utils: fdt: Add fdt helper functions to parse PMU DT nodes

The PMU DT node bindings are defined in docs/pmu_support.md
Add few fdt helper functions to parse the DT node and update the
event-counter mapping tables.

Reviewed-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>

include/sbi_utils/fdt/fdt_pmu.h

@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: BSD-2-Clause
+/*
+ * fdt_pmu.c - Flat Device Tree PMU helper routines
+ *
+ * Copyright (c) 2021 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *   Atish Patra <atish.patra@wdc.com>
+ */
+
+#ifndef __FDT_PMU_H__
+#define __FDT_PMU_H__
+
+#include <sbi/sbi_types.h>
+
+/**
+ * Fix up the PMU node in the device tree
+ *
+ * This routine:
+ * 1. Disables opensbi specific properties from the DT
+ *
+ * It is recommended that platform support call this function in
+ * their final_init() platform operation.
+ *
+ * @param fdt device tree blob
+ */
+void fdt_pmu_fixup(void *fdt);
+
+/**
+ * Setup PMU data from device tree
+ *
+ * @param fdt device tree blob
+ *
+ * @return 0 on success and negative error code on failure
+ */
+int fdt_pmu_setup(void *fdt);
+
+/**
+ * Get the mhpmevent select value read from DT for a given event
+ * @param event_idx Event ID of the given event
+ *
+ * @return The select value read from DT or 0 if given index was not found
+ */
+uint64_t fdt_pmu_get_select_value(uint32_t event_idx);
+
+#endif

lib/utils/fdt/fdt_fixup.c

@@ -15,6 +15,7 @@
 #include <sbi/sbi_scratch.h>
 #include <sbi/sbi_string.h>
 #include <sbi_utils/fdt/fdt_fixup.h>
+#include <sbi_utils/fdt/fdt_pmu.h>
 #include <sbi_utils/fdt/fdt_helper.h>
 
 void fdt_cpu_fixup(void *fdt)
@@ -263,6 +264,7 @@ void fdt_fixups(void *fdt)
 	fdt_plic_fixup(fdt);
 
 	fdt_reserved_memory_fixup(fdt);
+	fdt_pmu_fixup(fdt);
 }
 
 

lib/utils/fdt/fdt_pmu.c

@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: BSD-2-Clause
+/*
+ * fdt_pmu.c - Flat Device Tree PMU helper routines
+ *
+ * Copyright (c) 2021 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *	Atish Patra <atish.patra@wdc.com>
+ */
+
+#include <libfdt.h>
+#include <sbi/sbi_error.h>
+#include <sbi/sbi_pmu.h>
+#include <sbi_utils/fdt/fdt_helper.h>
+
+#define FDT_PMU_HW_EVENT_MAX (SBI_PMU_HW_EVENT_MAX * 2)
+
+struct fdt_pmu_hw_event_select {
+	uint32_t eidx;
+	uint64_t select;
+};
+
+static struct fdt_pmu_hw_event_select fdt_pmu_evt_select[FDT_PMU_HW_EVENT_MAX] = {0};
+static uint32_t hw_event_count;
+
+uint64_t fdt_pmu_get_select_value(uint32_t event_idx)
+{
+	int i;
+	struct fdt_pmu_hw_event_select *event;
+
+	for (i = 0; i < SBI_PMU_HW_EVENT_MAX; i++) {
+		event = &fdt_pmu_evt_select[i];
+		if (event->eidx == event_idx)
+			return event->select;
+	}
+
+	return 0;
+}
+
+int fdt_pmu_fixup(void *fdt)
+{
+	int pmu_offset;
+
+	if (!fdt)
+		return SBI_EINVAL;
+
+	pmu_offset = fdt_node_offset_by_compatible(fdt, -1, "riscv,pmu");
+	if (pmu_offset < 0)
+		return SBI_EFAIL;
+
+	fdt_delprop(fdt, pmu_offset, "pmu,event-to-mhpmcounters");
+	fdt_delprop(fdt, pmu_offset, "pmu,event-to-mhpmevent");
+	fdt_delprop(fdt, pmu_offset, "pmu,raw-event-to-mhpmcounters");
+
+	return 0;
+}
+
+int fdt_pmu_setup(void *fdt)
+{
+	int i, pmu_offset, len, result;
+	const u32 *event_val;
+	const u32 *event_ctr_map;
+	struct fdt_pmu_hw_event_select *event;
+	uint64_t raw_selector;
+	u32 event_idx_start, event_idx_end, ctr_map;
+
+	if (!fdt)
+		return SBI_EINVAL;
+
+	pmu_offset = fdt_node_offset_by_compatible(fdt, -1, "riscv,pmu");
+	if (pmu_offset < 0)
+		return SBI_EFAIL;
+
+	event_ctr_map = fdt_getprop(fdt, pmu_offset, "pmu,event-to-mhpmcounters", &len);
+	if (!event_ctr_map || len < 8)
+		return SBI_EFAIL;
+	len = len / (sizeof(u32) * 3);
+	for (i = 0; i < len; i++) {
+		event_idx_start = fdt32_to_cpu(event_ctr_map[3 * i]);
+		event_idx_end = fdt32_to_cpu(event_ctr_map[3 * i + 1]);
+		ctr_map = fdt32_to_cpu(event_ctr_map[3 * i + 2]);
+		sbi_pmu_add_hw_event_counter_map(event_idx_start, event_idx_end, ctr_map);
+	}
+
+	event_val = fdt_getprop(fdt, pmu_offset, "pmu,event-to-mhpmevent", &len);
+	if (!event_val || len < 8)
+		return SBI_EFAIL;
+	len = len / (sizeof(u32) * 3);
+	for (i = 0; i < len; i++) {
+		event = &fdt_pmu_evt_select[hw_event_count];
+		event->eidx = fdt32_to_cpu(event_val[3 * i]);
+		event->select = fdt32_to_cpu(event_val[3 * i + 1]);
+		event->select = (event->select << 32) | fdt32_to_cpu(event_val[3 * i + 2]);
+		hw_event_count++;
+	}
+
+	event_val = fdt_getprop(fdt, pmu_offset, "pmu,raw-event-to-mhpmcounters", &len);
+	if (!event_val || len < 8)
+		return SBI_EFAIL;
+	len = len / (sizeof(u32) * 3);
+	for (i = 0; i < len; i++) {
+		raw_selector = fdt32_to_cpu(event_val[3 * i]);
+		raw_selector = (raw_selector << 32) | fdt32_to_cpu(event_val[3 * i + 1]);
+		ctr_map = fdt32_to_cpu(event_val[3 * i + 2]);
+		result = sbi_pmu_add_raw_event_counter_map(raw_selector, ctr_map);
+		if (!result)
+			hw_event_count++;
+	}
+
+	return 0;
+}

lib/utils/fdt/objects.mk

@@ -5,5 +5,6 @@
 #
 
 libsbiutils-objs-y += fdt/fdt_domain.o
+libsbiutils-objs-y += fdt/fdt_pmu.o
 libsbiutils-objs-y += fdt/fdt_helper.o
 libsbiutils-objs-y += fdt/fdt_fixup.o