1 files changed, 59 insertions, 0 deletions
diff --git a/arch/arm/mach-tegra/tegra124/psci.c b/arch/arm/mach-tegra/tegra124/psci.c
new file mode 100644
index 0000000..16d1965
--- /dev/null
+++ b/arch/arm/mach-tegra/tegra124/psci.c
@@ -0,0 +1,59 @@
+/*
+ * (C) Copyright 2015, Siemens AG
+ * Author: Jan Kiszka <jan.kiszka@siemens.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/psci.h>
+#include <asm/arch/flow.h>
+#include <asm/arch/powergate.h>
+#include <asm/arch-tegra/ap.h>
+#include <asm/arch-tegra/pmc.h>
+
+static void park_cpu(void)
+{
+	while (1)
+		asm volatile("wfi");
+}
+
+/**
+ * Initialize power management for application processors
+ */
+void psci_board_init(void)
+{
+	struct flow_ctlr *flow = (struct flow_ctlr *)NV_PA_FLOW_BASE;
+
+	writel((u32)park_cpu, EXCEP_VECTOR_CPU_RESET_VECTOR);
+
+	/*
+	 * The naturally expected order of putting these CPUs under Flow
+	 * Controller regime would be
+	 *  - configure the Flow Controller
+	 *  - power up the CPUs
+	 *  - wait for the CPUs to hit wfi and be powered down again
+	 *
+	 * However, this doesn't work in practice. We rather need to power them
+	 * up first and park them in wfi. While they are waiting there, we can
+	 * indeed program the Flow Controller to powergate them on wfi, which
+	 * will then happen immediately as they are already in that state.
+	 */
+	tegra_powergate_power_on(TEGRA_POWERGATE_CPU1);
+	tegra_powergate_power_on(TEGRA_POWERGATE_CPU2);
+	tegra_powergate_power_on(TEGRA_POWERGATE_CPU3);
+
+	writel((2 << CSR_WAIT_WFI_SHIFT) | CSR_ENABLE, &flow->cpu1_csr);
+	writel((4 << CSR_WAIT_WFI_SHIFT) | CSR_ENABLE, &flow->cpu2_csr);
+	writel((8 << CSR_WAIT_WFI_SHIFT) | CSR_ENABLE, &flow->cpu3_csr);
+
+	writel(EVENT_MODE_STOP, &flow->halt_cpu1_events);
+	writel(EVENT_MODE_STOP, &flow->halt_cpu2_events);
+	writel(EVENT_MODE_STOP, &flow->halt_cpu3_events);
+
+	while (!(readl(&flow->cpu1_csr) & CSR_PWR_OFF_STS) ||
+		!(readl(&flow->cpu2_csr) & CSR_PWR_OFF_STS) ||
+		!(readl(&flow->cpu3_csr) & CSR_PWR_OFF_STS))
+		/* wait */;
+}