arm: stm32mp1: add PSCI support

Add PSCI v1.0 support for Linux and manage PSCI state
for each CPU (affinity 0 level) with all mandatory functions:
- PSCI_VERSION
- CPU_SUSPEND
- CPU_OFF
- CPU_ON
- AFFINITY_INFO
- SYSTEM_OFF
- SYSTEM_RESET
- PSCI_FEATURES
and 1 optional to avoid Linux warning
- MIGRATE_INFO_TYPE

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: CITOOLS <smet-aci-reviews@lists.codex.cro.st.com>

4 files changed, 186 insertions, 0 deletions

diff --git a/arch/arm/mach-stm32mp/Kconfig b/arch/arm/mach-stm32mp/Kconfig
index 4d59480c197..6e9b5088266 100644
--- a/arch/arm/mach-stm32mp/Kconfig
+++ b/arch/arm/mach-stm32mp/Kconfig
@@ -24,7 +24,10 @@ config SYS_SOC
 
 config TARGET_STM32MP1
 	bool "Support stm32mp1xx"
+	select ARCH_SUPPORT_PSCI
 	select CPU_V7
+	select CPU_V7_HAS_NONSEC
+	select CPU_V7_HAS_VIRT
 	select PINCTRL_STM32
 	select STM32_RESET
 	select SYS_ARCH_TIMER
diff --git a/arch/arm/mach-stm32mp/Makefile b/arch/arm/mach-stm32mp/Makefile
index cdb087c31fe..a9b523d96fd 100644
--- a/arch/arm/mach-stm32mp/Makefile
+++ b/arch/arm/mach-stm32mp/Makefile
@@ -8,3 +8,4 @@ obj-y += dram_init.o
 obj-y += syscon.o
 
 obj-$(CONFIG_SPL_BUILD) += spl.o
+obj-$(CONFIG_ARMV7_PSCI) += psci.o
diff --git a/arch/arm/mach-stm32mp/include/mach/stm32.h b/arch/arm/mach-stm32mp/include/mach/stm32.h
index 20904026323..afcab299cfa 100644
--- a/arch/arm/mach-stm32mp/include/mach/stm32.h
+++ b/arch/arm/mach-stm32mp/include/mach/stm32.h
@@ -73,6 +73,8 @@ enum boot_device {
 
 /* TAMP registers */
 #define TAMP_BACKUP_REGISTER(x)		(STM32_TAMP_BASE + 0x100 + 4 * x)
+#define TAMP_BACKUP_MAGIC_NUMBER	TAMP_BACKUP_REGISTER(4)
+#define TAMP_BACKUP_BRANCH_ADDRESS	TAMP_BACKUP_REGISTER(5)
 #define TAMP_BOOT_CONTEXT		TAMP_BACKUP_REGISTER(20)
 
 #define TAMP_BOOT_MODE_MASK		GENMASK(15, 8)
diff --git a/arch/arm/mach-stm32mp/psci.c b/arch/arm/mach-stm32mp/psci.c
new file mode 100644
index 00000000000..6ed2482080c
--- /dev/null
+++ b/arch/arm/mach-stm32mp/psci.c
@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause
+/*
+ * Copyright (C) 2018, STMicroelectronics - All Rights Reserved
+ */
+
+#include <config.h>
+#include <common.h>
+#include <asm/armv7.h>
+#include <asm/gic.h>
+#include <asm/io.h>
+#include <asm/psci.h>
+#include <asm/secure.h>
+
+#define BOOT_API_A7_CORE0_MAGIC_NUMBER	0xCA7FACE0
+#define BOOT_API_A7_CORE1_MAGIC_NUMBER	0xCA7FACE1
+
+#define MPIDR_AFF0			GENMASK(7, 0)
+
+#define RCC_MP_GRSTCSETR		(STM32_RCC_BASE + 0x0404)
+#define RCC_MP_GRSTCSETR_MPUP1RST	BIT(5)
+#define RCC_MP_GRSTCSETR_MPUP0RST	BIT(4)
+#define RCC_MP_GRSTCSETR_MPSYSRST	BIT(0)
+
+#define STM32MP1_PSCI_NR_CPUS		2
+#if STM32MP1_PSCI_NR_CPUS > CONFIG_ARMV7_PSCI_NR_CPUS
+#error "invalid value for CONFIG_ARMV7_PSCI_NR_CPUS"
+#endif
+
+u8 psci_state[STM32MP1_PSCI_NR_CPUS] __secure_data = {
+	 PSCI_AFFINITY_LEVEL_ON,
+	 PSCI_AFFINITY_LEVEL_OFF};
+
+void __secure psci_set_state(int cpu, u8 state)
+{
+	psci_state[cpu] = state;
+	dsb();
+	isb();
+}
+
+static u32 __secure stm32mp_get_gicd_base_address(void)
+{
+	u32 periphbase;
+
+	/* get the GIC base address from the CBAR register */
+	asm("mrc p15, 4, %0, c15, c0, 0\n" : "=r" (periphbase));
+
+	return (periphbase & CBAR_MASK) + GIC_DIST_OFFSET;
+}
+
+static void __secure stm32mp_smp_kick_all_cpus(void)
+{
+	u32 gic_dist_addr;
+
+	gic_dist_addr = stm32mp_get_gicd_base_address();
+
+	/* kick all CPUs (except this one) by writing to GICD_SGIR */
+	writel(1U << 24, gic_dist_addr + GICD_SGIR);
+}
+
+void __secure psci_arch_cpu_entry(void)
+{
+	u32 cpu = psci_get_cpu_id();
+
+	psci_set_state(cpu, PSCI_AFFINITY_LEVEL_ON);
+}
+
+int __secure psci_features(u32 function_id, u32 psci_fid)
+{
+	switch (psci_fid) {
+	case ARM_PSCI_0_2_FN_PSCI_VERSION:
+	case ARM_PSCI_0_2_FN_CPU_OFF:
+	case ARM_PSCI_0_2_FN_CPU_ON:
+	case ARM_PSCI_0_2_FN_AFFINITY_INFO:
+	case ARM_PSCI_0_2_FN_MIGRATE_INFO_TYPE:
+	case ARM_PSCI_0_2_FN_SYSTEM_OFF:
+	case ARM_PSCI_0_2_FN_SYSTEM_RESET:
+		return 0x0;
+	}
+	return ARM_PSCI_RET_NI;
+}
+
+unsigned int __secure psci_version(u32 function_id)
+{
+	return ARM_PSCI_VER_1_0;
+}
+
+int __secure psci_affinity_info(u32 function_id, u32 target_affinity,
+				u32  lowest_affinity_level)
+{
+	u32 cpu = target_affinity & MPIDR_AFF0;
+
+	if (lowest_affinity_level > 0)
+		return ARM_PSCI_RET_INVAL;
+
+	if (target_affinity & ~MPIDR_AFF0)
+		return ARM_PSCI_RET_INVAL;
+
+	if (cpu >= STM32MP1_PSCI_NR_CPUS)
+		return ARM_PSCI_RET_INVAL;
+
+	return psci_state[cpu];
+}
+
+int __secure psci_migrate_info_type(u32 function_id)
+{
+	/* Trusted OS is either not present or does not require migration */
+	return 2;
+}
+
+int __secure psci_cpu_on(u32 function_id, u32 target_cpu, u32 pc,
+			 u32 context_id)
+{
+	u32 cpu = target_cpu & MPIDR_AFF0;
+
+	if (target_cpu & ~MPIDR_AFF0)
+		return ARM_PSCI_RET_INVAL;
+
+	if (cpu >= STM32MP1_PSCI_NR_CPUS)
+		return ARM_PSCI_RET_INVAL;
+
+	if (psci_state[cpu] == PSCI_AFFINITY_LEVEL_ON)
+		return ARM_PSCI_RET_ALREADY_ON;
+
+	/* store target PC and context id*/
+	psci_save(cpu, pc, context_id);
+
+	/* write entrypoint in backup RAM register */
+	writel((u32)&psci_cpu_entry, TAMP_BACKUP_BRANCH_ADDRESS);
+	psci_set_state(cpu, PSCI_AFFINITY_LEVEL_ON_PENDING);
+
+	/* write magic number in backup register */
+	if (cpu == 0x01)
+		writel(BOOT_API_A7_CORE1_MAGIC_NUMBER,
+		       TAMP_BACKUP_MAGIC_NUMBER);
+	else
+		writel(BOOT_API_A7_CORE0_MAGIC_NUMBER,
+		       TAMP_BACKUP_MAGIC_NUMBER);
+
+	stm32mp_smp_kick_all_cpus();
+
+	return ARM_PSCI_RET_SUCCESS;
+}
+
+int __secure psci_cpu_off(u32 function_id)
+{
+	u32 cpu;
+
+	cpu = psci_get_cpu_id();
+
+	psci_cpu_off_common();
+	psci_set_state(cpu, PSCI_AFFINITY_LEVEL_OFF);
+
+	/* reset core: wfi is managed by BootRom */
+	if (cpu == 0x01)
+		writel(RCC_MP_GRSTCSETR_MPUP1RST, RCC_MP_GRSTCSETR);
+	else
+		writel(RCC_MP_GRSTCSETR_MPUP0RST, RCC_MP_GRSTCSETR);
+
+	/* just waiting reset */
+	while (1)
+		wfi();
+}
+
+void __secure psci_system_reset(u32 function_id)
+{
+	/* System reset */
+	writel(RCC_MP_GRSTCSETR_MPSYSRST, RCC_MP_GRSTCSETR);
+	/* just waiting reset */
+	while (1)
+		wfi();
+}
+
+void __secure psci_system_off(u32 function_id)
+{
+	/* System Off is not managed, waiting user power off
+	 * TODO: handle I2C write in PMIC Main Control register bit 0 = SWOFF
+	 */
+	while (1)
+		wfi();
+}