[v8,0/2] drm: add kms driver for loongson display controller

From: Sui Jingfeng <suijingfeng@loongson.cn>

Loongson display controller IP has been integrated in both Loongson
North Bridge chipset(ls7a1000 and ls7a2000) and Loongson SoCs(ls2k1000
and ls2k2000 etc), it even has been included in Loongson BMC products.

This display controller is a PCI device, it has two display pipe. For
the DC in LS7A1000 and LS2K1000 each way has a DVO output interface
which provide RGB888 signals, vertical & horizontal synchronisations,
and the pixel clock. Each CRTC is able to support 1920x1080@60Hz,
the maximum resolution is 2048x2048 according to the hardware spec.

For the DC in LS7A2000, each display pipe is equipped with a built-in
HDMI encoder which is compliant with HDMI 1.4 specification, thus it
support 3840x2160@30Hz. The first display pipe is also equipped with
a transparent vga encoder which is parallel with the HDMI encoder.
The DC in LS7A2000 is more complete, besides above feature, it has
two hardware cursors, two hardware vblank counter and two scanout
position recorders.

 v1 -> v2:
  1) Use hpd status reg when polling for ls7a2000
  2) Fix all warnings emerged when compile with W=1

 v2 -> v3:
  1) Add COMPILE_TEST in Kconfig and make the driver off by default
  2) Alphabetical sorting headers (Thomas)
  3) Untangle register access functions as much as possible (Thomas)
  4) Switch to TTM based memory manager and prefer cached mapping
     for Loongson SoC (Thomas)
  5) Add chip id detection method, now all models are distinguishable.
  6) Revise builtin HDMI phy driver, nearly all main stream mode
     below 4K@30Hz is tested, this driver supported these mode very
     well including clone display mode and extend display mode.

 v3 -> v4:
  1) Quickly fix a small mistake.

 v4 -> v5:
  1) Drop potential support for Loongson 2K series SoC temporary,
     this part should be resend with the DT binding patch in the future.
  2) Add per display pipe debugfs support to the builtin HDMI encoder.
  3) Rewrite atomic_update() for hardware cursors plane(Thomas)
  4) Rewrite encoder and connector initialization part, untangle it
     according to the chip(Thomas).

 v5 -> v6:
  1) Remove stray code which didn't get used, say lsdc_of_get_reserved_ram
  2) Fix all typos I could found, make sentences and code more readable
  3) Untange lsdc_hdmi*_connector_detect() function according to the pipe
  4) After a serious consideration, we rename this driver as loongson.
     Because we also have drivers toward the LoongGPU IP in LS7A2000 and
     LS2K2000. Besides, there are also drivers about the external encoder,
     HDMI audio driver and vbios support etc. This patch only provide DC
     driver part, my teammate Li Yi believe that loongson will be more
     suitable for loongson graphics than lsdc in the long run.

     loongson.ko = LSDC + LoongGPU + encoders driver + vbios/DT ...

  v6 -> v7:
  1) Add prime support, self-sharing is works. sharing buffer with etnaviv
     is also tested, and its works with limitation.
  2) Implement buffer objects tracking with list_head.
  3) S3(sleep to RAM) is tested on ls3a5000+ls7a2000 evb and it works.
  4) Rewrite lsdc_bo_move, since ttm core stop allocating resources
     during BO creation. Patch V1 ~ V6 of this series no longer works
     on Linux 6.3.0-rc2. Thus, we send V7 to revival them.
  5) Remove depends on LOONGARCH || MIPS || COMPILE_TEST to help review
     and compile on x86 machine.
  6) Add a cover letter to help patchwork tracking my patch.

     V1 ~ V4 can be found at link [1], V5 at link [2], V6 at link [3]

     [1] https://patchwork.freedesktop.org/series/113566/
     [2] https://patchwork.freedesktop.org/series/114386/
     [3] https://patchwork.freedesktop.org/patch/524532/

  v7 -> v8:
  1) Zero a compile warnnings on 32-bit platform, compile with W=1
  2) Revise lsdc_bo_gpu_offset() and minor cleanup
  3) Pageflip tested on the virtual terminal with following commands

       modetest -M loongson -s 32:1920x1080 -v
       modetest -M loongson -s 34:1920x1080 -v -F tiles

     It works like a charm, when running pageflip test with dual screnn
     configuration, another two additional bo created by the modetest
     emerged, VRAM usage up to 40+MB, well we have at least 64MB, still
     enough.

     # cat bos
       bo[0000]: size:     8112kB VRAM
       bo[0001]: size:       16kB VRAM
       bo[0002]: size:       16kB VRAM
       bo[0003]: size:    16208kB VRAM
       bo[0004]: size:     8112kB VRAM
       bo[0005]: size:     8112kB VRAM


Sui Jingfeng (2):
  MAINTAINERS: add maintainers for DRM LOONGSON driver
  drm: add kms driver for loongson display controller

 MAINTAINERS                             |   7 +
 drivers/gpu/drm/Kconfig                 |   2 +
 drivers/gpu/drm/Makefile                |   1 +
 drivers/gpu/drm/loongson/Kconfig        |  15 +
 drivers/gpu/drm/loongson/Makefile       |  16 +
 drivers/gpu/drm/loongson/lsdc_crtc.c    | 385 ++++++++++++++++
 drivers/gpu/drm/loongson/lsdc_debugfs.c | 261 +++++++++++
 drivers/gpu/drm/loongson/lsdc_drv.c     | 501 +++++++++++++++++++++
 drivers/gpu/drm/loongson/lsdc_drv.h     | 318 +++++++++++++
 drivers/gpu/drm/loongson/lsdc_gem.c     | 291 ++++++++++++
 drivers/gpu/drm/loongson/lsdc_gem.h     |  26 ++
 drivers/gpu/drm/loongson/lsdc_i2c.c     | 171 +++++++
 drivers/gpu/drm/loongson/lsdc_irq.c     |  88 ++++
 drivers/gpu/drm/loongson/lsdc_irq.h     |  11 +
 drivers/gpu/drm/loongson/lsdc_output.c  | 563 ++++++++++++++++++++++++
 drivers/gpu/drm/loongson/lsdc_output.h  |  14 +
 drivers/gpu/drm/loongson/lsdc_plane.c   | 416 +++++++++++++++++
 drivers/gpu/drm/loongson/lsdc_pll.c     | 338 ++++++++++++++
 drivers/gpu/drm/loongson/lsdc_pll.h     |  76 ++++
 drivers/gpu/drm/loongson/lsdc_probe.c   |  85 ++++
 drivers/gpu/drm/loongson/lsdc_probe.h   |  11 +
 drivers/gpu/drm/loongson/lsdc_regs.h    | 370 ++++++++++++++++
 drivers/gpu/drm/loongson/lsdc_ttm.c     | 430 ++++++++++++++++++
 drivers/gpu/drm/loongson/lsdc_ttm.h     |  68 +++
 24 files changed, 4464 insertions(+)
 create mode 100644 drivers/gpu/drm/loongson/Kconfig
 create mode 100644 drivers/gpu/drm/loongson/Makefile
 create mode 100644 drivers/gpu/drm/loongson/lsdc_crtc.c
 create mode 100644 drivers/gpu/drm/loongson/lsdc_debugfs.c
 create mode 100644 drivers/gpu/drm/loongson/lsdc_drv.c
 create mode 100644 drivers/gpu/drm/loongson/lsdc_drv.h
 create mode 100644 drivers/gpu/drm/loongson/lsdc_gem.c
 create mode 100644 drivers/gpu/drm/loongson/lsdc_gem.h
 create mode 100644 drivers/gpu/drm/loongson/lsdc_i2c.c
 create mode 100644 drivers/gpu/drm/loongson/lsdc_irq.c
 create mode 100644 drivers/gpu/drm/loongson/lsdc_irq.h
 create mode 100644 drivers/gpu/drm/loongson/lsdc_output.c
 create mode 100644 drivers/gpu/drm/loongson/lsdc_output.h
 create mode 100644 drivers/gpu/drm/loongson/lsdc_plane.c
 create mode 100644 drivers/gpu/drm/loongson/lsdc_pll.c
 create mode 100644 drivers/gpu/drm/loongson/lsdc_pll.h
 create mode 100644 drivers/gpu/drm/loongson/lsdc_probe.c
 create mode 100644 drivers/gpu/drm/loongson/lsdc_probe.h
 create mode 100644 drivers/gpu/drm/loongson/lsdc_regs.h
 create mode 100644 drivers/gpu/drm/loongson/lsdc_ttm.c
 create mode 100644 drivers/gpu/drm/loongson/lsdc_ttm.h