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ffdb20bea1
This adds a SPI flash driver which simulates SPI flash clients. Currently supports the bare min that U-Boot requires: you can probe, read, erase, and write. Should be easy to extend to make it behave more exactly like a real SPI flash, but this is good enough to merge now. sjg@chromium.org added a README and tidied up code a little. Added a required map_sysmem() for sandbox. Signed-off-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Simon Glass <sjg@chromium.org>
92 lines
2.4 KiB
Plaintext
92 lines
2.4 KiB
Plaintext
/*
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* Copyright (c) 2011 The Chromium OS Authors.
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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Native Execution of U-Boot
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==========================
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The 'sandbox' architecture is designed to allow U-Boot to run under Linux on
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almost any hardware. To achieve this it builds U-Boot (so far as possible)
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as a normal C application with a main() and normal C libraries.
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All of U-Boot's architecture-specific code therefore cannot be built as part
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of the sandbox U-Boot. The purpose of running U-Boot under Linux is to test
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all the generic code, not specific to any one architecture. The idea is to
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create unit tests which we can run to test this upper level code.
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CONFIG_SANDBOX is defined when building a native board.
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The chosen vendor and board names are also 'sandbox', so there is a single
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board in board/sandbox/sandbox.
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CONFIG_SANDBOX_BIG_ENDIAN should be defined when running on big-endian
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machines.
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Note that standalone/API support is not available at present.
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The serial driver is a very simple implementation which reads and writes to
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the console. It does not set the terminal into raw mode, so cursor keys and
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history will not work yet.
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SPI Emulation
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-------------
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Sandbox supports SPI and SPI flash emulation.
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This is controlled by the spi_sf argument, the format of which is:
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bus:cs:device:file
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bus - SPI bus number
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cs - SPI chip select number
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device - SPI device emulation name
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file - File on disk containing the data
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For example:
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dd if=/dev/zero of=spi.bin bs=1M count=4
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./u-boot --spi_sf 0:0:M25P16:spi.bin
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With this setup you can issue SPI flash commands as normal:
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=>sf probe
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SF: Detected M25P16 with page size 64 KiB, total 2 MiB
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=>sf read 0 0 10000
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SF: 65536 bytes @ 0x0 Read: OK
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=>
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Since this is a full SPI emulation (rather than just flash), you can
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also use low-level SPI commands:
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=>sspi 0:0 32 9f
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FF202015
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This is issuing a READ_ID command and getting back 20 (ST Micro) part
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0x2015 (the M25P16).
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Drivers are connected to a particular bus/cs using sandbox's state
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structure (see the 'spi' member). A set of operations must be provided
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for each driver.
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Configuration settings for the curious are:
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CONFIG_SANDBOX_SPI_MAX_BUS
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The maximum number of SPI buses supported by the driver (default 1).
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CONFIG_SANDBOX_SPI_MAX_CS
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The maximum number of chip selects supported by the driver
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(default 10).
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CONFIG_SPI_IDLE_VAL
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The idle value on the SPI bus
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Tests
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-----
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So far we have no tests, but when we do these will be documented here.
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