hw/riscv/virt: virt-acpi-build.c: Add RHCT Table

RISC-V ACPI platforms need to provide RISC-V Hart Capabilities
Table (RHCT). Add this to the ACPI tables.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Message-ID: <20230302091212.999767-7-sunilvl@ventanamicro.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

1 files changed, 78 insertions, 0 deletions

diff --git a/hw/riscv/virt-acpi-build.c b/hw/riscv/virt-acpi-build.c
index 026d1ea..82da0a2 100644
--- a/hw/riscv/virt-acpi-build.c
+++ b/hw/riscv/virt-acpi-build.c
@@ -33,6 +33,7 @@
 #include "migration/vmstate.h"
 #include "hw/riscv/virt.h"
 #include "hw/riscv/numa.h"
+#include "hw/intc/riscv_aclint.h"
 
 #define ACPI_BUILD_TABLE_SIZE             0x20000
 
@@ -111,6 +112,80 @@ static void acpi_dsdt_add_fw_cfg(Aml *scope, const MemMapEntry *fw_cfg_memmap)
     aml_append(scope, dev);
 }
 
+/* RHCT Node[N] starts at offset 56 */
+#define RHCT_NODE_ARRAY_OFFSET 56
+
+/*
+ * ACPI spec, Revision 6.5+
+ * 5.2.36 RISC-V Hart Capabilities Table (RHCT)
+ * REF: https://github.com/riscv-non-isa/riscv-acpi/issues/16
+ *      https://drive.google.com/file/d/1nP3nFiH4jkPMp6COOxP6123DCZKR-tia/view
+ */
+static void build_rhct(GArray *table_data,
+                       BIOSLinker *linker,
+                       RISCVVirtState *s)
+{
+    MachineClass *mc = MACHINE_GET_CLASS(s);
+    MachineState *ms = MACHINE(s);
+    const CPUArchIdList *arch_ids = mc->possible_cpu_arch_ids(ms);
+    size_t len, aligned_len;
+    uint32_t isa_offset, num_rhct_nodes;
+    RISCVCPU *cpu;
+    char *isa;
+
+    AcpiTable table = { .sig = "RHCT", .rev = 1, .oem_id = s->oem_id,
+                        .oem_table_id = s->oem_table_id };
+
+    acpi_table_begin(&table, table_data);
+
+    build_append_int_noprefix(table_data, 0x0, 4);   /* Reserved */
+
+    /* Time Base Frequency */
+    build_append_int_noprefix(table_data,
+                              RISCV_ACLINT_DEFAULT_TIMEBASE_FREQ, 8);
+
+    /* ISA + N hart info */
+    num_rhct_nodes = 1 + ms->smp.cpus;
+
+    /* Number of RHCT nodes*/
+    build_append_int_noprefix(table_data, num_rhct_nodes, 4);
+
+    /* Offset to the RHCT node array */
+    build_append_int_noprefix(table_data, RHCT_NODE_ARRAY_OFFSET, 4);
+
+    /* ISA String Node */
+    isa_offset = table_data->len - table.table_offset;
+    build_append_int_noprefix(table_data, 0, 2);   /* Type 0 */
+
+    cpu = &s->soc[0].harts[0];
+    isa = riscv_isa_string(cpu);
+    len = 8 + strlen(isa) + 1;
+    aligned_len = (len % 2) ? (len + 1) : len;
+
+    build_append_int_noprefix(table_data, aligned_len, 2);   /* Length */
+    build_append_int_noprefix(table_data, 0x1, 2);           /* Revision */
+
+    /* ISA string length including NUL */
+    build_append_int_noprefix(table_data, strlen(isa) + 1, 2);
+    g_array_append_vals(table_data, isa, strlen(isa) + 1);   /* ISA string */
+
+    if (aligned_len != len) {
+        build_append_int_noprefix(table_data, 0x0, 1);   /* Optional Padding */
+    }
+
+    /* Hart Info Node */
+    for (int i = 0; i < arch_ids->len; i++) {
+        build_append_int_noprefix(table_data, 0xFFFF, 2);  /* Type */
+        build_append_int_noprefix(table_data, 16, 2);      /* Length */
+        build_append_int_noprefix(table_data, 0x1, 2);     /* Revision */
+        build_append_int_noprefix(table_data, 1, 2);    /* Number of offsets */
+        build_append_int_noprefix(table_data, i, 4);    /* ACPI Processor UID */
+        build_append_int_noprefix(table_data, isa_offset, 4); /* Offsets[0] */
+    }
+
+    acpi_table_end(linker, &table);
+}
+
 /* FADT */
 static void build_fadt_rev6(GArray *table_data,
                             BIOSLinker *linker,
@@ -215,6 +290,9 @@ static void virt_acpi_build(RISCVVirtState *s, AcpiBuildTables *tables)
     acpi_add_table(table_offsets, tables_blob);
     build_madt(tables_blob, tables->linker, s);
 
+    acpi_add_table(table_offsets, tables_blob);
+    build_rhct(tables_blob, tables->linker, s);
+
     /* XSDT is pointed to by RSDP */
     xsdt = tables_blob->len;
     build_xsdt(tables_blob, tables->linker, table_offsets, s->oem_id,