[Linaro-mm-sig] Re: [PATCH v12 0/2] drm: add kms driver for loongson display controller

Hi,

If there are bugs, We will take the responsibility to fix.

Is there any chance to merge this patch?

comments and review are also welcome, help please!

On 2023/5/4 16:04, Sui Jingfeng wrote:

Loongson display controller IP has been integrated in both Loongson north bridge chipset(ls7a1000/ls7a2000) and Loongson SoCs(ls2k1000/ls2k2000), it has been even included in Loongson self-made BMC products.

This display controller is a PCI device. It has two display pipes and each display pipe support a primary plane and a cursor plane. For the DC in the ls7a1000 and ls2k1000, each display pipe has a DVO output interface which provide RGB888 signals, vertical & horizontal synchronisations and pixel clock. Each CRTC is able to support 1920x1080@60Hz, the maximum resolution of each display pipe 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 the 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 compare with the one in old chips, besides above feature, it has two hardware cursors, two hardware vblank counter and two scanout position recorders unit. It also support tiled framebuffer format which can be scanout the tiled framebuffer rendered by the LoongGPU directly.

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. Untangle 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 latest kernel. Thus, we send V7 to revival them.

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

v8 -> v9:

1. Select I2C and I2C_ALGOBIT in Kconfig and should depend on MMU.
2. Using pci_get_domain_bus_and_slot to get the GPU device.
3. Other minor improvements.

Those patches are tested on ls3a5000 + ls7a1000 CRB, ls3a5000 + ls7a2000 evb, and lemote a1901 board(ls3a4000 + ls7a1000). On loongson mips CPU, the write combine support should be enabled, to get a decent performance for writing framebuffer data to the VRAM.

v9 -> v10:

1. Revise lsdc_drm_freeze() to implement S3 completely and correctly. I suddenly realized that pinned buffer can not move and VRAM lost power when sleep to RAM. Thus, the data in the buffer who is pinned in VRAM will get lost when resume. Yet it's not big problem because we are software rendering solution which relay on the CPU update the front framebuffer. We can see the garbage data when resume from S3, but the screen will show correct image as I move the cursor. This is due to the cpu repaint. v10 of this patch make S3 perfect by unpin all of BOs in VRAM, evict them all to system RAM.

v10 -> v11:

1. On double screen case, the single giant framebuffer is referenced by two GEM object, hence, it will be pinned by prepare_fb() at lease two times. This cause its pin count > 1. V10 of this patch only unpin VRAM BOs once when suspend, which is not correct on double screen case. V11 of this patch unpin BOs until its pin count reach to zero when suspend. Then, we make the S3 support complete finally. With v11, I can't see any garbage data after resume. Teste on both ls7a1000 and ls7a2000 platform, with single screen and double screen configuration tested.
2. Fix vblank wait timeout when disable CRTC.
3. Test against IGT, at least fbdev test and kms_flip test of it passed, while most tests of it 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

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 | 17 + drivers/gpu/drm/loongson/Makefile | 19 + drivers/gpu/drm/loongson/ls7a1000_outputs.c | 160 +++ drivers/gpu/drm/loongson/ls7a2000_outputs.c | 534 ++++++++++ drivers/gpu/drm/loongson/lsdc_crtc.c | 1064 +++++++++++++++++++ drivers/gpu/drm/loongson/lsdc_debugfs.c | 78 ++ drivers/gpu/drm/loongson/lsdc_device.c | 104 ++ drivers/gpu/drm/loongson/lsdc_drv.c | 484 +++++++++ drivers/gpu/drm/loongson/lsdc_drv.h | 485 +++++++++ drivers/gpu/drm/loongson/lsdc_gem.c | 319 ++++++ 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 | 81 ++ drivers/gpu/drm/loongson/lsdc_irq.h | 16 + drivers/gpu/drm/loongson/lsdc_output.h | 21 + drivers/gpu/drm/loongson/lsdc_pixpll.c | 485 +++++++++ drivers/gpu/drm/loongson/lsdc_pixpll.h | 86 ++ drivers/gpu/drm/loongson/lsdc_plane.c | 639 +++++++++++ drivers/gpu/drm/loongson/lsdc_probe.c | 56 + drivers/gpu/drm/loongson/lsdc_probe.h | 12 + drivers/gpu/drm/loongson/lsdc_regs.h | 400 +++++++ drivers/gpu/drm/loongson/lsdc_ttm.c | 547 ++++++++++ drivers/gpu/drm/loongson/lsdc_ttm.h | 88 ++ 29 files changed, 6201 insertions(+) create mode 100644 drivers/gpu/drm/loongson/Kconfig create mode 100644 drivers/gpu/drm/loongson/Makefile create mode 100644 drivers/gpu/drm/loongson/ls7a1000_outputs.c create mode 100644 drivers/gpu/drm/loongson/ls7a2000_outputs.c 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_device.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_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