/*
 * Code to handle transition of Linux booting another kernel.
 *
 * Copyright (C) 2002-2003 Eric Biederman  <ebiederm@xmission.com>
 * GameCube/ppc32 port Copyright (C) 2004 Albert Herranz
 * Copyright (C) 2005 IBM Corporation.
 *
 * This source code is licensed under the GNU General Public License,
 * Version 2.  See the file COPYING for more details.
 */

#include <linux/kexec.h>
#include <linux/reboot.h>
#include <linux/threads.h>
#include <linux/memblock.h>
#include <linux/of.h>
#include <linux/irq.h>
#include <linux/ftrace.h>

#include <asm/machdep.h>
#include <asm/prom.h>
#include <asm/sections.h>

void machine_kexec_mask_interrupts(void) {
        unsigned int i;
        struct irq_desc *desc;

        for_each_irq_desc(i, desc) {
                struct irq_chip *chip;

                chip = irq_desc_get_chip(desc);
                if (!chip)
                        continue;

                if (chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data))
                        chip->irq_eoi(&desc->irq_data);

                if (chip->irq_mask)
                        chip->irq_mask(&desc->irq_data);

                if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data))
                        chip->irq_disable(&desc->irq_data);
        }
}

void machine_crash_shutdown(struct pt_regs *regs)
{
        default_machine_crash_shutdown(regs);
}

/*
 * Do what every setup is needed on image and the
 * reboot code buffer to allow us to avoid allocations
 * later.
 */
int machine_kexec_prepare(struct kimage *image)
{
        if (ppc_md.machine_kexec_prepare)
                return ppc_md.machine_kexec_prepare(image);
        else
                return default_machine_kexec_prepare(image);
}

void machine_kexec_cleanup(struct kimage *image)
{
}

void arch_crash_save_vmcoreinfo(void)
{

#ifdef CONFIG_NEED_MULTIPLE_NODES
        VMCOREINFO_SYMBOL(node_data);
        VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
#endif
#ifndef CONFIG_NEED_MULTIPLE_NODES
        VMCOREINFO_SYMBOL(contig_page_data);
#endif
}

/*
 * Do not allocate memory (or fail in any way) in machine_kexec().
 * We are past the point of no return, committed to rebooting now.
 */
void machine_kexec(struct kimage *image)
{
        int save_ftrace_enabled;

        save_ftrace_enabled = __ftrace_enabled_save();

        if (ppc_md.machine_kexec)
                ppc_md.machine_kexec(image);
        else
                default_machine_kexec(image);

        __ftrace_enabled_restore(save_ftrace_enabled);

        /* Fall back to normal restart if we're still alive. */
        machine_restart(NULL);
        for(;;);
}

void __init reserve_crashkernel(void)
{
        unsigned long long crash_size, crash_base;
        int ret;

        /* use common parsing */
        ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
                        &crash_size, &crash_base);
        if (ret == 0 && crash_size > 0) {
                crashk_res.start = crash_base;
                crashk_res.end = crash_base + crash_size - 1;
        }

        if (crashk_res.end == crashk_res.start) {
                crashk_res.start = crashk_res.end = 0;
                return;
        }

        /* We might have got these values via the command line or the
         * device tree, either way sanitise them now. */

        crash_size = resource_size(&crashk_res);

#ifndef CONFIG_NONSTATIC_KERNEL
        if (crashk_res.start != KDUMP_KERNELBASE)
                printk("Crash kernel location must be 0x%x\n",
                                KDUMP_KERNELBASE);

        crashk_res.start = KDUMP_KERNELBASE;
#else
        if (!crashk_res.start) {
#ifdef CONFIG_PPC64
                /*
                 * On 64bit we split the RMO in half but cap it at half of
                 * a small SLB (128MB) since the crash kernel needs to place
                 * itself and some stacks to be in the first segment.
                 */
                crashk_res.start = min(0x80000000ULL, (ppc64_rma_size / 2));
#else
                crashk_res.start = KDUMP_KERNELBASE;
#endif
        }

        crash_base = PAGE_ALIGN(crashk_res.start);
        if (crash_base != crashk_res.start) {
                printk("Crash kernel base must be aligned to 0x%lx\n",
                                PAGE_SIZE);
                crashk_res.start = crash_base;
        }

#endif
        crash_size = PAGE_ALIGN(crash_size);
        crashk_res.end = crashk_res.start + crash_size - 1;

        /* The crash region must not overlap the current kernel */
        if (overlaps_crashkernel(__pa(_stext), _end - _stext)) {
                printk(KERN_WARNING
                        "Crash kernel can not overlap current kernel\n");
                crashk_res.start = crashk_res.end = 0;
                return;
        }

        /* Crash kernel trumps memory limit */
        if (memory_limit && memory_limit <= crashk_res.end) {
                memory_limit = crashk_res.end + 1;
                printk("Adjusted memory limit for crashkernel, now 0x%llx\n",
                       memory_limit);
        }

        printk(KERN_INFO "Reserving %ldMB of memory at %ldMB "
                        "for crashkernel (System RAM: %ldMB)\n",
                        (unsigned long)(crash_size >> 20),
                        (unsigned long)(crashk_res.start >> 20),
                        (unsigned long)(memblock_phys_mem_size() >> 20));

        memblock_reserve(crashk_res.start, crash_size);
}

int overlaps_crashkernel(unsigned long start, unsigned long size)
{
        return (start + size) > crashk_res.start && start <= crashk_res.end;
}

/* Values we need to export to the second kernel via the device tree. */
static phys_addr_t kernel_end;
static phys_addr_t crashk_size;

static struct property kernel_end_prop = {
        .name = "linux,kernel-end",
        .length = sizeof(phys_addr_t),
        .value = &kernel_end,
};

static struct property crashk_base_prop = {
        .name = "linux,crashkernel-base",
        .length = sizeof(phys_addr_t),
        .value = &crashk_res.start,
};

static struct property crashk_size_prop = {
        .name = "linux,crashkernel-size",
        .length = sizeof(phys_addr_t),
        .value = &crashk_size,
};

static struct property memory_limit_prop = {
        .name = "linux,memory-limit",
        .length = sizeof(unsigned long long),
        .value = &memory_limit,
};

static void __init export_crashk_values(struct device_node *node)
{
        struct property *prop;

        /* There might be existing crash kernel properties, but we can't
         * be sure what's in them, so remove them. */
        prop = of_find_property(node, "linux,crashkernel-base", NULL);
        if (prop)
                of_remove_property(node, prop);

        prop = of_find_property(node, "linux,crashkernel-size", NULL);
        if (prop)
                of_remove_property(node, prop);

        if (crashk_res.start != 0) {
                of_add_property(node, &crashk_base_prop);
                crashk_size = resource_size(&crashk_res);
                of_add_property(node, &crashk_size_prop);
        }

        /*
         * memory_limit is required by the kexec-tools to limit the
         * crash regions to the actual memory used.
         */
        of_update_property(node, &memory_limit_prop);
}

static int __init kexec_setup(void)
{
        struct device_node *node;
        struct property *prop;

        node = of_find_node_by_path("/chosen");
        if (!node)
                return -ENOENT;

        /* remove any stale properties so ours can be found */
        prop = of_find_property(node, kernel_end_prop.name, NULL);
        if (prop)
                of_remove_property(node, prop);

        /* information needed by userspace when using default_machine_kexec */
        kernel_end = __pa(_end);
        of_add_property(node, &kernel_end_prop);

        export_crashk_values(node);

        of_node_put(node);
        return 0;
}
late_initcall(kexec_setup);