text: /*
   * Copyright (c) 2016 Linaro Limited
   *
   * SPDX-License-Identifier: Apache-2.0
   */
  
  /**
   * @brief Driver for CMSDK APB Watchdog.
   */
  
  #include <errno.h>
  #include <soc.h>
  #include <drivers/watchdog.h>
  #include <sys/printk.h>
  #include <power/reboot.h>
  
  struct wdog_cmsdk_apb {
  	/* offset: 0x000 (r/w) watchdog load register */
  	volatile u32_t  load;
  	/* offset: 0x004 (r/ ) watchdog value register */
  	volatile u32_t  value;
  	/* offset: 0x008 (r/w) watchdog control register */
  	volatile u32_t  ctrl;
  	/* offset: 0x00c ( /w) watchdog clear interrupt register */
  	volatile u32_t  intclr;
  	/* offset: 0x010 (r/ ) watchdog raw interrupt status register */
  	volatile u32_t  rawintstat;
  	/* offset: 0x014 (r/ ) watchdog interrupt status register */
  	volatile u32_t  maskintstat;
  	volatile u32_t  reserved0[762];
  	/* offset: 0xc00 (r/w) watchdog lock register */
  	volatile u32_t  lock;
  	volatile u32_t  reserved1[191];
  	/* offset: 0xf00 (r/w) watchdog integration test control register */
  	volatile u32_t  itcr;
  	/* offset: 0xf04 ( /w) watchdog integration test output set register */
  	volatile u32_t  itop;
  };
  
  #define CMSDK_APB_WDOG_LOAD		(0xFFFFFFFF << 0)
  #define CMSDK_APB_WDOG_RELOAD		(0xE4E1C00 << 0)
  #define CMSDK_APB_WDOG_VALUE		(0xFFFFFFFF << 0)
  #define CMSDK_APB_WDOG_CTRL_RESEN	(0x1 << 1)
  #define CMSDK_APB_WDOG_CTRL_INTEN	(0x1 << 0)
  #define CMSDK_APB_WDOG_INTCLR		(0x1 << 0)
  #define CMSDK_APB_WDOG_RAWINTSTAT	(0x1 << 0)
  #define CMSDK_APB_WDOG_MASKINTSTAT	(0x1 << 0)
  #define CMSDK_APB_WDOG_LOCK		(0x1 << 0)
  #define CMSDK_APB_WDOG_INTEGTESTEN	(0x1 << 0)
  #define CMSDK_APB_WDOG_INTEGTESTOUTSET	(0x1 << 1)
  
  /*
   * Value written to the LOCK register to lock or unlock the write access
   * to all of the registers of the watchdog (except the LOCK register)
   */
  #define CMSDK_APB_WDOG_UNLOCK_VALUE (0x1ACCE551)
  #define CMSDK_APB_WDOG_LOCK_VALUE (0x2BDDF662)
  
  #define WDOG_STRUCT \
  	((volatile struct wdog_cmsdk_apb *)(DT_INST_0_ARM_CMSDK_WATCHDOG_BASE_ADDRESS))
  
  /* Keep reference of the device to pass it to the callback */
  struct device *wdog_r;
  
  /* watchdog reload value in sec */
  static unsigned int reload_s = CMSDK_APB_WDOG_RELOAD;
  static u8_t flags;
  
  static void (*user_cb)(struct device *dev, int channel_id);
  
  static void wdog_cmsdk_apb_unlock(struct device *dev)
  {
  	volatile struct wdog_cmsdk_apb *wdog = WDOG_STRUCT;
  
  	ARG_UNUSED(dev);
  
  	wdog->lock = CMSDK_APB_WDOG_UNLOCK_VALUE;
  }
  
  static int wdog_cmsdk_apb_setup(struct device *dev, u8_t options)
  {
  	volatile struct wdog_cmsdk_apb *wdog = WDOG_STRUCT;
  
  	ARG_UNUSED(dev);
  	ARG_UNUSED(options);
  
  	/* Start the watchdog counter with INTEN bit */
  	wdog->ctrl = (CMSDK_APB_WDOG_CTRL_RESEN | CMSDK_APB_WDOG_CTRL_INTEN);
  
  	return 0;
  }
  
  static int wdog_cmsdk_apb_disable(struct device *dev)
  {
  	volatile struct wdog_cmsdk_apb *wdog = WDOG_STRUCT;
  
  	ARG_UNUSED(dev);
  
  	/* Stop the watchdog counter with INTEN bit */
  	wdog->ctrl = ~(CMSDK_APB_WDOG_CTRL_RESEN | CMSDK_APB_WDOG_CTRL_INTEN);
  
  	return 0;
  }
  
  static int wdog_cmsdk_apb_install_timeout(struct device *dev,
  					  const struct wdt_timeout_cfg *config)
  {
  	volatile struct wdog_cmsdk_apb *wdog = WDOG_STRUCT;
  
  	ARG_UNUSED(dev);
  
  	/* Reload value */
  	reload_s = config->window.max *
  			   DT_INST_0_ARM_CMSDK_WATCHDOG_CLOCKS_CLOCK_FREQUENCY;
  	flags = config->flags;
  
  	wdog->load = reload_s;
  
  	/* Configure only the callback */
  	user_cb = config->callback;
  
  	return 0;
  }
  
  static int wdog_cmsdk_apb_feed(struct device *dev, int channel_id)
  {
  	volatile struct wdog_cmsdk_apb *wdog = WDOG_STRUCT;
  
  	ARG_UNUSED(dev);
  	ARG_UNUSED(channel_id);
  
  	/* Clear the interrupt */
  	wdog->intclr = CMSDK_APB_WDOG_INTCLR;
  
  	/* Reload */
  	wdog->load = reload_s;
  
  	return 0;
  }
  
  static const struct wdt_driver_api wdog_cmsdk_apb_api = {
  	.setup = wdog_cmsdk_apb_setup,
  	.disable = wdog_cmsdk_apb_disable,
  	.install_timeout = wdog_cmsdk_apb_install_timeout,
  	.feed = wdog_cmsdk_apb_feed,
  };
  
  #ifdef CONFIG_RUNTIME_NMI
  extern void z_NmiHandlerSet(void (*pHandler)(void));
  
  static int wdog_cmsdk_apb_has_fired(void)
  {
  	volatile struct wdog_cmsdk_apb *wdog = WDOG_STRUCT;
  
  	return (wdog->maskintstat & CMSDK_APB_WDOG_MASKINTSTAT) != 0U;
  }
  
  static void wdog_cmsdk_apb_isr(void)
  {
  	/*
  	 * Check if the watchdog was the reason of the NMI interrupt
  	 * and if not, exit immediately
  	 */
  	if (!wdog_cmsdk_apb_has_fired()) {
  		printk("NMI received! Rebooting...\n");
  		/* In ARM implementation sys_reboot ignores the parameter */
  		sys_reboot(0);
  	} else {
  		if (user_cb != NULL) {
  			user_cb(wdog_r, 0);
  		}
  	}
  }
  #endif /* CONFIG_RUNTIME_NMI */
  
  static int wdog_cmsdk_apb_init(struct device *dev)
  {
  	volatile struct wdog_cmsdk_apb *wdog = WDOG_STRUCT;
  
  	wdog_r = dev;
  
  	/* unlock access to configuration registers */
  	wdog_cmsdk_apb_unlock(dev);
  
  	/* set default reload value */
  	wdog->load = reload_s;
  
  #ifdef CONFIG_RUNTIME_NMI
  	/* Configure the interrupts */
  	z_NmiHandlerSet(wdog_cmsdk_apb_isr);
  #endif
  
  #ifdef CONFIG_WDOG_CMSDK_APB_START_AT_BOOT
  	wdog_cmsdk_apb_enable(dev);
  #endif
  
  	return 0;
  }
  
  DEVICE_AND_API_INIT(wdog_cmsdk_apb, CONFIG_WDT_0_NAME,
  		    wdog_cmsdk_apb_init,
  		    NULL, NULL,
  		    PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_DEVICE,
  		    &wdog_cmsdk_apb_api);
  