Support for NXP's i.MX8QX SoC

NXP's i.MX8QX is an ARMv8 SoC with 4 Cortex-A35 cores and
system controller (Cortex-M4) inside, documentation can
be found in below link:

https://www.nxp.com/products/processors-and-microcontrollers/
applications-processors/i.mx-applications-processors/i.mx-8-processors:IMX8-SERIES

This patch adds support for booting up SMP linux kernel (v4.9).

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
diff --git a/plat/imx/imx8qx/imx8qx_psci.c b/plat/imx/imx8qx/imx8qx_psci.c
new file mode 100644
index 0000000..47233dc
--- /dev/null
+++ b/plat/imx/imx8qx/imx8qx_psci.c
@@ -0,0 +1,76 @@
+/*
+ * Copyright (c) 2015-2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch.h>
+#include <arch_helpers.h>
+#include <debug.h>
+#include <gicv3.h>
+#include <mmio.h>
+#include <plat_imx8.h>
+#include <psci.h>
+#include <sci/sci.h>
+#include <stdbool.h>
+
+const static int ap_core_index[PLATFORM_CORE_COUNT] = {
+	SC_R_A35_0, SC_R_A35_1, SC_R_A35_2, SC_R_A35_3
+};
+
+plat_local_state_t plat_get_target_pwr_state(unsigned int lvl,
+					     const plat_local_state_t *target_state,
+					     unsigned int ncpu)
+{
+	return 0;
+}
+
+int imx_pwr_domain_on(u_register_t mpidr)
+{
+	int ret = PSCI_E_SUCCESS;
+	unsigned int cpu_id;
+
+	cpu_id = MPIDR_AFFLVL0_VAL(mpidr);
+
+	tf_printf("imx_pwr_domain_on cpu_id %d\n", cpu_id);
+
+	if (sc_pm_set_resource_power_mode(ipc_handle, ap_core_index[cpu_id],
+	    SC_PM_PW_MODE_ON) != SC_ERR_NONE) {
+		ERROR("core %d power on failed!\n", cpu_id);
+		ret = PSCI_E_INTERN_FAIL;
+	}
+
+	if (sc_pm_cpu_start(ipc_handle, ap_core_index[cpu_id],
+	    true, BL31_BASE) != SC_ERR_NONE) {
+		ERROR("boot core %d failed!\n", cpu_id);
+		ret = PSCI_E_INTERN_FAIL;
+	}
+
+	return ret;
+}
+
+void imx_pwr_domain_on_finish(const psci_power_state_t *target_state)
+{
+	plat_gic_pcpu_init();
+	plat_gic_cpuif_enable();
+}
+
+int imx_validate_ns_entrypoint(uintptr_t ns_entrypoint)
+{
+	return PSCI_E_SUCCESS;
+}
+
+static const plat_psci_ops_t imx_plat_psci_ops = {
+	.pwr_domain_on = imx_pwr_domain_on,
+	.pwr_domain_on_finish = imx_pwr_domain_on_finish,
+	.validate_ns_entrypoint = imx_validate_ns_entrypoint,
+};
+
+int plat_setup_psci_ops(uintptr_t sec_entrypoint,
+			const plat_psci_ops_t **psci_ops)
+{
+	imx_mailbox_init(sec_entrypoint);
+	*psci_ops = &imx_plat_psci_ops;
+
+	return 0;
+}