Re: [RFC PATCH 3/8] drm: verisilicon: add a driver for Verisilicon display controllers

[Icenowy Zheng <uwu@icenowy.me>]

在 2025-08-15星期五的 11:05 +0200，Philipp Zabel写道：
> On Fr, 2025-08-15 at 00:40 +0800, Icenowy Zheng wrote:
> > This is a from-scratch driver targeting Verisilicon DC-series
> > display
> > controllers, which feature self-identification functionality like
> > their
> > GC-series GPUs.
> > 
> > Only DC8200 is being supported now, and only the main framebuffer
> > is set
> > up (as the DRM primary plane). Support for more DC models and more
> > features is my further targets.
> > 
> > As the display controller is delivered to SoC vendors as a whole
> > part,
> > this driver does not use component framework and extra bridges
> > inside a
> > SoC is expected to be implemented as dedicated bridges (this driver
> > properly supports bridge chaining).
> > 
> > Signed-off-by: Icenowy Zheng <uwu@icenowy.me>
> > ---
> >  drivers/gpu/drm/Kconfig                       |   2 +
> >  drivers/gpu/drm/Makefile                      |   1 +
> >  drivers/gpu/drm/verisilicon/Kconfig           |  15 +
> >  drivers/gpu/drm/verisilicon/Makefile          |   5 +
> >  drivers/gpu/drm/verisilicon/vs_bridge.c       | 330
> > ++++++++++++++++++
> >  drivers/gpu/drm/verisilicon/vs_bridge.h       |  40 +++
> >  drivers/gpu/drm/verisilicon/vs_bridge_regs.h  |  47 +++
> >  drivers/gpu/drm/verisilicon/vs_crtc.c         | 217 ++++++++++++
> >  drivers/gpu/drm/verisilicon/vs_crtc.h         |  29 ++
> >  drivers/gpu/drm/verisilicon/vs_crtc_regs.h    |  60 ++++
> >  drivers/gpu/drm/verisilicon/vs_dc.c           | 233 +++++++++++++
> >  drivers/gpu/drm/verisilicon/vs_dc.h           |  39 +++
> >  drivers/gpu/drm/verisilicon/vs_dc_top_regs.h  |  27 ++
> >  drivers/gpu/drm/verisilicon/vs_drm.c          | 177 ++++++++++
> >  drivers/gpu/drm/verisilicon/vs_drm.h          |  29 ++
> >  drivers/gpu/drm/verisilicon/vs_hwdb.c         | 150 ++++++++
> >  drivers/gpu/drm/verisilicon/vs_hwdb.h         |  29 ++
> >  drivers/gpu/drm/verisilicon/vs_plane.c        | 102 ++++++
> >  drivers/gpu/drm/verisilicon/vs_plane.h        |  68 ++++
> >  .../gpu/drm/verisilicon/vs_primary_plane.c    | 166 +++++++++
> >  .../drm/verisilicon/vs_primary_plane_regs.h   |  53 +++
> >  21 files changed, 1819 insertions(+)
> >  create mode 100644 drivers/gpu/drm/verisilicon/Kconfig
> >  create mode 100644 drivers/gpu/drm/verisilicon/Makefile
> >  create mode 100644 drivers/gpu/drm/verisilicon/vs_bridge.c
> >  create mode 100644 drivers/gpu/drm/verisilicon/vs_bridge.h
> >  create mode 100644 drivers/gpu/drm/verisilicon/vs_bridge_regs.h
> >  create mode 100644 drivers/gpu/drm/verisilicon/vs_crtc.c
> >  create mode 100644 drivers/gpu/drm/verisilicon/vs_crtc.h
> >  create mode 100644 drivers/gpu/drm/verisilicon/vs_crtc_regs.h
> >  create mode 100644 drivers/gpu/drm/verisilicon/vs_dc.c
> >  create mode 100644 drivers/gpu/drm/verisilicon/vs_dc.h
> >  create mode 100644 drivers/gpu/drm/verisilicon/vs_dc_top_regs.h
> >  create mode 100644 drivers/gpu/drm/verisilicon/vs_drm.c
> >  create mode 100644 drivers/gpu/drm/verisilicon/vs_drm.h
> >  create mode 100644 drivers/gpu/drm/verisilicon/vs_hwdb.c
> >  create mode 100644 drivers/gpu/drm/verisilicon/vs_hwdb.h
> >  create mode 100644 drivers/gpu/drm/verisilicon/vs_plane.c
> >  create mode 100644 drivers/gpu/drm/verisilicon/vs_plane.h
> >  create mode 100644 drivers/gpu/drm/verisilicon/vs_primary_plane.c
> >  create mode 100644
> > drivers/gpu/drm/verisilicon/vs_primary_plane_regs.h
> > 
> [...]
> > diff --git a/drivers/gpu/drm/verisilicon/vs_dc.c
> > b/drivers/gpu/drm/verisilicon/vs_dc.c
> > new file mode 100644
> > index 0000000000000..98384559568c4
> > --- /dev/null
> > +++ b/drivers/gpu/drm/verisilicon/vs_dc.c
> > @@ -0,0 +1,233 @@
> [...]
> > +static int vs_dc_probe(struct platform_device *pdev)
> > +{
> > +       struct device *dev = &pdev->dev;
> > +       struct vs_dc *dc;
> > +       void __iomem *regs;
> > +       unsigned int outputs, i;
> > +       /* pix0/pix1 */
> > +       char pixclk_name[5];
> > +       int irq, ret;
> > +
> > +       if (!dev->of_node) {
> > +               dev_err(dev, "can't find DC devices\n");
> > +               return -ENODEV;
> > +       }
> > +
> > +       outputs = of_graph_get_port_count(dev->of_node);
> > +       if (!outputs) {
> > +               dev_err(dev, "can't find DC downstream ports\n");
> > +               return -ENODEV;
> > +       }
> > +       if (outputs > VSDC_MAX_OUTPUTS) {
> > +               dev_err(dev, "too many DC downstream ports than
> > possible\n");
> > +               return -EINVAL;
> > +       }
> > +
> > +       ret = dma_set_mask_and_coherent(&pdev->dev,
> > DMA_BIT_MASK(32));
> > +       if (ret) {
> > +               dev_err(dev, "No suitable DMA available\n");
> > +               return ret;
> > +       }
> > +
> > +       dc = devm_kzalloc(dev, sizeof(*dc), GFP_KERNEL);
> > +       if (!dc)
> > +               return -ENOMEM;
> > +
> > +       dc->outputs = outputs;
> > +
> > +       dc->rsts[0].id = "core";
> > +       dc->rsts[1].id = "axi";
> > +       dc->rsts[0].id = "ahb";
> 
> I assume this should be:
> 
>         dc->rsts[2].id = "ahb";

Sure.

> 
> > +
> > +       ret = devm_reset_control_bulk_get_optional_shared(dev,
> > VSDC_RESET_COUNT,
> > +                                                         dc-
> > >rsts);
> > +       if (ret) {
> > +               dev_err(dev, "can't get reset lines\n");
> 
> Consider using dev_err_probe().

Sounds reasonable.

Thanks,
Icenowy

> 
> > +               return ret;
> > +       }
> [...]
> 
> regards
> Philipp