev, "encoder create failed\n");
>> - return PTR_ERR(enc);
>> - }
>> -
>> - ret = drm_bridge_attach(enc, pipes[i].bridge, NULL, 0);
>> - if (ret)
>> return ret;
>> + }
>> }
>>
>> /* create overlay planes of the leftover planes */
>
> This breaks the IOT2050 devices over 6.6, just bisected to it:
>
> [ 3.435153] [drm] Initialized tidss 1.0.0 20180215 for 4a00000.dss on minor 0
> [ 3.491246] tidss 4a00000.dss: [drm] Cannot find any crtc or sizes
>
> vs.
>
> [ 3.436116] [drm] Initialized tidss 1.0.0 20180215 for 4a00000.dss on minor 0
> [ 3.910574] Console: switching to colour frame buffer device 80x30
> [ 3.937614] tidss 4a00000.dss: [drm] fb0: tidssdrmfb frame buffer device
>
> Do we need to adjust its device tree to anything, or what may be the
> reason?
>

Hey Jan,

This patch series added support for the DRM_BRIDGE_ATTACH_NO_CONNECTOR
flag, for tidss, and for a few of the bridges.

Upon a quick look at the devicetree files, I see that the IOT-2050
platform is using Toshiba's TC358767 DPI to DP bridge, and it appears
that the TC358767 driver does not support the get_input_bus_fmt hook.

I have sent a patch for it[0].

Since I do not have hardware with me, I would appreciate it if you could
test and review it. The patch has only been build tested.

Regards
Aradhya

[0]: Patch Link:
https://lore.kernel.org/all/20231030192846.27934-1-a-bhatia1@xxxxxx/

Next message: Kui-Feng Lee: "Re: [PATCH bpf-next v3 2/2] selftests/bpf: Add malloc failure checks in bpf_iter"
Previous message: Kui-Feng Lee: "Re: [PATCH bpf-next v3 1/2] selftests/bpf: Convert CHECK macros to ASSERT_* macros in bpf_iter"
In reply to: Jan Kiszka: "Re: [PATCH v7 7/8] drm/tidss: Update encoder/bridge chain connect model"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]