> On Jul 5, 2017, at 18:56, Hyun Kwon <hyun.k...@xilinx.com> wrote:
>
> For VDMA, I think you can use the DMA engine complete callback to generate
> the vblank.
>
> But, please note that it's not a global solution, and it doesn't work for
> some other pipelines. For example, the ZU+ DPDMA operation is synchronized
> with vblank, not with the done event. Thus if the page flip request comes in
> between done event and vblank, it'll end up flipping pages while the
> application would expect the flip to take place after vblank.
Thanks for that warning. I will make sure I get the timing right for my
pipeline. I will probably not submit this work upstream... yet.
>
> For the xilinx drm clean up, what you described in the previous email, to use
> drm_of_component_probe(), makes sense. I'm doing the clean in that direction
> too.
In the end I did not use drm_of_component_probe() as it make assumptions that
the CRTC is a component and treats it specially, failing that, the function
aborts. Since I didn't want to refactor xilinx_drm_crtc to a component at this
stage, especially knowing the refactoring that is upcoming, I went for a
similar but manual way.
Here it is, just for fun...
/* component master bind callback */
static int xilinx_drm_bind(struct device *dev)
{
struct drm_device *drm;
struct xilinx_drm_private *private;
struct drm_encoder *encoder;
struct drm_connector *connector;
struct device_node *encoder_node;
unsigned int bpp, align, i = 0;
int ret;
private = devm_kzalloc(dev, sizeof(*private), GFP_KERNEL);
if (!private)
return -ENOMEM;
dev_set_drvdata(dev, private);
drm = drm_dev_alloc(&xilinx_drm_driver, dev);
if (IS_ERR(drm))
return PTR_ERR(drm);
drm->dev_private = private;
private->drm = drm;
platform_set_drvdata(to_platform_device(dev), private);
drm_mode_config_init(drm);
/* create a xilinx crtc */
private->crtc = xilinx_drm_crtc_create(drm);
if (IS_ERR(private->crtc)) {
DRM_DEBUG_DRIVER("failed to create xilinx crtc\n");
ret = PTR_ERR(private->crtc);
goto err_free;
}
xilinx_drm_mode_config_init(drm);
while ((encoder_node = of_parse_phandle(drm->dev->of_node,
"xlnx,encoder-slave", i))) {
encoder = xilinx_drm_encoder_create(drm, encoder_node);
of_node_put(encoder_node);
if (IS_ERR(encoder)) {
DRM_DEBUG_DRIVER("failed to create xilinx encoder\n");
ret = PTR_ERR(encoder);
goto err_free;
}
connector = xilinx_drm_connector_create(drm, encoder, i);
if (IS_ERR(connector)) {
DRM_DEBUG_DRIVER("failed to create xilinx connector\n");
ret = PTR_ERR(connector);
goto err_free;
}
i++;
}
ret = drm_dev_register(drm, 0);
if (ret) {
DRM_ERROR("failed to register drm_dev: %d\n", ret);
goto err_free;
}
ret = component_bind_all(dev, drm);
if (ret) {
DRM_ERROR("Failed to bind all components\n");
goto err_unregister;
}
ret = drm_vblank_init(drm, 1);
if (ret) {
dev_err(dev, "failed to initialize vblank\n");
goto err_unbind_all;
}
/* enable irq to enable vblank feature */
drm->irq_enabled = true;
/* initialize xilinx framebuffer */
bpp = xilinx_drm_format_bpp(xilinx_drm_crtc_get_format(private->crtc));
align = xilinx_drm_crtc_get_align(private->crtc);
private->fb = xilinx_drm_fb_init(drm, bpp, 1, 1, align,
xilinx_drm_fbdev_vres);
if (IS_ERR(private->fb)) {
DRM_ERROR("failed to initialize drm cma fb\n");
ret = PTR_ERR(private->fb);
goto err_vblank_cleanup;
}
drm_helper_disable_unused_functions(drm);
drm_mode_config_reset(drm);
drm_kms_helper_poll_init(drm);
return 0;
err_vblank_cleanup:
drm_vblank_cleanup(drm);
err_unbind_all:
component_unbind_all(dev, drm);
err_unregister:
drm_dev_unregister(drm);
err_free:
drm_mode_config_cleanup(drm);
dev_set_drvdata(dev, NULL);
drm_dev_unref(drm);
return ret;
}
static void xilinx_drm_unbind(struct device *dev)
{
struct xilinx_drm_private *private = dev_get_drvdata(dev);
struct drm_device *drm = private->drm;
drm_kms_helper_poll_fini(drm);
xilinx_drm_fb_fini(private->fb);
component_unbind_all(dev, drm);
drm_vblank_cleanup(drm);
drm_mode_config_cleanup(drm);
drm_dev_unregister(drm);
drm_dev_unref(drm);
drm->dev_private = NULL;
dev_set_drvdata(dev, NULL);
}
static const struct component_master_ops xilinx_drm_component_master_ops = {
.bind = xilinx_drm_bind,
.unbind = xilinx_drm_unbind,
};
static int compare_dev(struct device *dev, void *data)
{
return dev->of_node == data;
}
/* init xilinx drm platform */
static int xilinx_drm_platform_probe(struct platform_device *pdev)
{
struct device_node *remote_dev, *ep = NULL;
struct component_match *match = NULL;
while (1) {
ep = of_graph_get_next_endpoint(pdev->dev.of_node, ep);
if (!ep)
break;
of_node_put(ep);
remote_dev = of_graph_get_remote_port_parent(ep);
if (!remote_dev || !of_device_is_available(remote_dev)) {
of_node_put(remote_dev);
continue;
}
component_match_add(&pdev->dev, &match, compare_dev,
remote_dev);
of_node_put(remote_dev);
}
return component_master_add_with_match(&pdev->dev,
&xilinx_drm_component_master_ops,
match);
}
/* exit xilinx drm platform */
static int xilinx_drm_platform_remove(struct platform_device *pdev)
{
component_master_del(&pdev->dev, &xilinx_drm_component_master_ops);
return 0;
}
There is still a bad pointer dereference at unbind time which doesn't annoy me
enough yet since I never unbind, I just shutdown the device.
> I can post my local branch to github and point it to you, even though I'm not
> sure how much it'd be helpful as it's more like scribble for now. Then I can
> also include you when I post the patch to Xilinx mailing list for internal
> review, which I expect to happen in July timeframe.
You can flag your commit with "WIP: ..." to warn anyone looking, and detail
your commit with your concerns and challenges. Onlookers may just chime in to
provide insights ;)
It's a good timing for this work since I am actively building our support for
our display pipeline which is not covered by the current driver's state. If we
collaborate, I will want to submit my changes to allow others wanting to
integrate LVDS panels in xilinx_drm to do so. Right now, with xilinx_drm using
the legacy helpers, my approach requires a small hack in an atomic helper
function.
Cheers!
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