watchdog: add Intel MID watchdog driver support

Add initial Intel MID watchdog driver support.

This driver is an initial implementation of generic Intel MID watchdog
driver. Currently it supports Intel Merrifield platform.

Change-Id: I599eb10f89c622bb3ed1cfd4a56a93d443dca8fa
Signed-off-by: Eric Ernst <eric.ernst@intel.com>
Signed-off-by: David Cohen <david.a.cohen@linux.intel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

6 files changed, 224 insertions, 3 deletions

diff --git a/arch/x86/include/asm/intel_scu_ipc.h b/arch/x86/include/asm/intel_scu_ipc.h
index 3536ec9ae21..3055f5147ef 100644
--- a/arch/x86/include/asm/intel_scu_ipc.h
+++ b/arch/x86/include/asm/intel_scu_ipc.h
@@ -62,6 +62,10 @@
 /* check ipc status */
 int intel_scu_ipc_check_status(void);
 
+/* Issue commands to the SCU with or without data */
+int intel_scu_ipc_simple_command(int cmd, int sub);
+int intel_scu_ipc_command(u32 cmd, u32 sub, u8 *in, u32 inlen,
+				u32 *out, u32 outlen);
 /* I2C control api */
 int intel_scu_ipc_i2c_cntrl(u32 addr, u32 *data);
 
diff --git a/drivers/remoteproc/intel_mid_rproc_core.h b/drivers/remoteproc/intel_mid_rproc_core.h
index bfe6f6cdddf..8ce5721fa2b 100644
--- a/drivers/remoteproc/intel_mid_rproc_core.h
+++ b/drivers/remoteproc/intel_mid_rproc_core.h
@@ -71,9 +71,6 @@ extern void rpmsg_ns_del_list(struct rpmsg_ns_list *nslist);
 extern void intel_scu_ipc_send_command(u32 cmd);
 
 /* Issue commands to the SCU with or without data */
-extern int intel_scu_ipc_simple_command(int cmd, int sub);
-extern int intel_scu_ipc_command(u32 cmd, u32 sub, u8 *in, u32 inlen,
-		u32 *out, u32 outlen);
 extern int intel_scu_ipc_raw_cmd(u32 cmd, u32 sub, u8 *in, u32 inlen,
 		u32 *out, u32 outlen, u32 dptr, u32 sptr);
 
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 8b660e77538..7aea0b95601 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -636,6 +636,19 @@ config DISABLE_SCU_WATCHDOG
 
 	  Only for debug purpose.
 
+config INTEL_MID_WATCHDOG
+       tristate "Intel MID Watchdog Timer"
+       depends on X86_INTEL_MID
+       select WATCHDOG_CORE
+       ---help---
+         Watchdog timer driver built into the Intel SCU for Intel MID
+         Platforms.
+
+         This driver currently supports only the watchdog evolution
+         implementation in SCU, available for Merrifield generation.
+
+         To compile this driver as a module, choose M here.
+
 config ITCO_WDT
 	tristate "Intel TCO Timer/Watchdog"
 	depends on (X86 || IA64) && PCI
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 2d3cdd5dd5f..e5b56bca6cf 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -111,6 +111,7 @@ obj-$(CONFIG_MACHZ_WDT) += machzwd.o
 obj-$(CONFIG_SBC_EPX_C3_WATCHDOG) += sbc_epx_c3.o
 obj-$(CONFIG_INTEL_SCU_WATCHDOG) += intel_scu_watchdog.o
 obj-$(CONFIG_INTEL_SCU_WATCHDOG_EVO) += intel_scu_watchdog_evo.o
+obj-$(CONFIG_INTEL_MID_WATCHDOG) += intel-mid_wdt.o
 
 # M32R Architecture
 
diff --git a/drivers/watchdog/intel-mid_wdt.c b/drivers/watchdog/intel-mid_wdt.c
new file mode 100644
index 00000000000..ca66e8e7463
--- /dev/null
+++ b/drivers/watchdog/intel-mid_wdt.c
@@ -0,0 +1,184 @@
+/*
+ *      intel-mid_wdt: generic Intel MID SCU watchdog driver
+ *
+ *      Platforms supported so far:
+ *      - Merrifield only
+ *
+ *      Copyright (C) 2014 Intel Corporation. All rights reserved.
+ *      Contact: David Cohen <david.a.cohen@linux.intel.com>
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of version 2 of the GNU General
+ *      Public License as published by the Free Software Foundation.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/nmi.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+#include <linux/platform_data/intel-mid_wdt.h>
+
+#include <asm/intel_scu_ipc.h>
+#include <asm/intel-mid.h>
+
+#define IPC_WATCHDOG 0xf8
+
+#define MID_WDT_PRETIMEOUT		15
+#define MID_WDT_TIMEOUT_MIN		(1 + MID_WDT_PRETIMEOUT)
+#define MID_WDT_TIMEOUT_MAX		170
+#define MID_WDT_DEFAULT_TIMEOUT		90
+
+/* SCU watchdog messages */
+enum {
+	SCU_WATCHDOG_START = 0,
+	SCU_WATCHDOG_STOP,
+	SCU_WATCHDOG_KEEPALIVE,
+};
+
+static inline int wdt_command(int sub, u32 *in, int inlen)
+{
+	return intel_scu_ipc_command(IPC_WATCHDOG, sub, in, inlen, NULL, 0);
+}
+
+static int wdt_start(struct watchdog_device *wd)
+{
+	int ret, in_size;
+	int timeout = wd->timeout;
+	struct ipc_wd_start {
+		u32 pretimeout;
+		u32 timeout;
+	} ipc_wd_start = { timeout - MID_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);
+
+	ret = wdt_command(SCU_WATCHDOG_START, (u32 *)&ipc_wd_start, in_size);
+	if (ret) {
+		struct device *dev = watchdog_get_drvdata(wd);
+		dev_crit(dev, "error starting watchdog: %d\n", ret);
+	}
+
+	return ret;
+}
+
+static int wdt_ping(struct watchdog_device *wd)
+{
+	int ret;
+
+	ret = wdt_command(SCU_WATCHDOG_KEEPALIVE, NULL, 0);
+	if (ret) {
+		struct device *dev = watchdog_get_drvdata(wd);
+		dev_crit(dev, "Error executing keepalive: 0x%x\n", ret);
+	}
+
+	return ret;
+}
+
+static int wdt_stop(struct watchdog_device *wd)
+{
+	int ret;
+
+	ret = wdt_command(SCU_WATCHDOG_STOP, NULL, 0);
+	if (ret) {
+		struct device *dev = watchdog_get_drvdata(wd);
+		dev_crit(dev, "Error stopping watchdog: 0x%x\n", ret);
+	}
+
+	return ret;
+}
+
+static irqreturn_t mid_wdt_irq(int irq, void *dev_id)
+{
+	panic("Kernel Watchdog");
+
+	/* This code should not be reached */
+	return IRQ_HANDLED;
+}
+
+static const struct watchdog_info mid_wdt_info = {
+	.identity = "Intel MID SCU watchdog",
+	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
+};
+
+static const struct watchdog_ops mid_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = wdt_start,
+	.stop = wdt_stop,
+	.ping = wdt_ping,
+};
+
+static int mid_wdt_probe(struct platform_device *pdev)
+{
+	struct watchdog_device *wdt_dev;
+	struct intel_mid_wdt_pdata *pdata = pdev->dev.platform_data;
+	int ret;
+
+	if (!pdata) {
+		dev_err(&pdev->dev, "missing platform data\n");
+		return -EINVAL;
+	}
+
+	if (pdata->probe) {
+		ret = pdata->probe(pdev);
+		if (ret)
+			return ret;
+	}
+
+	wdt_dev = devm_kzalloc(&pdev->dev, sizeof(*wdt_dev), GFP_KERNEL);
+	if (!wdt_dev)
+		return -ENOMEM;
+
+	wdt_dev->info = &mid_wdt_info;
+	wdt_dev->ops = &mid_wdt_ops;
+	wdt_dev->min_timeout = MID_WDT_TIMEOUT_MIN;
+	wdt_dev->max_timeout = MID_WDT_TIMEOUT_MAX;
+	wdt_dev->timeout = MID_WDT_DEFAULT_TIMEOUT;
+
+	watchdog_set_drvdata(wdt_dev, &pdev->dev);
+	platform_set_drvdata(pdev, wdt_dev);
+
+	ret = devm_request_irq(&pdev->dev, pdata->irq, mid_wdt_irq,
+			       IRQF_SHARED | IRQF_NO_SUSPEND, "watchdog",
+			       wdt_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "error requesting warning irq %d\n",
+			pdata->irq);
+		return ret;
+	}
+
+	ret = watchdog_register_device(wdt_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "error registering watchdog device\n");
+		return ret;
+	}
+
+	dev_info(&pdev->dev, "Intel MID watchdog device probed\n");
+
+	return 0;
+}
+
+static int mid_wdt_remove(struct platform_device *pdev)
+{
+	struct watchdog_device *wd = platform_get_drvdata(pdev);
+	watchdog_unregister_device(wd);
+	return 0;
+}
+
+static struct platform_driver mid_wdt_driver = {
+	.probe		= mid_wdt_probe,
+	.remove		= mid_wdt_remove,
+	.driver		= {
+		.owner	= THIS_MODULE,
+		.name	= "intel_mid_wdt",
+	},
+};
+
+module_platform_driver(mid_wdt_driver);
+
+MODULE_AUTHOR("David Cohen <david.a.cohen@linux.intel.com>");
+MODULE_DESCRIPTION("Watchdog Driver for Intel MID platform");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/platform_data/intel-mid_wdt.h b/include/linux/platform_data/intel-mid_wdt.h
new file mode 100644
index 00000000000..b98253466ac
--- /dev/null
+++ b/include/linux/platform_data/intel-mid_wdt.h
@@ -0,0 +1,22 @@
+/*
+ *      intel-mid_wdt: generic Intel MID SCU watchdog driver
+ *
+ *      Copyright (C) 2014 Intel Corporation. All rights reserved.
+ *      Contact: David Cohen <david.a.cohen@linux.intel.com>
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of version 2 of the GNU General
+ *      Public License as published by the Free Software Foundation.
+ */
+
+#ifndef __INTEL_MID_WDT_H__
+#define __INTEL_MID_WDT_H__
+
+#include <linux/platform_device.h>
+
+struct intel_mid_wdt_pdata {
+	int irq;
+	int (*probe)(struct platform_device *pdev);
+};
+
+#endif /*__INTEL_MID_WDT_H__*/