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From:   David Ober <dober6023@gmail.com>
To:     wim@linux-watchdog.org
Cc:     linux@roeck-us.net, linux-kernel@vger.kernel.org,
        linux-watchdog@vger.kernel.org, mpearson@lenovo.com,
        dober@lenovo.com, David Ober <dober6023@gmail.com>
Subject: [PATCH v2] Watchdog: New module for ITE 5632 watchdog
Date:   Thu, 20 Jul 2023 10:14:21 -0400
Message-Id: <20230720141421.119237-1-dober6023@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

This modules is to allow for the new ITE 5632 EC chip
to support the watchdog for initial use in the Lenovo SE10

Signed-off-by: David Ober <dober6023@gmail.com>

V2 Fix stop to deactivate wdog on unload of module
V2 Remove extra logging that is not needed
V2 change udelays to usleep_range 
V2 Changed to now request region on start and release on stop instead 
   of for every ping and read/write 

---
 drivers/watchdog/Kconfig       |  10 ++
 drivers/watchdog/Makefile      |   1 +
 drivers/watchdog/ite5632_wdt.c | 273 +++++++++++++++++++++++++++++++++
 3 files changed, 284 insertions(+)
 create mode 100644 drivers/watchdog/ite5632_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index ee97d89dfc11..861cc0eff468 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -264,6 +264,16 @@ config MENZ069_WATCHDOG
 	  This driver can also be built as a module. If so the module
 	  will be called menz069_wdt.
 
+config ITE5632_WDT
+        tristate "ITE 5632"
+        select WATCHDOG_CORE
+        help
+          If you say yes here you get support for the watchdog
+          functionality of the ITE 5632 eSIO chip.
+
+          This driver can also be built as a module. If so, the module
+          will be called ite5632_wdt.
+
 config WDAT_WDT
 	tristate "ACPI Watchdog Action Table (WDAT)"
 	depends on ACPI
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 3633f5b98236..32c8340f3175 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -119,6 +119,7 @@ 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-$(CONFIG_ITE5632_WDT) += ite5632_wdt.o
 ifeq ($(CONFIG_ITCO_VENDOR_SUPPORT),y)
 obj-$(CONFIG_ITCO_WDT) += iTCO_vendor_support.o
 endif
diff --git a/drivers/watchdog/ite5632_wdt.c b/drivers/watchdog/ite5632_wdt.c
new file mode 100644
index 000000000000..4b1fe6de6f87
--- /dev/null
+++ b/drivers/watchdog/ite5632_wdt.c
@@ -0,0 +1,273 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	Customized ITE5632 WDT driver for Lenovo SE10.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/ioport.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 EC_STATUS_port	0x6C
+#define EC_CMD_port	0x6C
+#define EC_DATA_port	0x68
+#define EC_OBF		0x01
+#define EC_IBF		0x02
+#define CFG_LDN		0x07
+#define CFG_BRAM_LDN	0x10    /* for BRAM Base */
+#define CFG_PORT	0x2E
+
+#define CUS_WDT_SWI		0x1A
+#define CUS_WDT_CFG		0x1B
+#define CUS_WDT_FEED		0xB0
+#define CUS_WDT_CNT		0xB1
+
+#define DRVNAME			"ite5632"
+
+/*The timeout range is 1-255 seconds*/
+#define MIN_TIMEOUT		1
+#define MAX_TIMEOUT		255
+
+#define WATCHDOG_TIMEOUT	60	/* 60 sec default timeout */
+static unsigned short bram_base;
+
+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 ite5632_data_t {
+	struct watchdog_device wdt;
+	int region_locked;
+};
+
+/* Kernel methods. */
+static void set_bram(unsigned char offset, unsigned char val)
+{
+	outb(offset, bram_base);
+	outb(val, bram_base + 1);
+}
+
+/* wait EC output buffer full */
+static void wait_EC_OBF(void)
+{
+	while (1) {
+		if (inb(EC_STATUS_port) & EC_OBF)
+			break;
+		usleep_range(10, 125);
+	}
+}
+
+/* wait EC input buffer empty */
+static void wait_EC_IBE(void)
+{
+	while (1) {
+		if (!(inb(EC_STATUS_port) & EC_IBF))
+			break;
+		usleep_range(10, 125);
+	}
+}
+
+static void send_EC_cmd(unsigned char eccmd)
+{
+	wait_EC_IBE();
+	outb(eccmd, EC_CMD_port);
+	wait_EC_IBE();
+}
+
+static unsigned char Read_EC_data(void)
+{
+	wait_EC_OBF();
+	return inb(EC_DATA_port);
+}
+
+static void LPC_Write_Byte(unsigned char index, unsigned char data)
+{
+	outb(index, CFG_PORT);
+	outb(data, CFG_PORT + 1);
+}
+
+static unsigned char LPC_Read_Byte(unsigned char index)
+{
+	outb(index, CFG_PORT);
+	return inb(CFG_PORT + 1);
+}
+
+static int GetChipID(void)
+{
+	unsigned char MSB, LSB;
+	unsigned char cmd = 0x55;
+
+	outb(0x87, CFG_PORT);
+	outb(0x01, CFG_PORT);
+	outb(0x55, CFG_PORT);
+	outb(cmd, CFG_PORT);
+	outb(0x20, CFG_PORT);
+	MSB = inb(CFG_PORT + 1);
+	outb(0x21, CFG_PORT);
+	LSB = inb(CFG_PORT + 1);
+	return (MSB * 256 + LSB);
+}
+
+static int wdt_start(struct watchdog_device *wdog)
+{
+	struct ite5632_data_t *data = watchdog_get_drvdata(wdog);
+
+	if (!request_region(EC_DATA_port, 5, "EC")) {
+		dev_err(data->wdt.parent, ":request fail\n");
+		return 0;
+	}
+	data->region_locked = 1;
+	set_bram(CUS_WDT_SWI, 0x80);
+	return 0;
+}
+
+static int wdt_set_timeout(struct watchdog_device *wdog, unsigned int timeout)
+{
+	wdog->timeout = timeout;
+	set_bram(CUS_WDT_CFG, wdog->timeout);
+	return 0;
+}
+
+static int wdt_stop(struct watchdog_device *wdog)
+{
+	struct ite5632_data_t *data = watchdog_get_drvdata(wdog);
+
+	set_bram(CUS_WDT_SWI, 0);
+	if (data->region_locked == 1)
+		release_region(EC_DATA_port, 5);
+	return 0;
+}
+
+static unsigned int wdt_get_time(struct watchdog_device *wdog)
+{
+	unsigned int timeleft;
+
+	send_EC_cmd(CUS_WDT_CNT);
+
+	timeleft = Read_EC_data();
+	return timeleft;
+}
+
+static int wdt_ping(struct watchdog_device *wdog)
+{
+	send_EC_cmd(CUS_WDT_FEED);
+	return 0;
+}
+
+/* Kernel Interfaces */
+static const struct watchdog_info wdt_info = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+	.identity = "5632 Watchdog",
+};
+
+static const struct watchdog_ops 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 int ite5632_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct ite5632_data_t *data = NULL;
+
+	dev_info(&pdev->dev, "Probe ITE5632 called\n");
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->region_locked = 0;
+	data->wdt.info = &wdt_info,
+	data->wdt.ops = &wdt_ops,
+	data->wdt.timeout = WATCHDOG_TIMEOUT; /* Set default timeout */
+	data->wdt.min_timeout = MIN_TIMEOUT;
+	data->wdt.max_timeout = MAX_TIMEOUT;
+	data->wdt.parent = &pdev->dev;
+
+	watchdog_init_timeout(&data->wdt, timeout, &pdev->dev);
+	watchdog_set_drvdata(&data->wdt, data);
+
+	watchdog_set_nowayout(&data->wdt, nowayout);
+	watchdog_stop_on_reboot(&data->wdt);
+	watchdog_stop_on_unregister(&data->wdt);
+
+	dev_info(&pdev->dev, "initialized. timeout=%d sec (nowayout=%d)\n",
+		 data->wdt.timeout, nowayout);
+
+	return devm_watchdog_register_device(dev, &data->wdt);
+}
+
+static struct platform_driver ite5632_driver = {
+	.driver = {
+		.name = DRVNAME,
+	},
+	.probe  = ite5632_probe,
+};
+
+static struct platform_device *pdev;
+
+static int __init wdt_init(void)
+{
+	int ret;
+	int chip;
+
+	chip = GetChipID();
+
+	if (chip == 0x5632)
+		pr_info("Found ITE ChipID = %4X\n", chip);
+	else
+		return -ENODEV;
+
+	LPC_Write_Byte(CFG_LDN, CFG_BRAM_LDN);
+	bram_base = ((LPC_Read_Byte(0x60) << 8) | LPC_Read_Byte(0x61));
+
+	platform_driver_register(&ite5632_driver);
+
+	pdev = platform_device_alloc(DRVNAME, bram_base);
+
+	/* platform_device_add calls probe() */
+	ret = platform_device_add(pdev);
+	if (ret) {
+		platform_device_put(pdev);
+		if (pdev)
+			platform_device_unregister(pdev);
+		platform_driver_unregister(&ite5632_driver);
+	}
+	return ret;
+}
+
+static void __exit wdt_exit(void)
+{
+	platform_device_unregister(pdev);
+	platform_driver_unregister(&ite5632_driver);
+
+	LPC_Write_Byte(2, 2);
+}
+
+module_init(wdt_init);
+module_exit(wdt_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("David Ober<dober@lenovo.com>");
+MODULE_DESCRIPTION("WDT driver for ITE5632");
-- 
2.34.1