1 files changed, 239 insertions, 0 deletions
diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
new file mode 100644
index 000000000..264827281
--- /dev/null
+++ b/arch/arm/kernel/devtree.c
@@ -0,0 +1,239 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/arch/arm/kernel/devtree.c
+ *
+ *  Copyright (C) 2009 Canonical Ltd. <jeremy.kerr@canonical.com>
+ */
+
+#include <linux/init.h>
+#include <linux/export.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/memblock.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/smp.h>
+
+#include <asm/cputype.h>
+#include <asm/setup.h>
+#include <asm/page.h>
+#include <asm/prom.h>
+#include <asm/smp_plat.h>
+#include <asm/mach/arch.h>
+#include <asm/mach-types.h>
+
+
+#ifdef CONFIG_SMP
+extern struct of_cpu_method __cpu_method_of_table[];
+
+static const struct of_cpu_method __cpu_method_of_table_sentinel
+	__used __section("__cpu_method_of_table_end");
+
+
+static int __init set_smp_ops_by_method(struct device_node *node)
+{
+	const char *method;
+	struct of_cpu_method *m = __cpu_method_of_table;
+
+	if (of_property_read_string(node, "enable-method", &method))
+		return 0;
+
+	for (; m->method; m++)
+		if (!strcmp(m->method, method)) {
+			smp_set_ops(m->ops);
+			return 1;
+		}
+
+	return 0;
+}
+#else
+static inline int set_smp_ops_by_method(struct device_node *node)
+{
+	return 1;
+}
+#endif
+
+
+/*
+ * arm_dt_init_cpu_maps - Function retrieves cpu nodes from the device tree
+ * and builds the cpu logical map array containing MPIDR values related to
+ * logical cpus
+ *
+ * Updates the cpu possible mask with the number of parsed cpu nodes
+ */
+void __init arm_dt_init_cpu_maps(void)
+{
+	/*
+	 * Temp logical map is initialized with UINT_MAX values that are
+	 * considered invalid logical map entries since the logical map must
+	 * contain a list of MPIDR[23:0] values where MPIDR[31:24] must
+	 * read as 0.
+	 */
+	struct device_node *cpu, *cpus;
+	int found_method = 0;
+	u32 i, j, cpuidx = 1;
+	u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0;
+
+	u32 tmp_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID };
+	bool bootcpu_valid = false;
+	cpus = of_find_node_by_path("/cpus");
+
+	if (!cpus)
+		return;
+
+	for_each_of_cpu_node(cpu) {
+		u32 hwid = of_get_cpu_hwid(cpu, 0);
+
+		pr_debug(" * %pOF...\n", cpu);
+
+		/*
+		 * Bits n:24 must be set to 0 in the DT since the reg property
+		 * defines the MPIDR[23:0].
+		 */
+		if (hwid & ~MPIDR_HWID_BITMASK) {
+			of_node_put(cpu);
+			return;
+		}
+
+		/*
+		 * Duplicate MPIDRs are a recipe for disaster.
+		 * Scan all initialized entries and check for
+		 * duplicates. If any is found just bail out.
+		 * temp values were initialized to UINT_MAX
+		 * to avoid matching valid MPIDR[23:0] values.
+		 */
+		for (j = 0; j < cpuidx; j++)
+			if (WARN(tmp_map[j] == hwid,
+				 "Duplicate /cpu reg properties in the DT\n")) {
+				of_node_put(cpu);
+				return;
+			}
+
+		/*
+		 * Build a stashed array of MPIDR values. Numbering scheme
+		 * requires that if detected the boot CPU must be assigned
+		 * logical id 0. Other CPUs get sequential indexes starting
+		 * from 1. If a CPU node with a reg property matching the
+		 * boot CPU MPIDR is detected, this is recorded so that the
+		 * logical map built from DT is validated and can be used
+		 * to override the map created in smp_setup_processor_id().
+		 */
+		if (hwid == mpidr) {
+			i = 0;
+			bootcpu_valid = true;
+		} else {
+			i = cpuidx++;
+		}
+
+		if (WARN(cpuidx > nr_cpu_ids, "DT /cpu %u nodes greater than "
+					       "max cores %u, capping them\n",
+					       cpuidx, nr_cpu_ids)) {
+			cpuidx = nr_cpu_ids;
+			of_node_put(cpu);
+			break;
+		}
+
+		tmp_map[i] = hwid;
+
+		if (!found_method)
+			found_method = set_smp_ops_by_method(cpu);
+	}
+
+	/*
+	 * Fallback to an enable-method in the cpus node if nothing found in
+	 * a cpu node.
+	 */
+	if (!found_method)
+		set_smp_ops_by_method(cpus);
+
+	if (!bootcpu_valid) {
+		pr_warn("DT missing boot CPU MPIDR[23:0], fall back to default cpu_logical_map\n");
+		return;
+	}
+
+	/*
+	 * Since the boot CPU node contains proper data, and all nodes have
+	 * a reg property, the DT CPU list can be considered valid and the
+	 * logical map created in smp_setup_processor_id() can be overridden
+	 */
+	for (i = 0; i < cpuidx; i++) {
+		set_cpu_possible(i, true);
+		cpu_logical_map(i) = tmp_map[i];
+		pr_debug("cpu logical map 0x%x\n", cpu_logical_map(i));
+	}
+}
+
+bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
+{
+	return phys_id == cpu_logical_map(cpu);
+}
+
+static const void * __init arch_get_next_mach(const char *const **match)
+{
+	static const struct machine_desc *mdesc = __arch_info_begin;
+	const struct machine_desc *m = mdesc;
+
+	if (m >= __arch_info_end)
+		return NULL;
+
+	mdesc++;
+	*match = m->dt_compat;
+	return m;
+}
+
+/**
+ * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
+ * @dt_virt: virtual address of dt blob
+ *
+ * If a dtb was passed to the kernel in r2, then use it to choose the
+ * correct machine_desc and to setup the system.
+ */
+const struct machine_desc * __init setup_machine_fdt(void *dt_virt)
+{
+	const struct machine_desc *mdesc, *mdesc_best = NULL;
+
+	DT_MACHINE_START(GENERIC_DT, "Generic DT based system")
+		.l2c_aux_val = 0x0,
+		.l2c_aux_mask = ~0x0,
+	MACHINE_END
+
+	mdesc_best = &__mach_desc_GENERIC_DT;
+
+	if (!dt_virt || !early_init_dt_verify(dt_virt))
+		return NULL;
+
+	mdesc = of_flat_dt_match_machine(mdesc_best, arch_get_next_mach);
+
+	if (!mdesc) {
+		const char *prop;
+		int size;
+		unsigned long dt_root;
+
+		early_print("\nError: unrecognized/unsupported "
+			    "device tree compatible list:\n[ ");
+
+		dt_root = of_get_flat_dt_root();
+		prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
+		while (size > 0) {
+			early_print("'%s' ", prop);
+			size -= strlen(prop) + 1;
+			prop += strlen(prop) + 1;
+		}
+		early_print("]\n\n");
+
+		dump_machine_table(); /* does not return */
+	}
+
+	/* We really don't want to do this, but sometimes firmware provides buggy data */
+	if (mdesc->dt_fixup)
+		mdesc->dt_fixup();
+
+	early_init_dt_scan_nodes();
+
+	/* Change machine number to match the mdesc we're using */
+	__machine_arch_type = mdesc->nr;
+
+	return mdesc;
+}