/*
* Copyright (c) 2011 The Chromium OS Authors.
*
- * SPDX-License-Identifier: GPL-2.0+
+ * SPDX-License-Identifier: GPL-2.0+
*/
Native Execution of U-Boot
history will not work yet.
+SPI Emulation
+-------------
+
+Sandbox supports SPI and SPI flash emulation.
+
+This is controlled by the spi_sf argument, the format of which is:
+
+ bus:cs:device:file
+
+ bus - SPI bus number
+ cs - SPI chip select number
+ device - SPI device emulation name
+ file - File on disk containing the data
+
+For example:
+
+ dd if=/dev/zero of=spi.bin bs=1M count=4
+ ./u-boot --spi_sf 0:0:M25P16:spi.bin
+
+With this setup you can issue SPI flash commands as normal:
+
+=>sf probe
+SF: Detected M25P16 with page size 64 KiB, total 2 MiB
+=>sf read 0 0 10000
+SF: 65536 bytes @ 0x0 Read: OK
+=>
+
+Since this is a full SPI emulation (rather than just flash), you can
+also use low-level SPI commands:
+
+=>sspi 0:0 32 9f
+FF202015
+
+This is issuing a READ_ID command and getting back 20 (ST Micro) part
+0x2015 (the M25P16).
+
+Drivers are connected to a particular bus/cs using sandbox's state
+structure (see the 'spi' member). A set of operations must be provided
+for each driver.
+
+
+Configuration settings for the curious are:
+
+CONFIG_SANDBOX_SPI_MAX_BUS
+ The maximum number of SPI buses supported by the driver (default 1).
+
+CONFIG_SANDBOX_SPI_MAX_CS
+ The maximum number of chip selects supported by the driver
+ (default 10).
+
+CONFIG_SPI_IDLE_VAL
+ The idle value on the SPI bus
+
+
Tests
-----