Re: [PATCH v15 0/2] drm: Add kms driver for loongson display controller

[Sui Jingfeng <suijingfeng@loongson.cn>]

Hi,

Dear maintainers:


Any chance to get this driver merged ?

I have already write this driver by myself from the zero, iterate about 
15 times?

it there anything missing?


On 2023/6/15 22:36, Sui Jingfeng wrote:
> From: Sui Jingfeng <suijingfeng@loongson.cn>
>
> Loongson display controller IP has been integrated in both Loongson north
> bridge chipset (ls7a1000/ls7a2000) and Loongson SoCs (ls2k1000/ls2k2000).
> It has even been included in Loongson's BMC products. It has two display
> pipes, and each display pipe supports a primary plane and a cursor plane.
>
> For the DC in the LS7a1000, each display pipe has a DVO output interface,
> which is able to support 1920x1080@60Hz. For the DC in the LS7A2000, each
> display pipe is equipped with a built-in HDMI encoder, which is compliant
> with the HDMI 1.4 specification. The first display pipe is also equipped
> with a transparent VGA encoder, which is parallel with the HDMI encoder.
> To get a decent performance for writing framebuffer data to the VRAM, the
> write combine support should be enabled.
>
> v1 -> v2:
>   1) Use hpd status reg when polling for ls7a2000.
>   2) Fix all warnings that emerged when compiling with W=1.
>
> v2 -> v3:
>   1) Add COMPILE_TEST to 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 (Thomas)
>   5) Add the chip ID detection function which can be used to distinguish
>      chip models
>   6) Revise the built-in HDMI phy driver, nearly all main stream mode below
>      4K@30Hz is tested, and this driver supports clone(mirror) display mode
>      and extend(joint) display mode.
>
> v3 -> v4:
>   1) Quickly fix a small mistake.
>
> v4 -> v5:
>   1) Add per display pipe debugfs support to the builtin HDMI encoder.
>
> 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) Untangle lsdc_hdmi*_connector_detect() function according to the pipe
>   4) Rename this driver as loongson.
>
> v6 -> v7:
> 1) Add prime support for buffer self-sharing, sharing buffer with
>     drm/etnaviv is also tested and it works with limitations.
> 2) Implement buffer object tracking with list_head.
> 3) Add S3(sleep to RAM) support
> 4) Rewrite lsdc_bo_move since TTM core stop allocating resources
>      during BO creation. Patch V1 ~ V6 of this series no longer work.
>      Thus, we send V7.
>
> v7 -> v8:
>   1) Zero a compile warning on a 32-bit platform, compile with W=1
>   2) Revise lsdc_bo_gpu_offset() and make minor cleanups.
>   3) Pageflip tested on the virtual terminal with the 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 the pageflip test with dual screens
>     configuration, another two additional BOs were created by the modetest,
>     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
>
> v8 -> v9:
>   1) Select I2C and I2C_ALGOBIT in Kconfig, should depend on MMU.
>   2) Using pci_get_domain_bus_and_slot to get the GPU device.
>
> v9 -> v10:
>   1) Revise lsdc_drm_freeze() to implement S3 correctly. We realized that
>      the pinned BO could not be moved, the VRAM lost power when sleeping
>      to RAM. Thus, the data in the buffer who is pinned in VRAM will get
>      lost when resumed. Yet it's not a big problem because this driver
>      relies on the CPU to update the front framebuffer. We can see the
>      garbage data when resume from S3, but the screen will show the right
>      image as I move the cursor. This is due to the CPU repaint. v10 of
>      this patch makes S3 perfect by unpin all of the BOs in VRAM, evict
>      them all to system RAM in lsdc_drm_freeze().
>
> v10 -> v11:
>   1) On a double-screen case, The buffer object backing the single giant
>      framebuffer is referenced by two GEM objects; hence, it will be
>      pinned at least twice by prepare_fb() function. This causes its pin
>      count > 1. V10 of this patch only unpins VRAM BOs once when suspend,
>      which is not correct on double-screen case. V11 of this patch unpin
>      the BOs until its pin count reaches zero when suspend. Then, we make
>      the S3 support complete finally. With v11, I can't see any garbage
>      data when resume.
>
>   2) Fix vblank wait timeout when disable CRTC.
>   3) Test against IGT, at least fbdev test and kms_flip test passed.
>   4) Rewrite pixel PLL update function, magic numbers eliminated (Emil)
>   5) Drop a few common hardware features description in lsdc_desc (Emil)
>   6) Drop lsdc_mode_config_mode_valid(), instead add restrictions in dumb
>      create function. (Emil)
>   7) Untangle the ls7a1000 case and ls7a2000 case completely (Thomas)
>
> v11 -> v12:
>   none
>
> v12 -> v13:
>   1) Add benchmarks to figure out the bandwidth of the hardware platform.
>      Usage:
>      # cd /sys/kernel/debug/dri/0/
>      # cat benchmark
>
>   2) VRAM is filled with garbage data if uninitialized, add a buffer
>      clearing procedure (lsdc_bo_clear), clear the BO on creation time.
>   3) Update copyrights and adjust coding style (Huacai)
>
> v13 -> v14:
>   1) Trying to add async update support for cursor plane.
>
> v14 -> v15:
>   1) Add lsdc_vga_set_decode() funciton, which allow us remove multi-video
>      cards workaround, now it allow drm/loongson, drm/amdgpu, drm/etnaviv
>      co-exist in the system, more is also possible (Emil and Xuerui)
>   2) Fix typos and grammar mistakes as much as possible (Xuerui)
>   3) Unify copyrights as GPL-2.0+ (Xuerui)
>   4) Fix a bug introduce since V13, TTM may import BO from other drivers,
>      we shouldn't clear it on such a case.
>
> Sui Jingfeng (2):
>    drm: Add kms driver for loongson display controller
>    MAINTAINERS: add maintainers for DRM LOONGSON driver
>
>   MAINTAINERS                                   |    7 +
>   drivers/gpu/drm/Kconfig                       |    2 +
>   drivers/gpu/drm/Makefile                      |    1 +
>   drivers/gpu/drm/loongson/Kconfig              |   17 +
>   drivers/gpu/drm/loongson/Makefile             |   22 +
>   drivers/gpu/drm/loongson/loongson_device.c    |  102 ++
>   drivers/gpu/drm/loongson/loongson_module.c    |   33 +
>   drivers/gpu/drm/loongson/loongson_module.h    |   12 +
>   drivers/gpu/drm/loongson/lsdc_benchmark.c     |  133 +++
>   drivers/gpu/drm/loongson/lsdc_benchmark.h     |   13 +
>   drivers/gpu/drm/loongson/lsdc_crtc.c          | 1024 +++++++++++++++++
>   drivers/gpu/drm/loongson/lsdc_debugfs.c       |  110 ++
>   drivers/gpu/drm/loongson/lsdc_drv.c           |  458 ++++++++
>   drivers/gpu/drm/loongson/lsdc_drv.h           |  388 +++++++
>   drivers/gpu/drm/loongson/lsdc_gem.c           |  311 +++++
>   drivers/gpu/drm/loongson/lsdc_gem.h           |   37 +
>   drivers/gpu/drm/loongson/lsdc_gfxpll.c        |  199 ++++
>   drivers/gpu/drm/loongson/lsdc_gfxpll.h        |   52 +
>   drivers/gpu/drm/loongson/lsdc_i2c.c           |  179 +++
>   drivers/gpu/drm/loongson/lsdc_i2c.h           |   29 +
>   drivers/gpu/drm/loongson/lsdc_irq.c           |   74 ++
>   drivers/gpu/drm/loongson/lsdc_irq.h           |   16 +
>   drivers/gpu/drm/loongson/lsdc_output.h        |   21 +
>   drivers/gpu/drm/loongson/lsdc_output_7a1000.c |  178 +++
>   drivers/gpu/drm/loongson/lsdc_output_7a2000.c |  552 +++++++++
>   drivers/gpu/drm/loongson/lsdc_pixpll.c        |  481 ++++++++
>   drivers/gpu/drm/loongson/lsdc_pixpll.h        |   86 ++
>   drivers/gpu/drm/loongson/lsdc_plane.c         |  799 +++++++++++++
>   drivers/gpu/drm/loongson/lsdc_probe.c         |   56 +
>   drivers/gpu/drm/loongson/lsdc_probe.h         |   12 +
>   drivers/gpu/drm/loongson/lsdc_regs.h          |  406 +++++++
>   drivers/gpu/drm/loongson/lsdc_ttm.c           |  591 ++++++++++
>   drivers/gpu/drm/loongson/lsdc_ttm.h           |   99 ++
>   33 files changed, 6500 insertions(+)
>   create mode 100644 drivers/gpu/drm/loongson/Kconfig
>   create mode 100644 drivers/gpu/drm/loongson/Makefile
>   create mode 100644 drivers/gpu/drm/loongson/loongson_device.c
>   create mode 100644 drivers/gpu/drm/loongson/loongson_module.c
>   create mode 100644 drivers/gpu/drm/loongson/loongson_module.h
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_benchmark.c
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_benchmark.h
>   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_gfxpll.c
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_gfxpll.h
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_i2c.c
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_i2c.h
>   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.h
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_output_7a1000.c
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_output_7a2000.c
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_pixpll.c
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_pixpll.h
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_plane.c
>   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
>
-- 
Jingfeng