[PATCH v10 0/2] drm: add kms driver for loongson display controller

From: Sui Jingfeng
Date: Mon Apr 03 2023 - 13:13:16 EST

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

This display controller is a PCI device in all of chips mentiond, it has
two display pipes which support primary planes and cursor plane. For the
DC in ls7a1000 and ls2k1000, each display pipe 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 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 used to scan out the 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 which 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.

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 | 16 +
drivers/gpu/drm/loongson/lsdc_crtc.c | 381 ++++++++++++++++
drivers/gpu/drm/loongson/lsdc_debugfs.c | 261 +++++++++++
drivers/gpu/drm/loongson/lsdc_drv.c | 526 ++++++++++++++++++++++
drivers/gpu/drm/loongson/lsdc_drv.h | 324 ++++++++++++++
drivers/gpu/drm/loongson/lsdc_gem.c | 294 +++++++++++++
drivers/gpu/drm/loongson/lsdc_gem.h | 26 ++
drivers/gpu/drm/loongson/lsdc_i2c.c | 171 +++++++
drivers/gpu/drm/loongson/lsdc_irq.c | 86 ++++
drivers/gpu/drm/loongson/lsdc_irq.h | 12 +
drivers/gpu/drm/loongson/lsdc_output.c | 563 ++++++++++++++++++++++++
drivers/gpu/drm/loongson/lsdc_output.h | 14 +
drivers/gpu/drm/loongson/lsdc_plane.c | 432 ++++++++++++++++++
drivers/gpu/drm/loongson/lsdc_pll.c | 338 ++++++++++++++
drivers/gpu/drm/loongson/lsdc_pll.h | 76 ++++
drivers/gpu/drm/loongson/lsdc_probe.c | 86 ++++
drivers/gpu/drm/loongson/lsdc_probe.h | 11 +
drivers/gpu/drm/loongson/lsdc_regs.h | 370 ++++++++++++++++
drivers/gpu/drm/loongson/lsdc_ttm.c | 438 ++++++++++++++++++
drivers/gpu/drm/loongson/lsdc_ttm.h | 72 +++
24 files changed, 4524 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

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2.25.1