watchdog: Exar/MaxLinear XR28V38x driver
Simple driver for the watchdog present in some Exar/MaxLinear UART chips. Please see https://www.maxlinear.com/product/interface/uarts/lpc-uarts/xr28v384 for more info. Signed-off-by: David Müller <d.mueller@elsoft.ch> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/20220914094605.93377-1-d.mueller@elsoft.ch Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
This commit is contained in:
David Müller
Wim Van Sebroeck
parent
64ee937509
commit
81126222bd
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@ -1089,6 +1089,17 @@ config EBC_C384_WDT
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WinSystems EBC-C384 motherboard. The timeout may be configured via
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the timeout module parameter.
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config EXAR_WDT
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tristate "Exar Watchdog Timer"
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depends on X86
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select WATCHDOG_CORE
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help
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Enables watchdog timer support for the watchdog timer present
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in some Exar/MaxLinear UART chips like the XR28V38x.
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To compile this driver as a module, choose M here: the
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module will be called exar_wdt.
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config F71808E_WDT
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tristate "Fintek F718xx, F818xx Super I/O Watchdog"
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depends on X86
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@ -105,6 +105,7 @@ obj-$(CONFIG_ADVANTECH_WDT) += advantechwdt.o
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obj-$(CONFIG_ALIM1535_WDT) += alim1535_wdt.o
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obj-$(CONFIG_ALIM7101_WDT) += alim7101_wdt.o
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obj-$(CONFIG_EBC_C384_WDT) += ebc-c384_wdt.o
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obj-$(CONFIG_EXAR_WDT) += exar_wdt.o
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obj-$(CONFIG_F71808E_WDT) += f71808e_wdt.o
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obj-$(CONFIG_SP5100_TCO) += sp5100_tco.o
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obj-$(CONFIG_GEODE_WDT) += geodewdt.o
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@ -0,0 +1,427 @@
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// SPDX-License-Identifier: GPL-2.0+
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/*
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* exar_wdt.c - Driver for the watchdog present in some
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* Exar/MaxLinear UART chips like the XR28V38x.
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*
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* (c) Copyright 2022 D. Müller <d.mueller@elsoft.ch>.
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*
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/io.h>
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#include <linux/list.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/watchdog.h>
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#define DRV_NAME "exar_wdt"
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static const unsigned short sio_config_ports[] = { 0x2e, 0x4e };
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static const unsigned char sio_enter_keys[] = { 0x67, 0x77, 0x87, 0xA0 };
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#define EXAR_EXIT_KEY 0xAA
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#define EXAR_LDN 0x07
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#define EXAR_DID 0x20
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#define EXAR_VID 0x23
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#define EXAR_WDT 0x26
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#define EXAR_ACT 0x30
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#define EXAR_RTBASE 0x60
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#define EXAR_WDT_LDEV 0x08
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#define EXAR_VEN_ID 0x13A8
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#define EXAR_DEV_382 0x0382
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#define EXAR_DEV_384 0x0384
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/* WDT runtime registers */
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#define WDT_CTRL 0x00
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#define WDT_VAL 0x01
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#define WDT_UNITS_10MS 0x0 /* the 10 millisec unit of the HW is not used */
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#define WDT_UNITS_SEC 0x2
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#define WDT_UNITS_MIN 0x4
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/* default WDT control for WDTOUT signal activ / rearm by read */
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#define EXAR_WDT_DEF_CONF 0
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struct wdt_pdev_node {
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struct list_head list;
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struct platform_device *pdev;
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const char name[16];
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};
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struct wdt_priv {
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/* the lock for WDT io operations */
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spinlock_t io_lock;
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struct resource wdt_res;
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struct watchdog_device wdt_dev;
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unsigned short did;
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unsigned short config_port;
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unsigned char enter_key;
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unsigned char unit;
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unsigned char timeout;
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};
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#define WATCHDOG_TIMEOUT 60
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static int timeout = WATCHDOG_TIMEOUT;
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module_param(timeout, int, 0);
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MODULE_PARM_DESC(timeout,
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"Watchdog timeout in seconds. 1<=timeout<=15300, default="
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__MODULE_STRING(WATCHDOG_TIMEOUT) ".");
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static bool nowayout = WATCHDOG_NOWAYOUT;
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module_param(nowayout, bool, 0);
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MODULE_PARM_DESC(nowayout,
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"Watchdog cannot be stopped once started (default="
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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static int exar_sio_enter(const unsigned short config_port,
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const unsigned char key)
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{
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if (!request_muxed_region(config_port, 2, DRV_NAME))
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return -EBUSY;
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/* write the ENTER-KEY twice */
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outb(key, config_port);
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outb(key, config_port);
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return 0;
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}
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static void exar_sio_exit(const unsigned short config_port)
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{
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outb(EXAR_EXIT_KEY, config_port);
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release_region(config_port, 2);
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}
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static unsigned char exar_sio_read(const unsigned short config_port,
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const unsigned char reg)
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{
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outb(reg, config_port);
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return inb(config_port + 1);
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}
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static void exar_sio_write(const unsigned short config_port,
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const unsigned char reg, const unsigned char val)
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{
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outb(reg, config_port);
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outb(val, config_port + 1);
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}
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static unsigned short exar_sio_read16(const unsigned short config_port,
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const unsigned char reg)
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{
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unsigned char msb, lsb;
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msb = exar_sio_read(config_port, reg);
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lsb = exar_sio_read(config_port, reg + 1);
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return (msb << 8) | lsb;
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}
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static void exar_sio_select_wdt(const unsigned short config_port)
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{
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exar_sio_write(config_port, EXAR_LDN, EXAR_WDT_LDEV);
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}
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static void exar_wdt_arm(const struct wdt_priv *priv)
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{
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unsigned short rt_base = priv->wdt_res.start;
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/* write timeout value twice to arm watchdog */
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outb(priv->timeout, rt_base + WDT_VAL);
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outb(priv->timeout, rt_base + WDT_VAL);
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}
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static void exar_wdt_disarm(const struct wdt_priv *priv)
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{
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unsigned short rt_base = priv->wdt_res.start;
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/*
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* use two accesses with different values to make sure
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* that a combination of a previous single access and
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* the ones below with the same value are not falsely
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* interpreted as "arm watchdog"
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*/
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outb(0xFF, rt_base + WDT_VAL);
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outb(0, rt_base + WDT_VAL);
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}
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static int exar_wdt_start(struct watchdog_device *wdog)
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{
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struct wdt_priv *priv = watchdog_get_drvdata(wdog);
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unsigned short rt_base = priv->wdt_res.start;
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spin_lock(&priv->io_lock);
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exar_wdt_disarm(priv);
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outb(priv->unit, rt_base + WDT_CTRL);
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exar_wdt_arm(priv);
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spin_unlock(&priv->io_lock);
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return 0;
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}
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static int exar_wdt_stop(struct watchdog_device *wdog)
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{
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struct wdt_priv *priv = watchdog_get_drvdata(wdog);
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spin_lock(&priv->io_lock);
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exar_wdt_disarm(priv);
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spin_unlock(&priv->io_lock);
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return 0;
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}
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static int exar_wdt_keepalive(struct watchdog_device *wdog)
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{
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struct wdt_priv *priv = watchdog_get_drvdata(wdog);
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unsigned short rt_base = priv->wdt_res.start;
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spin_lock(&priv->io_lock);
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/* reading the WDT_VAL reg will feed the watchdog */
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inb(rt_base + WDT_VAL);
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spin_unlock(&priv->io_lock);
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return 0;
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}
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static int exar_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t)
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{
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struct wdt_priv *priv = watchdog_get_drvdata(wdog);
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bool unit_min = false;
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/*
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* if new timeout is bigger then 255 seconds, change the
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* unit to minutes and round the timeout up to the next whole minute
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*/
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if (t > 255) {
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unit_min = true;
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t = DIV_ROUND_UP(t, 60);
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}
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/* save for later use in exar_wdt_start() */
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priv->unit = unit_min ? WDT_UNITS_MIN : WDT_UNITS_SEC;
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priv->timeout = t;
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wdog->timeout = unit_min ? t * 60 : t;
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if (watchdog_hw_running(wdog))
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exar_wdt_start(wdog);
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return 0;
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}
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static const struct watchdog_info exar_wdt_info = {
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.options = WDIOF_KEEPALIVEPING |
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WDIOF_SETTIMEOUT |
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WDIOF_MAGICCLOSE,
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.identity = "Exar/MaxLinear XR28V38x Watchdog",
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};
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static const struct watchdog_ops exar_wdt_ops = {
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.owner = THIS_MODULE,
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.start = exar_wdt_start,
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.stop = exar_wdt_stop,
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.ping = exar_wdt_keepalive,
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.set_timeout = exar_wdt_set_timeout,
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};
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static int exar_wdt_config(struct watchdog_device *wdog,
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const unsigned char conf)
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{
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struct wdt_priv *priv = watchdog_get_drvdata(wdog);
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int ret;
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ret = exar_sio_enter(priv->config_port, priv->enter_key);
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if (ret)
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return ret;
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exar_sio_select_wdt(priv->config_port);
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exar_sio_write(priv->config_port, EXAR_WDT, conf);
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exar_sio_exit(priv->config_port);
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return 0;
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}
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static int __init exar_wdt_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct wdt_priv *priv = dev->platform_data;
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struct watchdog_device *wdt_dev = &priv->wdt_dev;
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struct resource *res;
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int ret;
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res = platform_get_resource(pdev, IORESOURCE_IO, 0);
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if (!res)
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return -ENXIO;
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spin_lock_init(&priv->io_lock);
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wdt_dev->info = &exar_wdt_info;
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wdt_dev->ops = &exar_wdt_ops;
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wdt_dev->min_timeout = 1;
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wdt_dev->max_timeout = 255 * 60;
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watchdog_init_timeout(wdt_dev, timeout, NULL);
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watchdog_set_nowayout(wdt_dev, nowayout);
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watchdog_stop_on_reboot(wdt_dev);
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watchdog_stop_on_unregister(wdt_dev);
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watchdog_set_drvdata(wdt_dev, priv);
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ret = exar_wdt_config(wdt_dev, EXAR_WDT_DEF_CONF);
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if (ret)
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return ret;
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exar_wdt_set_timeout(wdt_dev, timeout);
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/* Make sure that the watchdog is not running */
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exar_wdt_stop(wdt_dev);
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ret = devm_watchdog_register_device(dev, wdt_dev);
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if (ret)
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return ret;
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dev_info(dev, "XR28V%X WDT initialized. timeout=%d sec (nowayout=%d)\n",
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priv->did, timeout, nowayout);
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return 0;
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}
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static unsigned short __init exar_detect(const unsigned short config_port,
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const unsigned char key,
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unsigned short *rt_base)
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{
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int ret;
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unsigned short base = 0;
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unsigned short vid, did;
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ret = exar_sio_enter(config_port, key);
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if (ret)
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return 0;
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vid = exar_sio_read16(config_port, EXAR_VID);
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did = exar_sio_read16(config_port, EXAR_DID);
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/* check for the vendor and device IDs we currently know about */
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if (vid == EXAR_VEN_ID &&
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(did == EXAR_DEV_382 ||
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did == EXAR_DEV_384)) {
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exar_sio_select_wdt(config_port);
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/* is device active? */
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if (exar_sio_read(config_port, EXAR_ACT) == 0x01)
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base = exar_sio_read16(config_port, EXAR_RTBASE);
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}
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exar_sio_exit(config_port);
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if (base) {
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pr_debug("Found a XR28V%X WDT (conf: 0x%x / rt: 0x%04x)\n",
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did, config_port, base);
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*rt_base = base;
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return did;
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}
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return 0;
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}
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static struct platform_driver exar_wdt_driver = {
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.driver = {
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.name = DRV_NAME,
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},
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};
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static LIST_HEAD(pdev_list);
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static int __init exar_wdt_register(struct wdt_priv *priv, const int idx)
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{
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struct wdt_pdev_node *n;
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n = kzalloc(sizeof(*n), GFP_KERNEL);
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if (!n)
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return -ENOMEM;
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INIT_LIST_HEAD(&n->list);
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scnprintf((char *)n->name, sizeof(n->name), DRV_NAME ".%d", idx);
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priv->wdt_res.name = n->name;
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n->pdev = platform_device_register_resndata(NULL, DRV_NAME, idx,
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&priv->wdt_res, 1,
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priv, sizeof(*priv));
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if (IS_ERR(n->pdev)) {
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kfree(n);
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return PTR_ERR(n->pdev);
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}
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list_add_tail(&n->list, &pdev_list);
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return 0;
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}
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static void exar_wdt_unregister(void)
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{
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struct wdt_pdev_node *n, *t;
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list_for_each_entry_safe(n, t, &pdev_list, list) {
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platform_device_unregister(n->pdev);
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list_del(&n->list);
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kfree(n);
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}
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}
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static int __init exar_wdt_init(void)
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{
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int ret, i, j, idx = 0;
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/* search for active Exar watchdogs on all possible locations */
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for (i = 0; i < ARRAY_SIZE(sio_config_ports); i++) {
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for (j = 0; j < ARRAY_SIZE(sio_enter_keys); j++) {
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unsigned short did, rt_base = 0;
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did = exar_detect(sio_config_ports[i],
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sio_enter_keys[j],
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&rt_base);
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if (did) {
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struct wdt_priv priv = {
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.wdt_res = DEFINE_RES_IO(rt_base, 2),
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.did = did,
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.config_port = sio_config_ports[i],
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.enter_key = sio_enter_keys[j],
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};
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ret = exar_wdt_register(&priv, idx);
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if (!ret)
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idx++;
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}
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}
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}
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if (!idx)
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return -ENODEV;
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ret = platform_driver_probe(&exar_wdt_driver, exar_wdt_probe);
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if (ret)
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exar_wdt_unregister();
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return ret;
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}
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static void __exit exar_wdt_exit(void)
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{
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exar_wdt_unregister();
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platform_driver_unregister(&exar_wdt_driver);
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}
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module_init(exar_wdt_init);
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module_exit(exar_wdt_exit);
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MODULE_AUTHOR("David Müller <d.mueller@elsoft.ch>");
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MODULE_DESCRIPTION("Exar/MaxLinear Watchdog Driver");
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MODULE_LICENSE("GPL");
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