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hw/riscv: virt: Add PMU DT node to the device tree

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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.

Acked-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Message-Id: <20220824221701.41932-5-atishp@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
This commit is contained in:
Atish Patra 2022-08-24 15:17:00 -07:00 committed by Alistair Francis
parent 892320facd
commit abd9a20665
3 changed files with 74 additions and 0 deletions
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16
hw/riscv/virt.c
View File

@ -30,6 +30,7 @@
#include "hw/char/serial.h"
#include "target/riscv/cpu.h"
#include "hw/core/sysbus-fdt.h"
#include "target/riscv/pmu.h"
#include "hw/riscv/riscv_hart.h"
#include "hw/riscv/virt.h"
#include "hw/riscv/boot.h"
@ -708,6 +709,20 @@ static void create_fdt_socket_aplic(RISCVVirtState *s,
aplic_phandles[socket] = aplic_s_phandle;
}
static void create_fdt_pmu(RISCVVirtState *s)
{
char *pmu_name;
MachineState *mc = MACHINE(s);
RISCVCPU hart = s->soc[0].harts[0];
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");
riscv_pmu_generate_fdt_node(mc->fdt, hart.cfg.pmu_num, pmu_name);
g_free(pmu_name);
}
static void create_fdt_sockets(RISCVVirtState *s, const MemMapEntry *memmap,
bool is_32_bit, uint32_t *phandle,
uint32_t *irq_mmio_phandle,
@ -1036,6 +1051,7 @@ static void create_fdt(RISCVVirtState *s, const MemMapEntry *memmap,
create_fdt_flash(s, memmap);
create_fdt_fw_cfg(s, memmap);
create_fdt_pmu(s);
update_bootargs:
if (cmdline && *cmdline) {

57
target/riscv/pmu.c
View File

@ -20,11 +20,68 @@
#include "cpu.h"
#include "pmu.h"
#include "sysemu/cpu-timers.h"
#include "sysemu/device_tree.h"
#define RISCV_TIMEBASE_FREQ 1000000000 /* 1Ghz */
#define MAKE_32BIT_MASK(shift, length) \
(((uint32_t)(~0UL) >> (32 - (length))) << (shift))
/*
* 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. Heterogeneous PMU per hart is not
* supported yet. Thus, number of counters are same across all harts.
*/
void riscv_pmu_generate_fdt_node(void *fdt, int num_ctrs, char *pmu_name)
{
uint32_t fdt_event_ctr_map[20] = {};
uint32_t cmask;
/* All the programmable counters can map to any event */
cmask = MAKE_32BIT_MASK(3, num_ctrs);
/*
* The event encoding is specified in the SBI specification
* Event idx is a 20bits wide number encoded as follows:
* event_idx[19:16] = type
* event_idx[15:0] = code
* The code field in cache events are encoded as follows:
* event_idx.code[15:3] = cache_id
* event_idx.code[2:1] = op_id
* event_idx.code[0:0] = result_id
*/
/* SBI_PMU_HW_CPU_CYCLES: 0x01 : type(0x00) */
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(cmask | 1 << 0);
/* SBI_PMU_HW_INSTRUCTIONS: 0x02 : type(0x00) */
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(cmask | 1 << 2);
/* SBI_PMU_HW_CACHE_DTLB : 0x03 READ : 0x00 MISS : 0x00 type(0x01) */
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(cmask);
/* SBI_PMU_HW_CACHE_DTLB : 0x03 WRITE : 0x01 MISS : 0x00 type(0x01) */
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(cmask);
/* SBI_PMU_HW_CACHE_ITLB : 0x04 READ : 0x00 MISS : 0x00 type(0x01) */
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(cmask);
/* This a OpenSBI specific DT property documented in OpenSBI docs */
qemu_fdt_setprop(fdt, pmu_name, "riscv,event-to-mhpmcounters",
fdt_event_ctr_map, sizeof(fdt_event_ctr_map));
}
static bool riscv_pmu_counter_valid(RISCVCPU *cpu, uint32_t ctr_idx)
{
if (ctr_idx < 3 || ctr_idx >= RV_MAX_MHPMCOUNTERS ||

1
target/riscv/pmu.h
View File

@ -31,5 +31,6 @@ int riscv_pmu_init(RISCVCPU *cpu, int num_counters);
int riscv_pmu_update_event_map(CPURISCVState *env, uint64_t value,
uint32_t ctr_idx);
int riscv_pmu_incr_ctr(RISCVCPU *cpu, enum riscv_pmu_event_idx event_idx);
void riscv_pmu_generate_fdt_node(void *fdt, int num_counters, char *pmu_name);
int riscv_pmu_setup_timer(CPURISCVState *env, uint64_t value,
uint32_t ctr_idx);