[PATCH] watchdog: lenovo_se10_wdt: Watchdog driver for Lenovo SE10 platform

[Mark Pearson]

Watchdog driver implementation for Lenovo SE10 platform.

Signed-off-by: Mark Pearson <mpearson-lenovo@xxxxxxxxx>
Signed-off-by: David Ober <dober@xxxxxxxxxx>
---
This is based off the original ite5632 WD driver submission by David
but modified to take in feedback during that review:
 - Watchdog is made specific to the SE10 platform only
 - Added in region request/release when accessing IO registers
 - Some cosmetic or style cleanups during the update 

 drivers/watchdog/Kconfig           |  10 +
 drivers/watchdog/Makefile          |   1 +
 drivers/watchdog/lenovo_se10_wdt.c | 308 +++++++++++++++++++++++++++++
 3 files changed, 319 insertions(+)
 create mode 100644 drivers/watchdog/lenovo_se10_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 7d22051b15a2..c0a013f708ab 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -243,6 +243,16 @@ config GPIO_WATCHDOG_ARCH_INITCALL
 	  arch_initcall.
 	  If in doubt, say N.
 
+config LENOVO_SE10_WDT
+        tristate "Lenovo SE10 Watchdog"
+        select WATCHDOG_CORE
+        help
+          If you say yes here you get support for the watchdog
+          functionality for the Lenovo SE10 platform.
+
+          This driver can also be built as a module. If so, the module
+          will be called lenovo-se10-wdt.
+
 config MENF21BMC_WATCHDOG
 	tristate "MEN 14F021P00 BMC Watchdog"
 	depends on MFD_MENF21BMC || COMPILE_TEST
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 7cbc34514ec1..0259fee048b2 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -120,6 +120,7 @@ obj-$(CONFIG_WAFER_WDT) += wafer5823wdt.o
 obj-$(CONFIG_I6300ESB_WDT) += i6300esb.o
 obj-$(CONFIG_IE6XX_WDT) += ie6xx_wdt.o
 obj-$(CONFIG_ITCO_WDT) += iTCO_wdt.o
+obj-$(CONFIG_LENOVO_SE10_WDT) += lenovo_se10_wdt.o
 ifeq ($(CONFIG_ITCO_VENDOR_SUPPORT),y)
 obj-$(CONFIG_ITCO_WDT) += iTCO_vendor_support.o
 endif
diff --git a/drivers/watchdog/lenovo_se10_wdt.c b/drivers/watchdog/lenovo_se10_wdt.c
new file mode 100644
index 000000000000..139ff0e8220f
--- /dev/null
+++ b/drivers/watchdog/lenovo_se10_wdt.c
@@ -0,0 +1,308 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * WDT driver for Lenovo SE10.
+ */
+
+#include <linux/delay.h>
+#include <linux/dmi.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+
+#define STATUS_PORT	0x6C
+#define CMD_PORT	0x6C
+#define DATA_PORT	0x68
+#define OUTBUF_FULL	0x01
+#define INBUF_EMPTY	0x02
+#define CFG_LDN		0x07
+#define CFG_BRAM_LDN	0x10 /* for BRAM Base */
+#define CFG_PORT	0x2E
+#define CFG_SIZE           2
+#define CMD_SIZE           4
+#define BRAM_SIZE          2
+
+#define UNLOCK_KEY	0x87
+#define LOCK_KEY	0xAA
+
+#define CUS_WDT_SWI	0x1A
+#define CUS_WDT_CFG	0x1B
+#define CUS_WDT_FEED	0xB0
+#define CUS_WDT_CNT	0xB1
+
+#define DRVNAME	"lenovo-se10-wdt"
+
+/*The timeout range is 1-255 seconds*/
+#define MIN_TIMEOUT 1
+#define MAX_TIMEOUT 255
+#define MAX_WAIT    10
+
+#define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */
+static unsigned short bram_base;
+static struct platform_device *se10_pdev;
+
+static int timeout; /* in seconds */
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout,
+		 "Watchdog timeout in seconds. 1 <= timeout <= 255, default="
+		 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout,
+		 "Watchdog cannot be stopped once started (default="
+		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+struct se10_wdt {
+	struct watchdog_device wdd;
+};
+
+static int set_bram(unsigned char offset, unsigned char val)
+{
+	if (!request_muxed_region(bram_base, BRAM_SIZE, DRVNAME))
+		return -EBUSY;
+	outb(offset, bram_base);
+	outb(val, bram_base + 1);
+	release_region(bram_base, BRAM_SIZE);
+	return 0;
+}
+
+static void wait_for_buffer(int condition)
+{
+	int loop = 0;
+
+	while (1) {
+		if (inb(STATUS_PORT) & condition || loop > MAX_WAIT)
+			break;
+		loop++;
+		usleep_range(10, 125);
+	}
+}
+
+static void send_cmd(unsigned char cmd)
+{
+	wait_for_buffer(INBUF_EMPTY);
+	outb(cmd, CMD_PORT);
+	wait_for_buffer(INBUF_EMPTY);
+}
+
+static void lpc_write(unsigned char index, unsigned char data)
+{
+	outb(index, CFG_PORT);
+	outb(data, CFG_PORT + 1);
+}
+
+static unsigned char lpc_read(unsigned char index)
+{
+	outb(index, CFG_PORT);
+	return inb(CFG_PORT + 1);
+}
+
+static int wdt_start(struct watchdog_device *wdog)
+{
+	return set_bram(CUS_WDT_SWI, 0x80);
+}
+
+static int wdt_set_timeout(struct watchdog_device *wdog, unsigned int timeout)
+{
+	wdog->timeout = timeout;
+	return set_bram(CUS_WDT_CFG, wdog->timeout);
+}
+
+static int wdt_stop(struct watchdog_device *wdog)
+{
+	return set_bram(CUS_WDT_SWI, 0);
+}
+
+static unsigned int wdt_get_time(struct watchdog_device *wdog)
+{
+	unsigned char time;
+
+	if (!request_muxed_region(CMD_PORT, CMD_SIZE, DRVNAME))
+		return -EBUSY;
+	send_cmd(CUS_WDT_CNT);
+	wait_for_buffer(OUTBUF_FULL);
+	time = inb(DATA_PORT);
+	release_region(CMD_PORT, CMD_SIZE);
+	return time;
+}
+
+static int wdt_ping(struct watchdog_device *wdog)
+{
+	if (!request_muxed_region(CMD_PORT, CMD_SIZE, DRVNAME))
+		return -EBUSY;
+	send_cmd(CUS_WDT_FEED);
+	release_region(CMD_PORT, CMD_SIZE);
+	return 0;
+}
+
+static const struct watchdog_info wdt_info = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+	.identity = "Lenovo SE10 Watchdog",
+};
+
+static const struct watchdog_ops se10_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = wdt_start,
+	.stop = wdt_stop,
+	.ping = wdt_ping,
+	.set_timeout = wdt_set_timeout,
+	.get_timeleft = wdt_get_time,
+};
+
+static unsigned int get_chipID(void)
+{
+	unsigned char msb, lsb;
+
+	outb(UNLOCK_KEY, CFG_PORT);
+	outb(0x01, CFG_PORT);
+	outb(0x55, CFG_PORT);
+	outb(0x55, CFG_PORT);
+	msb = lpc_read(0x20);
+	lsb = lpc_read(0x21);
+	outb(LOCK_KEY, CFG_PORT);
+	return (msb * 256 + lsb);
+}
+
+static int se10_wdt_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct se10_wdt *priv;
+	unsigned int chip_id;
+	int ret;
+
+	if (!request_muxed_region(CFG_PORT, CFG_SIZE, DRVNAME))
+		return -EBUSY;
+
+	chip_id = get_chipID();
+	if (chip_id != 0x5632) {
+		release_region(CFG_PORT, CFG_SIZE);
+		return -ENODEV;
+	}
+
+	lpc_write(CFG_LDN, CFG_BRAM_LDN);
+	bram_base = (lpc_read(0x60) << 8) | lpc_read(0x61);
+	release_region(CFG_PORT, CFG_SIZE);
+
+	dev_info(dev, "Found Lenovo SE10 0x%x\n", chip_id);
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	watchdog_set_drvdata(&priv->wdd, priv);
+
+	priv->wdd.parent = dev;
+	priv->wdd.info = &wdt_info,
+	priv->wdd.ops = &se10_wdt_ops,
+	priv->wdd.timeout = WATCHDOG_TIMEOUT; /* Set default timeout */
+	priv->wdd.min_timeout = MIN_TIMEOUT;
+	priv->wdd.max_timeout = MAX_TIMEOUT;
+
+	set_bram(CUS_WDT_CFG, WATCHDOG_TIMEOUT); /* Set time to default */
+
+	watchdog_init_timeout(&priv->wdd, timeout, dev);
+	watchdog_set_nowayout(&priv->wdd, nowayout);
+	watchdog_stop_on_reboot(&priv->wdd);
+	watchdog_stop_on_unregister(&priv->wdd);
+
+	ret = devm_watchdog_register_device(dev, &priv->wdd);
+
+	dev_dbg(&pdev->dev, "initialized. timeout=%d sec (nowayout=%d)\n",
+		priv->wdd.timeout, nowayout);
+
+	return ret;
+}
+
+static struct platform_driver se10_wdt_driver = {
+	.driver = {
+		.name = DRVNAME,
+	},
+	.probe  = se10_wdt_probe,
+};
+
+static int se10_create_platform_device(const struct dmi_system_id *id)
+{
+	int err;
+
+	se10_pdev = platform_device_alloc("lenovo-se10-wdt", -1);
+	if (!se10_pdev)
+		return -ENOMEM;
+
+	err = platform_device_add(se10_pdev);
+	if (err)
+		platform_device_put(se10_pdev);
+
+	return err;
+}
+
+static const struct dmi_system_id se10_dmi_table[] __initconst = {
+	{
+		.ident = "LENOVO-SE10",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "12NH"),
+		},
+		.callback = se10_create_platform_device,
+	},
+	{
+		.ident = "LENOVO-SE10",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "12NJ"),
+		},
+		.callback = se10_create_platform_device,
+	},
+	{
+		.ident = "LENOVO-SE10",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "12NK"),
+		},
+		.callback = se10_create_platform_device,
+	},
+	{
+		.ident = "LENOVO-SE10",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "12NL"),
+		},
+		.callback = se10_create_platform_device,
+	},
+	{
+		.ident = "LENOVO-SE10",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "12NM"),
+		},
+		.callback = se10_create_platform_device,
+	},
+	{}
+};
+MODULE_DEVICE_TABLE(dmi, se10_dmi_table);
+
+static int __init se10_wdt_init(void)
+{
+	if (!dmi_check_system(se10_dmi_table))
+		return -ENODEV;
+
+	return platform_driver_register(&se10_wdt_driver);
+}
+
+static void __exit se10_wdt_exit(void)
+{
+	if (se10_pdev)
+		platform_device_unregister(se10_pdev);
+	platform_driver_unregister(&se10_wdt_driver);
+}
+
+module_init(se10_wdt_init);
+module_exit(se10_wdt_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("David Ober<dober@xxxxxxxxxx>");
+MODULE_AUTHOR("Mark Pearson <mpearson-lenovo@xxxxxxxxx>");
+MODULE_DESCRIPTION("WDT driver for Lenovo SE10");
-- 
2.43.2