Re: [PATCH v3] drm/komeda: Add writeback support

james qian wang (Arm Technology China)
2019-05-21T08:17:34Z

Hi Ayan:

Sorry for late.

On Thu, May 16, 2019 at 08:33:45PM +0800, Ayan Halder wrote:
> On Thu, May 16, 2019 at 09:13:27AM +0100, james qian wang (Arm Technology China) wrote:
> > Komeda driver uses a individual component to describe the HW's writeback
> > caps, but drivers doesn't define a new structure and still uses the
> > existing "struct komeda_layer" to describe this new component.
> > The detailed changes as follow:
> >
> > 1. Initialize wb_layer according to HW and report it to CORE.
> > 2. CORE exposes wb_layer as a resource to KMS by private_obj.
> > 3. Report writeback supporting by add a wb_connector to KMS, and then
> > wb_connector will take act as a component resources user,
> > so the func komeda_wb_encoder_atomic_check claims komeda resources
> > (scaler and wb_layer) accroding to its state configuration to the
> > wb_connector. and the wb_state configuration will be validated on the
> > specific component resources to see if the caps of component can
> > meet the requirement of wb_connector. if not check failed.
> > 4. Update irq_handler to notify the completion of writeback.
> >
> > NOTE:
> > This change doesn't add scaling writeback support, that support will
> > be added in the future after the scaler support.
> >
> > v2: Rebase
> > v3: Rebase and constify the d71_wb_layer_funcs
> >
> > Depends on:
> > - https://patchwork.freedesktop.org/series/59915/
> >
> > Signed-off-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>
> > ---
> > drivers/gpu/drm/arm/display/komeda/Makefile | 1 +
> > .../arm/display/komeda/d71/d71_component.c | 90 ++++++++-
> > .../gpu/drm/arm/display/komeda/komeda_crtc.c | 15 ++
> > .../arm/display/komeda/komeda_framebuffer.c | 19 ++
> > .../gpu/drm/arm/display/komeda/komeda_kms.c | 4 +
> > .../gpu/drm/arm/display/komeda/komeda_kms.h | 27 +++
> > .../drm/arm/display/komeda/komeda_pipeline.h | 7 +
> > .../display/komeda/komeda_pipeline_state.c | 51 ++++-
> > .../arm/display/komeda/komeda_private_obj.c | 6 +
> > .../arm/display/komeda/komeda_wb_connector.c | 181 ++++++++++++++++++
> > 10 files changed, 398 insertions(+), 3 deletions(-)
> > create mode 100644 drivers/gpu/drm/arm/display/komeda/komeda_wb_connector.c
> >
> > diff --git a/drivers/gpu/drm/arm/display/komeda/Makefile b/drivers/gpu/drm/arm/display/komeda/Makefile
> > index 62bd1bff66a3..d7e29fc688c3 100644
> > --- a/drivers/gpu/drm/arm/display/komeda/Makefile
> > +++ b/drivers/gpu/drm/arm/display/komeda/Makefile
> > @@ -14,6 +14,7 @@ komeda-y := \
> > komeda_kms.o \
> > komeda_crtc.o \
> > komeda_plane.o \
> > + komeda_wb_connector.o \
> > komeda_private_obj.o
> >
> > komeda-y += \
> > diff --git a/drivers/gpu/drm/arm/display/komeda/d71/d71_component.c b/drivers/gpu/drm/arm/display/komeda/d71/d71_component.c
> > index 6bab816ed8e7..67e698d0e6aa 100644
> > --- a/drivers/gpu/drm/arm/display/komeda/d71/d71_component.c
> > +++ b/drivers/gpu/drm/arm/display/komeda/d71/d71_component.c
> > @@ -288,10 +288,98 @@ static int d71_layer_init(struct d71_dev *d71,
> > return 0;
> > }
> >
> > +static void d71_wb_layer_update(struct komeda_component *c,
> > + struct komeda_component_state *state)
> > +{
> > + struct komeda_layer_state *st = to_layer_st(state);
> > + struct drm_connector_state *conn_st = state->wb_conn->state;
> > + struct drm_framebuffer *fb = conn_st->writeback_job->fb;
> > + struct komeda_fb *kfb = to_kfb(fb);
> > + u32 __iomem *reg = c->reg;
> > + u32 ctrl = L_EN | LW_OFM, mask = L_EN | LW_OFM | LW_TBU_EN;
> > + int i;
> > +
> > + for (i = 0; i < fb->format->num_planes; i++) {
> > + malidp_write32(reg + i * LAYER_PER_PLANE_REGS, BLK_P0_PTR_LOW,
> > + lower_32_bits(st->addr[i]));
> > + malidp_write32(reg + i * LAYER_PER_PLANE_REGS, BLK_P0_PTR_HIGH,
> > + upper_32_bits(st->addr[i]));
> > +
> > + malidp_write32(reg + i * LAYER_PER_PLANE_REGS, BLK_P0_STRIDE,
> > + fb->pitches[i] & 0xFFFF);
> > + }
> > +
> > + malidp_write32(reg, LAYER_FMT, kfb->format_caps->hw_id);
> > + malidp_write32(reg, BLK_IN_SIZE, HV_SIZE(st->hsize, st->vsize));
> > + malidp_write32(reg, BLK_INPUT_ID0, to_d71_input_id(&state->inputs[0]));
> > + malidp_write32_mask(reg, BLK_CONTROL, mask, ctrl);
> > +}
> > +
> > +static void d71_wb_layer_dump(struct komeda_component *c, struct seq_file *sf)
> > +{
> > + u32 v[12], i;
> > +
> > + dump_block_header(sf, c->reg);
> > +
> > + get_values_from_reg(c->reg, 0x80, 1, v);
> > + seq_printf(sf, "LW_INPUT_ID0:\t\t0x%X\n", v[0]);
> > +
> > + get_values_from_reg(c->reg, 0xD0, 3, v);
> > + seq_printf(sf, "LW_CONTROL:\t\t0x%X\n", v[0]);
> > + seq_printf(sf, "LW_PROG_LINE:\t\t0x%X\n", v[1]);
> > + seq_printf(sf, "LW_FORMAT:\t\t0x%X\n", v[2]);
> > +
> > + get_values_from_reg(c->reg, 0xE0, 1, v);
> > + seq_printf(sf, "LW_IN_SIZE:\t\t0x%X\n", v[0]);
> > +
> > + for (i = 0; i < 2; i++) {
> > + get_values_from_reg(c->reg, 0x100 + i * 0x10, 3, v);
> > + seq_printf(sf, "LW_P%u_PTR_LOW:\t\t0x%X\n", i, v[0]);
> > + seq_printf(sf, "LW_P%u_PTR_HIGH:\t\t0x%X\n", i, v[1]);
> > + seq_printf(sf, "LW_P%u_STRIDE:\t\t0x%X\n", i, v[2]);
> > + }
> > +
> > + get_values_from_reg(c->reg, 0x130, 12, v);
> > + for (i = 0; i < 12; i++)
> > + seq_printf(sf, "LW_RGB_YUV_COEFF%u:\t0x%X\n", i, v[i]);
> > +}
> > +
> > +static void d71_wb_layer_disable(struct komeda_component *c)
> > +{
> > + malidp_write32(c->reg, BLK_INPUT_ID0, 0);
> > + malidp_write32_mask(c->reg, BLK_CONTROL, L_EN, 0);
> > +}
> > +
> > +static const struct komeda_component_funcs d71_wb_layer_funcs = {
> > + .update = d71_wb_layer_update,
> > + .disable = d71_wb_layer_disable,
> > + .dump_register = d71_wb_layer_dump,
> > +};
> > +
> > static int d71_wb_layer_init(struct d71_dev *d71,
> > struct block_header *blk, u32 __iomem *reg)
> > {
> > - DRM_DEBUG("Detect D71_Wb_Layer.\n");
> > + struct komeda_component *c;
> > + struct komeda_layer *wb_layer;
> > + u32 pipe_id, layer_id;
> > +
> > + get_resources_id(blk->block_info, &pipe_id, &layer_id);
> > +
> > + c = komeda_component_add(&d71->pipes[pipe_id]->base, sizeof(*wb_layer),
> > + layer_id, BLOCK_INFO_INPUT_ID(blk->block_info),
> > + &d71_wb_layer_funcs,
> > + 1, get_valid_inputs(blk), 0, reg,
> > + "LPU%d_LAYER_WR", pipe_id);
> > + if (!c) {
> I think we should use 'IS_ERR(c)' as komeda_component_add() returns a valid
> error code.

Yes, you're right it should be IS_ERR(c).
thank you for pointing this out.
and seems I also need the check all the pending reviews. :)

>
> > + DRM_ERROR("Failed to add wb_layer component\n");
> > + return -EINVAL;
> > + }
> > +
> > + wb_layer = to_layer(c);
> > + wb_layer->layer_type = KOMEDA_FMT_WB_LAYER;
> > +
> > + set_range(&wb_layer->hsize_in, D71_MIN_LINE_SIZE, d71->max_line_size);
> > + set_range(&wb_layer->vsize_in, D71_MIN_VERTICAL_SIZE, d71->max_vsize);
> >
> > return 0;
> > }
> > diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c b/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c
> > index 284ce079d8c4..6712603b8c7a 100644
> > --- a/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c
> > +++ b/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c
> > @@ -165,6 +165,15 @@ void komeda_crtc_handle_event(struct komeda_crtc *kcrtc,
> > if (events & KOMEDA_EVENT_VSYNC)
> > drm_crtc_handle_vblank(crtc);
> >
> > + if (events & KOMEDA_EVENT_EOW) {
> > + struct komeda_wb_connector *wb_conn = kcrtc->wb_conn;
> > +
> > + if (wb_conn)
> > + drm_writeback_signal_completion(&wb_conn->base, 0);
> > + else
> > + DRM_WARN("CRTC[%d]: EOW happen but no wb_connector.\n",
> > + drm_crtc_index(&kcrtc->base));
> > + }
> > /* will handle it together with the write back support */
> > if (events & KOMEDA_EVENT_EOW)
> > DRM_DEBUG("EOW.\n");
> > @@ -201,6 +210,8 @@ komeda_crtc_do_flush(struct drm_crtc *crtc,
> > struct komeda_crtc_state *kcrtc_st = to_kcrtc_st(crtc->state);
> > struct komeda_dev *mdev = kcrtc->base.dev->dev_private;
> > struct komeda_pipeline *master = kcrtc->master;
> > + struct komeda_wb_connector *wb_conn = kcrtc->wb_conn;
> > + struct drm_connector_state *conn_st;
> >
> > DRM_DEBUG_ATOMIC("CRTC%d_FLUSH: active_pipes: 0x%x, affected: 0x%x.\n",
> > drm_crtc_index(crtc),
> > @@ -210,6 +221,10 @@ komeda_crtc_do_flush(struct drm_crtc *crtc,
> > if (has_bit(master->id, kcrtc_st->affected_pipes))
> > komeda_pipeline_update(master, old->state);
> >
> > + conn_st = wb_conn ? wb_conn->base.base.state : NULL;
> > + if (conn_st && conn_st->writeback_job)
> > + drm_writeback_queue_job(&wb_conn->base, conn_st);
> > +
> > /* step 2: notify the HW to kickoff the update */
> > mdev->funcs->flush(mdev, master->id, kcrtc_st->active_pipes);
> > }
> > diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_framebuffer.c b/drivers/gpu/drm/arm/display/komeda/komeda_framebuffer.c
> > index 9cc9935024f7..4d8160cf09c3 100644
> > --- a/drivers/gpu/drm/arm/display/komeda/komeda_framebuffer.c
> > +++ b/drivers/gpu/drm/arm/display/komeda/komeda_framebuffer.c
> > @@ -165,3 +165,22 @@ komeda_fb_get_pixel_addr(struct komeda_fb *kfb, int x, int y, int plane)
> >
> > return obj->paddr + offset;
> > }
> > +
> > +/* if the fb can be supported by a specific layer */
> > +bool komeda_fb_is_layer_supported(struct komeda_fb *kfb, u32 layer_type)
> > +{
> > + struct drm_framebuffer *fb = &kfb->base;
> > + struct komeda_dev *mdev = fb->dev->dev_private;
> > + const struct komeda_format_caps *caps;
> > + u32 fourcc = fb->format->format;
> > + u64 modifier = fb->modifier;
> > +
> > + caps = komeda_get_format_caps(&mdev->fmt_tbl, fourcc, modifier);
> > + if (!caps)
> > + return false;
> > +
> > + if (!(caps->supported_layer_types & layer_type))
> > + return false;
> > +
> > + return true;
> > +}
> > diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_kms.c b/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
> > index 86f6542afb40..3e58901fb776 100644
> > --- a/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
> > +++ b/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
> > @@ -188,6 +188,10 @@ struct komeda_kms_dev *komeda_kms_attach(struct komeda_dev *mdev)
> > if (err)
> > goto cleanup_mode_config;
> >
> > + err = komeda_kms_add_wb_connectors(kms, mdev);
> > + if (err)
> > + goto cleanup_mode_config;
> > +
> > err = component_bind_all(mdev->dev, kms);
> > if (err)
> > goto cleanup_mode_config;
> > diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_kms.h b/drivers/gpu/drm/arm/display/komeda/komeda_kms.h
> > index ac3d9209b4d9..f16e9e577593 100644
> > --- a/drivers/gpu/drm/arm/display/komeda/komeda_kms.h
> > +++ b/drivers/gpu/drm/arm/display/komeda/komeda_kms.h
> > @@ -12,6 +12,7 @@
> > #include <drm/drm_crtc_helper.h>
> > #include <drm/drm_device.h>
> > #include <drm/drm_writeback.h>
> > +#include <drm/drm_print.h>
> > #include <video/videomode.h>
> > #include <video/display_timing.h>
> >
> > @@ -73,6 +74,9 @@ struct komeda_crtc {
> > */
> > struct komeda_pipeline *slave;
> >
> > + /** @wb_conn: komeda write back connector */
> > + struct komeda_wb_connector *wb_conn;
> > +
> > /** @disable_done: this flip_done is for tracing the disable */
> > struct completion *disable_done;
> > };
> > @@ -116,6 +120,27 @@ struct komeda_kms_dev {
> > #define to_kcrtc(p) container_of(p, struct komeda_crtc, base)
> > #define to_kcrtc_st(p) container_of(p, struct komeda_crtc_state, base)
> > #define to_kdev(p) container_of(p, struct komeda_kms_dev, base)
> > +#define to_wb_conn(x) container_of(x, struct drm_writeback_connector, base)
> > +
> > +static inline bool is_writeback_only(struct drm_crtc_state *st)
> > +{
> > + struct komeda_wb_connector *wb_conn = to_kcrtc(st->crtc)->wb_conn;
> > + struct drm_connector *conn = wb_conn ? &wb_conn->base.base : NULL;
> > +
> > + return conn && (st->connector_mask == BIT(drm_connector_index(conn)));
> > +}
> > +
> > +static inline bool
> > +is_only_changed_connector(struct drm_crtc_state *st, struct drm_connector *conn)
> > +{
> > + struct drm_crtc_state *old_st;
> > + u32 changed_connectors;
> > +
> > + old_st = drm_atomic_get_old_crtc_state(st->state, st->crtc);
> > + changed_connectors = st->connector_mask ^ old_st->connector_mask;
> > +
> > + return BIT(drm_connector_index(conn)) == changed_connectors;
> > +}
> >
> > int komeda_kms_setup_crtcs(struct komeda_kms_dev *kms, struct komeda_dev *mdev);
> >
> > @@ -123,6 +148,8 @@ int komeda_kms_add_crtcs(struct komeda_kms_dev *kms, struct komeda_dev *mdev);
> > int komeda_kms_add_planes(struct komeda_kms_dev *kms, struct komeda_dev *mdev);
> > int komeda_kms_add_private_objs(struct komeda_kms_dev *kms,
> > struct komeda_dev *mdev);
> > +int komeda_kms_add_wb_connectors(struct komeda_kms_dev *kms,
> > + struct komeda_dev *mdev);
> > void komeda_kms_cleanup_private_objs(struct komeda_kms_dev *kms);
> >
> > void komeda_crtc_handle_event(struct komeda_crtc *kcrtc,
> > diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_pipeline.h b/drivers/gpu/drm/arm/display/komeda/komeda_pipeline.h
> > index bae8a32b81a6..1b7e933ea303 100644
> > --- a/drivers/gpu/drm/arm/display/komeda/komeda_pipeline.h
> > +++ b/drivers/gpu/drm/arm/display/komeda/komeda_pipeline.h
> > @@ -423,10 +423,17 @@ struct komeda_plane_state;
> > struct komeda_crtc_state;
> > struct komeda_crtc;
> >
> > +void pipeline_composition_size(struct komeda_crtc_state *kcrtc_st,
> > + u16 *hsize, u16 *vsize);
> > +
> > int komeda_build_layer_data_flow(struct komeda_layer *layer,
> > struct komeda_plane_state *kplane_st,
> > struct komeda_crtc_state *kcrtc_st,
> > struct komeda_data_flow_cfg *dflow);
> > +int komeda_build_wb_data_flow(struct komeda_layer *wb_layer,
> > + struct drm_connector_state *conn_st,
> > + struct komeda_crtc_state *kcrtc_st,
> > + struct komeda_data_flow_cfg *dflow);
> > int komeda_build_display_data_flow(struct komeda_crtc *kcrtc,
> > struct komeda_crtc_state *kcrtc_st);
> >
> > diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c b/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c
> > index 36570d7dad61..9748c9438868 100644
> > --- a/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c
> > +++ b/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c
> > @@ -308,8 +308,41 @@ komeda_layer_validate(struct komeda_layer *layer,
> > return 0;
> > }
> >
> > -static void pipeline_composition_size(struct komeda_crtc_state *kcrtc_st,
> > - u16 *hsize, u16 *vsize)
> > +static int
> > +komeda_wb_layer_validate(struct komeda_layer *wb_layer,
> > + struct drm_connector_state *conn_st,
> > + struct komeda_data_flow_cfg *dflow)
> > +{
> > + struct komeda_fb *kfb = to_kfb(conn_st->writeback_job->fb);
> > + struct komeda_component_state *c_st;
> > + struct komeda_layer_state *st;
> > + int i;
> > +
> > + if (!komeda_fb_is_layer_supported(kfb, wb_layer->layer_type))
> > + return -EINVAL;
> > +
> > + c_st = komeda_component_get_state_and_set_user(&wb_layer->base,
> > + conn_st->state, conn_st->connector, conn_st->crtc);
> > + if (IS_ERR(c_st))
> > + return PTR_ERR(c_st);
> > +
> > + st = to_layer_st(c_st);
> > +
> > + st->hsize = dflow->out_w;
> > + st->vsize = dflow->out_h;
> > +
> > + for (i = 0; i < kfb->base.format->num_planes; i++)
> > + st->addr[i] = komeda_fb_get_pixel_addr(kfb, dflow->out_x,
> > + dflow->out_y, i);
> > +
> > + komeda_component_add_input(&st->base, &dflow->input, 0);
> > + komeda_component_set_output(&dflow->input, &wb_layer->base, 0);
> > +
> > + return 0;
> > +}
> > +
> > +void pipeline_composition_size(struct komeda_crtc_state *kcrtc_st,
> > + u16 *hsize, u16 *vsize)
> > {
> > struct drm_display_mode *m = &kcrtc_st->base.adjusted_mode;
> >
> > @@ -478,6 +511,20 @@ int komeda_build_layer_data_flow(struct komeda_layer *layer,
> > return err;
> > }
> >
> > +int komeda_build_wb_data_flow(struct komeda_layer *wb_layer,
> > + struct drm_connector_state *conn_st,
> > + struct komeda_crtc_state *kcrtc_st,
> > + struct komeda_data_flow_cfg *dflow)
> > +{
> > + if ((dflow->in_w != dflow->out_w) ||
> > + (dflow->in_h != dflow->out_h)) {
> > + DRM_DEBUG_ATOMIC("current do not support scaling writeback.\n");
> > + return -EINVAL;
> > + }
> > +
> > + return komeda_wb_layer_validate(wb_layer, conn_st, dflow);
> > +}
> > +
> > /* build display output data flow, the data path is:
> > * compiz -> improc -> timing_ctrlr
> > */
> > diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_private_obj.c b/drivers/gpu/drm/arm/display/komeda/komeda_private_obj.c
> > index a54878cbd6e4..d53bd6c23c5d 100644
> > --- a/drivers/gpu/drm/arm/display/komeda/komeda_private_obj.c
> > +++ b/drivers/gpu/drm/arm/display/komeda/komeda_private_obj.c
> > @@ -252,6 +252,12 @@ int komeda_kms_add_private_objs(struct komeda_kms_dev *kms,
> > return err;
> > }
> >
> > + if (pipe->wb_layer) {
> > + err = komeda_layer_obj_add(kms, pipe->wb_layer);
> > + if (err)
> > + return err;
> > + }
> > +
> > err = komeda_compiz_obj_add(kms, pipe->compiz);
> > if (err)
> > return err;
> > diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_wb_connector.c b/drivers/gpu/drm/arm/display/komeda/komeda_wb_connector.c
> > new file mode 100644
> > index 000000000000..0c1a4220c280
> > --- /dev/null
> > +++ b/drivers/gpu/drm/arm/display/komeda/komeda_wb_connector.c
> > @@ -0,0 +1,181 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * (C) COPYRIGHT 2018 ARM Limited. All rights reserved.
> > + * Author: James.Qian.Wang <james.qian.wang@arm.com>
> > + *
> > + */
> > +#include "komeda_dev.h"
> > +#include "komeda_kms.h"
> > +
> > +static int
> > +komeda_wb_init_data_flow(struct komeda_layer *wb_layer,
> > + struct drm_connector_state *conn_st,
> > + struct komeda_crtc_state *kcrtc_st,
> > + struct komeda_data_flow_cfg *dflow)
> > +{
> > + struct drm_framebuffer *fb = conn_st->writeback_job ?
> > + conn_st->writeback_job->fb : NULL;
> > +
> > + if (!fb)
> > + return -EINVAL;
> > +
> > + memset(dflow, 0, sizeof(*dflow));
> > +
> > + dflow->out_w = fb->width;
> > + dflow->out_h = fb->height;
> > +
> > + /* the write back data comes from the compiz */
> > + pipeline_composition_size(kcrtc_st, &dflow->in_w, &dflow->in_h);
> > + dflow->input.component = &wb_layer->base.pipeline->compiz->base;
> > + /* compiz doesn't output alpha */
> > + dflow->pixel_blend_mode = DRM_MODE_BLEND_PIXEL_NONE;
> > + dflow->rot = DRM_MODE_ROTATE_0;
> > +
> > + return 0;
> > +}
> > +
> > +static int
> > +komeda_wb_encoder_atomic_check(struct drm_encoder *encoder,
> > + struct drm_crtc_state *crtc_st,
> > + struct drm_connector_state *conn_st)
> > +{
> > + struct komeda_crtc_state *kcrtc_st = to_kcrtc_st(crtc_st);
> > + struct komeda_layer *wb_layer;
> > + struct komeda_data_flow_cfg dflow;
> > + int err;
> > +
> > + if (!crtc_st->active) {
> > + DRM_DEBUG_ATOMIC("Cannot write the composition result out on a inactive CRTC.\n");
> > + return -EINVAL;
> > + }
> > +
> > + wb_layer = to_kconn(to_wb_conn(conn_st->connector))->wb_layer;
> > +
> > + /*
> > + * No need for a full modested when the only connector changed is the
> > + * writeback connector.
> > + */
> > + if (crtc_st->connectors_changed &&
> > + is_only_changed_connector(crtc_st, conn_st->connector))
> > + crtc_st->connectors_changed = false;
> > +
> > + err = komeda_wb_init_data_flow(wb_layer, conn_st, kcrtc_st, &dflow);
> > + if (err)
> > + return err;
> > +
> > + return komeda_build_wb_data_flow(wb_layer, conn_st, kcrtc_st, &dflow);
> > +}
> > +
> > +static const struct drm_encoder_helper_funcs komeda_wb_encoder_helper_funcs = {
> > + .atomic_check = komeda_wb_encoder_atomic_check,
> > +};
> > +
> > +static int
> > +komeda_wb_connector_get_modes(struct drm_connector *connector)
> > +{
> > + return 0;
> > +}
> Can we remove this ?
>

this function is for drm_connector_helper_funcs->get_modes, which is
essential, we can not set it to NULL.

> > +
> > +static enum drm_mode_status
> > +komeda_wb_connector_mode_valid(struct drm_connector *connector,
> > + struct drm_display_mode *mode)
> > +{
> > + struct drm_device *dev = connector->dev;
> > + struct drm_mode_config *mode_config = &dev->mode_config;
> > + int w = mode->hdisplay, h = mode->vdisplay;
> > +
> > + if ((w < mode_config->min_width) || (w > mode_config->max_width))
> > + return MODE_BAD_HVALUE;
> > +
> > + if ((h < mode_config->min_height) || (h > mode_config->max_height))
> > + return MODE_BAD_VVALUE;
> > +
> > + return MODE_OK;
> > +}
> > +
> > +static const struct drm_connector_helper_funcs komeda_wb_conn_helper_funcs = {
> > + .get_modes = komeda_wb_connector_get_modes,
> > + .mode_valid = komeda_wb_connector_mode_valid,
> > +};
> > +
> > +static enum drm_connector_status
> > +komeda_wb_connector_detect(struct drm_connector *connector, bool force)
> > +{
> > + return connector_status_connected;
> > +}
> > +
> > +static int
> > +komeda_wb_connector_fill_modes(struct drm_connector *connector,
> > + uint32_t maxX, uint32_t maxY)
> > +{
> > + return 0;
> > +}
> Can we remove this as well ?

This function is for drm_connector_func->fill_modes which also is essential.
>
> > +
> > +static void komeda_wb_connector_destroy(struct drm_connector *connector)
> > +{
> > + drm_connector_cleanup(connector);
> > + kfree(to_kconn(to_wb_conn(connector)));
> > +}
> > +
> > +static const struct drm_connector_funcs komeda_wb_connector_funcs = {
> > + .reset = drm_atomic_helper_connector_reset,
> > + .detect = komeda_wb_connector_detect,
> > + .fill_modes = komeda_wb_connector_fill_modes,
> > + .destroy = komeda_wb_connector_destroy,
> > + .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
> > + .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
> > +};
> > +
> > +static int komeda_wb_connector_add(struct komeda_kms_dev *kms,
> > + struct komeda_crtc *kcrtc)
> > +{
> > + struct komeda_dev *mdev = kms->base.dev_private;
> > + struct komeda_wb_connector *kwb_conn;
> > + struct drm_writeback_connector *wb_conn;
> > + u32 *formats, n_formats = 0;
> > + int err;
> > +
> > + if (!kcrtc->master->wb_layer)
> > + return 0;
> > +
> > + kwb_conn = kzalloc(sizeof(*wb_conn), GFP_KERNEL);
> > + if (!kwb_conn)
> > + return -ENOMEM;
> > +
> > + kwb_conn->wb_layer = kcrtc->master->wb_layer;
> > +
> > + wb_conn = &kwb_conn->base;
> > + wb_conn->encoder.possible_crtcs = BIT(drm_crtc_index(&kcrtc->base));
> > +
> > + formats = komeda_get_layer_fourcc_list(&mdev->fmt_tbl,
> > + kwb_conn->wb_layer->layer_type,
> > + &n_formats);
> > +
> We be doing a null check on formats here as we are dereferencing it
> in the next function.
>

Do you mean the valid check for formats,

I don't think it is necessary.

Since even it is a NULL ptr, and which may lead drm_writeback_connector_init
fail. and for the put_fourcc_list which is a kfree acctually. and
kfree always ignore the free if the input ptr is NULL.

> > + err = drm_writeback_connector_init(&kms->base, wb_conn,
> > + &komeda_wb_connector_funcs,
> > + &komeda_wb_encoder_helper_funcs,
> > + formats, n_formats);
> > + komeda_put_fourcc_list(formats);
> > + if (err)
> > + return err;
> > +
> > + drm_connector_helper_add(&wb_conn->base, &komeda_wb_conn_helper_funcs);
> > +
> > + kcrtc->wb_conn = kwb_conn;
> > +
> > + return 0;
> > +}
> > +
> > +int komeda_kms_add_wb_connectors(struct komeda_kms_dev *kms,
> > + struct komeda_dev *mdev)
> > +{
> > + int i, err;
> > +
> > + for (i = 0; i < kms->n_crtcs; i++) {
> > + err = komeda_wb_connector_add(kms, &kms->crtcs[i]);
> > + if (err)
> > + return err;
> > + }
> > +
> > + return 0;
> > +}
> > --
> > 2.17.1
> >