aspeed: Watchdog Timer Driver

This driver supports ast2500 and ast2400 SoCs.
Only ast2500 supports reset_mask and thus the option of resettting
individual peripherals using WDT.

Signed-off-by: Maxim Sloyko <maxims@google.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

2 files changed, 80 insertions, 13 deletions

diff --git a/arch/arm/include/asm/arch-aspeed/wdt.h b/arch/arm/include/asm/arch-aspeed/wdt.h
index b292a0e..981fa05 100644
--- a/arch/arm/include/asm/arch-aspeed/wdt.h
+++ b/arch/arm/include/asm/arch-aspeed/wdt.h
@@ -67,15 +67,60 @@ struct ast_wdt {
 	u32 timeout_status;
 	u32 clr_timeout_status;
 	u32 reset_width;
-#ifdef CONFIG_ASPEED_AST2500
+	/* On pre-ast2500 SoCs this register is reserved. */
 	u32 reset_mask;
-#else
-	u32 reserved0;
-#endif
 };
 
+/**
+ * Given flags parameter passed to wdt_reset or wdt_start uclass functions,
+ * gets Reset Mode value from it.
+ *
+ * @flags: flags parameter passed into wdt_reset or wdt_start
+ * @return Reset Mode value
+ */
+u32 ast_reset_mode_from_flags(ulong flags);
+
+/**
+ * Given flags parameter passed to wdt_reset or wdt_start uclass functions,
+ * gets Reset Mask value from it. Reset Mask is only supported on ast2500
+ *
+ * @flags: flags parameter passed into wdt_reset or wdt_start
+ * @return Reset Mask value
+ */
+u32 ast_reset_mask_from_flags(ulong flags);
+
+/**
+ * Given Reset Mask and Reset Mode values, converts them to flags,
+ * suitable for passing into wdt_start or wdt_reset uclass functions.
+ *
+ * On ast2500 Reset Mask is 25 bits wide and Reset Mode is 2 bits wide, so they
+ * can both be packed into single 32 bits wide value.
+ *
+ * @reset_mode: Reset Mode
+ * @reset_mask: Reset Mask
+ */
+ulong ast_flags_from_reset_mode_mask(u32 reset_mode, u32 reset_mask);
+
+#ifndef CONFIG_WDT
+/**
+ * Stop WDT
+ *
+ * @wdt: watchdog to stop
+ *
+ * When using driver model this function has different signature
+ */
 void wdt_stop(struct ast_wdt *wdt);
+
+/**
+ * Stop WDT
+ *
+ * @wdt: watchdog to start
+ * @timeout	watchdog timeout in number of clock ticks
+ *
+ * When using driver model this function has different signature
+ */
 void wdt_start(struct ast_wdt *wdt, u32 timeout);
+#endif  /* CONFIG_WDT */
 
 /**
  * Reset peripherals specified by mask
diff --git a/arch/arm/mach-aspeed/ast_wdt.c b/arch/arm/mach-aspeed/ast_wdt.c
index 22481ab..895fba3 100644
--- a/arch/arm/mach-aspeed/ast_wdt.c
+++ b/arch/arm/mach-aspeed/ast_wdt.c
@@ -9,6 +9,27 @@
 #include <asm/arch/wdt.h>
 #include <linux/err.h>
 
+u32 ast_reset_mode_from_flags(ulong flags)
+{
+	return flags & WDT_CTRL_RESET_MASK;
+}
+
+u32 ast_reset_mask_from_flags(ulong flags)
+{
+	return flags >> 2;
+}
+
+ulong ast_flags_from_reset_mode_mask(u32 reset_mode, u32 reset_mask)
+{
+	ulong ret = reset_mode & WDT_CTRL_RESET_MASK;
+
+	if (ret == WDT_CTRL_RESET_SOC)
+		ret |= (reset_mask << 2);
+
+	return ret;
+}
+
+#ifndef CONFIG_WDT
 void wdt_stop(struct ast_wdt *wdt)
 {
 	clrbits_le32(&wdt->ctrl, WDT_CTRL_EN);
@@ -26,15 +47,7 @@ void wdt_start(struct ast_wdt *wdt, u32 timeout)
 	setbits_le32(&wdt->ctrl,
 		     WDT_CTRL_EN | WDT_CTRL_RESET | WDT_CTRL_CLK1MHZ);
 }
-
-struct ast_wdt *ast_get_wdt(u8 wdt_number)
-{
-	if (wdt_number > CONFIG_WDT_NUM - 1)
-		return ERR_PTR(-EINVAL);
-
-	return (struct ast_wdt *)(WDT_BASE +
-				  sizeof(struct ast_wdt) * wdt_number);
-}
+#endif  /* CONFIG_WDT */
 
 int ast_wdt_reset_masked(struct ast_wdt *wdt, u32 mask)
 {
@@ -57,3 +70,12 @@ int ast_wdt_reset_masked(struct ast_wdt *wdt, u32 mask)
 	return -EINVAL;
 #endif
 }
+
+struct ast_wdt *ast_get_wdt(u8 wdt_number)
+{
+	if (wdt_number > CONFIG_WDT_NUM - 1)
+		return ERR_PTR(-EINVAL);
+
+	return (struct ast_wdt *)(WDT_BASE +
+				  sizeof(struct ast_wdt) * wdt_number);
+}