programmer: Add Developerbox/CP2104 bit bang driver

The 96Boards Developerbox (a.k.a. Synquacer E-series) provides a CP2102
debug UART with its GPIO pins hooked up to the SPI NOR FLASH. The
circuit is intended to provide emergency recovery functions without
requiring any additional tools (such as a JTAG or SPI programmer). This
was expected to be very slow (and it is) but CP2102 is much cheaper than
a full dual channel USB comms chip.

Read performance is roughly on par with a 2400 baud modem (between 60
and 70 minutes per megabyte if you prefer) and write performance is 50%
slower still. The full recovery process, with backup and verification of
4MB data written takes between 14 and 15 hours. Thus it is only really
practical as an emergency recovery tool, firmware developers will need
to use an alternative programmer.

Change-Id: I2547a96c1a2259ad0d52cd4b6ef42261b37cccf3
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/26948
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>

1 files changed, 22 insertions, 2 deletions

diff --git a/Makefile b/Makefile
index cd729724..ddfd7116 100644
--- a/Makefile
+++ b/Makefile
@@ -154,12 +154,17 @@ UNSUPPORTED_FEATURES += CONFIG_PONY_SPI=yes
 else
 override CONFIG_PONY_SPI = no
 endif
-# Dediprog, USB-Blaster, PICkit2, CH341A and FT2232 are not supported under DOS (missing USB support).
+# Dediprog, Developerbox, USB-Blaster, PICkit2, CH341A and FT2232 are not supported under DOS (missing USB support).
 ifeq ($(CONFIG_DEDIPROG), yes)
 UNSUPPORTED_FEATURES += CONFIG_DEDIPROG=yes
 else
 override CONFIG_DEDIPROG = no
 endif
+ifeq ($(CONFIG_DEVELOPERBOX_SPI), yes)
+UNSUPPORTED_FEATURES += CONFIG_DEVELOPERBOX_SPI=yes
+else
+override CONFIG_DEVELOPERBOX_SPI = no
+endif
 ifeq ($(CONFIG_FT2232_SPI), yes)
 UNSUPPORTED_FEATURES += CONFIG_FT2232_SPI=yes
 else
@@ -311,12 +316,17 @@ UNSUPPORTED_FEATURES += CONFIG_PONY_SPI=yes
 else
 override CONFIG_PONY_SPI = no
 endif
-# Dediprog, USB-Blaster, PICkit2, CH341A and FT2232 are not supported with libpayload (missing libusb support).
+# Dediprog, Developerbox, USB-Blaster, PICkit2, CH341A and FT2232 are not supported with libpayload (missing libusb support).
 ifeq ($(CONFIG_DEDIPROG), yes)
 UNSUPPORTED_FEATURES += CONFIG_DEDIPROG=yes
 else
 override CONFIG_DEDIPROG = no
 endif
+ifeq ($(CONFIG_DEVELOPERBOX_SPI), yes)
+UNSUPPORTED_FEATURES += CONFIG_DEVELOPERBOX_SPI=yes
+else
+override CONFIG_DEVELOPERBOX_SPI = no
+endif
 ifeq ($(CONFIG_FT2232_SPI), yes)
 UNSUPPORTED_FEATURES += CONFIG_FT2232_SPI=yes
 else
@@ -627,6 +637,9 @@ CONFIG_BUSPIRATE_SPI ?= yes
 # Always enable Dediprog SF100 for now.
 CONFIG_DEDIPROG ?= yes
 
+# Always enable Developerbox emergency recovery for now.
+CONFIG_DEVELOPERBOX_SPI ?= yes
+
 # Always enable Marvell SATA controllers for now.
 CONFIG_SATAMV ?= yes
 
@@ -671,6 +684,7 @@ ifeq ($(CONFIG_ENABLE_LIBUSB1_PROGRAMMERS), no)
 override CONFIG_CH341A_SPI = no
 override CONFIG_DEDIPROG = no
 override CONFIG_DIGILENT_SPI = no
+override CONFIG_DEVELOPERBOX_SPI = no
 endif
 ifeq ($(CONFIG_ENABLE_LIBPCI_PROGRAMMERS), no)
 override CONFIG_INTERNAL = no
@@ -907,6 +921,12 @@ PROGRAMMER_OBJS += dediprog.o
 NEED_LIBUSB1 += CONFIG_DEDIPROG
 endif
 
+ifeq ($(CONFIG_DEVELOPERBOX_SPI), yes)
+FEATURE_CFLAGS += -D'CONFIG_DEVELOPERBOX_SPI=1'
+PROGRAMMER_OBJS += developerbox_spi.o
+NEED_LIBUSB1 += CONFIG_DEVELOPERBOX_SPI
+endif
+
 ifeq ($(CONFIG_SATAMV), yes)
 FEATURE_CFLAGS += -D'CONFIG_SATAMV=1'
 PROGRAMMER_OBJS += satamv.o