[RESEND PATCH v1 4/4] doc: t-head: lpi4a: document Lichee PI 4A board

[Yixun Lan <dlan@gentoo.org>]

Reviewed-by: Wei Fu <wefu@redhat.com>
Signed-off-by: Yixun Lan <dlan@gentoo.org>
---
 doc/board/index.rst       |   1 +
 doc/board/thead/index.rst |   9 +++
 doc/board/thead/lpi4a.rst | 112 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 122 insertions(+)
 create mode 100644 doc/board/thead/index.rst
 create mode 100644 doc/board/thead/lpi4a.rst

diff --git a/doc/board/index.rst b/doc/board/index.rst
index 9ef25b1091..aadc90af89 100644
--- a/doc/board/index.rst
+++ b/doc/board/index.rst
@@ -45,6 +45,7 @@ Board-specific doc
    starfive/index
    ste/index
    tbs/index
+   thead/index
    ti/index
    toradex/index
    variscite/index
diff --git a/doc/board/thead/index.rst b/doc/board/thead/index.rst
new file mode 100644
index 0000000000..41566d3a36
--- /dev/null
+++ b/doc/board/thead/index.rst
@@ -0,0 +1,9 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+T-HEAD
+========
+
+.. toctree::
+   :maxdepth: 1
+
+   lpi4a
diff --git a/doc/board/thead/lpi4a.rst b/doc/board/thead/lpi4a.rst
new file mode 100644
index 0000000000..3764e732af
--- /dev/null
+++ b/doc/board/thead/lpi4a.rst
@@ -0,0 +1,112 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+Sipeed's Lichee PI 4A based on T-HEAD TH1520 SoC
+====================
+
+TH1520 RISC-V SoC
+---------------------
+The TH1520 is 4+2 core 64-bit RISC-V SoC from Alibaba T-HEAD, it's capable of
+running highest CPU frequency at 2.5 GHz, integrate Imagination GPU for graphics,
+also with 4 TOPS NPU for AI acceleration.
+
+Mainline support
+----------------
+
+The support for following drivers are already enabled:
+
+1. ns16550 UART Driver.
+
+Building
+~~~~~~~~
+
+1. Add the RISC-V toolchain to your PATH.
+2. Setup ARCH & cross compilation environment variable:
+
+.. code-block:: none
+
+   export CROSS_COMPILE=<riscv64 toolchain prefix>
+
+The U-Boot is capable of running in M-Mode, so we can directly build it.
+
+.. code-block:: console
+
+	cd <U-Boot-dir>
+	make th1520_lpi4a_defconfig
+	make
+
+This will generate u-boot-dtb.bin
+
+Booting
+~~~~~~~
+
+Currently, we rely on vendor u-boot to initialize the clock, pinctrl subsystem,
+and chain load the mainline u-boot image either via tftp or emmc storage,
+then bootup from it.
+
+Sample boot log from Lichee PI 4A board via tftp
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. code-block:: none
+
+	brom_ver 8
+	[APP][E] protocol_connect failed, exit.
+
+	U-Boot SPL 2020.01-00016-g8c870a6be8 (May 20 2023 - 01:04:49 +0000)
+	FM[1] lpddr4x dualrank freq=3733 64bit dbi_off=n sdram init
+	ddr initialized, jump to uboot
+	image has no header
+
+
+	U-Boot 2020.01-00016-g8c870a6be8 (May 20 2023 - 01:04:49 +0000)
+
+	CPU:   rv64imafdcvsu
+	Model: T-HEAD c910 light
+	DRAM:  8 GiB
+	C910 CPU FREQ: 750MHz
+	AHB2_CPUSYS_HCLK FREQ: 250MHz
+	AHB3_CPUSYS_PCLK FREQ: 125MHz
+	PERISYS_AHB_HCLK FREQ: 250MHz
+	PERISYS_APB_PCLK FREQ: 62MHz
+	GMAC PLL POSTDIV FREQ: 1000MHZ
+	DPU0 PLL POSTDIV FREQ: 1188MHZ
+	DPU1 PLL POSTDIV FREQ: 1188MHZ
+	MMC:   sdhci@ffe7080000: 0, sd@ffe7090000: 1
+	Loading Environment from MMC... OK
+	Error reading output register
+	Warning: cannot get lcd-en GPIO
+	LCD panel cannot be found : -121
+	splash screen startup cost 16 ms
+	In:    serial
+	Out:   serial
+	Err:   serial
+	Net:
+	Warning: ethernet@ffe7070000 using MAC address from ROM
+	eth0: ethernet@ffe7070000ethernet@ffe7070000:0 is connected to ethernet@ffe7070000.  Reconnecting to ethernet@ffe7060000
+
+	Warning: ethernet@ffe7060000 (eth1) using random MAC address - 42:25:d4:16:5f:fc
+	, eth1: ethernet@ffe7060000
+	Hit any key to stop autoboot:  2
+	ethernet@ffe7060000 Waiting for PHY auto negotiation to complete.. done
+	Speed: 1000, full duplex
+	Using ethernet@ffe7070000 device
+	TFTP from server 192.168.8.50; our IP address is 192.168.8.45
+	Filename 'u-boot-dtb.bin'.
+	Load address: 0x1c00000
+	Loading: * #########################
+		 8 MiB/s
+	done
+	Bytes transferred = 376686 (5bf6e hex)
+	## Starting application at 0x01C00000 ...
+
+        U-Boot 2023.07-rc2-00004-g1befbe31c1 (May 23 2023 - 18:40:01 +0800)
+
+        CPU:   rv64imafdc
+        Model: Sipeed Lichee Pi 4A
+        DRAM:  8 GiB
+        Core:  13 devices, 6 uclasses, devicetree: separate
+        Loading Environment from <NULL>... OK
+        In:    serial@ffe7014000
+        Out:   serial@ffe7014000
+        Err:   serial@ffe7014000
+        Model: Sipeed Lichee Pi 4A
+        LPI4A=>
-- 
2.40.0