[PATCH v2 05/20] sunxi: spl: add support for Allwinner A523 watchdog

[Andre Przywara <andre.przywara@arm.com>]

The watchdog in the Allwinner A523 SoC differs a bit from the one in the
previous SoCs: it lives in a separate register frame, so no longer
inside some timer device, and it manages to shuffle around some
registers a bit. But it also conveniently adds a direct reset
functionality, so we don't need to use a dummy timeout period.

Avoid introducing a new MMIO register frame C struct, but just define
the one needed register offset as a macro. Then just trigger this new
direct reset functionality in the A523 specific reset_cpu()
implementation.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 arch/arm/include/asm/arch-sunxi/watchdog.h | 2 ++
 arch/arm/mach-sunxi/board.c                | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/arch/arm/include/asm/arch-sunxi/watchdog.h b/arch/arm/include/asm/arch-sunxi/watchdog.h
index 38e2ef2aca3..14a6e89ccfa 100644
--- a/arch/arm/include/asm/arch-sunxi/watchdog.h
+++ b/arch/arm/include/asm/arch-sunxi/watchdog.h
@@ -12,6 +12,8 @@
 #define WDT_CTRL_RESTART	(0x1 << 0)
 #define WDT_CTRL_KEY		(0x0a57 << 1)
 
+#define WDT_SRST_REG		0x08
+
 #if defined(CONFIG_MACH_SUN4I) || \
     defined(CONFIG_MACH_SUN5I) || \
     defined(CONFIG_MACH_SUN7I) || \
diff --git a/arch/arm/mach-sunxi/board.c b/arch/arm/mach-sunxi/board.c
index 08d55b3a0e3..13caefda884 100644
--- a/arch/arm/mach-sunxi/board.c
+++ b/arch/arm/mach-sunxi/board.c
@@ -502,6 +502,12 @@ void reset_cpu(void)
 		/* sun5i sometimes gets stuck without this */
 		writel(WDT_MODE_RESET_EN | WDT_MODE_EN, &wdog->mode);
 	}
+#elif defined(CONFIG_MACH_SUN55I_A523)
+	static const void *wdog = (void *)SUNXI_TIMER_BASE;
+
+	writel(WDT_CTRL_KEY | WDT_CTRL_RESTART, wdog + WDT_SRST_REG);
+	while (1)
+		;
 #elif defined(CONFIG_SUNXI_GEN_SUN6I) || defined(CONFIG_SUN50I_GEN_H6) || defined(CONFIG_SUNXI_GEN_NCAT2)
 #if defined(CONFIG_MACH_SUN50I_H6)
 	/* WDOG is broken for some H6 rev. use the R_WDOG instead */
-- 
2.46.3