/*
 * PowerNV setup code.
 *
 * Copyright 2011 IBM Corp.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#undef DEBUG

#include <linux/cpu.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/tty.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/seq_file.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/interrupt.h>
#include <linux/bug.h>
#include <linux/pci.h>
#include <linux/cpufreq.h>

#include <asm/machdep.h>
#include <asm/firmware.h>
#include <asm/xics.h>
#include <asm/opal.h>
#include <asm/kexec.h>
#include <asm/smp.h>

#include "powernv.h"

static void __init pnv_setup_arch(void)
{
        set_arch_panic_timeout(10, ARCH_PANIC_TIMEOUT);

        /* Initialize SMP */
        pnv_smp_init();

        /* Setup PCI */
        pnv_pci_init();

        /* Setup RTC and NVRAM callbacks */
        if (firmware_has_feature(FW_FEATURE_OPAL))
                opal_nvram_init();

        /* Enable NAP mode */
        powersave_nap = 1;

        /* XXX PMCS */
}

static void __init pnv_init_early(void)
{
        /*
         * Initialize the LPC bus now so that legacy serial
         * ports can be found on it
         */
        opal_lpc_init();

#ifdef CONFIG_HVC_OPAL
        if (firmware_has_feature(FW_FEATURE_OPAL))
                hvc_opal_init_early();
        else
#endif
                add_preferred_console("hvc", 0, NULL);
}

static void __init pnv_init_IRQ(void)
{
        xics_init();

        WARN_ON(!ppc_md.get_irq);
}

static void pnv_show_cpuinfo(struct seq_file *m)
{
        struct device_node *root;
        const char *model = "";

        root = of_find_node_by_path("/");
        if (root)
                model = of_get_property(root, "model", NULL);
        seq_printf(m, "machine\t\t: PowerNV %s\n", model);
        if (firmware_has_feature(FW_FEATURE_OPALv3))
                seq_printf(m, "firmware\t: OPAL v3\n");
        else if (firmware_has_feature(FW_FEATURE_OPALv2))
                seq_printf(m, "firmware\t: OPAL v2\n");
        else if (firmware_has_feature(FW_FEATURE_OPAL))
                seq_printf(m, "firmware\t: OPAL v1\n");
        else
                seq_printf(m, "firmware\t: BML\n");
        of_node_put(root);
}

static void pnv_prepare_going_down(void)
{
        /*
         * Disable all notifiers from OPAL, we can't
         * service interrupts anymore anyway
         */
        opal_event_shutdown();

        /* Soft disable interrupts */
        local_irq_disable();

        /*
         * Return secondary CPUs to firwmare if a flash update
         * is pending otherwise we will get all sort of error
         * messages about CPU being stuck etc.. This will also
         * have the side effect of hard disabling interrupts so
         * past this point, the kernel is effectively dead.
         */
        opal_flash_term_callback();
}

static void  __noreturn pnv_restart(char *cmd)
{
        long rc = OPAL_BUSY;

        pnv_prepare_going_down();

        while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
                rc = opal_cec_reboot();
                if (rc == OPAL_BUSY_EVENT)
                        opal_poll_events(NULL);
                else
                        mdelay(10);
        }
        for (;;)
                opal_poll_events(NULL);
}

static void __noreturn pnv_power_off(void)
{
        long rc = OPAL_BUSY;

        pnv_prepare_going_down();

        while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
                rc = opal_cec_power_down(0);
                if (rc == OPAL_BUSY_EVENT)
                        opal_poll_events(NULL);
                else
                        mdelay(10);
        }
        for (;;)
                opal_poll_events(NULL);
}

static void __noreturn pnv_halt(void)
{
        pnv_power_off();
}

static void pnv_progress(char *s, unsigned short hex)
{
}

static void pnv_shutdown(void)
{
        /* Let the PCI code clear up IODA tables */
        pnv_pci_shutdown();

        /*
         * Stop OPAL activity: Unregister all OPAL interrupts so they
         * don't fire up while we kexec and make sure all potentially
         * DMA'ing ops are complete (such as dump retrieval).
         */
        opal_shutdown();
}

#ifdef CONFIG_KEXEC
static void pnv_kexec_wait_secondaries_down(void)
{
        int my_cpu, i, notified = -1;

        my_cpu = get_cpu();

        for_each_online_cpu(i) {
                uint8_t status;
                int64_t rc;

                if (i == my_cpu)
                        continue;

                for (;;) {
                        rc = opal_query_cpu_status(get_hard_smp_processor_id(i),
                                                   &status);
                        if (rc != OPAL_SUCCESS || status != OPAL_THREAD_STARTED)
                                break;
                        barrier();
                        if (i != notified) {
                                printk(KERN_INFO "kexec: waiting for cpu %d "
                                       "(physical %d) to enter OPAL\n",
                                       i, paca[i].hw_cpu_id);
                                notified = i;
                        }
                }
        }
}

static void pnv_kexec_cpu_down(int crash_shutdown, int secondary)
{
        xics_kexec_teardown_cpu(secondary);

        /* On OPAL v3, we return all CPUs to firmware */

        if (!firmware_has_feature(FW_FEATURE_OPALv3))
                return;

        if (secondary) {
                /* Return secondary CPUs to firmware on OPAL v3 */
                mb();
                get_paca()->kexec_state = KEXEC_STATE_REAL_MODE;
                mb();

                /* Return the CPU to OPAL */
                opal_return_cpu();
        } else if (crash_shutdown) {
                /*
                 * On crash, we don't wait for secondaries to go
                 * down as they might be unreachable or hung, so
                 * instead we just wait a bit and move on.
                 */
                mdelay(1);
        } else {
                /* Primary waits for the secondaries to have reached OPAL */
                pnv_kexec_wait_secondaries_down();

                /*
                 * We might be running as little-endian - now that interrupts
                 * are disabled, reset the HILE bit to big-endian so we don't
                 * take interrupts in the wrong endian later
                 */
                opal_reinit_cpus(OPAL_REINIT_CPUS_HILE_BE);
        }
}
#endif /* CONFIG_KEXEC */

#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
static unsigned long pnv_memory_block_size(void)
{
        return 256UL * 1024 * 1024;
}
#endif

static void __init pnv_setup_machdep_opal(void)
{
        ppc_md.get_boot_time = opal_get_boot_time;
        ppc_md.restart = pnv_restart;
        pm_power_off = pnv_power_off;
        ppc_md.halt = pnv_halt;
        ppc_md.machine_check_exception = opal_machine_check;
        ppc_md.mce_check_early_recovery = opal_mce_check_early_recovery;
        ppc_md.hmi_exception_early = opal_hmi_exception_early;
        ppc_md.handle_hmi_exception = opal_handle_hmi_exception;
}

static int __init pnv_probe(void)
{
        unsigned long root = of_get_flat_dt_root();

        if (!of_flat_dt_is_compatible(root, "ibm,powernv"))
                return 0;

        hpte_init_native();

        if (firmware_has_feature(FW_FEATURE_OPAL))
                pnv_setup_machdep_opal();

        pr_debug("PowerNV detected !\n");

        return 1;
}

/*
 * Returns the cpu frequency for 'cpu' in Hz. This is used by
 * /proc/cpuinfo
 */
static unsigned long pnv_get_proc_freq(unsigned int cpu)
{
        unsigned long ret_freq;

        ret_freq = cpufreq_quick_get(cpu) * 1000ul;

        /*
         * If the backend cpufreq driver does not exist,
         * then fallback to old way of reporting the clockrate.
         */
        if (!ret_freq)
                ret_freq = ppc_proc_freq;
        return ret_freq;
}

define_machine(powernv) {
        .name                   = "PowerNV",
        .probe                  = pnv_probe,
        .init_early             = pnv_init_early,
        .setup_arch             = pnv_setup_arch,
        .init_IRQ               = pnv_init_IRQ,
        .show_cpuinfo           = pnv_show_cpuinfo,
        .get_proc_freq          = pnv_get_proc_freq,
        .progress               = pnv_progress,
        .machine_shutdown       = pnv_shutdown,
        .power_save             = power7_idle,
        .calibrate_decr         = generic_calibrate_decr,
#ifdef CONFIG_KEXEC
        .kexec_cpu_down         = pnv_kexec_cpu_down,
#endif
#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
        .memory_block_size      = pnv_memory_block_size,
#endif
};