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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>.
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