Sandbox SPI/SPI Flash Implementation
====================================

U-Boot supports SPI and SPI flash emuation 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
<vapier@gentoo.org>.