1 files changed, 126 insertions, 0 deletions
diff --git a/drivers/power/reset/stm32-reboot.c b/drivers/power/reset/stm32-reboot.c
new file mode 100644
index 0000000000..809531e713
--- /dev/null
+++ b/drivers/power/reset/stm32-reboot.c
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
+ * Copyright (C) 2019, Ahmad Fatoum, Pengutronix
+ * Author(s): Patrice Chotard, <patrice.chotard@st.com> for STMicroelectronics.
+ */
+
+#include <common.h>
+#include <linux/err.h>
+#include <restart.h>
+#include <reset_source.h>
+#include <asm/io.h>
+#include <soc/stm32/reboot.h>
+
+#define RCC_CL 0x4
+
+#define RCC_MP_GRSTCSETR		0x404
+#define RCC_MP_RSTSCLRR			0x408
+
+#define STM32MP_RCC_RSTF_POR		BIT(0)
+#define STM32MP_RCC_RSTF_BOR		BIT(1)
+#define STM32MP_RCC_RSTF_PAD		BIT(2)
+#define STM32MP_RCC_RSTF_HCSS		BIT(3)
+#define STM32MP_RCC_RSTF_VCORE		BIT(4)
+
+#define STM32MP_RCC_RSTF_MPSYS		BIT(6)
+#define STM32MP_RCC_RSTF_MCSYS		BIT(7)
+#define STM32MP_RCC_RSTF_IWDG1		BIT(8)
+#define STM32MP_RCC_RSTF_IWDG2		BIT(9)
+
+#define STM32MP_RCC_RSTF_STDBY		BIT(11)
+#define STM32MP_RCC_RSTF_CSTDBY		BIT(12)
+#define STM32MP_RCC_RSTF_MPUP0		BIT(13)
+#define STM32MP_RCC_RSTF_MPUP1		BIT(14)
+
+struct stm32_reset_reason {
+	uint32_t mask;
+	enum reset_src_type type;
+	int instance;
+};
+
+struct stm32_reset {
+	void __iomem *base;
+	struct restart_handler restart;
+};
+
+static u32 stm32_reset_status(struct stm32_reset *priv, unsigned long bank)
+{
+	return readl(priv->base + bank);
+}
+
+static void stm32_reset(struct stm32_reset *priv, unsigned long id, bool assert)
+{
+	int bank = (id / 32) * 4;
+	int offset = id % 32;
+	void __iomem *reg = priv->base + bank;
+
+	if (!assert)
+		reg += RCC_CL;
+
+	writel(BIT(offset), reg);
+}
+
+static void __noreturn stm32mp_rcc_restart_handler(struct restart_handler *rst)
+{
+	struct stm32_reset *priv = container_of(rst, struct stm32_reset, restart);
+
+	stm32_reset(priv, RCC_MP_GRSTCSETR * BITS_PER_BYTE, true);
+
+	mdelay(1000);
+	hang();
+}
+
+static const struct stm32_reset_reason stm32mp_reset_reasons[] = {
+	{ STM32MP_RCC_RSTF_POR,		RESET_POR, 0 },
+	{ STM32MP_RCC_RSTF_BOR,		RESET_BROWNOUT, 0 },
+	{ STM32MP_RCC_RSTF_STDBY,	RESET_WKE, 0 },
+	{ STM32MP_RCC_RSTF_CSTDBY,	RESET_WKE, 1 },
+	{ STM32MP_RCC_RSTF_MPSYS,	RESET_RST, 2 },
+	{ STM32MP_RCC_RSTF_MPUP0,	RESET_RST, 0 },
+	{ STM32MP_RCC_RSTF_MPUP1,	RESET_RST, 1 },
+	{ STM32MP_RCC_RSTF_IWDG1,	RESET_WDG, 0 },
+	{ STM32MP_RCC_RSTF_IWDG2,	RESET_WDG, 1 },
+	{ STM32MP_RCC_RSTF_PAD,		RESET_EXT, 1 },
+	{ /* sentinel */ }
+};
+
+static void stm32_set_reset_reason(struct stm32_reset *priv,
+				   const struct stm32_reset_reason *reasons)
+{
+	enum reset_src_type type = RESET_UKWN;
+	u32 reg;
+	int i, instance = 0;
+
+	reg = stm32_reset_status(priv, RCC_MP_RSTSCLRR);
+
+	for (i = 0; reasons[i].mask; i++) {
+		if (reg & reasons[i].mask) {
+			type     = reasons[i].type;
+			instance = reasons[i].instance;
+			break;
+		}
+	}
+
+	reset_source_set_prinst(type, RESET_SOURCE_DEFAULT_PRIORITY, instance);
+
+	pr_info("STM32 RCC reset reason %s (MP_RSTSR: 0x%08x)\n",
+		reset_source_to_string(type), reg);
+}
+
+void stm32mp_system_restart_init(void __iomem *base)
+{
+	struct stm32_reset *priv;
+
+	priv = xzalloc(sizeof(*priv));
+
+	priv->base = base;
+
+	priv->restart.name = "stm32-rcc";
+	priv->restart.restart = stm32mp_rcc_restart_handler;
+	priv->restart.priority = 200;
+
+	restart_handler_register(&priv->restart);
+
+	stm32_set_reset_reason(priv, stm32mp_reset_reasons);
+}