LoongArch: Add Non-Uniform Memory Access (NUMA) support

Add Non-Uniform Memory Access (NUMA) support for LoongArch. LoongArch
has 48-bit physical address, but the HyperTransport I/O bus only support
40-bit address, so we need a custom phys_to_dma() and dma_to_phys() to
extract the 4-bit node id (bit 44~47) from Loongson-3's 48-bit physical
address space and embed it into 40-bit. In the 40-bit dma address, node
id offset can be read from the LS7A_DMA_CFG register.

Reviewed-by: WANG Xuerui <git@xen0n.name>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

1 files changed, 95 insertions, 0 deletions

diff --git a/arch/loongarch/kernel/acpi.c b/arch/loongarch/kernel/acpi.c
index 181c59493b63..b16c3dea5eeb 100644
--- a/arch/loongarch/kernel/acpi.c
+++ b/arch/loongarch/kernel/acpi.c
@@ -14,6 +14,7 @@
 #include <linux/memblock.h>
 #include <linux/serial_core.h>
 #include <asm/io.h>
+#include <asm/numa.h>
 #include <asm/loongson.h>
 
 int acpi_disabled;
@@ -199,6 +200,79 @@ int __init acpi_boot_init(void)
 	return 0;
 }
 
+#ifdef CONFIG_ACPI_NUMA
+
+static __init int setup_node(int pxm)
+{
+	return acpi_map_pxm_to_node(pxm);
+}
+
+/*
+ * Callback for SLIT parsing.  pxm_to_node() returns NUMA_NO_NODE for
+ * I/O localities since SRAT does not list them.  I/O localities are
+ * not supported at this point.
+ */
+unsigned int numa_distance_cnt;
+
+static inline unsigned int get_numa_distances_cnt(struct acpi_table_slit *slit)
+{
+	return slit->locality_count;
+}
+
+void __init numa_set_distance(int from, int to, int distance)
+{
+	if ((u8)distance != distance || (from == to && distance != LOCAL_DISTANCE)) {
+		pr_warn_once("Warning: invalid distance parameter, from=%d to=%d distance=%d\n",
+				from, to, distance);
+		return;
+	}
+
+	node_distances[from][to] = distance;
+}
+
+/* Callback for Proximity Domain -> CPUID mapping */
+void __init
+acpi_numa_processor_affinity_init(struct acpi_srat_cpu_affinity *pa)
+{
+	int pxm, node;
+
+	if (srat_disabled())
+		return;
+	if (pa->header.length != sizeof(struct acpi_srat_cpu_affinity)) {
+		bad_srat();
+		return;
+	}
+	if ((pa->flags & ACPI_SRAT_CPU_ENABLED) == 0)
+		return;
+	pxm = pa->proximity_domain_lo;
+	if (acpi_srat_revision >= 2) {
+		pxm |= (pa->proximity_domain_hi[0] << 8);
+		pxm |= (pa->proximity_domain_hi[1] << 16);
+		pxm |= (pa->proximity_domain_hi[2] << 24);
+	}
+	node = setup_node(pxm);
+	if (node < 0) {
+		pr_err("SRAT: Too many proximity domains %x\n", pxm);
+		bad_srat();
+		return;
+	}
+
+	if (pa->apic_id >= CONFIG_NR_CPUS) {
+		pr_info("SRAT: PXM %u -> CPU 0x%02x -> Node %u skipped apicid that is too big\n",
+				pxm, pa->apic_id, node);
+		return;
+	}
+
+	early_numa_add_cpu(pa->apic_id, node);
+
+	set_cpuid_to_node(pa->apic_id, node);
+	node_set(node, numa_nodes_parsed);
+	pr_info("SRAT: PXM %u -> CPU 0x%02x -> Node %u\n", pxm, pa->apic_id, node);
+}
+
+void __init acpi_numa_arch_fixup(void) {}
+#endif
+
 void __init arch_reserve_mem_area(acpi_physical_address addr, size_t size)
 {
 	memblock_reserve(addr, size);
@@ -208,6 +282,22 @@ void __init arch_reserve_mem_area(acpi_physical_address addr, size_t size)
 
 #include <acpi/processor.h>
 
+static int __ref acpi_map_cpu2node(acpi_handle handle, int cpu, int physid)
+{
+#ifdef CONFIG_ACPI_NUMA
+	int nid;
+
+	nid = acpi_get_node(handle);
+	if (nid != NUMA_NO_NODE) {
+		set_cpuid_to_node(physid, nid);
+		node_set(nid, numa_nodes_parsed);
+		set_cpu_numa_node(cpu, nid);
+		cpumask_set_cpu(cpu, cpumask_of_node(nid));
+	}
+#endif
+	return 0;
+}
+
 int acpi_map_cpu(acpi_handle handle, phys_cpuid_t physid, u32 acpi_id, int *pcpu)
 {
 	int cpu;
@@ -218,6 +308,8 @@ int acpi_map_cpu(acpi_handle handle, phys_cpuid_t physid, u32 acpi_id, int *pcpu
 		return cpu;
 	}
 
+	acpi_map_cpu2node(handle, cpu, physid);
+
 	*pcpu = cpu;
 
 	return 0;
@@ -226,6 +318,9 @@ EXPORT_SYMBOL(acpi_map_cpu);
 
 int acpi_unmap_cpu(int cpu)
 {
+#ifdef CONFIG_ACPI_NUMA
+	set_cpuid_to_node(cpu_logical_map(cpu), NUMA_NO_NODE);
+#endif
 	set_cpu_present(cpu, false);
 	num_processors--;