Hi Philipp,

This driver is looking very good now to me.

Sorry for the delay reviewing.   Some comments inline below.

On Tue, Jan 12, 2016 at 7:15 AM, Philipp Zabel [off-list ref] wrote:

From: CK Hu <redacted>

This patch adds an initial DRM driver for the Mediatek MT8173 DISP
subsystem. It currently supports two fixed output streams from the
OVL0/OVL1 sources to the DSI0/DPI0 sinks, respectively.

Signed-off-by: CK Hu <redacted>
Signed-off-by: YT Shen <redacted>
Signed-off-by: Daniel Kurtz <redacted>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

[snip...]

Storing the crtc here would be more consistent with the comment above.

+};
+
+static irqreturn_t mtk_disp_ovl_irq_handler(int irq, void *dev_id)
+{
+       struct mtk_disp_ovl *priv = dev_id;
+       struct mtk_ddp_comp *ovl = &priv->ddp_comp;
+
+       /* Clear frame completion interrupt */
+       writel(0x0, ovl->regs + DISP_REG_OVL_INTSTA);
+
+       mtk_crtc_ddp_irq(priv->drm_dev, ovl);

Likewise, passing the crtc here would be a bit more consistent with the name
of this function mtk_crtc_ddp_irq().  Also, see below; if the CRTC is not found,
we can return IRQ_NONE here to indicate that this was a spurious
(unhandled) interrupt.

+
+       return IRQ_HANDLED;
+}

[snip...]

+static void mtk_ovl_layer_config(struct mtk_ddp_comp *comp, unsigned int idx,
+               struct mtk_plane_state *state)
+{
+       struct mtk_plane_pending_state *pending = &state->pending;
+       unsigned int addr = pending->addr;
+       unsigned int pitch = pending->pitch & 0xffff;
+       unsigned int fmt = pending->format;
+       unsigned int offset = (pending->y << 16) | pending->x;
+       unsigned int src_size = (pending->height << 16) | pending->width;
+       unsigned int con;
+
+       con = has_rb_swapped(fmt) << 24 | ovl_fmt_convert(fmt) << 12;

Since has_rb_swapped() and ovl_fmt_convert() can theoretically fail, but we
can't fail here during .layer_config, can we instead do this in an atomic state
check phase, and just store the resulting .has_rb_swapped and .ovl_infmt values
to mtk_plane_pending_state for later application during .layer_config?

+       if (idx != 0)
+               con |= OVL_AEN | OVL_ALPHA;
+
+       writel(con, comp->regs + DISP_REG_OVL_CON(idx));
+       writel(pitch, comp->regs + DISP_REG_OVL_PITCH(idx));
+       writel(src_size, comp->regs + DISP_REG_OVL_SRC_SIZE(idx));
+       writel(offset, comp->regs + DISP_REG_OVL_OFFSET(idx));
+       writel(addr, comp->regs + DISP_REG_OVL_ADDR(idx));

Can the above all be writel_relaxed() ?

+}

[snip...]

+static int mtk_crtc_ddp_hw_init(struct mtk_drm_crtc *mtk_crtc)
+{
+       struct drm_crtc *crtc = &mtk_crtc->base;
+       unsigned int width, height, vrefresh;
+       int ret;
+       int i;
+
+       DRM_DEBUG_DRIVER("%s\n", __func__);
+       if (WARN_ON(!crtc->state))
+               return -EINVAL;
+
+       width = crtc->state->adjusted_mode.hdisplay;
+       height = crtc->state->adjusted_mode.vdisplay;
+       vrefresh = crtc->state->adjusted_mode.vrefresh;
+
+       ret = pm_runtime_get_sync(crtc->dev->dev);
+       if (ret < 0) {
+               DRM_ERROR("Failed to enable power domain: %d\n", ret);
+               return ret;
+       }
+
+       ret = mtk_disp_mutex_prepare(mtk_crtc->mutex);
+       if (ret < 0) {
+               DRM_ERROR("Failed to enable mutex clock: %d\n", ret);
+               goto err_pm_runtime_put;
+       }
+
+       ret = mtk_crtc_ddp_clk_enable(mtk_crtc);
+       if (ret < 0) {
+               DRM_ERROR("Failed to enable component clocks: %d\n", ret);
+               goto err_mutex_unprepare;
+       }
+
+       DRM_DEBUG_DRIVER("mediatek_ddp_ddp_path_setup\n");
+       for (i = 0; i < mtk_crtc->ddp_comp_nr - 1; i++) {
+               mtk_ddp_add_comp_to_path(mtk_crtc->config_regs,
+                                        mtk_crtc->ddp_comp[i]->id,
+                                        mtk_crtc->ddp_comp[i + 1]->id);
+               mtk_disp_mutex_add_comp(mtk_crtc->mutex,
+                                       mtk_crtc->ddp_comp[i]->id);
+       }
+       mtk_disp_mutex_add_comp(mtk_crtc->mutex, mtk_crtc->ddp_comp[i]->id);
+       mtk_disp_mutex_enable(mtk_crtc->mutex);
+
+       DRM_DEBUG_DRIVER("ddp_disp_path_power_on %dx%d\n", width, height);

I think this debug message is now stale?

+       for (i = 0; i < mtk_crtc->ddp_comp_nr; i++) {
+               struct mtk_ddp_comp *comp = mtk_crtc->ddp_comp[i];
+
+               mtk_ddp_comp_config(comp, width, height, vrefresh);
+               mtk_ddp_comp_start(comp);
+       }
+
+       return 0;
+
+err_mutex_unprepare:
+       mtk_disp_mutex_unprepare(mtk_crtc->mutex);
+err_pm_runtime_put:
+       pm_runtime_put(crtc->dev->dev);
+       return ret;
+}

[snip...]

+void mtk_drm_crtc_check_flush(struct drm_crtc *crtc)
+{
+       struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
+       int i;
+
+       if (mtk_crtc->do_flush) {
+               if (mtk_crtc->event)
+                       mtk_crtc->pending_needs_vblank = true;
+               for (i = 0; i < OVL_LAYER_NR; i++) {
+                       struct drm_plane *plane = &mtk_crtc->planes[i].base;
+                       struct mtk_plane_state *plane_state;
+
+                       plane_state = to_mtk_plane_state(plane->state);
+                       if (plane_state->pending.dirty) {
+                               plane_state->pending.config = true;
+                               plane_state->pending.dirty = false;
+                       }
+               }
+               mtk_crtc->pending_planes = true;

Only set pending_planes is true iff at least 1 of the ovl was
pending.dirty, right?

+               mtk_crtc->do_flush = false;
+       }
+}
+
+static void mtk_drm_crtc_atomic_flush(struct drm_crtc *crtc,
+                                     struct drm_crtc_state *old_crtc_state)
+{
+       struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
+
+       mtk_crtc->do_flush = true;
+       mtk_drm_crtc_check_flush(crtc);

I can't figure out how this is supposed to work.
mtk_drm_crtc_check_flush() only does something if do_flush is set.
And, do_flush is only set here in mtk_drm_crtc_atomic_flush(), just
above mtk_drm_crtc_check_flush(), and it is cleared by that function.

So, why do we also call mtk_drm_crtc_check_flush() from
mtk_plane_atomic_update()?
In what condition will the call to mtk_drm_crtc_check_flush() from
mtk_plane_atomic_update() have do_flush == true?

+}

[snip...]

+void mtk_crtc_ddp_irq(struct drm_device *drm_dev, struct mtk_ddp_comp *ovl)
+{
+       struct mtk_drm_private *priv = drm_dev->dev_private;
+       struct mtk_drm_crtc *mtk_crtc;
+       struct mtk_crtc_state *state;
+       unsigned int i;
+
+       mtk_crtc = mtk_crtc_by_src_comp(priv, ovl);

Hmm.  Can we do this lookup once and store it somewhere to avoid this
lookup during every IRQ?

+       if (WARN_ON(!mtk_crtc))
+               return;

I think the typical thing to do if we can't handle an interrupt is to
return IRQ_NONE, so that it can be tracked by the kernel's spurious
interrupt infrastructure.  We can probably remove the WARN_ON, too.

+
+       state = to_mtk_crtc_state(mtk_crtc->base.state);
+
+       /*
+        * TODO: instead of updating the registers here, we should prepare
+        * working registers in atomic_commit and let the hardware command
+        * queue update module registers on vblank.
+        */
+       if (state->pending_config) {
+               mtk_ddp_comp_config(ovl, state->pending_width,
+                                   state->pending_height,
+                                   state->pending_vrefresh);
+
+               state->pending_config = false;
+       }
+
+       if (mtk_crtc->pending_planes) {
+               for (i = 0; i < OVL_LAYER_NR; i++) {
+                       struct drm_plane *plane = &mtk_crtc->planes[i].base;
+                       struct mtk_plane_state *plane_state;
+
+                       plane_state = to_mtk_plane_state(plane->state);
+
+                       if (plane_state->pending.config) {
+                               if (!plane_state->pending.enable)
+                                       mtk_ddp_comp_layer_off(ovl, i);
+
+                               mtk_ddp_comp_layer_config(ovl, i, plane_state);
+
+                               if (plane_state->pending.enable)
+                                       mtk_ddp_comp_layer_on(ovl, i);

.layer_off() and .layer_on() are redundant, and can just be handled inside
.layer_config(), since we pass plane_state to .layer_config() anyway.

That will also be slightly more efficient, since the mtk_ddp_comp_layer*() will
then all be static functions in the same file and on/off can be inlined.

+
+                               plane_state->pending.config = false;
+                       }
+               }
+               mtk_crtc->pending_planes = false;
+       }
+
+       mtk_drm_finish_page_flip(mtk_crtc);
+}

[snip...]

+
+struct mtk_ddp_comp_match {
+       enum mtk_ddp_comp_type type;
+       int alias_id;
+       const struct mtk_ddp_comp_funcs *funcs;
+};
+
+static struct mtk_ddp_comp_match mtk_ddp_matches[DDP_COMPONENT_ID_MAX] = {

static const struct ...

+       [DDP_COMPONENT_AAL]     = { MTK_DISP_AAL,       0, NULL },
+       [DDP_COMPONENT_COLOR0]  = { MTK_DISP_COLOR,     0, &ddp_color },
+       [DDP_COMPONENT_COLOR1]  = { MTK_DISP_COLOR,     1, &ddp_color },
+       [DDP_COMPONENT_DPI0]    = { MTK_DPI,            0, NULL },
+       [DDP_COMPONENT_DSI0]    = { MTK_DSI,            0, NULL },
+       [DDP_COMPONENT_DSI1]    = { MTK_DSI,            1, NULL },
+       [DDP_COMPONENT_GAMMA]   = { MTK_DISP_GAMMA,     0, NULL },
+       [DDP_COMPONENT_OD]      = { MTK_DISP_OD,        0, &ddp_od },
+       [DDP_COMPONENT_OVL0]    = { MTK_DISP_OVL,       0, NULL },
+       [DDP_COMPONENT_OVL1]    = { MTK_DISP_OVL,       1, NULL },
+       [DDP_COMPONENT_PWM0]    = { MTK_DISP_PWM,       0, NULL },
+       [DDP_COMPONENT_RDMA0]   = { MTK_DISP_RDMA,      0, &ddp_rdma },
+       [DDP_COMPONENT_RDMA1]   = { MTK_DISP_RDMA,      1, &ddp_rdma },
+       [DDP_COMPONENT_RDMA2]   = { MTK_DISP_RDMA,      2, &ddp_rdma },
+       [DDP_COMPONENT_UFOE]    = { MTK_DISP_UFOE,      0, &ddp_ufoe },
+       [DDP_COMPONENT_WDMA0]   = { MTK_DISP_WDMA,      0, NULL },
+       [DDP_COMPONENT_WDMA1]   = { MTK_DISP_WDMA,      1, NULL },
+};

[snip...]

+int mtk_ddp_comp_init(struct device *dev, struct device_node *node,
+                     struct mtk_ddp_comp *comp, enum mtk_ddp_comp_id comp_id,
+                     const struct mtk_ddp_comp_funcs *funcs)
+{
+       enum mtk_ddp_comp_type type;
+       struct device_node *larb_node;
+       struct platform_device *larb_pdev;
+
+       if (comp_id < 0 || comp_id >= DDP_COMPONENT_ID_MAX)
+               return -EINVAL;
+
+       comp->id = comp_id;
+       comp->funcs = funcs ?: mtk_ddp_matches[comp_id].funcs;
+
+       if (comp_id == DDP_COMPONENT_DPI0 ||
+           comp_id == DDP_COMPONENT_DSI0 ||
+           comp_id == DDP_COMPONENT_PWM0) {
+               comp->regs = NULL;
+               comp->clk = NULL;
+               comp->irq = 0;
+               return 0;
+       }
+
+       comp->regs = of_iomap(node, 0);
+       comp->irq = of_irq_get(node, 0);
+       comp->clk = of_clk_get(node, 0);
+       if (IS_ERR(comp->clk))
+               comp->clk = NULL;
+
+       type = mtk_ddp_matches[comp_id].type;
+
+       /* Only DMA capable components need the LARB property */
+       comp->larb_dev = NULL;
+       if (type != MTK_DISP_OVL &&
+           type != MTK_DISP_RDMA &&
+           type != MTK_DISP_WDMA)
+               return 0;
+
+       larb_node = of_parse_phandle(node, "mediatek,larb", 0);

Need to call of_node_put() for larb_node somewhere.

+       if (!larb_node) {
+               dev_err(dev,
+                       "Missing mediadek,larb phandle in %s node\n",
+                       node->full_name);
+               return -EINVAL;
+       }
+
+       larb_pdev = of_find_device_by_node(larb_node);
+       if (!larb_pdev) {
+               dev_warn(dev, "Waiting for larb device %s\n",
+                        larb_node->full_name);
+               return -EPROBE_DEFER;
+       }
+
+       comp->larb_dev = &larb_pdev->dev;
+
+       return 0;
+}

[snip...]

Remove from this patch

+
+struct drm_gem_object *mtk_fb_get_gem_obj(struct drm_framebuffer *fb);
+int mtk_fb_wait(struct drm_framebuffer *fb);
+struct drm_framebuffer *mtk_drm_mode_fb_create(struct drm_device *dev,
+                                              struct drm_file *file,
+                                              struct drm_mode_fb_cmd2 *cmd);
+
+void mtk_drm_mode_output_poll_changed(struct drm_device *dev);
+int mtk_fbdev_create(struct drm_device *dev);
+void mtk_fbdev_destroy(struct drm_device *dev);

Remove these last three function prototypes from this patch.

nit: I think these "size in bytes" parameters should use size_t.

+{
+       struct mtk_drm_gem_obj *mtk_gem_obj;
+       int ret;
+
+       size = round_up(size, PAGE_SIZE);
+
+       mtk_gem_obj = kzalloc(sizeof(*mtk_gem_obj), GFP_KERNEL);
+       if (!mtk_gem_obj)
+               return ERR_PTR(-ENOMEM);
+
+       ret = drm_gem_object_init(dev, &mtk_gem_obj->base, size);
+       if (ret < 0) {
+               DRM_ERROR("failed to initialize gem object\n");
+               kfree(mtk_gem_obj);
+               return ERR_PTR(ret);
+       }
+
+       return mtk_gem_obj;
+}
+
+struct mtk_drm_gem_obj *mtk_drm_gem_create(struct drm_device *dev,
+                                          unsigned long size, bool alloc_kmap)
+{
+       struct mtk_drm_gem_obj *mtk_gem;
+       struct drm_gem_object *obj;
+       int ret;
+
+       mtk_gem = mtk_drm_gem_init(dev, size);
+       if (IS_ERR(mtk_gem))
+               return ERR_CAST(mtk_gem);
+
+       obj = &mtk_gem->base;
+
+       init_dma_attrs(&mtk_gem->dma_attrs);
+       dma_set_attr(DMA_ATTR_WRITE_COMBINE, &mtk_gem->dma_attrs);
+
+       if (!alloc_kmap)
+               dma_set_attr(DMA_ATTR_NO_KERNEL_MAPPING, &mtk_gem->dma_attrs);
+
+       mtk_gem->cookie = dma_alloc_attrs(dev->dev, obj->size,
+                               (dma_addr_t *)&mtk_gem->dma_addr, GFP_KERNEL,

Cast here is not necessary, since dma_addr is dma_addr_t.

+                               &mtk_gem->dma_attrs);
+       if (!mtk_gem->cookie) {
+               DRM_ERROR("failed to allocate %zx byte dma buffer", obj->size);
+               ret = -ENOMEM;
+               goto err_gem_free;
+       }
+
+       if (alloc_kmap)
+               mtk_gem->kvaddr = mtk_gem->cookie;
+
+       DRM_DEBUG_DRIVER("cookie = %p dma_addr = %pad\n",
+                        mtk_gem->cookie, &mtk_gem->dma_addr);

Print size too.

+
+       return mtk_gem;
+
+err_gem_free:
+       drm_gem_object_release(obj);
+       kfree(mtk_gem);
+       return ERR_PTR(ret);
+}
+
+void mtk_drm_gem_free_object(struct drm_gem_object *obj)
+{
+       struct mtk_drm_gem_obj *mtk_gem = to_mtk_gem_obj(obj);
+
+       dma_free_attrs(obj->dev->dev, obj->size, mtk_gem->cookie,
+                      mtk_gem->dma_addr, &mtk_gem->dma_attrs);
+
+       /* release file pointer to gem object. */
+       drm_gem_object_release(obj);
+
+       kfree(mtk_gem);
+}
+
+int mtk_drm_gem_dumb_create(struct drm_file *file_priv, struct drm_device *dev,
+                           struct drm_mode_create_dumb *args)
+{
+       struct mtk_drm_gem_obj *mtk_gem;
+       int ret;
+
+       args->pitch = args->width * DIV_ROUND_UP(args->bpp, 8);

Perhaps this more correctly aligns the pitch (this is what cma does):
  args->pitch = DIV_ROUND_UP(args->width * args->bpp, 8);

+       args->size = args->pitch * args->height;
+
+       mtk_gem = mtk_drm_gem_create(dev, args->size, false);
+       if (IS_ERR(mtk_gem))
+               return PTR_ERR(mtk_gem);
+
+       /*
+        * allocate a id of idr table where the obj is registered
+        * and handle has the id what user can see.
+        */
+       ret = drm_gem_handle_create(file_priv, &mtk_gem->base, &args->handle);
+       if (ret)
+               goto err_handle_create;
+
+       /* drop reference from allocate - handle holds it now. */
+       drm_gem_object_unreference_unlocked(&mtk_gem->base);
+
+       return 0;
+
+err_handle_create:
+       mtk_drm_gem_free_object(&mtk_gem->base);
+       return ret;
+}
+
+int mtk_drm_gem_dumb_map_offset(struct drm_file *file_priv,
+                               struct drm_device *dev, uint32_t handle,
+                               uint64_t *offset)
+{
+       struct drm_gem_object *obj;
+       int ret;
+

The cma helper locks struct_mutex here.

+       obj = drm_gem_object_lookup(dev, file_priv, handle);
+       if (!obj) {
+               DRM_ERROR("failed to lookup gem object.\n");
+               return -EINVAL;
+       }
+
+       ret = drm_gem_create_mmap_offset(obj);
+       if (ret)
+               goto out;
+
+       *offset = drm_vma_node_offset_addr(&obj->vma_node);
+       DRM_DEBUG_KMS("offset = 0x%llx\n", *offset);
+
+out:
+       drm_gem_object_unreference_unlocked(obj);
+       return ret;
+}

[snip...]

+/*
+ * Allocate a sg_table for this GEM object.
+ * Note: Both the table's contents, and the sg_table itself must be freed by
+ *       the caller.
+ * Returns a pointer to the newly allocated sg_table, or an ERR_PTR() error.
+ */
+struct sg_table *mtk_gem_prime_get_sg_table(struct drm_gem_object *obj)
+{
+       struct mtk_drm_gem_obj *mtk_gem = to_mtk_gem_obj(obj);
+       struct drm_device *drm = obj->dev;
+       struct sg_table *sgt;
+       int ret;
+
+       sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
+       if (!sgt)
+               return ERR_PTR(-ENOMEM);
+
+       ret = dma_get_sgtable_attrs(drm->dev, sgt, mtk_gem->cookie,
+                                   mtk_gem->dma_addr, obj->size,
+                                   &mtk_gem->dma_attrs);
+       if (ret) {
+               DRM_ERROR("failed to allocate sgt, %d\n", ret);
+               kfree(sgt);
+               return ERR_PTR(ret);
+       }
+
+       return sgt;
+}

Do we also want a prime_import_sg_table() here for importing foreign allocated
dma bufs for display?

[snip...]

wmb(); ?

BTW, it is a good idea to document all wmb() calls.
If you forget, I believe checkpatch.pl will remind you.

+       state->pending.dirty = true;
+}
+

That's it!

Thanks,
-Dan
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