1 files changed, 103 insertions, 0 deletions
diff --git a/plat/arm/board/arm_fpga/fpga_pm.c b/plat/arm/board/arm_fpga/fpga_pm.c
new file mode 100644
index 0000000..a306a23
--- /dev/null
+++ b/plat/arm/board/arm_fpga/fpga_pm.c
@@ -0,0 +1,103 @@
+/*
+ * Copyright (c) 2020, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+
+#include <lib/psci/psci.h>
+#include <plat/arm/common/plat_arm.h>
+#include <plat/common/platform.h>
+
+#include "fpga_private.h"
+#include <platform_def.h>
+
+/*
+ * This is a basic PSCI implementation that allows secondary CPUs to be
+ * released from their initial state and continue to the warm boot entrypoint.
+ *
+ * The secondary CPUs are placed in a holding pen and released by calls
+ * to fpga_pwr_domain_on(mpidr), which updates the hold entry for the CPU
+ * specified by the mpidr argument - the (polling) target CPU will then branch
+ * to the BL31 warm boot sequence at the entrypoint address.
+ *
+ * Additionally, the secondary CPUs are kept in a low-power wfe() state
+ * (placed there at the end of each poll) and woken when necessary through
+ * calls to sev() in fpga_pwr_domain_on(mpidr), once the hold state for the
+ * relevant CPU has been updated.
+ *
+ * Hotplug is currently implemented using a wfi-loop, which removes the
+ * dependencies on any power controllers or other mechanism that is specific
+ * to the running system as specified by the FPGA image.
+ */
+
+uint64_t hold_base[PLATFORM_CORE_COUNT];
+uintptr_t fpga_sec_entrypoint;
+
+/*
+ * Calls to the CPU specified by the mpidr will set its hold entry to a value
+ * indicating that it should stop polling and branch off to the warm entrypoint.
+ */
+static int fpga_pwr_domain_on(u_register_t mpidr)
+{
+	int pos = plat_core_pos_by_mpidr(mpidr);
+	unsigned long current_mpidr = read_mpidr_el1();
+
+	if (pos < 0) {
+		panic();
+	}
+
+	if (mpidr == current_mpidr) {
+		return PSCI_E_ALREADY_ON;
+	}
+	hold_base[pos] = PLAT_FPGA_HOLD_STATE_GO;
+	flush_dcache_range((uintptr_t)&hold_base[pos], sizeof(uint64_t));
+	sev(); /* Wake any CPUs from wfe */
+
+	return PSCI_E_SUCCESS;
+}
+
+void fpga_pwr_domain_on_finish(const psci_power_state_t *target_state)
+{
+	fpga_pwr_gic_on_finish();
+}
+
+static void fpga_pwr_domain_off(const psci_power_state_t *target_state)
+{
+	fpga_pwr_gic_off();
+
+	while (1) {
+		wfi();
+	}
+}
+
+static void fpga_cpu_standby(plat_local_state_t cpu_state)
+{
+	/*
+	 * Enter standby state
+	 * dsb is good practice before using wfi to enter low power states
+	 */
+	u_register_t scr = read_scr_el3();
+	write_scr_el3(scr|SCR_IRQ_BIT);
+	dsb();
+	wfi();
+	write_scr_el3(scr);
+}
+
+plat_psci_ops_t plat_fpga_psci_pm_ops = {
+	.pwr_domain_on = fpga_pwr_domain_on,
+	.pwr_domain_on_finish = fpga_pwr_domain_on_finish,
+	.pwr_domain_off = fpga_pwr_domain_off,
+	.cpu_standby = fpga_cpu_standby
+};
+
+int plat_setup_psci_ops(uintptr_t sec_entrypoint,
+			const plat_psci_ops_t **psci_ops)
+{
+	fpga_sec_entrypoint = sec_entrypoint;
+	flush_dcache_range((uint64_t)&fpga_sec_entrypoint,
+			   sizeof(fpga_sec_entrypoint));
+	*psci_ops = &plat_fpga_psci_pm_ops;
+	return 0;
+}