/*
 * 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/xive.h>
#include <asm/opal.h>
#include <asm/kexec.h>
#include <asm/smp.h>
#include <asm/tm.h>
#include <asm/setup.h>
#include <asm/security_features.h>

#include "powernv.h"


static bool fw_feature_is(const char *state, const char *name,
                          struct device_node *fw_features)
{
        struct device_node *np;
        bool rc = false;

        np = of_get_child_by_name(fw_features, name);
        if (np) {
                rc = of_property_read_bool(np, state);
                of_node_put(np);
        }

        return rc;
}

static void init_fw_feat_flags(struct device_node *np)
{
        if (fw_feature_is("enabled", "inst-spec-barrier-ori31,31,0", np))
                security_ftr_set(SEC_FTR_SPEC_BAR_ORI31);

        if (fw_feature_is("enabled", "fw-bcctrl-serialized", np))
                security_ftr_set(SEC_FTR_BCCTRL_SERIALISED);

        if (fw_feature_is("enabled", "inst-l1d-flush-ori30,30,0", np))
                security_ftr_set(SEC_FTR_L1D_FLUSH_ORI30);

        if (fw_feature_is("enabled", "inst-l1d-flush-trig2", np))
                security_ftr_set(SEC_FTR_L1D_FLUSH_TRIG2);

        if (fw_feature_is("enabled", "fw-l1d-thread-split", np))
                security_ftr_set(SEC_FTR_L1D_THREAD_PRIV);

        if (fw_feature_is("enabled", "fw-count-cache-disabled", np))
                security_ftr_set(SEC_FTR_COUNT_CACHE_DISABLED);

        if (fw_feature_is("enabled", "fw-count-cache-flush-bcctr2,0,0", np))
                security_ftr_set(SEC_FTR_BCCTR_FLUSH_ASSIST);

        if (fw_feature_is("enabled", "needs-count-cache-flush-on-context-switch", np))
                security_ftr_set(SEC_FTR_FLUSH_COUNT_CACHE);

        /*
         * The features below are enabled by default, so we instead look to see
         * if firmware has *disabled* them, and clear them if so.
         */
        if (fw_feature_is("disabled", "speculation-policy-favor-security", np))
                security_ftr_clear(SEC_FTR_FAVOUR_SECURITY);

        if (fw_feature_is("disabled", "needs-l1d-flush-msr-pr-0-to-1", np))
                security_ftr_clear(SEC_FTR_L1D_FLUSH_PR);

        if (fw_feature_is("disabled", "needs-l1d-flush-msr-hv-1-to-0", np))
                security_ftr_clear(SEC_FTR_L1D_FLUSH_HV);

        if (fw_feature_is("disabled", "needs-spec-barrier-for-bound-checks", np))
                security_ftr_clear(SEC_FTR_BNDS_CHK_SPEC_BAR);
}

static void pnv_setup_rfi_flush(void)
{
        struct device_node *np, *fw_features;
        enum l1d_flush_type type;
        bool enable;

        /* Default to fallback in case fw-features are not available */
        type = L1D_FLUSH_FALLBACK;

        np = of_find_node_by_name(NULL, "ibm,opal");
        fw_features = of_get_child_by_name(np, "fw-features");
        of_node_put(np);

        if (fw_features) {
                init_fw_feat_flags(fw_features);
                of_node_put(fw_features);

                if (security_ftr_enabled(SEC_FTR_L1D_FLUSH_TRIG2))
                        type = L1D_FLUSH_MTTRIG;

                if (security_ftr_enabled(SEC_FTR_L1D_FLUSH_ORI30))
                        type = L1D_FLUSH_ORI;
        }

        /*
         * The issues addressed by the entry and uaccess flush don't affect P7
         * or P8, so on bare metal disable them explicitly in case firmware does
         * not include the features to disable them. POWER9 and newer processors
         * should have the appropriate firmware flags.
         */
        if (pvr_version_is(PVR_POWER7) || pvr_version_is(PVR_POWER7p) ||
            pvr_version_is(PVR_POWER8E) || pvr_version_is(PVR_POWER8NVL) ||
            pvr_version_is(PVR_POWER8)) {
                security_ftr_clear(SEC_FTR_L1D_FLUSH_ENTRY);
                security_ftr_clear(SEC_FTR_L1D_FLUSH_UACCESS);
        }

        enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) && \
                 (security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR)   || \
                  security_ftr_enabled(SEC_FTR_L1D_FLUSH_HV));

        setup_rfi_flush(type, enable);
        setup_count_cache_flush();

        enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
                 security_ftr_enabled(SEC_FTR_L1D_FLUSH_ENTRY);
        setup_entry_flush(enable);

        enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
                 security_ftr_enabled(SEC_FTR_L1D_FLUSH_UACCESS);
        setup_uaccess_flush(enable);
}

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

        pnv_setup_rfi_flush();
        setup_stf_barrier();

        /* Initialize SMP */
        pnv_smp_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(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)
{
        /* Try using a XIVE if available, otherwise use a XICS */
        if (!xive_native_init())
                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_OPAL))
                seq_printf(m, "firmware\t: OPAL\n");
        else
                seq_printf(m, "firmware\t: BML\n");
        of_node_put(root);
        if (radix_enabled())
                seq_printf(m, "MMU\t\t: Radix\n");
        else
                seq_printf(m, "MMU\t\t: Hash\n");
}

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

        /* Print flash update message if one is scheduled. */
        opal_flash_update_print_message();

        smp_send_stop();

        hard_irq_disable();
}

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

        pnv_prepare_going_down();

        do {
                if (!cmd)
                        rc = opal_cec_reboot();
                else if (strcmp(cmd, "full") == 0)
                        rc = opal_cec_reboot2(OPAL_REBOOT_FULL_IPL, NULL);
                else
                        rc = OPAL_UNSUPPORTED;

                if (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
                        /* Opal is busy wait for some time and retry */
                        opal_poll_events(NULL);
                        mdelay(10);

                } else  if (cmd && rc) {
                        /* Unknown error while issuing reboot */
                        if (rc == OPAL_UNSUPPORTED)
                                pr_err("Unsupported '%s' reboot.\n", cmd);
                        else
                                pr_err("Unable to issue '%s' reboot. Err=%ld\n",
                                       cmd, rc);
                        pr_info("Forcing a cec-reboot\n");
                        cmd = NULL;
                        rc = OPAL_BUSY;

                } else if (rc != OPAL_SUCCESS) {
                        /* Unknown error while issuing cec-reboot */
                        pr_err("Unable to reboot. Err=%ld\n", rc);
                }

        } while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT);

        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_CORE
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, timeout = 1000;

                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_ptrs[i]->hw_cpu_id);
                                notified = i;
                        }

                        /*
                         * On crash secondaries might be unreachable or hung,
                         * so timeout if we've waited too long
                         * */
                        mdelay(1);
                        if (timeout-- == 0) {
                                printk(KERN_ERR "kexec: timed out waiting for "
                                       "cpu %d (physical %d) to enter OPAL\n",
                                       i, paca_ptrs[i]->hw_cpu_id);
                                break;
                        }
                }
        }
}

static void pnv_kexec_cpu_down(int crash_shutdown, int secondary)
{
        u64 reinit_flags;

        if (xive_enabled())
                xive_kexec_teardown_cpu(secondary);
        else
                xics_kexec_teardown_cpu(secondary);

        /* On OPAL, we return all CPUs to firmware */
        if (!firmware_has_feature(FW_FEATURE_OPAL))
                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 {
                /* Primary waits for the secondaries to have reached OPAL */
                pnv_kexec_wait_secondaries_down();

                /* Switch XIVE back to emulation mode */
                if (xive_enabled())
                        xive_shutdown();

                /*
                 * 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
                 *
                 * We reinit to enable both radix and hash on P9 to ensure
                 * the mode used by the next kernel is always supported.
                 */
                reinit_flags = OPAL_REINIT_CPUS_HILE_BE;
                if (cpu_has_feature(CPU_FTR_ARCH_300))
                        reinit_flags |= OPAL_REINIT_CPUS_MMU_RADIX |
                                OPAL_REINIT_CPUS_MMU_HASH;
                opal_reinit_cpus(reinit_flags);
        }
}
#endif /* CONFIG_KEXEC_CORE */

#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
static unsigned long pnv_memory_block_size(void)
{
        /*
         * We map the kernel linear region with 1GB large pages on radix. For
         * memory hot unplug to work our memory block size must be at least
         * this size.
         */
        if (radix_enabled())
                return radix_mem_block_size;
        else
                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.system_reset_exception gets filled in by pnv_smp_init() */
        ppc_md.machine_check_exception = opal_machine_check;
        ppc_md.mce_check_early_recovery = opal_mce_check_early_recovery;
        if (opal_check_token(OPAL_HANDLE_HMI2))
                ppc_md.hmi_exception_early = opal_hmi_exception_early2;
        else
                ppc_md.hmi_exception_early = opal_hmi_exception_early;
        ppc_md.handle_hmi_exception = opal_handle_hmi_exception;
}

static int __init pnv_probe(void)
{
        if (!of_machine_is_compatible("ibm,powernv"))
                return 0;

        if (firmware_has_feature(FW_FEATURE_OPAL))
                pnv_setup_machdep_opal();

        pr_debug("PowerNV detected !\n");

        pnv_init();

        return 1;
}

#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
void __init pnv_tm_init(void)
{
        if (!firmware_has_feature(FW_FEATURE_OPAL) ||
            !pvr_version_is(PVR_POWER9) ||
            early_cpu_has_feature(CPU_FTR_TM))
                return;

        if (opal_reinit_cpus(OPAL_REINIT_CPUS_TM_SUSPEND_DISABLED) != OPAL_SUCCESS)
                return;

        pr_info("Enabling TM (Transactional Memory) with Suspend Disabled\n");
        cur_cpu_spec->cpu_features |= CPU_FTR_TM;
        /* Make sure "normal" HTM is off (it should be) */
        cur_cpu_spec->cpu_user_features2 &= ~PPC_FEATURE2_HTM;
        /* Turn on no suspend mode, and HTM no SC */
        cur_cpu_spec->cpu_user_features2 |= PPC_FEATURE2_HTM_NO_SUSPEND | \
                                            PPC_FEATURE2_HTM_NOSC;
        tm_suspend_disabled = true;
}
#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */

/*
 * 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_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;
}

static long pnv_machine_check_early(struct pt_regs *regs)
{
        long handled = 0;

        if (cur_cpu_spec && cur_cpu_spec->machine_check_early)
                handled = cur_cpu_spec->machine_check_early(regs);

        return handled;
}

define_machine(powernv) {
        .name                   = "PowerNV",
        .probe                  = pnv_probe,
        .setup_arch             = pnv_setup_arch,
        .init_IRQ               = pnv_init_IRQ,
        .show_cpuinfo           = pnv_show_cpuinfo,
        .get_proc_freq          = pnv_get_proc_freq,
        .discover_phbs          = pnv_pci_init,
        .progress               = pnv_progress,
        .machine_shutdown       = pnv_shutdown,
        .power_save             = NULL,
        .calibrate_decr         = generic_calibrate_decr,
        .machine_check_early    = pnv_machine_check_early,
#ifdef CONFIG_KEXEC_CORE
        .kexec_cpu_down         = pnv_kexec_cpu_down,
#endif
#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
        .memory_block_size      = pnv_memory_block_size,
#endif
};