watchdog: Introduce watchdog driver for Intel Tangier

Add watchdog driver for Intel Tangier based platforms.

Signed-off-by: Vincent Tinelli <vincent.tinelli@intel.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

drivers/watchdog/Kconfig

@@ -19,7 +19,16 @@ config OMAP_WATCHDOG
 	default y if AM33XX
 	help
 	  Say Y here to enable the OMAP3+ watchdog driver.
-	
+
+config TANGIER_WATCHDOG
+	bool "Intel Tangier watchdog"
+	depends on INTEL_MID
+	select HW_WATCHDOG
+	help
+	  This enables support for watchdog controller available on
+	  Intel Tangier SoC. If you're using a board with Intel Tangier
+	  SoC, say Y here.
+
 config ULP_WATCHDOG
 	bool "i.MX7ULP watchdog"
 	help

drivers/watchdog/Makefile

@@ -14,6 +14,7 @@ obj-$(CONFIG_S5P)               += s5p_wdt.o
 obj-$(CONFIG_XILINX_TB_WATCHDOG) += xilinx_tb_wdt.o
 obj-$(CONFIG_OMAP_WATCHDOG) += omap_wdt.o
 obj-$(CONFIG_DESIGNWARE_WATCHDOG) += designware_wdt.o
+obj-$(CONFIG_TANGIER_WATCHDOG) += tangier_wdt.o
 obj-$(CONFIG_ULP_WATCHDOG) += ulp_wdog.o
 obj-$(CONFIG_WDT) += wdt-uclass.o
 obj-$(CONFIG_WDT_SANDBOX) += sandbox_wdt.o

drivers/watchdog/tangier_wdt.c

@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2017 Intel Corporation
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+#include <common.h>
+#include <watchdog.h>
+#include <asm/scu.h>
+
+/* Hardware timeout in seconds */
+#define WDT_PRETIMEOUT		15
+#define WDT_TIMEOUT_MIN		(1 + WDT_PRETIMEOUT)
+#define WDT_TIMEOUT_MAX		170
+#define WDT_DEFAULT_TIMEOUT	90
+
+#ifndef CONFIG_WATCHDOG_TIMEOUT_MSECS
+#define WATCHDOG_HEARTBEAT 60000
+#else
+#define WATCHDOG_HEARTBEAT CONFIG_WATCHDOG_TIMEOUT_MSECS
+#endif
+
+enum {
+	SCU_WATCHDOG_START			= 0,
+	SCU_WATCHDOG_STOP			= 1,
+	SCU_WATCHDOG_KEEPALIVE			= 2,
+	SCU_WATCHDOG_SET_ACTION_ON_TIMEOUT	= 3,
+};
+
+void hw_watchdog_reset(void)
+{
+	static unsigned long last;
+	unsigned long now;
+
+	if (gd->timer)
+		now = timer_get_us();
+	else
+		now = rdtsc() / 1000;
+
+	/* Do not flood SCU */
+	if (last > now)
+		last = 0;
+
+	if (unlikely((now - last) > (WDT_PRETIMEOUT / 2) * 1000000)) {
+		last = now;
+		scu_ipc_simple_command(IPCMSG_WATCHDOG_TIMER, SCU_WATCHDOG_KEEPALIVE);
+	}
+}
+
+int hw_watchdog_disable(void)
+{
+	return scu_ipc_simple_command(IPCMSG_WATCHDOG_TIMER, SCU_WATCHDOG_STOP);
+}
+
+void hw_watchdog_init(void)
+{
+	u32 timeout = WATCHDOG_HEARTBEAT / 1000;
+	int in_size;
+	struct ipc_wd_start {
+		u32 pretimeout;
+		u32 timeout;
+	} ipc_wd_start = { timeout - WDT_PRETIMEOUT, timeout };
+
+	/*
+	 * SCU expects the input size for watchdog IPC
+	 * to be based on 4 bytes
+	 */
+	in_size = DIV_ROUND_UP(sizeof(ipc_wd_start), 4);
+
+	scu_ipc_command(IPCMSG_WATCHDOG_TIMER, SCU_WATCHDOG_START,
+			(u32 *)&ipc_wd_start, in_size, NULL, 0);
+}