board: sl28: add basic PSCI implementation

For now, this only provides reset and poweroff functions.

Signed-off-by: Michael Walle <michael@walle.cc>
[Rebased]
Signed-off-by: Priyanka Jain <priyanka.jain@nxp.com>

board/kontron/sl28/Makefile

@@ -6,6 +6,8 @@ endif
 
 obj-y += common.o ddr.o
 
+obj-$(CONFIG_ARMV8_PSCI) += psci.o
+
 ifdef CONFIG_SPL_BUILD
 obj-y += spl.o
 obj-$(CONFIG_SPL_ATF) += spl_atf.o

board/kontron/sl28/psci.c

@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#include <asm/secure.h>
+#include <asm/psci.h>
+#include <asm/types.h>
+#include <asm/io.h>
+#include <asm/system.h>
+
+#define GPIO2_GPDIR	0x2310000
+#define GPIO2_GPDAT	0x2310008
+#define RSTCR		0x1e60000
+#define RESET_REQ	BIT(1)
+
+u32 __secure psci_version(void)
+{
+	return ARM_PSCI_VER_0_2;
+}
+
+void __secure psci_system_reset(void)
+{
+	writel(RESET_REQ, RSTCR);
+
+	while (1)
+		wfi();
+}
+
+void __secure psci_system_off(void)
+{
+	int i;
+
+	writel(0x02000000, GPIO2_GPDIR);
+	writel(0, GPIO2_GPDAT);
+
+	/* make sure the management controller has sampled the input */
+	for (i = 0; i < (1 << 11); i++)
+		asm("nop");
+
+	writel(RESET_REQ, RSTCR);
+
+	while (1)
+		wfi();
+}

configs/kontron_sl28_defconfig

@@ -20,6 +20,8 @@ CONFIG_ENV_OFFSET_REDUND=0x3f0000
 CONFIG_SPL_SPI_FLASH_SUPPORT=y
 CONFIG_SPL_SPI=y
 # CONFIG_PSCI_RESET is not set
+CONFIG_ARMV8_PSCI=y
+CONFIG_ARMV8_PSCI_RELOCATE=y
 CONFIG_SYS_LOAD_ADDR=0x82000000
 CONFIG_AHCI=y
 CONFIG_DISTRO_DEFAULTS=y