/*
 *  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/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) {
                u32 hwid;

                if (of_node_cmp(cpu->type, "cpu"))
                        continue;

                pr_debug(" * %s...\n", cpu->full_name);
                /*
                 * A device tree containing CPU nodes with missing "reg"
                 * properties is considered invalid to build the
                 * cpu_logical_map.
                 */
                if (of_property_read_u32(cpu, "reg", &hwid)) {
                        pr_debug(" * %s missing reg property\n",
                                     cpu->full_name);
                        return;
                }

                /*
                 * 8 MSBs must be set to 0 in the DT since the reg property
                 * defines the MPIDR[23:0].
                 */
                if (hwid & ~MPIDR_HWID_BITMASK)
                        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"))
                                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;
                        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;

#ifdef CONFIG_ARCH_MULTIPLATFORM
        DT_MACHINE_START(GENERIC_DT, "Generic DT based system")
        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;
}