| Sandbox SPI/SPI Flash Implementation |
| ==================================== |
| |
| U-Boot supports SPI and SPI flash emulation in sandbox. This must be enabled |
| via a device tree. |
| |
| For example: |
| |
| spi@0 { |
| #address-cells = <1>; |
| #size-cells = <0>; |
| reg = <0 1>; |
| compatible = "sandbox,spi"; |
| cs-gpios = <0>, <&gpio_a 0>; |
| spi.bin@0 { |
| reg = <0>; |
| compatible = "spansion,m25p16", "jedec,spi-nor"; |
| spi-max-frequency = <40000000>; |
| sandbox,filename = "spi.bin"; |
| }; |
| }; |
| |
| Supported chips are W25Q16 (2MB), W25Q32 (4MB) and W25Q128 (16MB). Once |
| U-Boot it started you can use 'sf' commands as normal. For example: |
| |
| $ dd if=/dev/zero of=spi.bin bs=1M count=2 |
| $ u-boot -T |
| |
| Since the SPI bus is fully implemented as well as the SPI flash connected to |
| it, you can also use low-level SPI commands to access the flash. For example |
| this reads the device ID from the emulated chip: |
| |
| => sspi 0 32 9f |
| SF: Detected m25p16 with page size 256 Bytes, erase size 64 KiB, total 2 MiB |
| FF202015 |
| |
| |
| Simon Glass |
| sjg@chromium.org |
| 7/11/2013 |
| Note that the sandbox SPI implementation was written by Mike Frysinger |
| <vapier@gentoo.org>. |
