flash: Add support for Atheros (ath79) SPI interface

Supported SoCs: AR71xx, AR724x, AR91xx, AR93xx, QCA9558

Extended and revised version of my original patch submitted by Dmytro
here: http://openocd.zylin.com/#/c/3390

This driver is using pure SPI mode, so the flash base address is not
used except some flash commands (e.g. "flash program") need it to
distinguish the banks.

Example config with all 3 chip selects:
flash bank flash0 ath79 0 0 0 0 $_TARGETNAME cs0
flash bank flash1 ath79 0x10000000 0 0 0 $_TARGETNAME cs1
flash bank flash2 ath79 0x20000000 0 0 0 $_TARGETNAME cs2

Example usage:
> flash probe flash0
Found flash device 'win w25q128fv' (ID 0x001840ef)
flash 'ath79' found at 0x00000000
> flash probe flash1
No SPI flash found
> flash probe flash2
No SPI flash found
> flash banks
> flash read_bank flash0 /tmp/test.bin 0x00000000 0x1000
reading 4096 bytes from flash @0x00000000
wrote 4096 bytes to file /tmp/test.bin from flash bank 0 at offset
0x00000000 in 28.688066s (0.139 KiB/s)

Change-Id: I5feb697722c07e83a9c1b361a9db7b06bc699aa8
Signed-off-by: Tobias Diedrich <ranma+openocd@tdiedrich.de>
Reviewed-on: http://openocd.zylin.com/3612
Tested-by: jenkins
Reviewed-by: Dmytro <dioptimizer@hotmail.com>
Reviewed-by: Paul Fertser <fercerpav@gmail.com>

1 files changed, 39 insertions, 0 deletions

diff --git a/doc/openocd.texi b/doc/openocd.texi
index 373eacb..59d2d4f 100644
--- a/doc/openocd.texi
+++ b/doc/openocd.texi
@@ -4999,6 +4999,45 @@ flash bank $_FLASHNAME mrvlqspi 0x0 0 0 0 $_TARGETNAME 0x46010000
 
 @end deffn
 
+@deffn {Flash Driver} ath79
+@cindex Atheros ath79 SPI driver
+@cindex ath79
+Members of ATH79 SoC family from Atheros include a SPI interface with 3
+chip selects.
+On reset a SPI flash connected to the first chip select (CS0) is made
+directly read-accessible in the CPU address space (up to 16MBytes)
+and is usually used to store the bootloader and operating system.
+Normal OpenOCD commands like @command{mdw} can be used to display
+the flash content while it is in memory-mapped mode (only the first
+4MBytes are accessible without additional configuration on reset).
+
+The setup command only requires the @var{base} parameter in order
+to identify the memory bank. The actual value for the base address
+is not otherwise used by the driver. However the mapping is passed
+to gdb. Thus for the memory mapped flash (chipselect CS0) the base
+address should be the actual memory mapped base address. For unmapped
+chipselects (CS1 and CS2) care should be taken to use a base address
+that does not overlap with real memory regions.
+Additional information, like flash size, are detected automatically.
+An optional additional parameter sets the chipselect for the bank,
+with the default CS0.
+CS1 and CS2 require additional GPIO setup before they can be used
+since the alternate function must be enabled on the GPIO pin
+CS1/CS2 is routed to on the given SoC.
+
+@example
+flash bank $_FLASHNAME ath79 0 0 0 0 $_TARGETNAME
+
+# When using multiple chipselects the base should be different for each,
+# otherwise the write_image command is not able to distinguish the
+# banks.
+flash bank flash0 ath79 0x00000000 0 0 0 $_TARGETNAME cs0
+flash bank flash1 ath79 0x10000000 0 0 0 $_TARGETNAME cs1
+flash bank flash2 ath79 0x20000000 0 0 0 $_TARGETNAME cs2
+@end example
+
+@end deffn
+
 @subsection Internal Flash (Microcontrollers)
 
 @deffn {Flash Driver} aduc702x