There is a display controller in loongson's LS2K1000 SoC and LS7A1000 bridge, and the DC in those chip is a PCI device. This display controller have two display pipes but with only one hardware cursor. Each way has a DVO output interface and the CRTC is able to scanout from 1920x1080 resolution at 60Hz. LS2K1000 is a SoC, only system memory is available. Therefore scanout form system memory is the only choice and we prefer the cma helper base solution even through it is possible to use VRAM helper base solution on ls2k1000 by carving out part of system memory as VRAM.
The dc in ls7a1000 can scanout from both the system memory and the dedicate VRAM attached to the ddr3 memory controller. Sadly, only scanout from the VRAM is proved to be a reliable solution for massive product. Scanout from the system memory suffer from some hardware deficiency which cause the screen flickering under RAM pressure. This is the reason why we integrate two distict helpers into one piece of device driver.
+------+ | DDR4 | +------+ || MC0 +-----------------------+------------+ +----------+ Hyper | LS7A1000 | DDR3 | +------+ | LS3A4000 |<--------->| +--------+ +-------+ | memory |<->| VRAM | | CPU |<--------->| | GC1000 | | LSDC | | controller | +------+ +----------+ Transport | +--------+ +-+---+-+ +------------| || MC1 +---------------|---|----------------+ +------+ | | | DDR4 | +-------+ DVO0 | | DVO1 +------+ +------+ VGA <--|ADV7125|<---------+ +------->|TFP410|--> DVI/HDMI +-------+ +------+
The above picture give a simple usage of LS7A1000, note that the encoder is not necessary adv7125 or tfp410, it is a choice of the downstream board manufacturer. Other candicate encoder can be ch7034b, sil9022 and ite66121 etc. This is the reason why we still need device tree to provide board specific information. Beside, the dc in both LS2L1000 and LS7A1000 have the vendor:device id of 0x0014:0x7a06. even the reverison id is also same. We can't tell it apart simply(this is the firmware engineer's mistake). But firmware already flushed to the board and sold out, so we resolve those issues by using the device tree which already have certain support.
Nevertheless, this patch try to provided a minimal support for this display controller which is mainly for graphic environment bring up. Hope that the code can speak for itself.
For LS7A1000, there are 4 gpios who register is located at dc register space which is used to emulation i2c. LS2K1000 and LS2K0500 SoC don't have those hardware, they use general purpose gpio or hardware i2c to serve this purpose. For ladc, there is only a 1:1 mapping of encoders and connectors.
+-------------------+ _________ | | | | | CRTC0 --> DVO0 ---------> Encoder0 --> Connector0 ---> | Monotor | | | ^ ^ |_________| | | | | | <----- i2c0 ----------------+ | LSDC IP CORE | | <----- i2c1 ----------------+ | | | | _________ | | | | | | | CRTC1 --> DVO1 ---------> Encoder1 --> Connector1 ---> | Panel | | | |_________| +-------------------+
Below is a brief introduction of loongson's CPU, bridge chip and SoC. LS2K1000 is a double core 1.0Ghz mips64r2 compatible SoC[1]. LS7A1000 is a bridge chip made by Loongson corporation which act as north and/or south bridge of loongson's desktop and server level processor. It is equivalent to RS780E or something like that. More details can be read from its user manual[2].
This bridge chip is typically use with LS3A3000, LS3A4000 and LS3A5000 cpu. LS3A3000 is 4 core 1.45gHz mips64r2 compatible cpu. LS3A4000 is 4 core 1.8gHz mips64r5 compatible cpu. LS3A5000 is 4 core 2.5gHz loongarch cpu[3].
v2: fixup warnings reported by kernel test robot
v3: fix more grammar mistakes in Kconfig reported by Randy Dunlap and give more details about lsdc.
v4: 1) Add dts required and explain why device tree is required. 2) Give more description about lsdc and vram helper base driver. 3) Fix warnings reported by kernel test robot. 4) Introduce stride_alignment member into struct lsdc_chip_desc, the stride alignment is 256 bytes for ls7a1000, ls2k1000 and ls2k0500 SoC. But ls7a2000 improve it to 32 bytes, We are prepare for extend the support for the on coming device.
v5: 1) using writel and readl replace writeq and readq, to fix kernel test robot report build error on other archtecture 2) set default fb format to XRGB8888 at crtc reset time. 3) fix typos.
[1] https://wiki.debian.org/InstallingDebianOn/Lemote/Loongson2K1000 [2] https://loongson.github.io/LoongArch-Documentation/Loongson-7A1000-usermanua... [3] https://loongson.github.io/LoongArch-Documentation/Loongson-3A5000-usermanua...
Reported-by: Randy Dunlap rdunlap@infradead.org Reported-by: kernel test robot Signed-off-by: suijingfeng suijingfeng@loongson.cn Signed-off-by: Sui Jingfeng 15330273260@189.cn
suijingfeng (3): drm/lsdc: add drm driver for loongson display controller dt-bindings: ls2k1000: add the display controller device node dt-bindings: mips: loongson: introduce board specific dts
arch/mips/boot/dts/loongson/lemote_a1901.dts | 64 ++ .../boot/dts/loongson/loongson64-2k1000.dtsi | 11 + .../boot/dts/loongson/ls3a4000_7a1000_evb.dts | 68 ++ arch/mips/boot/dts/loongson/ls7a-pch.dtsi | 2 +- drivers/gpu/drm/Kconfig | 2 + drivers/gpu/drm/Makefile | 1 + drivers/gpu/drm/lsdc/Kconfig | 38 + drivers/gpu/drm/lsdc/Makefile | 15 + drivers/gpu/drm/lsdc/lsdc_connector.c | 439 +++++++++ drivers/gpu/drm/lsdc/lsdc_connector.h | 60 ++ drivers/gpu/drm/lsdc/lsdc_crtc.c | 440 +++++++++ drivers/gpu/drm/lsdc/lsdc_drv.c | 845 ++++++++++++++++++ drivers/gpu/drm/lsdc/lsdc_drv.h | 216 +++++ drivers/gpu/drm/lsdc/lsdc_encoder.c | 79 ++ drivers/gpu/drm/lsdc/lsdc_i2c.c | 220 +++++ drivers/gpu/drm/lsdc/lsdc_i2c.h | 61 ++ drivers/gpu/drm/lsdc/lsdc_irq.c | 77 ++ drivers/gpu/drm/lsdc/lsdc_irq.h | 37 + drivers/gpu/drm/lsdc/lsdc_plane.c | 681 ++++++++++++++ drivers/gpu/drm/lsdc/lsdc_pll.c | 657 ++++++++++++++ drivers/gpu/drm/lsdc/lsdc_pll.h | 109 +++ drivers/gpu/drm/lsdc/lsdc_regs.h | 246 +++++ 22 files changed, 4367 insertions(+), 1 deletion(-) create mode 100644 arch/mips/boot/dts/loongson/lemote_a1901.dts create mode 100644 arch/mips/boot/dts/loongson/ls3a4000_7a1000_evb.dts create mode 100644 drivers/gpu/drm/lsdc/Kconfig create mode 100644 drivers/gpu/drm/lsdc/Makefile create mode 100644 drivers/gpu/drm/lsdc/lsdc_connector.c create mode 100644 drivers/gpu/drm/lsdc/lsdc_connector.h create mode 100644 drivers/gpu/drm/lsdc/lsdc_crtc.c create mode 100644 drivers/gpu/drm/lsdc/lsdc_drv.c create mode 100644 drivers/gpu/drm/lsdc/lsdc_drv.h create mode 100644 drivers/gpu/drm/lsdc/lsdc_encoder.c create mode 100644 drivers/gpu/drm/lsdc/lsdc_i2c.c create mode 100644 drivers/gpu/drm/lsdc/lsdc_i2c.h create mode 100644 drivers/gpu/drm/lsdc/lsdc_irq.c create mode 100644 drivers/gpu/drm/lsdc/lsdc_irq.h create mode 100644 drivers/gpu/drm/lsdc/lsdc_plane.c create mode 100644 drivers/gpu/drm/lsdc/lsdc_pll.c create mode 100644 drivers/gpu/drm/lsdc/lsdc_pll.h create mode 100644 drivers/gpu/drm/lsdc/lsdc_regs.h