plat: intel: Add BL31 support to Intel Stratix10 SoCFPGA platform

This adds BL31 support to Intel Stratix10 SoCFPGA platform. BL31 in TF-A
supports:
- PSCI calls to enable 4 CPU cores
- PSCI mailbox calls for FPGA reconfiguration

Signed-off-by: Loh Tien Hock <tien.hock.loh@intel.com>
diff --git a/plat/intel/soc/stratix10/plat_psci.c b/plat/intel/soc/stratix10/plat_psci.c
new file mode 100644
index 0000000..7578528
--- /dev/null
+++ b/plat/intel/soc/stratix10/plat_psci.c
@@ -0,0 +1,209 @@
+/*
+ * Copyright (c) 2019, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch_helpers.h>
+#include <assert.h>
+#include <common/debug.h>
+#include <errno.h>
+#include <lib/mmio.h>
+#include <drivers/arm/gic_common.h>
+#include <drivers/arm/gicv2.h>
+#include <plat/common/platform.h>
+#include <lib/psci/psci.h>
+
+#include "platform_def.h"
+#include "platform_private.h"
+#include "s10_reset_manager.h"
+#include "s10_mailbox.h"
+
+#define S10_RSTMGR_OFST			0xffd11000
+#define S10_RSTMGR_MPUMODRST_OFST	0x20
+
+uintptr_t *stratix10_sec_entry = (uintptr_t *) PLAT_S10_SEC_ENTRY;
+uintptr_t *cpuid_release = (uintptr_t *) PLAT_CPUID_RELEASE;
+
+/*******************************************************************************
+ * plat handler called when a CPU is about to enter standby.
+ ******************************************************************************/
+void plat_cpu_standby(plat_local_state_t cpu_state)
+{
+	/*
+	 * Enter standby state
+	 * dsb is good practice before using wfi to enter low power states
+	 */
+	VERBOSE("%s: cpu_state: 0x%x\n", __func__, cpu_state);
+	dsb();
+	wfi();
+}
+
+/*******************************************************************************
+ * plat handler called when a power domain is about to be turned on. The
+ * mpidr determines the CPU to be turned on.
+ ******************************************************************************/
+int plat_pwr_domain_on(u_register_t mpidr)
+{
+	unsigned int cpu_id = plat_core_pos_by_mpidr(mpidr);
+
+	VERBOSE("%s: mpidr: 0x%lx\n", __func__, mpidr);
+
+	if (cpu_id == -1)
+		return PSCI_E_INTERN_FAIL;
+
+	*cpuid_release = cpu_id;
+
+	/* release core reset */
+	mmio_setbits_32(S10_RSTMGR_OFST + S10_RSTMGR_MPUMODRST_OFST,
+		1 << cpu_id);
+	return PSCI_E_SUCCESS;
+}
+
+/*******************************************************************************
+ * plat handler called when a power domain is about to be turned off. The
+ * target_state encodes the power state that each level should transition to.
+ ******************************************************************************/
+void plat_pwr_domain_off(const psci_power_state_t *target_state)
+{
+	unsigned int cpu_id = plat_my_core_pos();
+
+	for (size_t i = 0; i <= PLAT_MAX_PWR_LVL; i++)
+		VERBOSE("%s: target_state->pwr_domain_state[%lu]=%x\n",
+			__func__, i, target_state->pwr_domain_state[i]);
+
+	/* TODO: Prevent interrupts from spuriously waking up this cpu */
+	/* gicv2_cpuif_disable(); */
+
+	/* assert core reset */
+	mmio_setbits_32(S10_RSTMGR_OFST + S10_RSTMGR_MPUMODRST_OFST,
+		1 << cpu_id);
+}
+
+/*******************************************************************************
+ * plat handler called when a power domain is about to be suspended. The
+ * target_state encodes the power state that each level should transition to.
+ ******************************************************************************/
+void plat_pwr_domain_suspend(const psci_power_state_t *target_state)
+{
+	unsigned int cpu_id = plat_my_core_pos();
+
+	for (size_t i = 0; i <= PLAT_MAX_PWR_LVL; i++)
+		VERBOSE("%s: target_state->pwr_domain_state[%lu]=%x\n",
+			__func__, i, target_state->pwr_domain_state[i]);
+	/* assert core reset */
+	mmio_setbits_32(S10_RSTMGR_OFST + S10_RSTMGR_MPUMODRST_OFST,
+		1 << cpu_id);
+
+}
+
+/*******************************************************************************
+ * plat handler called when a power domain has just been powered on after
+ * being turned off earlier. The target_state encodes the low power state that
+ * each level has woken up from.
+ ******************************************************************************/
+void plat_pwr_domain_on_finish(const psci_power_state_t *target_state)
+{
+	for (size_t i = 0; i <= PLAT_MAX_PWR_LVL; i++)
+		VERBOSE("%s: target_state->pwr_domain_state[%lu]=%x\n",
+			__func__, i, target_state->pwr_domain_state[i]);
+
+	/* Program the gic per-cpu distributor or re-distributor interface */
+	gicv2_pcpu_distif_init();
+	gicv2_set_pe_target_mask(plat_my_core_pos());
+
+	/* Enable the gic cpu interface */
+	gicv2_cpuif_enable();
+}
+
+/*******************************************************************************
+ * plat handler called when a power domain has just been powered on after
+ * having been suspended earlier. The target_state encodes the low power state
+ * that each level has woken up from.
+ * TODO: At the moment we reuse the on finisher and reinitialize the secure
+ * context. Need to implement a separate suspend finisher.
+ ******************************************************************************/
+void plat_pwr_domain_suspend_finish(const psci_power_state_t *target_state)
+{
+	unsigned int cpu_id = plat_my_core_pos();
+
+	for (size_t i = 0; i <= PLAT_MAX_PWR_LVL; i++)
+		VERBOSE("%s: target_state->pwr_domain_state[%lu]=%x\n",
+			__func__, i, target_state->pwr_domain_state[i]);
+
+	/* release core reset */
+	mmio_clrbits_32(S10_RSTMGR_OFST + S10_RSTMGR_MPUMODRST_OFST,
+		1 << cpu_id);
+}
+
+/*******************************************************************************
+ * plat handlers to shutdown/reboot the system
+ ******************************************************************************/
+static void __dead2 plat_system_off(void)
+{
+	wfi();
+	ERROR("System Off: operation not handled.\n");
+	panic();
+}
+
+static void __dead2 plat_system_reset(void)
+{
+	INFO("assert Peripheral from Reset\r\n");
+
+	deassert_peripheral_reset();
+	mailbox_reset_cold();
+
+	while (1)
+		wfi();
+}
+
+int plat_validate_power_state(unsigned int power_state,
+				psci_power_state_t *req_state)
+{
+	VERBOSE("%s: power_state: 0x%x\n", __func__, power_state);
+
+	return PSCI_E_SUCCESS;
+}
+
+int plat_validate_ns_entrypoint(unsigned long ns_entrypoint)
+{
+	VERBOSE("%s: ns_entrypoint: 0x%lx\n", __func__, ns_entrypoint);
+	return PSCI_E_SUCCESS;
+}
+
+void plat_get_sys_suspend_power_state(psci_power_state_t *req_state)
+{
+	req_state->pwr_domain_state[PSCI_CPU_PWR_LVL] = PLAT_MAX_OFF_STATE;
+	req_state->pwr_domain_state[1] = PLAT_MAX_OFF_STATE;
+}
+
+/*******************************************************************************
+ * Export the platform handlers via plat_arm_psci_pm_ops. The ARM Standard
+ * platform layer will take care of registering the handlers with PSCI.
+ ******************************************************************************/
+const plat_psci_ops_t plat_psci_pm_ops = {
+	.cpu_standby = plat_cpu_standby,
+	.pwr_domain_on = plat_pwr_domain_on,
+	.pwr_domain_off = plat_pwr_domain_off,
+	.pwr_domain_suspend = plat_pwr_domain_suspend,
+	.pwr_domain_on_finish = plat_pwr_domain_on_finish,
+	.pwr_domain_suspend_finish = plat_pwr_domain_suspend_finish,
+	.system_off = plat_system_off,
+	.system_reset = plat_system_reset,
+	.validate_power_state = plat_validate_power_state,
+	.validate_ns_entrypoint = plat_validate_ns_entrypoint,
+	.get_sys_suspend_power_state = plat_get_sys_suspend_power_state
+};
+
+/*******************************************************************************
+ * Export the platform specific power ops.
+ ******************************************************************************/
+int plat_setup_psci_ops(uintptr_t sec_entrypoint,
+			const struct plat_psci_ops **psci_ops)
+{
+	/* Save warm boot entrypoint.*/
+	*stratix10_sec_entry = sec_entrypoint;
+
+	*psci_ops = &plat_psci_pm_ops;
+	return 0;
+}