From 28a4df979a2ef92d9129886cd9dcb00c497ac4cb Mon Sep 17 00:00:00 2001 From: Atish Patra Date: Mon, 24 Jun 2019 16:41:44 -0700 Subject: [PATCH] riscv: virt: Add cpu-topology DT node. Currently, there is no cpu topology defined in RISC-V. Define a device tree node that clearly describes the entire topology. This saves the trouble of scanning individual cache to figure out the topology. Here is the linux kernel patch series that enables topology for RISC-V. http://lists.infradead.org/pipermail/linux-riscv/2019-June/005072.html CPU topology after applying this patch in QEMU & above series in kernel / # cat /sys/devices/system/cpu/cpu2/topology/thread_siblings_list 2 / # cat /sys/devices/system/cpu/cpu2/topology/physical_package_id 0 / # cat /sys/devices/system/cpu/cpu2/topology/core_siblings_list 0-7 Signed-off-by: Atish Patra Reviewed-by: Alistair Francis Signed-off-by: Palmer Dabbelt --- hw/riscv/virt.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c index 487f61404b..28d96daf8c 100644 --- a/hw/riscv/virt.c +++ b/hw/riscv/virt.c @@ -191,6 +191,7 @@ static void *create_fdt(RISCVVirtState *s, const struct MemmapEntry *memmap, for (cpu = s->soc.num_harts - 1; cpu >= 0; cpu--) { int cpu_phandle = phandle++; + int intc_phandle; nodename = g_strdup_printf("/cpus/cpu@%d", cpu); char *intc = g_strdup_printf("/cpus/cpu@%d/interrupt-controller", cpu); char *isa = riscv_isa_string(&s->soc.harts[cpu]); @@ -203,9 +204,12 @@ static void *create_fdt(RISCVVirtState *s, const struct MemmapEntry *memmap, qemu_fdt_setprop_string(fdt, nodename, "status", "okay"); qemu_fdt_setprop_cell(fdt, nodename, "reg", cpu); qemu_fdt_setprop_string(fdt, nodename, "device_type", "cpu"); + qemu_fdt_setprop_cell(fdt, nodename, "phandle", cpu_phandle); + qemu_fdt_setprop_cell(fdt, nodename, "linux,phandle", cpu_phandle); + intc_phandle = phandle++; qemu_fdt_add_subnode(fdt, intc); - qemu_fdt_setprop_cell(fdt, intc, "phandle", cpu_phandle); - qemu_fdt_setprop_cell(fdt, intc, "linux,phandle", cpu_phandle); + qemu_fdt_setprop_cell(fdt, intc, "phandle", intc_phandle); + qemu_fdt_setprop_cell(fdt, intc, "linux,phandle", intc_phandle); qemu_fdt_setprop_string(fdt, intc, "compatible", "riscv,cpu-intc"); qemu_fdt_setprop(fdt, intc, "interrupt-controller", NULL, 0); qemu_fdt_setprop_cell(fdt, intc, "#interrupt-cells", 1); @@ -214,6 +218,20 @@ static void *create_fdt(RISCVVirtState *s, const struct MemmapEntry *memmap, g_free(nodename); } + /* Add cpu-topology node */ + qemu_fdt_add_subnode(fdt, "/cpus/cpu-map"); + qemu_fdt_add_subnode(fdt, "/cpus/cpu-map/cluster0"); + for (cpu = s->soc.num_harts - 1; cpu >= 0; cpu--) { + char *core_nodename = g_strdup_printf("/cpus/cpu-map/cluster0/core%d", + cpu); + char *cpu_nodename = g_strdup_printf("/cpus/cpu@%d", cpu); + uint32_t intc_phandle = qemu_fdt_get_phandle(fdt, cpu_nodename); + qemu_fdt_add_subnode(fdt, core_nodename); + qemu_fdt_setprop_cell(fdt, core_nodename, "cpu", intc_phandle); + g_free(core_nodename); + g_free(cpu_nodename); + } + cells = g_new0(uint32_t, s->soc.num_harts * 4); for (cpu = 0; cpu < s->soc.num_harts; cpu++) { nodename =