f39db26c - drm: Add kms driver for loongson display controller

Thu, 15 Jun 2023 14:36:12 +0000

drm: Add kms driver for loongson display controllerLoongson display controller IP has been integrated in both Loongson northbridge chipset (ls7a1000/ls7a2000) and Loongson SoCs (ls2k1000/ls2k2000).It has even been included in Loongson's BMC products. It has two displaypipes, 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, eachdisplay pipe is equipped with a built-in HDMI encoder, which is compliantwith the HDMI 1.4 specification. The first display pipe is also equippedwith a transparent VGA encoder, which is parallel with the HDMI encoder.To get a decent performance for writing framebuffer data to the VRAM, thewrite 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) support4) 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 VRAMv8 -> 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: nonev12 -> 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.Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Thomas Zimmermann Cc: David Airlie Cc: Daniel Vetter Cc: Sumit Semwal Cc: "Christian König" Cc: Nathan Chancellor Cc: Emil Velikov Cc: Geert Uytterhoeven Cc: loongson-kernel@lists.loongnix.cnTested-by: Liu Peibao Tested-by: Li Yi Acked-by: Thomas Zimmermann Signed-off-by: Sui Jingfeng Link: https://patchwork.freedesktop.org/patch/msgid/20230615143613.1236245-2-15330273260@189.cn List of files: /linux-6.15/drivers/gpu/drm/loongson/Makefile

Changes in Makefile

f39db26c - drm: Add kms driver for loongson display controller