commit 618994707d5ba556704ad9555191379cf46df6ae
author Steve Markgraf <steve@steve-m.de> Mon Jan 09 23:06:52 2023 +0100
committer Nico Huber <nico.h@gmx.de> Sat Mar 04 12:33:03 2023 +0000
tree ad771fb01ca88cbf4ed3e93da0576f4a831a3929
parent 28790a23f71d942f7ec9aa03c5ec90fb90503d0f

programmer: Add bitbanging programmer driver for Linux libgpiod

With this driver, any single board computer, old smartphone, etc. with
a few spare GPIOs can be used for flashrom.

Tested by reading of a 2048 kB flash chip on a Qualcomm MSM8916 SoC
@800 MHz, ran the following command:

time flashrom -p linux_gpiod:gpiochip=0,cs=18,sck=19,mosi=13,miso=56 -r test.bin

This command uses /dev/gpiochip0 with the specified GPIO numbers for the
SPI lines. All arguments are mandatory.

Output:
[...]
Found GigaDevice flash chip "GD25LQ16" (2048 kB, SPI) on linux_gpiod.
[...]
real    1m 33.96s

Change-Id: Icad3eb7764f28feaea51bda3a7893da724c86d06
Signed-off-by: Steve Markgraf <steve@steve-m.de>
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/73290
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

meson.build

diff --git a/meson.build b/meson.build
index cd98e5b..3090808 100644
--- a/meson.build
+++ b/meson.build
@@ -109,6 +109,7 @@
 group_i2c    = get_option('programmer').contains('group_i2c')
 group_serial = get_option('programmer').contains('group_serial')
 group_jlink  = get_option('programmer').contains('group_jlink')
+group_gpiod  = get_option('programmer').contains('group_gpiod')
 group_internal = get_option('programmer').contains('group_internal')
 group_external = get_option('programmer').contains('group_external')
 
@@ -116,6 +117,7 @@
 libusb1    = dependency('libusb-1.0', required : group_usb)
 libftdi1   = dependency('libftdi1', required : group_ftdi)
 libjaylink = dependency('libjaylink', required : group_jlink)
+libgpiod   = dependency('libgpiod', required : group_gpiod)
 
 subdir('platform')
 
@@ -284,6 +286,13 @@
     'flags'   : [ '-DCONFIG_JLINK_SPI=1' ],
     'default' : false,
   },
+  'linux_gpio_spi' : {
+    'systems' : [ 'linux' ],
+    'deps'    : [ libgpiod ],
+    'groups'  : [ group_gpiod, group_external ],
+    'srcs'    : files('linux_gpio_spi.c'),
+    'flags'   : [ '-DCONFIG_LINUX_GPIOD=1' ],
+  },
   'linux_mtd' : {
     'systems' : [ 'linux' ],
     'deps'    : [ linux_headers ],