libwifi-hal: add flag to wait for kernel driver to get ready

If the wifi hal comes up before the kernel driver gets ready then wifi
will be disabled after the device has fully booted up regardless of the previous state.

This confuses users and is not an expected behaviour.

Example:
WIFI_DRIVER_OPERSTATE_PATH := "/sys/class/net/wlan0/operstate"

Bug: Wifi down after boot
Test: Enable wifi, reboot and check if it's still up

Change-Id: If23d5d6ef0fe75e64053ea779feb6acb37d98850

2 files changed, 53 insertions, 0 deletions

diff --git a/libwifi_hal/Android.mk b/libwifi_hal/Android.mk
index 1179a091d..9ed2fbd70 100644
--- a/libwifi_hal/Android.mk
+++ b/libwifi_hal/Android.mk
@@ -60,6 +60,12 @@ ifdef WIFI_DRIVER_STATE_OFF
 wifi_hal_cflags += -DWIFI_DRIVER_STATE_OFF=\"$(WIFI_DRIVER_STATE_OFF)\"
 endif
 
+# Wait for Wifi driver to get ready
+# Example: WIFI_DRIVER_OPERSTATE_PATH := "/sys/class/net/wlan0/operstate"
+ifdef WIFI_DRIVER_OPERSTATE_PATH
+wifi_hal_cflags += -DWIFI_DRIVER_OPERSTATE_PATH=\"$(WIFI_DRIVER_OPERSTATE_PATH)\"
+endif
+
 # Common code shared between the HALs.
 # ============================================================
 include $(CLEAR_VARS)
diff --git a/libwifi_hal/wifi_hal_common.cpp b/libwifi_hal/wifi_hal_common.cpp
index 04e592595..14a0b6247 100644
--- a/libwifi_hal/wifi_hal_common.cpp
+++ b/libwifi_hal/wifi_hal_common.cpp
@@ -41,6 +41,12 @@ extern "C" int delete_module(const char *, unsigned int);
 #define WIFI_DRIVER_MODULE_ARG ""
 #endif
 
+#ifdef WIFI_DRIVER_OPERSTATE_PATH
+#include <sys/stat.h>
+#define OPERSTATE_UP "up"
+#define OPERSTATE_DOWN "down"
+#endif
+
 static const char DRIVER_PROP_NAME[] = "wlan.driver.status";
 #ifdef WIFI_DRIVER_MODULE_PATH
 static const char DRIVER_MODULE_NAME[] = WIFI_DRIVER_MODULE_NAME;
@@ -141,6 +147,40 @@ int is_wifi_driver_loaded() {
 #endif
 }
 
+#ifdef WIFI_DRIVER_OPERSTATE_PATH
+int is_wifi_driver_ready() {
+  struct stat sbuf;
+  FILE *fstate;
+  char operstate[8];
+  int open_count = 25, read_count = 25;
+  while (open_count-- >= 0) {
+    if (stat(WIFI_DRIVER_OPERSTATE_PATH, &sbuf) == 0) {
+      if ((fstate = fopen(WIFI_DRIVER_OPERSTATE_PATH, "r")) == NULL) {
+        usleep(500000);
+      } else {
+        break;
+      }
+    } else {
+      usleep(500000);
+    }
+  }
+  if (fstate != NULL) {
+    while (read_count-- >= 0) {
+      fgets(operstate, sizeof(operstate), fstate);
+      if (strncmp(operstate, OPERSTATE_UP, strlen(OPERSTATE_UP)) == 0 ||
+          strncmp(operstate, OPERSTATE_DOWN, strlen(OPERSTATE_DOWN)) == 0) {
+        PLOG(INFO) << "Wifi driver is ready";
+        return 1;
+      }
+      PLOG(WARNING) << "Waiting for Wifi driver to get ready. (" << read_count << ")";
+      usleep(500000);
+    }
+    fclose(fstate);
+  }
+  return 0;
+}
+#endif
+
 int wifi_load_driver() {
 #ifdef WIFI_DRIVER_MODULE_PATH
   if (is_wifi_driver_loaded()) {
@@ -157,6 +197,13 @@ int wifi_load_driver() {
 
   if (wifi_change_driver_state(WIFI_DRIVER_STATE_ON) < 0) return -1;
 #endif
+
+#ifdef WIFI_DRIVER_OPERSTATE_PATH
+  if (!is_wifi_driver_ready()) {
+    PLOG(ERROR) << "Wifi driver didn't get ready in time, giving up!";
+    return -1;
+  }
+#endif
   property_set(DRIVER_PROP_NAME, "ok");
   return 0;
 }