ARM: tegra: flush console before reboot

If the console_sem was held while the system was rebooted, the messages
in the temporary logbuffer would not have propogated to all the console
drivers.

This force releases the console sem if it failed to be acquired.

Change-Id: I6eba9d744ef41209d26328a17c7ae19c32d6e8cb
Signed-off-by: Dima Zavin <dima@android.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/arch/arm/mach-tegra/common.c b/arch/arm/mach-tegra/common.c
index 2fdb99b6fdc5..12ce86b7ab9c 100644
--- a/arch/arm/mach-tegra/common.c
+++ b/arch/arm/mach-tegra/common.c
@@ -17,6 +17,7 @@
  *
  */
 
+#include <linux/console.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/clk.h>
@@ -25,6 +26,7 @@
 #include <linux/memblock.h>
 
 #include <asm/hardware/cache-l2x0.h>
+#include <asm/system.h>
 
 #include <mach/iomap.h>
 #include <mach/dma.h>
@@ -98,8 +100,41 @@ static void __init tegra_init_power(void)
 	tegra_powergate_power_off(TEGRA_POWERGATE_3D);
 }
 
+static bool console_flushed;
+
+static void tegra_pm_flush_console(void)
+{
+	if (console_flushed)
+		return;
+	console_flushed = true;
+
+	printk("\n");
+	pr_emerg("Restarting %s\n", linux_banner);
+	if (!try_acquire_console_sem()) {
+		release_console_sem();
+		return;
+	}
+
+	mdelay(50);
+
+	local_irq_disable();
+	if (try_acquire_console_sem())
+		pr_emerg("tegra_restart: Console was locked! Busting\n");
+	else
+		pr_emerg("tegra_restart: Console was locked!\n");
+	release_console_sem();
+}
+
+static void tegra_pm_restart(char mode, const char *cmd)
+{
+	tegra_pm_flush_console();
+	arm_machine_restart(mode, cmd);
+}
+
 void __init tegra_common_init(void)
 {
+	arm_pm_restart = tegra_pm_restart;
+
 	tegra_init_fuse();
 	tegra_init_clock();
 	tegra_clk_init_from_table(common_clk_init_table);