[PATCH 13/24] RISC-V: ACPI: smpboot: Add ACPI support in smp_setup()

Sunil V L
2023-01-30T18:26:17Z

Add function to parse the RINTC structure in
the MADT table and create the required initializations to
enable SMP boot on ACPI based platforms.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
---
arch/riscv/include/asm/acpi.h | 7 ++++
arch/riscv/kernel/smpboot.c | 73 ++++++++++++++++++++++++++++++++++-
2 files changed, 79 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/acpi.h b/arch/riscv/include/asm/acpi.h
index c5cb9f96d404..d1f1e53ec657 100644
--- a/arch/riscv/include/asm/acpi.h
+++ b/arch/riscv/include/asm/acpi.h
@@ -58,6 +58,13 @@ static inline bool acpi_has_cpu_in_madt(void)
}

static inline void arch_fix_phys_package_id(int num, u32 slot) { }
+
+#ifdef CONFIG_ACPI_NUMA
+int acpi_numa_get_nid(unsigned int cpu);
+#else
+static inline int acpi_numa_get_nid(unsigned int cpu) { return NUMA_NO_NODE; }
+#endif /* CONFIG_ACPI_NUMA */
+
#endif

#endif /*_ASM_ACPI_H*/
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 26214ddefaa4..e48cf88d0bc1 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -8,6 +8,7 @@
* Copyright (C) 2017 SiFive
*/

+#include <linux/acpi.h>
#include <linux/arch_topology.h>
#include <linux/module.h>
#include <linux/init.h>
@@ -70,6 +71,73 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
}
}

+#ifdef CONFIG_ACPI
+static unsigned int cpu_count = 1;
+
+static int __init
+acpi_parse_rintc(union acpi_subtable_headers *header,
+ const unsigned long end)
+{
+ unsigned long hart;
+ bool found_boot_cpu = false;
+
+ struct acpi_madt_rintc *processor;
+
+ processor = (struct acpi_madt_rintc *)header;
+
+ /* RINTC entry which has !ACPI_MADT_ENABLED is not enabled so skip */
+ if (!(processor->flags & ACPI_MADT_ENABLED))
+ return 0;
+
+ hart = processor->hart_id;
+ if (hart < 0)
+ return 0;
+ if (hart == cpuid_to_hartid_map(0)) {
+ BUG_ON(found_boot_cpu);
+ found_boot_cpu = 1;
+ early_map_cpu_to_node(0, acpi_numa_get_nid(cpu_count));
+ return 0;
+ }
+ if (cpu_count >= NR_CPUS) {
+ pr_warn("Invalid cpuid [%d] for hartid [%lu]\n",
+ cpu_count, hart);
+ return 0;
+ }
+
+ cpuid_to_hartid_map(cpu_count) = hart;
+ early_map_cpu_to_node(cpu_count, acpi_numa_get_nid(cpu_count));
+ cpu_count++;
+ return 0;
+}
+
+static void __init acpi_parse_and_init_cpus(void)
+{
+ int cpuid;
+
+ cpu_set_ops(0);
+ /*
+ * do a walk of MADT to determine how many CPUs
+ * we have including disabled CPUs, and get information
+ * we need for SMP init.
+ */
+ acpi_table_parse_madt(ACPI_MADT_TYPE_RINTC,
+ acpi_parse_rintc, 0);
+
+ /*
+ * NUMA - TODO
+ */
+
+ for (cpuid = 1; cpuid < nr_cpu_ids; cpuid++) {
+ if (cpuid_to_hartid_map(cpuid) != INVALID_HARTID) {
+ cpu_set_ops(cpuid);
+ set_cpu_possible(cpuid, true);
+ }
+ }
+}
+#else
+#define acpi_parse_and_init_cpus(...) do { } while (0)
+#endif
+
static void __init of_parse_and_init_cpus(void)
{
struct device_node *dn;
@@ -118,7 +186,10 @@ static void __init of_parse_and_init_cpus(void)

void __init setup_smp(void)
{
- of_parse_and_init_cpus();
+ if (acpi_disabled)
+ of_parse_and_init_cpus();
+ else
+ acpi_parse_and_init_cpus();
}

static int start_secondary_cpu(int cpu, struct task_struct *tidle)
--
2.38.0