Make crossystem look for the write protect switch in the chromeos_arm device

The value of the ChromeOS write protect switch is now provided through the new
chromeos_arm platform device which avoids the mismatch between U-Boot and
kernel GPIO numbering.

BUG=chrome-os-partner:11297
TEST=gmerge-ed onto a snow and verified that crossystem got the right value of
the write protect switch.
BRANCH=snow

Change-Id: I466370e4f6bf2d14c067518a9d620e9e60142a0b
Signed-off-by: Gabe Black <gabeblack@google.com>
Reviewed-on: https://gerrit.chromium.org/gerrit/30534
Reviewed-by: Simon Glass <sjg@chromium.org>
Commit-Ready: Randall Spangler <rspangler@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>

1 files changed, 20 insertions, 2 deletions

diff --git a/host/arch/arm/lib/crossystem_arch.c b/host/arch/arm/lib/crossystem_arch.c
index 3ccb0baf..f9606745 100644
--- a/host/arch/arm/lib/crossystem_arch.c
+++ b/host/arch/arm/lib/crossystem_arch.c
@@ -23,6 +23,8 @@
 #define FDT_BASE_PATH "/proc/device-tree/firmware/chromeos"
 /* Path to compatible FDT entry */
 #define FDT_COMPATIBLE_PATH "/proc/device-tree/compatible"
+/* Path to the chromeos_arm platform device */
+#define PLATFORM_DEV_PATH "/sys/devices/platform/chromeos_arm"
 /* Device for NVCTX write */
 #define NVCTX_PATH "/dev/mmcblk%d"
 /* Base name for GPIO files */
@@ -179,6 +181,17 @@ static char * ReadFdtPlatformFamily(void) {
   return NULL;
 }
 
+static int VbGetPlatformGpioStatus(const char* name) {
+  char gpio_name[FNAME_SIZE];
+  int value;
+
+  snprintf(gpio_name, sizeof(gpio_name), "%s/%s/value",
+           PLATFORM_DEV_PATH, name);
+  value = ReadFileInt(gpio_name);
+
+  return value;
+}
+
 static int VbGetGpioStatus(unsigned gpio_number) {
   char gpio_name[FNAME_SIZE];
   int value;
@@ -358,9 +371,14 @@ int VbGetArchPropertyInt(const char* name) {
     return VbGetVarGpio("developer-switch");
   else if (!strcasecmp(name, "recoverysw_cur"))
     return VbGetVarGpio("recovery-switch");
-  else if (!strcasecmp(name, "wpsw_cur"))
+  else if (!strcasecmp(name, "wpsw_cur")) {
+    int value;
+    /* Try finding the GPIO through the chromeos_arm platform device first. */
+    value = VbGetPlatformGpioStatus("write-protect");
+    if (value != -1)
+      return value;
     return VbGetVarGpio("write-protect-switch");
-  else if (!strcasecmp(name, "recoverysw_ec_boot"))
+  } else if (!strcasecmp(name, "recoverysw_ec_boot"))
     /* TODO: read correct value using ectool */
     return 0;
   else