[ PATCH v3 10/10] hw/riscv: virt: Add PMU DT node to the device tree

[Atish Patra]

Qemu virt machine can support few cache events and cycle/instret counters.
It also supports counter overflow for these events.

Add a DT node so that OpenSBI/Linux kernel is aware of the virt machine
capabilities. There are some dummy nodes added for testing as well.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
---
 hw/riscv/virt.c    | 36 ++++++++++++++++++++++++++
 target/riscv/pmp.c |  1 +
 target/riscv/pmu.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 100 insertions(+)

diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c
index ec0cb69b8c73..b246d2e339eb 100644
--- a/hw/riscv/virt.c
+++ b/hw/riscv/virt.c
@@ -28,6 +28,7 @@
 #include "hw/qdev-properties.h"
 #include "hw/char/serial.h"
 #include "target/riscv/cpu.h"
+#include "target/riscv/pmu.h"
 #include "hw/riscv/riscv_hart.h"
 #include "hw/riscv/virt.h"
 #include "hw/riscv/boot.h"
@@ -406,6 +407,39 @@ static void create_fdt_socket_plic(RISCVVirtState *s,
     g_free(plic_cells);
 }
 
+static void create_fdt_socket_pmu(RISCVVirtState *s,
+                                  int socket, uint32_t *phandle,
+                                  uint32_t *intc_phandles)
+{
+    int cpu;
+    char *pmu_name;
+    RISCVCPU hart;
+    uint32_t *pmu_cells;
+    MachineState *mc = MACHINE(s);
+
+    pmu_cells = g_new0(uint32_t, s->soc[socket].num_harts * 2);
+
+    for (cpu = 0; cpu < s->soc[socket].num_harts; cpu++) {
+        pmu_cells[cpu * 2 + 0] = cpu_to_be32(intc_phandles[cpu]);
+        pmu_cells[cpu * 2 + 1] = cpu_to_be32(IRQ_PMU_OVF);
+    }
+
+    pmu_name = g_strdup_printf("/soc/pmu");
+    qemu_fdt_add_subnode(mc->fdt, pmu_name);
+    qemu_fdt_setprop_string(mc->fdt, pmu_name, "compatible", "riscv,pmu");
+    hart = s->soc[0].harts[0];
+    if (hart.cfg.ext_sscof) {
+        qemu_fdt_setprop_cell(mc->fdt, pmu_name, "#interrupt-cells", 1);
+        qemu_fdt_setprop(mc->fdt, pmu_name, "interrupts-extended", pmu_cells,
+                         s->soc[socket].num_harts * sizeof(uint32_t) * 2);
+    }
+    riscv_pmu_generate_fdt_node(mc->fdt, pmu_name);
+
+    g_free(pmu_name);
+    g_free(pmu_cells);
+}
+
+
 static void create_fdt_sockets(RISCVVirtState *s, const MemMapEntry *memmap,
                                bool is_32_bit, uint32_t *phandle,
                                uint32_t *irq_mmio_phandle,
@@ -445,6 +479,8 @@ static void create_fdt_sockets(RISCVVirtState *s, const 
MemMapEntry *memmap,
         create_fdt_socket_plic(s, memmap, socket, phandle,
             intc_phandles, xplic_phandles);
 
+        create_fdt_socket_pmu(s, socket, phandle, intc_phandles);
+
         g_free(intc_phandles);
         g_free(clust_name);
     }
diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c
index 54abf425835c..2e2145e51903 100644
--- a/target/riscv/pmp.c
+++ b/target/riscv/pmp.c
@@ -25,6 +25,7 @@
 #include "cpu.h"
 #include "trace.h"
 #include "exec/exec-all.h"
+#include "sysemu/device_tree.h"
 
 static void pmp_write_cfg(CPURISCVState *env, uint32_t addr_index,
     uint8_t val);
diff --git a/target/riscv/pmu.c b/target/riscv/pmu.c
index 25bdbdf48ff7..9e11af85576d 100644
--- a/target/riscv/pmu.c
+++ b/target/riscv/pmu.c
@@ -19,9 +19,72 @@
 #include "qemu/osdep.h"
 #include "cpu.h"
 #include "pmu.h"
+#include "sysemu/device_tree.h"
 
 #define RISCV_TIMEBASE_FREQ 1000000000 /* 1Ghz */
 
+/**
+ * To keep it simple, any event can be mapped to any programmable counters in
+ * QEMU. The generic cycle & instruction count events can also be monitored
+ * using programmable counters. In that case, mcycle & minstret must continue
+ * to provide the correct value as well.
+ */
+void riscv_pmu_generate_fdt_node(void *fdt, char *pmu_name)
+{
+    uint32_t fdt_event_map[6] = {};
+    uint32_t fdt_event_ctr_map[20] = {};
+    uint32_t fdt_raw_event_ctr_map[6] = {};
+
+    /* Dummy event and mhpmevent values */
+    fdt_event_map[0] = cpu_to_be32(0x00000009);
+    fdt_event_map[1] = cpu_to_be32(0x00000000);
+    fdt_event_map[2] = cpu_to_be32(0x00000200);
+    fdt_event_map[3] = cpu_to_be32(0x00010000);
+    fdt_event_map[4] = cpu_to_be32(0x00000100);
+    fdt_event_map[5] = cpu_to_be32(0x00000002);
+    qemu_fdt_setprop(fdt, pmu_name, "pmu,event-to-mhpmevent",
+                     fdt_event_map, sizeof(fdt_event_map));
+
+   /* SBI_PMU_HW_CPU_CYCLES */
+   fdt_event_ctr_map[0] = cpu_to_be32(0x00000001);
+   fdt_event_ctr_map[1] = cpu_to_be32(0x00000001);
+   fdt_event_ctr_map[2] = cpu_to_be32(0x00000FF9);
+
+   /* SBI_PMU_HW_INSTRUCTIONS */
+   fdt_event_ctr_map[3] = cpu_to_be32(0x00000002);
+   fdt_event_ctr_map[4] = cpu_to_be32(0x00000002);
+   fdt_event_ctr_map[5] = cpu_to_be32(0x00000FFC);
+
+   /* SBI_PMU_HW_CACHE_DTLB : READ : MISS */
+   fdt_event_ctr_map[6] = cpu_to_be32(0x00010019);
+   fdt_event_ctr_map[7] = cpu_to_be32(0x00010019);
+   fdt_event_ctr_map[8] = cpu_to_be32(0x00001F0);
+
+   /* SBI_PMU_HW_CACHE_DTLB : WRITE : MISS */
+   fdt_event_ctr_map[9] = cpu_to_be32(0x0001001B);
+   fdt_event_ctr_map[10] = cpu_to_be32(0x0001001B);
+   fdt_event_ctr_map[11] = cpu_to_be32(0x00001F0);
+
+   /* SBI_PMU_HW_CACHE_ITLB : READ : MISS */
+   fdt_event_ctr_map[12] = cpu_to_be32(0x00010021);
+   fdt_event_ctr_map[13] = cpu_to_be32(0x00010021);
+   fdt_event_ctr_map[14] = cpu_to_be32(0x00001F0);
+
+   qemu_fdt_setprop(fdt, pmu_name, "pmu,event-to-mhpmcounters",
+                    fdt_event_ctr_map, sizeof(fdt_event_ctr_map));
+
+   /* Dummy raw events */
+   fdt_raw_event_ctr_map[0] = cpu_to_be32(0x00000000);
+   fdt_raw_event_ctr_map[1] = cpu_to_be32(0x00020002);
+   fdt_raw_event_ctr_map[2] = cpu_to_be32(0x00000F00);
+   fdt_raw_event_ctr_map[3] = cpu_to_be32(0x00000000);
+   fdt_raw_event_ctr_map[4] = cpu_to_be32(0x00020003);
+   fdt_raw_event_ctr_map[5] = cpu_to_be32(0x000000F0);
+   qemu_fdt_setprop(fdt, pmu_name, "pmu,raw-event-to-mhpmcounters",
+                    fdt_raw_event_ctr_map,
+                    sizeof(fdt_raw_event_ctr_map));
+}
+
 static bool riscv_pmu_counter_valid(RISCVCPU *cpu, uint32_t ctr_idx)
 {
     if (ctr_idx < 3 || ctr_idx >= RV_MAX_MHPMCOUNTERS ||
-- 
2.31.1