/* * linux/arch/arm/kernel/devtree.c * * Copyright (C) 2009 Canonical Ltd. <jeremy.kerr@canonical.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/init.h> #include <linux/export.h> #include <linux/errno.h> #include <linux/types.h> #include <linux/bootmem.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_child_of_node(cpus, cpu) { const __be32 *cell; int prop_bytes; u32 hwid; if (of_node_cmp(cpu->type, "cpu")) continue; pr_debug(" * %pOF...\n", cpu); /* * A device tree containing CPU nodes with missing "reg" * properties is considered invalid to build the * cpu_logical_map. */ cell = of_get_property(cpu, "reg", &prop_bytes); if (!cell || prop_bytes < sizeof(*cell)) { pr_debug(" * %pOF missing reg property\n", cpu); of_node_put(cpu); return; } /* * Bits n:24 must be set to 0 in the DT since the reg property * defines the MPIDR[23:0]. */ do { hwid = be32_to_cpu(*cell++); prop_bytes -= sizeof(*cell); } while (!hwid && prop_bytes > 0); if (prop_bytes || (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_phys: physical 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(unsigned int dt_phys) { const struct machine_desc *mdesc, *mdesc_best = NULL; #if defined(CONFIG_ARCH_MULTIPLATFORM) || defined(CONFIG_ARM_SINGLE_ARMV7M) 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; #endif if (!dt_phys || !early_init_dt_verify(phys_to_virt(dt_phys))) 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; }