Introduce arm support in crossystem.
This CL builds upon earlier firmware and kernel changes (see CLs
related to the same bug, chromium-os:12522).
ARM firmware now simulates both Nvram storage and VDAT buffer, the
structures the x86 version uses extensively to communicate back and
forth between firmware/kernel/userland.
So, to make crossystem work on arm, all what's needed is to provide
architecture specific interface to Nvram and VDAT simulation, and
architecture specific processing for variables which are accessed on
ARM platforms in a different way.
The few discrepancies and platform specifics which had to be addressed
for ARM specifically are as follows:
- the Nvram contents are cached in the shared memory and available for
reading as part of /sys/kernel/debug/chromeos_arm. When writing
Nvram, the same file needs to be written, but only the 16 bytes
(representing the Nvram contents) are aacepted.
- the VDAT buffer also comes from the shared memory (as part of the
same sysfs file)
- when crossystem starts, it needs to read in this shared memory
contents, a` weak' function VbArchInit() is being added such that it
is provided on ARM platforms only, on x86 an empty stub is called.
- current developer/recovery request/ro firmware switch states are
retrieved through GPIO drivers. The GPIO numbers are defined in the
file, the GPIO driver is supposed to be configured before
crsossystem can operate.
- the BINF values are supplied through an array within shared memory,
it would be easy to refactor both x86 and ARM use the same code to
process BINF values, but with this submission the code is duplicated
to minimize x86 impact.
- the following crossystem variables do not have ARM equivalents,
thier values are reported as '(error)':
recoverysw_ec_boot
savedmem_base
savedmem_size
BUG=chromium-os:12522
TEST=manual:
. bring up a kaen system
. execute the following script to enable the appropriate GPIOSs:
for gpio in 56 59 168; do echo $gpio > /sys/class/gpio/export; done
. run `crossystem' and observe reasonable output values
. to verify that it reads GPIOs properly, try
echo $(./crossystem recoverysw_cur)
with the miniservo 'GOOG_REC' button pressed and released, observe
different readings (note that the state of the button is reversed,
the released button is reported as '1')
. to verify the write capabilities, note that the nvram contents can
be accessed using the following shell commands
echo 3 > /proc/sys/vm/drop_caches
2>/dev/null dd if=/dev/mmcblk0 of=/tmp/blk bs=16 count=1 && \
od -t x1 /tmp/blk | head -1
(the first command cause the device cache dropped, and the second
command accesses the device contents.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
localhost var # echo $(./crossystem fwb_tries)
10
localhost var # echo 3 > /proc/sys/vm/drop_caches
localhost var # 2>/dev/null dd if=/dev/mmcblk0 of=/tmp/blk bs=16 count=1 && od -t x1 /tmp/blk | head -1
0000000 60 0a 00 be 00 00 00 00 00 00 00 02 00 00 00 a2
localhost var # ./crossystem fwb_tries=9
localhost var # echo $(./crossystem fwb_tries)
9
localhost var # echo 3 > /proc/sys/vm/drop_caches
localhost var # 2>/dev/null dd if=/dev/mmcblk0 of=/tmp/blk bs=16 count=1 && od -t x1 /tmp/blk | head -1
0000000 60 09 00 be 00 00 00 00 00 00 00 02 00 00 00 8a
localhost var #
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Change-Id: Ie4c6ff44441d98a42b1057953208fdb90c08f46d
Reviewed-on: http://gerrit.chromium.org/gerrit/113
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Tested-by: Vadim Bendebury <vbendeb@chromium.org>
diff --git a/utility/crossystem_main.c b/utility/crossystem_main.c
index 14b7e22..6b249e0 100644
--- a/utility/crossystem_main.c
+++ b/utility/crossystem_main.c
@@ -14,6 +14,11 @@
/* Max length of a string parameter */
#define MAX_STRING 8192
+/*
+ * Call arch specific init, if provided, otherwise use the 'weak' stub.
+ */
+int __VbArchInit(void) { return 0; }
+int VbArchInit(void) __attribute__((weak, alias("__VbArchInit")));
/* Flags for Param */
#define IS_STRING 0x01 /* String (not present = integer) */
#define CAN_WRITE 0x02 /* Writable (not present = read-only */
@@ -212,6 +217,11 @@
else
progname = argv[0];
+ if (VbArchInit()) {
+ fprintf(stderr, "Failed to initialize\n");
+ return -1;
+ }
+
/* If no args specified, print all params */
if (argc == 1)
return PrintAllParams(0);