Add script for writing to flash on arty

Add script for writing to flash on arty

You must have openocd 0.10.0 installed.

$ ./openocd/flash-arty ~/microwatt-fusesoc/build/microwatt_0/arty_a7-35-vivado/microwatt_0.bit
Open On-Chip Debugger 0.10.0
Licensed under GNU GPL v2
For bug reports, read
	http://openocd.org/doc/doxygen/bugs.html
none separate
Info : auto-selecting first available session transport "jtag". To override use 'transport select <transport>'.
adapter speed: 25000 kHz
fpga_program
Info : ftdi: if you experience problems at higher adapter clocks, try the command "ftdi_tdo_sample_edge falling"
Info : clock speed 25000 kHz
Info : JTAG tap: xc7.tap tap/device found: 0x0362d093 (mfg: 0x049 (Xilinx), part: 0x362d, ver: 0x0)
loaded file microwatt/openocd/bscan_spi_xc7a35t.bit to pld device 0 in 0s 136459us
Info : JTAG tap: xc7.tap tap/device found: 0x0362d093 (mfg: 0x049 (Xilinx), part: 0x362d, ver: 0x0)
Info : Found flash device 'micron n25q128' (ID 0x0018ba20)
flash 'jtagspi' found at 0x00000000
auto erase enabled
Info : Found flash device 'micron n25q128' (ID 0x0018ba20)
Info : Found flash device 'micron n25q128' (ID 0x0018ba20)
Info : Found flash device 'micron n25q128' (ID 0x0018ba20)
Info : sector 0 took 241 ms
Info : sector 1 took 242 ms
Info : sector 2 took 241 ms
Info : sector 3 took 247 ms
Info : sector 4 took 253 ms
Info : sector 5 took 244 ms
Info : sector 6 took 246 ms
Info : sector 7 took 237 ms
Info : sector 8 took 258 ms
Info : sector 9 took 260 ms
Info : sector 10 took 262 ms
Info : sector 11 took 253 ms
Info : sector 12 took 256 ms
Info : sector 13 took 255 ms
wrote 917504 bytes from file microwatt-fusesoc/build/microwatt_0/arty_a7-35-vivado/microwatt_0.bit in 9.642746s (92.920 KiB/s)
Info : Found flash device 'micron n25q128' (ID 0x0018ba20)
read 907483 bytes from file microwatt-fusesoc/build/microwatt_0/arty_a7-35-vivado/microwatt_0.bit and flash bank 0 at offset 0x00000000 in 0.557387s (1589.944 KiB/s)
contents match

Signed-off-by: Joel Stanley <joel@jms.id.au>