Sandbox SPI/SPI Flash Implementation ==================================== U-Boot supports SPI and SPI flash emulation in sandbox. This must be enabled using the --spi_sf paramter when starting U-Boot. For example: $ make O=sandbox sandbox_config $ make O=sandbox $ ./sandbox/u-boot --spi_sf 0:0:W25Q128:b/chromeos_peach/out/image.bin The four parameters to spi_sf are: SPI bus number (typically 0) SPI chip select number (typically 0) SPI chip to emulate File containing emulated data Supported chips are W25Q16 (2MB), W25Q32 (4MB) and W25Q128 (16MB). Once U-Boot it started you can use 'sf' commands as normal. For example: $ ./b/sandbox/u-boot --spi_sf 0:0:W25Q128:b/chromeos_peach/out/image.bin \ -c "sf probe; sf test 0 100000; sf read 0 1000 1000; \ sf erase 1000 1000; sf write 0 1000 1000" U-Boot 2013.10-00237-gd4e0fdb (Nov 07 2013 - 20:08:15) DRAM: 128 MiB Using default environment In: serial Out: serial Err: serial SF: Detected W25Q128BV with page size 256 Bytes, erase size 4 KiB, total 16 MiB SPI flash test: 0 erase: 1 ticks, 1024000 KiB/s 8192.000 Mbps 1 check: 2 ticks, 512000 KiB/s 4096.000 Mbps 2 write: 6 ticks, 170666 KiB/s 1365.328 Mbps 3 read: 0 ticks, 1048576000 KiB/s -201326.-592 Mbps Test passed 0 erase: 1 ticks, 1024000 KiB/s 8192.000 Mbps 1 check: 2 ticks, 512000 KiB/s 4096.000 Mbps 2 write: 6 ticks, 170666 KiB/s 1365.328 Mbps 3 read: 0 ticks, 1048576000 KiB/s -201326.-592 Mbps SF: 4096 bytes @ 0x1000 Read: OK SF: 4096 bytes @ 0x1000 Erased: OK SF: 4096 bytes @ 0x1000 Written: OK 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 FFEF4018 Simon Glass sjg@chromium.org 7/11/2013 Note that the sandbox SPI implementation was written by Mike Frysinger .