[PATCH 1/7] ARM: zynqmp: set reset source

[Michael Tretter]

The reset reason is available in the APB register set on the ZynqMP.
Read the reset reason and set the reset source accordingly.

There might be multiple bits set in the APB register. Use the MSB for
determining the actual reset source.

Signed-off-by: Michael Tretter <m.tretter at pengutronix.de>
---
 arch/arm/mach-zynqmp/Makefile              |  1 +
 arch/arm/mach-zynqmp/include/mach/zynqmp.h |  6 ++
 arch/arm/mach-zynqmp/zynqmp.c              | 74 ++++++++++++++++++++++
 3 files changed, 81 insertions(+)
 create mode 100644 arch/arm/mach-zynqmp/include/mach/zynqmp.h
 create mode 100644 arch/arm/mach-zynqmp/zynqmp.c

diff --git a/arch/arm/mach-zynqmp/Makefile b/arch/arm/mach-zynqmp/Makefile
index 021efc94afaf..14b8a4e46b87 100644
--- a/arch/arm/mach-zynqmp/Makefile
+++ b/arch/arm/mach-zynqmp/Makefile
@@ -1,2 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0-or-later
 obj-y += firmware-zynqmp.o
+obj-y += zynqmp.o
diff --git a/arch/arm/mach-zynqmp/include/mach/zynqmp.h b/arch/arm/mach-zynqmp/include/mach/zynqmp.h
new file mode 100644
index 000000000000..f6c05f35a470
--- /dev/null
+++ b/arch/arm/mach-zynqmp/include/mach/zynqmp.h
@@ -0,0 +1,6 @@
+#ifndef __MACH_ZYNQMP_H
+#define __MACH_ZYNQMP_H
+
+int zynqmp_soc_revision(void);
+
+#endif /* __MACH_ZYNQMP_H */
diff --git a/arch/arm/mach-zynqmp/zynqmp.c b/arch/arm/mach-zynqmp/zynqmp.c
new file mode 100644
index 000000000000..2b3bd8406ce9
--- /dev/null
+++ b/arch/arm/mach-zynqmp/zynqmp.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 Michael Tretter <m.tretter at pengutronix.de>
+ */
+
+#include <common.h>
+#include <init.h>
+#include <linux/types.h>
+#include <reset_source.h>
+
+#include <mach/zynqmp.h>
+
+#define ZYNQMP_CRL_APB_BASE		0xff5e0000
+#define ZYNQMP_CRL_APB_RESET_REASON	(ZYNQMP_CRL_APB_BASE + 0x220)
+
+/* External POR: The PS_POR_B reset signal pin was asserted. */
+#define ZYNQMP_CRL_APB_RESET_REASON_EXTERNAL   BIT(0)
+/* Internal POR: A system error triggered a POR reset. */
+#define ZYNQMP_CRL_APB_RESET_REASON_INTERNAL   BIT(1)
+/* Internal system reset; A system error triggered a system reset. */
+#define ZYNQMP_CRL_APB_RESET_REASON_PMU        BIT(2)
+/* PS-only reset: Write to PMU_GLOBAL.GLOBAL_RESET [PS_ONLY_RST]. */
+#define ZYNQMP_CRL_APB_RESET_REASON_PSONLY     BIT(3)
+/* External system reset: The PS_SRST_B reset signal pin was asserted. */
+#define ZYNQMP_CRL_APB_RESET_REASON_SRST       BIT(4)
+/* Software system reset: Write to RESET_CTRL [soft_reset]. */
+#define ZYNQMP_CRL_APB_RESET_REASON_SOFT       BIT(5)
+/* Software debugger reset: Write to BLOCKONLY_RST [debug_only]. */
+#define ZYNQMP_CRL_APB_RESET_REASON_DEBUG_SYS  BIT(6)
+
+struct zynqmp_reset_reason {
+	u32 mask;
+	enum reset_src_type type;
+};
+
+static const struct zynqmp_reset_reason reset_reasons[] = {
+	{ ZYNQMP_CRL_APB_RESET_REASON_DEBUG_SYS,	RESET_UKWN },
+	{ ZYNQMP_CRL_APB_RESET_REASON_SOFT,		RESET_RST },
+	{ ZYNQMP_CRL_APB_RESET_REASON_SRST,		RESET_POR },
+	{ ZYNQMP_CRL_APB_RESET_REASON_PSONLY,		RESET_POR },
+	{ ZYNQMP_CRL_APB_RESET_REASON_PMU,		RESET_POR },
+	{ ZYNQMP_CRL_APB_RESET_REASON_INTERNAL,		RESET_POR },
+	{ ZYNQMP_CRL_APB_RESET_REASON_EXTERNAL,		RESET_POR },
+	{ /* sentinel */ }
+};
+
+static enum reset_src_type zynqmp_get_reset_src(void)
+{
+	enum reset_src_type type = RESET_UKWN;
+	unsigned int i;
+	u32 val;
+
+	val = readl(ZYNQMP_CRL_APB_RESET_REASON);
+
+	for (i = 0; i < ARRAY_SIZE(reset_reasons); i++) {
+		if (val & reset_reasons[i].mask) {
+			type = reset_reasons[i].type;
+			break;
+		}
+	}
+
+	pr_info("ZynqMP reset reason %s (ZYNQMP_CRL_APB_RESET_REASON: 0x%08x)\n",
+		reset_source_to_string(type), val);
+
+	return type;
+}
+
+static int zynqmp_init(void)
+{
+	reset_source_set(zynqmp_get_reset_src());
+
+	return 0;
+}
+postcore_initcall(zynqmp_init);
-- 
2.29.2