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path: root/drivers/acpi/riscv/cpuidle.c
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Diffstat (limited to 'drivers/acpi/riscv/cpuidle.c')
-rw-r--r--drivers/acpi/riscv/cpuidle.c81
1 files changed, 81 insertions, 0 deletions
diff --git a/drivers/acpi/riscv/cpuidle.c b/drivers/acpi/riscv/cpuidle.c
new file mode 100644
index 000000000000..624f9bbdb58c
--- /dev/null
+++ b/drivers/acpi/riscv/cpuidle.c
@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2024, Ventana Micro Systems Inc
+ * Author: Sunil V L <sunilvl@ventanamicro.com>
+ *
+ */
+
+#include <linux/acpi.h>
+#include <acpi/processor.h>
+#include <linux/cpu_pm.h>
+#include <linux/cpuidle.h>
+#include <linux/suspend.h>
+#include <asm/cpuidle.h>
+#include <asm/sbi.h>
+#include <asm/suspend.h>
+
+#define RISCV_FFH_LPI_TYPE_MASK GENMASK_ULL(63, 60)
+#define RISCV_FFH_LPI_RSVD_MASK GENMASK_ULL(59, 32)
+
+#define RISCV_FFH_LPI_TYPE_SBI BIT_ULL(60)
+
+static int acpi_cpu_init_idle(unsigned int cpu)
+{
+ int i;
+ struct acpi_lpi_state *lpi;
+ struct acpi_processor *pr = per_cpu(processors, cpu);
+
+ if (unlikely(!pr || !pr->flags.has_lpi))
+ return -EINVAL;
+
+ if (!riscv_sbi_hsm_is_supported())
+ return -ENODEV;
+
+ if (pr->power.count <= 1)
+ return -ENODEV;
+
+ for (i = 1; i < pr->power.count; i++) {
+ u32 state;
+
+ lpi = &pr->power.lpi_states[i];
+
+ /*
+ * Validate Entry Method as per FFH spec.
+ * bits[63:60] should be 0x1
+ * bits[59:32] should be 0x0
+ * bits[31:0] represent a SBI power_state
+ */
+ if (((lpi->address & RISCV_FFH_LPI_TYPE_MASK) != RISCV_FFH_LPI_TYPE_SBI) ||
+ (lpi->address & RISCV_FFH_LPI_RSVD_MASK)) {
+ pr_warn("Invalid LPI entry method %#llx\n", lpi->address);
+ return -EINVAL;
+ }
+
+ state = lpi->address;
+ if (!riscv_sbi_suspend_state_is_valid(state)) {
+ pr_warn("Invalid SBI power state %#x\n", state);
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
+int acpi_processor_ffh_lpi_probe(unsigned int cpu)
+{
+ return acpi_cpu_init_idle(cpu);
+}
+
+int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
+{
+ u32 state = lpi->address;
+
+ if (state & SBI_HSM_SUSP_NON_RET_BIT)
+ return CPU_PM_CPU_IDLE_ENTER_PARAM(riscv_sbi_hart_suspend,
+ lpi->index,
+ state);
+ else
+ return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(riscv_sbi_hart_suspend,
+ lpi->index,
+ state);
+}