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Subject[PATCH v2 1/2] watchdog: add Intel MID watchdog driver support
Date
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.

Signed-off-by: Eric Ernst <eric.ernst@intel.com>
Signed-off-by: David Cohen <david.a.cohen@linux.intel.com>
---
drivers/watchdog/Kconfig | 13 +++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/intel-mid_wdt.c | 209 +++++++++++++++++++++++++++++++++++++++
3 files changed, 223 insertions(+)
create mode 100644 drivers/watchdog/intel-mid_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 79d25894343a..0e110c37aa5c 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -643,6 +643,19 @@ config INTEL_SCU_WATCHDOG

To compile this driver as a module, choose M here.

+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 985a66cda76f..b927e7496eb4 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -113,6 +113,7 @@ obj-$(CONFIG_W83977F_WDT) += w83977f_wdt.o
obj-$(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_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 000000000000..6339c6351454
--- /dev/null
+++ b/drivers/watchdog/intel-mid_wdt.c
@@ -0,0 +1,209 @@
+/*
+ * 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 <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 double-word
+ */
+ in_size = (sizeof(ipc_wd_start) + 3) / 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 -EIO;
+ }
+
+ return 0;
+}
+
+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 -EIO;
+ }
+
+ return 0;
+}
+
+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 -EIO;
+ }
+
+ return 0;
+}
+
+static irqreturn_t mid_wdt_warning_irq(int irq, void *dev_id)
+{
+ /* Let's dump some data before panic */
+ trigger_all_cpu_backtrace();
+ panic("Kernel Watchdog");
+
+ /* This code should not be reached */
+ return IRQ_HANDLED;
+}
+
+/*
+ * Current driver supports Merrifield only.
+ * This function will get more generic when necessary.
+ */
+static int handle_dev_ioapic(struct device *dev, int irq)
+{
+ int ioapic;
+ struct io_apic_irq_attr irq_attr;
+
+ ioapic = mp_find_ioapic(irq);
+ if (ioapic >= 0) {
+ irq_attr.ioapic = ioapic;
+ irq_attr.ioapic_pin = irq;
+ irq_attr.trigger = 1;
+ irq_attr.polarity = 0; /* Active high */
+ io_apic_set_pci_routing(NULL, irq, &irq_attr);
+ } else {
+ dev_warn(dev, "can not find interrupt %d in ioapic\n", irq);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+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 resource *res;
+ int ret;
+ int irq;
+
+ 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);
+
+ res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+ if (!res) {
+ dev_err(&pdev->dev, "missing IRQ resource\n");
+ return -EINVAL;
+ }
+ irq = res->start;
+
+ handle_dev_ioapic(&pdev->dev, irq);
+ ret = devm_request_irq(&pdev->dev, irq, mid_wdt_warning_irq,
+ IRQF_SHARED | IRQF_NO_SUSPEND, "watchdog",
+ wdt_dev);
+ if (ret) {
+ dev_err(&pdev->dev, "error requesting warning irq %d\n", 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");
--
1.9.1


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