[PATCH v1 8/8] riscv: Add support for SPI on Kendryte K210

[Sean Anderson <seanga2@gmail.com>]

This patch enables configs necessary for usign SPI. It also adds some
documentation.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
---

 board/sipeed/maix/Kconfig          | 10 ++++
 configs/sipeed_maix_bitm_defconfig |  8 +++
 doc/board/sipeed/maix.rst          | 94 +++++++++++++++++++-----------
 3 files changed, 79 insertions(+), 33 deletions(-)

diff --git a/board/sipeed/maix/Kconfig b/board/sipeed/maix/Kconfig
index a5a095d4ff..8ce7a11a9f 100644
--- a/board/sipeed/maix/Kconfig
+++ b/board/sipeed/maix/Kconfig
@@ -57,4 +57,14 @@ config BOARD_SPECIFIC_OPTIONS
 	imply CMD_GPIO
 	imply LED
 	imply LED_GPIO
+	imply SPI
+	imply DESIGNWARE_SPI
+	imply SPI_FLASH_WINBOND
+	imply DM_MTD
+	imply SPI_FLASH_MTD
+	imply CMD_MTD
+	imply ENV_IS_IN_SPI_FLASH
+	imply MMC
+	imply MMC_BROKEN_CD
+	imply MMC_SPI
 endif
diff --git a/configs/sipeed_maix_bitm_defconfig b/configs/sipeed_maix_bitm_defconfig
index f48f7f06e9..7f644e7a37 100644
--- a/configs/sipeed_maix_bitm_defconfig
+++ b/configs/sipeed_maix_bitm_defconfig
@@ -1,6 +1,14 @@
 CONFIG_RISCV=y
+CONFIG_ENV_SIZE=0x2000
+CONFIG_ENV_SECT_SIZE=0x1000
+CONFIG_ENV_OFFSET=0x7C000
+CONFIG_ENV_OFFSET_REDUND=0x7E000
 CONFIG_TARGET_SIPEED_MAIX=y
 CONFIG_ARCH_RV64I=y
+CONFIG_USE_BOOTCOMMAND=y
+CONFIG_BOOTCOMMAND="sf probe;mtd read kernel 80000000;go 80000000"
+CONFIG_MTDIDS_DEFAULT="nor0=spi3.0"
+CONFIG_MTDPARTS_DEFAULT="spi3.0:496k(u-boot),16k(env),5632k(kernel),10240k(data)"
 CONFIG_SYS_REDUNDAND_ENVIRONMENT=y
 # CONFIG_NET is not set
 # CONFIG_INPUT is not set
diff --git a/doc/board/sipeed/maix.rst b/doc/board/sipeed/maix.rst
index 312da1e7bb..0216f9b893 100644
--- a/doc/board/sipeed/maix.rst
+++ b/doc/board/sipeed/maix.rst
@@ -46,42 +46,14 @@ Boot output should look like the following:
     U-Boot 2020.04-rc2-00087-g2221cc09c1-dirty (Feb 28 2020 - 13:53:09 -0500)
 
     DRAM:  8 MiB
+    MMC:   spi at 53000000:slot at 0: 0
     In:    serial at 38000000
     Out:   serial at 38000000
     Err:   serial at 38000000
-    =>
-
-Loading Images
-^^^^^^^^^^^^^^
-
-To load a kernel, transfer it over serial.
-
-.. code-block:: none
-
-    => loady 80000000 1500000
-    ## Switch baudrate to 1500000 bps and press ENTER ...
-
-    *** baud: 1500000
-
-    *** baud: 1500000 ***
-    ## Ready for binary (ymodem) download to 0x80000000 at 1500000 bps...
-    C
-    *** file: loader.bin
-    $ sz -vv loader.bin
-    Sending: loader.bin
-    Bytes Sent:2478208   BPS:72937
-    Sending:
-    Ymodem sectors/kbytes sent:   0/ 0k
-    Transfer complete
-
-    *** exit status: 0 ***
-    ## Total Size      = 0x0025d052 = 2478162 Bytes
-    ## Switch baudrate to 115200 bps and press ESC ...
-
-    *** baud: 115200
-
-    *** baud: 115200 ***
-    =>
+    Hit any key to stop autoboot:  0
+    SF: Detected w25q128fw with page size 256 Bytes, erase size 4 KiB, total 16 MiB
+    Reading 5242880 byte(s) at offset 0x00000000
+    ## Starting application at 0x80000000 ...
 
 Running Programs
 ^^^^^^^^^^^^^^^^
@@ -163,6 +135,62 @@ To run legacy images, use the ``bootm`` command:
     argv[0] = "<NULL>"
     Hit any key to exit ...
 
+Flashing Images
+---------------
+
+To flash a kernel, transfer it over serial, then write it to the kernel
+partition.
+
+.. code-block:: none
+
+    => loady 80000000 1500000
+    ## Switch baudrate to 1500000 bps and press ENTER ...
+
+    *** baud: 1500000
+
+    *** baud: 1500000 ***
+    ## Ready for binary (ymodem) download to 0x80000000 at 1500000 bps...
+    C
+    *** file: loader.bin
+    $ sz -vv loader.bin
+    Sending: loader.bin
+    Bytes Sent:2478208   BPS:72937
+    Sending:
+    Ymodem sectors/kbytes sent:   0/ 0k
+    Transfer complete
+
+    *** exit status: 0 ***
+    ## Total Size      = 0x0025d052 = 2478162 Bytes
+    ## Switch baudrate to 115200 bps and press ESC ...
+
+    *** baud: 115200
+
+    *** baud: 115200 ***
+    => sf probe
+    SF: Detected w25q128fw with page size 256 Bytes, erase size 4 KiB, total 16 MiB
+    => mtd write kernel 80000000 0 25d052
+    Writing 2478162 byte(s) at offset 0x00000000
+
+Partition Scheme
+^^^^^^^^^^^^^^^^
+
+There is no partition scheme specified by the manufacturer. The only requirement
+imposed by the firmware is that offset 0 will be loaded and ran. The default
+partition scheme is
+
+========= ======== ======
+Partition Offset   Size
+========= ======== ======
+u-boot    0x000000 496k
+env       0x07C000 16k
+kernel    0x080000 5M
+data      0x580000 10.5M
+========= ======== ======
+
+**NB:** kflash adds a 5-byte header to payloads (and a 32-byte trailer) to all
+payloads it flashes. If you use kflash to flash your payload, you will need to
+account for this header when specifying what offset in spi flash to load from.
+
 Pin Assignment
 --------------
 
-- 
2.25.0