arm: at91: wdt: Convert watchdog driver to dm/dt

Convert the Watchdog driver for AT91SAM9x processors to support
the driver model and device tree. Changes "CONFIG_AT91SAM9_WATCHDOG"
to new "CONFIG_WDT_AT91" Kconfig option.

Signed-off-by: Prasanthi Chellakumar <prasanthi.chellakumar@microchip.com>

arch/arm/dts/at91sam9260-smartweb.dts

@@ -89,6 +89,7 @@
 			};
 
 			watchdog@fffffd40 {
+				timeout-sec = <15>;
 				status = "okay";
 			};
 

arch/arm/dts/at91sam9g20-taurus.dts

@@ -98,6 +98,7 @@
 			};
 
 			watchdog@fffffd40 {
+				timeout-sec = <15>;
 				status = "okay";
 			};
 

arch/arm/mach-at91/include/mach/at91_wdt.h

@@ -4,7 +4,7 @@
  *
  * Copyright (C) 2008 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
  * Copyright (C) 2007 Andrew Victor
- * Copyright (C) 2007 Atmel Corporation.
+ * Copyright (C) 2018 Microchip Technology Inc.
  *
  * Watchdog Timer (WDT) - System peripherals regsters.
  * Based on AT91SAM9261 datasheet revision D.
@@ -27,9 +27,13 @@ typedef struct at91_wdt {
 
 #endif
 
+/* Watchdog Control Register */
+#define AT91_WDT_CR			0x00
 #define AT91_WDT_CR_WDRSTT		1
 #define AT91_WDT_CR_KEY			0xa5000000	/* KEY Password */
 
+/* Watchdog Mode Register*/
+#define AT91_WDT_MR			0X04
 #define AT91_WDT_MR_WDV(x)		(x & 0xfff)
 #define AT91_WDT_MR_WDFIEN		0x00001000
 #define AT91_WDT_MR_WDRSTEN		0x00002000

arch/arm/mach-at91/spl.c

@@ -11,7 +11,7 @@
 #include <asm/arch/clk.h>
 #include <spl.h>
 
-#if !defined(CONFIG_AT91SAM9_WATCHDOG)
+#if !defined(CONFIG_WDT_AT91)
 void at91_disable_wdt(void)
 {
 	struct at91_wdt *wdt = (struct at91_wdt *)ATMEL_BASE_WDT;

arch/arm/mach-at91/spl_at91.c

@@ -76,7 +76,7 @@ void __weak spl_board_init(void)
 void board_init_f(ulong dummy)
 {
 	lowlevel_clock_init();
-#if !defined(CONFIG_AT91SAM9_WATCHDOG)
+#if !defined(CONFIG_WDT_AT91)
 	at91_disable_wdt();
 #endif
 

arch/arm/mach-at91/spl_atmel.c

@@ -98,7 +98,7 @@ void board_init_f(ulong dummy)
 	configure_2nd_sram_as_l2_cache();
 #endif
 
-#if !defined(CONFIG_AT91SAM9_WATCHDOG)
+#if !defined(CONFIG_WDT_AT91)
 	/* disable watchdog */
 	at91_disable_wdt();
 #endif

common/board_f.c

@@ -91,7 +91,7 @@ static int init_func_watchdog_init(void)
 {
 # if defined(CONFIG_HW_WATCHDOG) && \
 	(defined(CONFIG_M68K) || defined(CONFIG_MICROBLAZE) || \
-	defined(CONFIG_SH) || defined(CONFIG_AT91SAM9_WATCHDOG) || \
+	defined(CONFIG_SH) || \
 	defined(CONFIG_DESIGNWARE_WATCHDOG) || \
 	defined(CONFIG_IMX_WATCHDOG))
 	hw_watchdog_init();

configs/picosam9g45_defconfig

@@ -40,3 +40,7 @@ CONFIG_USB_EHCI_HCD=y
 CONFIG_USB_STORAGE=y
 CONFIG_LCD=y
 CONFIG_OF_LIBFDT=y
+CONFIG_DM=y
+CONFIG_SPL_DM=y
+CONFIG_WDT=y
+CONFIG_WDT_AT91=y

configs/smartweb_defconfig

@@ -59,3 +59,6 @@ CONFIG_USB_ETHER_ASIX=y
 CONFIG_USB_ETHER_MCS7830=y
 CONFIG_SPL_TINY_MEMSET=y
 # CONFIG_EFI_LOADER is not set
+CONFIG_WDT=y
+CONFIG_WDT_AT91=y
+CONFIG_AT91_HW_WDT_TIMEOUT=y

configs/taurus_defconfig

@@ -61,3 +61,6 @@ CONFIG_USB_GADGET_VENDOR_NUM=0x0908
 CONFIG_USB_GADGET_PRODUCT_NUM=0x02d2
 CONFIG_USB_GADGET_DOWNLOAD=y
 CONFIG_USE_TINY_PRINTF=y
+CONFIG_WDT=y
+CONFIG_WDT_AT91=y
+CONFIG_AT91_HW_WDT_TIMEOUT=y

doc/README.at91

@@ -171,4 +171,4 @@ III. Watchdog support
 	your code (make sure not to disable it in AT91Bootstrap for instance).
 
 	In the U-Boot configuration, the AT91 watchdog support is enabled using
-	the CONFIG_AT91SAM9_WATCHDOG and CONFIG_HW_WATCHDOG options.
+	the CONFIG_WDT and CONFIG_WDT_AT91 options.

doc/README.watchdog

@@ -14,7 +14,7 @@ CONFIG_WATCHDOG_TIMEOUT_MSECS
 	If not given, will default to maximum timeout. This would
 	be 128000 msec for i.mx31/35/5x/6x.
 
-CONFIG_AT91SAM9_WATCHDOG
+CONFIG_WDT_AT91
 	Available for AT91SAM9 to service the watchdog.
 
 CONFIG_FTWDT010_WATCHDOG

drivers/watchdog/Kconfig

@@ -118,4 +118,14 @@ config IMX_WATCHDOG
 	   Select this to enable the IMX and LSCH2 of Layerscape watchdog
 	   driver.
 
+config WDT_AT91
+	bool "AT91 watchdog timer support"
+	depends on WDT
+	help
+	   Select this to enable Microchip watchdog timer, which can be found on
+	   some AT91 devices.
+
+config AT91_HW_WDT_TIMEOUT
+	bool "AT91 watchdog timeout specified"
+	depends on WDT_AT91
 endmenu

drivers/watchdog/Makefile

@@ -3,7 +3,7 @@
 # (C) Copyright 2008
 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 
-obj-$(CONFIG_AT91SAM9_WATCHDOG) += at91sam9_wdt.o
+obj-$(CONFIG_WDT_AT91) += at91sam9_wdt.o
 obj-$(CONFIG_FTWDT010_WATCHDOG) += ftwdt010_wdt.o
 ifneq (,$(filter $(SOC), mx25 mx31 mx35 mx5 mx6 mx7 vf610))
 obj-y += imx_watchdog.o

drivers/watchdog/at91sam9_wdt.c

@@ -2,7 +2,7 @@
 /*
  * [origin: Linux kernel drivers/watchdog/at91sam9_wdt.c]
  *
- * Watchdog driver for Atmel AT91SAM9x processors.
+ * Watchdog driver for AT91SAM9x processors.
  *
  * Copyright (C) 2008 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
  * Copyright (C) 2008 Renaud CERRATO r.cerrato@til-technologies.fr
@@ -14,38 +14,47 @@
  * write to this register. Inform Linux to it too
  */
 
-#include <common.h>
-#include <watchdog.h>
-#include <asm/arch/hardware.h>
 #include <asm/io.h>
 #include <asm/arch/at91_wdt.h>
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <wdt.h>
+
+DECLARE_GLOBAL_DATA_PTR;
 
 /*
  * AT91SAM9 watchdog runs a 12bit counter @ 256Hz,
  * use this to convert a watchdog
- * value from/to milliseconds.
+ * value from seconds.
  */
-#define ms_to_ticks(t)	(((t << 8) / 1000) - 1)
+#define WDT_SEC2TICKS(s)	(((s) << 8) - 1)
-#define ticks_to_ms(t)	(((t + 1) * 1000) >> 8)
 
 /* Hardware timeout in seconds */
-#if !defined(CONFIG_AT91_HW_WDT_TIMEOUT)
+#define WDT_MAX_TIMEOUT 16
-#define WDT_HW_TIMEOUT 2
+#define WDT_MIN_TIMEOUT 0
-#else
+#define WDT_DEFAULT_TIMEOUT 2
-#define WDT_HW_TIMEOUT CONFIG_AT91_HW_WDT_TIMEOUT
+
-#endif
+struct at91_wdt_priv {
+	void __iomem *regs;
+	u32	regval;
+	u32	timeout;
+};
 
 /*
  * Set the watchdog time interval in 1/256Hz (write-once)
  * Counter is 12 bit.
  */
-static int at91_wdt_settimeout(unsigned int timeout)
+static int at91_wdt_start(struct udevice *dev, u64 timeout_s, ulong flags)
 {
-	unsigned int reg;
+	struct at91_wdt_priv *priv = dev_get_priv(dev);
-	at91_wdt_t *wd = (at91_wdt_t *) ATMEL_BASE_WDT;
+	u32 timeout = WDT_SEC2TICKS(timeout_s);
+
+	if (timeout_s > WDT_MAX_TIMEOUT || timeout_s < WDT_MIN_TIMEOUT)
+		timeout = priv->timeout;
 
 	/* Check if disabled */
-	if (readl(&wd->mr) & AT91_WDT_MR_WDDIS) {
+	if (readl(priv->regs + AT91_WDT_MR) & AT91_WDT_MR_WDDIS) {
 		printf("sorry, watchdog is disabled\n");
 		return -1;
 	}
@@ -57,24 +66,71 @@ static int at91_wdt_settimeout(unsigned int timeout)
 	 * 4096 / 256 = 16 seconds.
 	 */
 
-	reg = AT91_WDT_MR_WDRSTEN		/* causes watchdog reset */
+	priv->regval = AT91_WDT_MR_WDRSTEN	/* causes watchdog reset */
 		| AT91_WDT_MR_WDDBGHLT		/* disabled in debug mode */
 		| AT91_WDT_MR_WDD(0xfff)	/* restart at any time */
 		| AT91_WDT_MR_WDV(timeout);	/* timer value */
 
-	writel(reg, &wd->mr);
+	writel(priv->regval, priv->regs + AT91_WDT_MR);
 
 	return 0;
 }
 
-void hw_watchdog_reset(void)
+static int at91_wdt_stop(struct udevice *dev)
 {
-	at91_wdt_t *wd = (at91_wdt_t *) ATMEL_BASE_WDT;
+	struct at91_wdt_priv *priv = dev_get_priv(dev);
-	writel(AT91_WDT_CR_WDRSTT | AT91_WDT_CR_KEY, &wd->cr);
+
+	/* Disable Watchdog Timer */
+	priv->regval |= AT91_WDT_MR_WDDIS;
+	writel(priv->regval, priv->regs + AT91_WDT_MR);
+
+	return 0;
 }
 
-void hw_watchdog_init(void)
+static int at91_wdt_reset(struct udevice *dev)
 {
-	/* 16 seconds timer, resets enabled */
+	struct at91_wdt_priv *priv = dev_get_priv(dev);
-	at91_wdt_settimeout(ms_to_ticks(WDT_HW_TIMEOUT * 1000));
+
+	writel(AT91_WDT_CR_WDRSTT | AT91_WDT_CR_KEY, priv->regs + AT91_WDT_CR);
+
+	return 0;
 }
+
+static const struct wdt_ops at91_wdt_ops = {
+	.start = at91_wdt_start,
+	.stop = at91_wdt_stop,
+	.reset = at91_wdt_reset,
+};
+
+static const struct udevice_id at91_wdt_ids[] = {
+	{ .compatible = "atmel,at91sam9260-wdt" },
+	{}
+};
+
+static int at91_wdt_probe(struct udevice *dev)
+{
+	struct at91_wdt_priv *priv = dev_get_priv(dev);
+
+	priv->regs = dev_remap_addr(dev);
+	if (!priv->regs)
+		return -EINVAL;
+
+#ifdef CONFIG_AT91_HW_WDT_TIMEOUT
+	priv->timeout = dev_read_u32_default(dev, "timeout-sec",
+					     WDT_DEFAULT_TIMEOUT);
+	debug("%s: timeout %d", __func__, priv->timeout);
+#endif
+
+	debug("%s: Probing wdt%u\n", __func__, dev->seq);
+
+	return 0;
+}
+
+U_BOOT_DRIVER(at91_wdt) = {
+	.name = "at91_wdt",
+	.id = UCLASS_WDT,
+	.of_match = at91_wdt_ids,
+	.priv_auto_alloc_size = sizeof(struct at91_wdt_priv),
+	.ops = &at91_wdt_ops,
+	.probe = at91_wdt_probe,
+};

include/configs/picosam9g45.h

@@ -57,10 +57,6 @@
  */
 #define CONFIG_BOOTP_BOOTFILESIZE
 
-/* Enable the watchdog */
-#define CONFIG_AT91SAM9_WATCHDOG
-#define CONFIG_HW_WATCHDOG
-
 /*
  * Command line configuration.
  */

include/configs/smartweb.h

@@ -112,13 +112,6 @@
 	"root=/dev/nfs ip=dhcp nfsroot=${serverip}:/srv/nfs/rootfs; "	\
 	"dhcp"
 
-/* Enable the watchdog */
-#define CONFIG_AT91SAM9_WATCHDOG
-#if !defined(CONFIG_SPL_BUILD)
-#define CONFIG_HW_WATCHDOG
-#endif
-#define CONFIG_AT91_HW_WDT_TIMEOUT	15
-
 #if !defined(CONFIG_SPL_BUILD)
 /* USB configuration */
 #define CONFIG_USB_ATMEL

include/configs/taurus.h

@@ -85,13 +85,6 @@
 #define CONFIG_RMII
 #define CONFIG_AT91_WANTS_COMMON_PHY
 
-#define CONFIG_AT91SAM9_WATCHDOG
-#define CONFIG_AT91_HW_WDT_TIMEOUT	15
-#if !defined(CONFIG_SPL_BUILD)
-/* Enable the watchdog */
-#define CONFIG_HW_WATCHDOG
-#endif
-
 /* USB */
 #if defined(CONFIG_BOARD_TAURUS)
 #define CONFIG_USB_ATMEL

scripts/config_whitelist.txt

@@ -82,7 +82,6 @@ CONFIG_AT91SAM9G20EK_2MMC
 CONFIG_AT91SAM9G45EKES
 CONFIG_AT91SAM9G45_LCD_BASE
 CONFIG_AT91SAM9M10G45EK
-CONFIG_AT91SAM9_WATCHDOG
 CONFIG_AT91_CAN
 CONFIG_AT91_EFLASH
 CONFIG_AT91_GPIO_PULLUP