/*
 * Low-level SPU handling
 *
 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
 *
 * Author: Arnd Bergmann <arndb@de.ibm.com>
 *
 * 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, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#undef DEBUG

#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/wait.h>
#include <linux/mm.h>
#include <linux/io.h>
#include <linux/mutex.h>
#include <linux/linux_logo.h>
#include <asm/spu.h>
#include <asm/spu_priv1.h>
#include <asm/xmon.h>
#include <asm/prom.h>

const struct spu_management_ops *spu_management_ops;
EXPORT_SYMBOL_GPL(spu_management_ops);

const struct spu_priv1_ops *spu_priv1_ops;
EXPORT_SYMBOL_GPL(spu_priv1_ops);

struct cbe_spu_info cbe_spu_info[MAX_NUMNODES];
EXPORT_SYMBOL_GPL(cbe_spu_info);

/*
 * Protects cbe_spu_info and spu->number.
 */
static DEFINE_SPINLOCK(spu_lock);

/*
 * List of all spus in the system.
 *
 * This list is iterated by callers from irq context and callers that
 * want to sleep.  Thus modifications need to be done with both
 * spu_full_list_lock and spu_full_list_mutex held, while iterating
 * through it requires either of these locks.
 *
 * In addition spu_full_list_lock protects all assignmens to
 * spu->mm.
 */
static LIST_HEAD(spu_full_list);
static DEFINE_SPINLOCK(spu_full_list_lock);
static DEFINE_MUTEX(spu_full_list_mutex);

void spu_invalidate_slbs(struct spu *spu)
{
        struct spu_priv2 __iomem *priv2 = spu->priv2;

        if (spu_mfc_sr1_get(spu) & MFC_STATE1_RELOCATE_MASK)
                out_be64(&priv2->slb_invalidate_all_W, 0UL);
}
EXPORT_SYMBOL_GPL(spu_invalidate_slbs);

/* This is called by the MM core when a segment size is changed, to
 * request a flush of all the SPEs using a given mm
 */
void spu_flush_all_slbs(struct mm_struct *mm)
{
        struct spu *spu;
        unsigned long flags;

        spin_lock_irqsave(&spu_full_list_lock, flags);
        list_for_each_entry(spu, &spu_full_list, full_list) {
                if (spu->mm == mm)
                        spu_invalidate_slbs(spu);
        }
        spin_unlock_irqrestore(&spu_full_list_lock, flags);
}

/* The hack below stinks... try to do something better one of
 * these days... Does it even work properly with NR_CPUS == 1 ?
 */
static inline void mm_needs_global_tlbie(struct mm_struct *mm)
{
        int nr = (NR_CPUS > 1) ? NR_CPUS : NR_CPUS + 1;

        /* Global TLBIE broadcast required with SPEs. */
        __cpus_setall(&mm->cpu_vm_mask, nr);
}

void spu_associate_mm(struct spu *spu, struct mm_struct *mm)
{
        unsigned long flags;

        spin_lock_irqsave(&spu_full_list_lock, flags);
        spu->mm = mm;
        spin_unlock_irqrestore(&spu_full_list_lock, flags);
        if (mm)
                mm_needs_global_tlbie(mm);
}
EXPORT_SYMBOL_GPL(spu_associate_mm);

static int __spu_trap_invalid_dma(struct spu *spu)
{
        pr_debug("%s\n", __FUNCTION__);
        spu->dma_callback(spu, SPE_EVENT_INVALID_DMA);
        return 0;
}

static int __spu_trap_dma_align(struct spu *spu)
{
        pr_debug("%s\n", __FUNCTION__);
        spu->dma_callback(spu, SPE_EVENT_DMA_ALIGNMENT);
        return 0;
}

static int __spu_trap_error(struct spu *spu)
{
        pr_debug("%s\n", __FUNCTION__);
        spu->dma_callback(spu, SPE_EVENT_SPE_ERROR);
        return 0;
}

static void spu_restart_dma(struct spu *spu)
{
        struct spu_priv2 __iomem *priv2 = spu->priv2;

        if (!test_bit(SPU_CONTEXT_SWITCH_PENDING, &spu->flags))
                out_be64(&priv2->mfc_control_RW, MFC_CNTL_RESTART_DMA_COMMAND);
}

static int __spu_trap_data_seg(struct spu *spu, unsigned long ea)
{
        struct spu_priv2 __iomem *priv2 = spu->priv2;
        struct mm_struct *mm = spu->mm;
        u64 esid, vsid, llp;
        int psize;

        pr_debug("%s\n", __FUNCTION__);

        if (test_bit(SPU_CONTEXT_SWITCH_ACTIVE, &spu->flags)) {
                /* SLBs are pre-loaded for context switch, so
                 * we should never get here!
                 */
                printk("%s: invalid access during switch!\n", __func__);
                return 1;
        }
        esid = (ea & ESID_MASK) | SLB_ESID_V;

        switch(REGION_ID(ea)) {
        case USER_REGION_ID:
#ifdef CONFIG_PPC_MM_SLICES
                psize = get_slice_psize(mm, ea);
#else
                psize = mm->context.user_psize;
#endif
                vsid = (get_vsid(mm->context.id, ea, MMU_SEGSIZE_256M) << SLB_VSID_SHIFT) |
                                SLB_VSID_USER;
                break;
        case VMALLOC_REGION_ID:
                if (ea < VMALLOC_END)
                        psize = mmu_vmalloc_psize;
                else
                        psize = mmu_io_psize;
                vsid = (get_kernel_vsid(ea, MMU_SEGSIZE_256M) << SLB_VSID_SHIFT) |
                        SLB_VSID_KERNEL;
                break;
        case KERNEL_REGION_ID:
                psize = mmu_linear_psize;
                vsid = (get_kernel_vsid(ea, MMU_SEGSIZE_256M) << SLB_VSID_SHIFT) |
                        SLB_VSID_KERNEL;
                break;
        default:
                /* Future: support kernel segments so that drivers
                 * can use SPUs.
                 */
                pr_debug("invalid region access at %016lx\n", ea);
                return 1;
        }
        llp = mmu_psize_defs[psize].sllp;

        out_be64(&priv2->slb_index_W, spu->slb_replace);
        out_be64(&priv2->slb_vsid_RW, vsid | llp);
        out_be64(&priv2->slb_esid_RW, esid);

        spu->slb_replace++;
        if (spu->slb_replace >= 8)
                spu->slb_replace = 0;

        spu_restart_dma(spu);
        spu->stats.slb_flt++;
        return 0;
}

extern int hash_page(unsigned long ea, unsigned long access, unsigned long trap); //XXX
static int __spu_trap_data_map(struct spu *spu, unsigned long ea, u64 dsisr)
{
        pr_debug("%s, %lx, %lx\n", __FUNCTION__, dsisr, ea);

        /* Handle kernel space hash faults immediately.
           User hash faults need to be deferred to process context. */
        if ((dsisr & MFC_DSISR_PTE_NOT_FOUND)
            && REGION_ID(ea) != USER_REGION_ID
            && hash_page(ea, _PAGE_PRESENT, 0x300) == 0) {
                spu_restart_dma(spu);
                return 0;
        }

        if (test_bit(SPU_CONTEXT_SWITCH_ACTIVE, &spu->flags)) {
                printk("%s: invalid access during switch!\n", __func__);
                return 1;
        }

        spu->dar = ea;
        spu->dsisr = dsisr;
        mb();
        spu->stop_callback(spu);
        return 0;
}

static irqreturn_t
spu_irq_class_0(int irq, void *data)
{
        struct spu *spu;
        unsigned long stat, mask;

        spu = data;

        mask = spu_int_mask_get(spu, 0);
        stat = spu_int_stat_get(spu, 0);
        stat &= mask;

        spin_lock(&spu->register_lock);
        spu->class_0_pending |= stat;
        spin_unlock(&spu->register_lock);

        spu->stop_callback(spu);

        spu_int_stat_clear(spu, 0, stat);

        return IRQ_HANDLED;
}

int
spu_irq_class_0_bottom(struct spu *spu)
{
        unsigned long flags;
        unsigned long stat;

        spin_lock_irqsave(&spu->register_lock, flags);
        stat = spu->class_0_pending;
        spu->class_0_pending = 0;

        if (stat & 1) /* invalid DMA alignment */
                __spu_trap_dma_align(spu);

        if (stat & 2) /* invalid MFC DMA */
                __spu_trap_invalid_dma(spu);

        if (stat & 4) /* error on SPU */
                __spu_trap_error(spu);

        spin_unlock_irqrestore(&spu->register_lock, flags);

        return (stat & 0x7) ? -EIO : 0;
}
EXPORT_SYMBOL_GPL(spu_irq_class_0_bottom);

static irqreturn_t
spu_irq_class_1(int irq, void *data)
{
        struct spu *spu;
        unsigned long stat, mask, dar, dsisr;

        spu = data;

        /* atomically read & clear class1 status. */
        spin_lock(&spu->register_lock);
        mask  = spu_int_mask_get(spu, 1);
        stat  = spu_int_stat_get(spu, 1) & mask;
        dar   = spu_mfc_dar_get(spu);
        dsisr = spu_mfc_dsisr_get(spu);
        if (stat & 2) /* mapping fault */
                spu_mfc_dsisr_set(spu, 0ul);
        spu_int_stat_clear(spu, 1, stat);
        spin_unlock(&spu->register_lock);
        pr_debug("%s: %lx %lx %lx %lx\n", __FUNCTION__, mask, stat,
                        dar, dsisr);

        if (stat & 1) /* segment fault */
                __spu_trap_data_seg(spu, dar);

        if (stat & 2) { /* mapping fault */
                __spu_trap_data_map(spu, dar, dsisr);
        }

        if (stat & 4) /* ls compare & suspend on get */
                ;

        if (stat & 8) /* ls compare & suspend on put */
                ;

        return stat ? IRQ_HANDLED : IRQ_NONE;
}

static irqreturn_t
spu_irq_class_2(int irq, void *data)
{
        struct spu *spu;
        unsigned long stat;
        unsigned long mask;

        spu = data;
        spin_lock(&spu->register_lock);
        stat = spu_int_stat_get(spu, 2);
        mask = spu_int_mask_get(spu, 2);
        /* ignore interrupts we're not waiting for */
        stat &= mask;
        /*
         * mailbox interrupts (0x1 and 0x10) are level triggered.
         * mask them now before acknowledging.
         */
        if (stat & 0x11)
                spu_int_mask_and(spu, 2, ~(stat & 0x11));
        /* acknowledge all interrupts before the callbacks */
        spu_int_stat_clear(spu, 2, stat);
        spin_unlock(&spu->register_lock);

        pr_debug("class 2 interrupt %d, %lx, %lx\n", irq, stat, mask);

        if (stat & 1)  /* PPC core mailbox */
                spu->ibox_callback(spu);

        if (stat & 2) /* SPU stop-and-signal */
                spu->stop_callback(spu);

        if (stat & 4) /* SPU halted */
                spu->stop_callback(spu);

        if (stat & 8) /* DMA tag group complete */
                spu->mfc_callback(spu);

        if (stat & 0x10) /* SPU mailbox threshold */
                spu->wbox_callback(spu);

        spu->stats.class2_intr++;
        return stat ? IRQ_HANDLED : IRQ_NONE;
}

static int spu_request_irqs(struct spu *spu)
{
        int ret = 0;

        if (spu->irqs[0] != NO_IRQ) {
                snprintf(spu->irq_c0, sizeof (spu->irq_c0), "spe%02d.0",
                         spu->number);
                ret = request_irq(spu->irqs[0], spu_irq_class_0,
                                  IRQF_DISABLED,
                                  spu->irq_c0, spu);
                if (ret)
                        goto bail0;
        }
        if (spu->irqs[1] != NO_IRQ) {
                snprintf(spu->irq_c1, sizeof (spu->irq_c1), "spe%02d.1",
                         spu->number);
                ret = request_irq(spu->irqs[1], spu_irq_class_1,
                                  IRQF_DISABLED,
                                  spu->irq_c1, spu);
                if (ret)
                        goto bail1;
        }
        if (spu->irqs[2] != NO_IRQ) {
                snprintf(spu->irq_c2, sizeof (spu->irq_c2), "spe%02d.2",
                         spu->number);
                ret = request_irq(spu->irqs[2], spu_irq_class_2,
                                  IRQF_DISABLED,
                                  spu->irq_c2, spu);
                if (ret)
                        goto bail2;
        }
        return 0;

bail2:
        if (spu->irqs[1] != NO_IRQ)
                free_irq(spu->irqs[1], spu);
bail1:
        if (spu->irqs[0] != NO_IRQ)
                free_irq(spu->irqs[0], spu);
bail0:
        return ret;
}

static void spu_free_irqs(struct spu *spu)
{
        if (spu->irqs[0] != NO_IRQ)
                free_irq(spu->irqs[0], spu);
        if (spu->irqs[1] != NO_IRQ)
                free_irq(spu->irqs[1], spu);
        if (spu->irqs[2] != NO_IRQ)
                free_irq(spu->irqs[2], spu);
}

void spu_init_channels(struct spu *spu)
{
        static const struct {
                 unsigned channel;
                 unsigned count;
        } zero_list[] = {
                { 0x00, 1, }, { 0x01, 1, }, { 0x03, 1, }, { 0x04, 1, },
                { 0x18, 1, }, { 0x19, 1, }, { 0x1b, 1, }, { 0x1d, 1, },
        }, count_list[] = {
                { 0x00, 0, }, { 0x03, 0, }, { 0x04, 0, }, { 0x15, 16, },
                { 0x17, 1, }, { 0x18, 0, }, { 0x19, 0, }, { 0x1b, 0, },
                { 0x1c, 1, }, { 0x1d, 0, }, { 0x1e, 1, },
        };
        struct spu_priv2 __iomem *priv2;
        int i;

        priv2 = spu->priv2;

        /* initialize all channel data to zero */
        for (i = 0; i < ARRAY_SIZE(zero_list); i++) {
                int count;

                out_be64(&priv2->spu_chnlcntptr_RW, zero_list[i].channel);
                for (count = 0; count < zero_list[i].count; count++)
                        out_be64(&priv2->spu_chnldata_RW, 0);
        }

        /* initialize channel counts to meaningful values */
        for (i = 0; i < ARRAY_SIZE(count_list); i++) {
                out_be64(&priv2->spu_chnlcntptr_RW, count_list[i].channel);
                out_be64(&priv2->spu_chnlcnt_RW, count_list[i].count);
        }
}
EXPORT_SYMBOL_GPL(spu_init_channels);

static int spu_shutdown(struct sys_device *sysdev)
{
        struct spu *spu = container_of(sysdev, struct spu, sysdev);

        spu_free_irqs(spu);
        spu_destroy_spu(spu);
        return 0;
}

static struct sysdev_class spu_sysdev_class = {
        set_kset_name("spu"),
        .shutdown = spu_shutdown,
};

int spu_add_sysdev_attr(struct sysdev_attribute *attr)
{
        struct spu *spu;

        mutex_lock(&spu_full_list_mutex);
        list_for_each_entry(spu, &spu_full_list, full_list)
                sysdev_create_file(&spu->sysdev, attr);
        mutex_unlock(&spu_full_list_mutex);

        return 0;
}
EXPORT_SYMBOL_GPL(spu_add_sysdev_attr);

int spu_add_sysdev_attr_group(struct attribute_group *attrs)
{
        struct spu *spu;

        mutex_lock(&spu_full_list_mutex);
        list_for_each_entry(spu, &spu_full_list, full_list)
                sysfs_create_group(&spu->sysdev.kobj, attrs);
        mutex_unlock(&spu_full_list_mutex);

        return 0;
}
EXPORT_SYMBOL_GPL(spu_add_sysdev_attr_group);


void spu_remove_sysdev_attr(struct sysdev_attribute *attr)
{
        struct spu *spu;

        mutex_lock(&spu_full_list_mutex);
        list_for_each_entry(spu, &spu_full_list, full_list)
                sysdev_remove_file(&spu->sysdev, attr);
        mutex_unlock(&spu_full_list_mutex);
}
EXPORT_SYMBOL_GPL(spu_remove_sysdev_attr);

void spu_remove_sysdev_attr_group(struct attribute_group *attrs)
{
        struct spu *spu;

        mutex_lock(&spu_full_list_mutex);
        list_for_each_entry(spu, &spu_full_list, full_list)
                sysfs_remove_group(&spu->sysdev.kobj, attrs);
        mutex_unlock(&spu_full_list_mutex);
}
EXPORT_SYMBOL_GPL(spu_remove_sysdev_attr_group);

static int spu_create_sysdev(struct spu *spu)
{
        int ret;

        spu->sysdev.id = spu->number;
        spu->sysdev.cls = &spu_sysdev_class;
        ret = sysdev_register(&spu->sysdev);
        if (ret) {
                printk(KERN_ERR "Can't register SPU %d with sysfs\n",
                                spu->number);
                return ret;
        }

        sysfs_add_device_to_node(&spu->sysdev, spu->node);

        return 0;
}

static int __init create_spu(void *data)
{
        struct spu *spu;
        int ret;
        static int number;
        unsigned long flags;
        struct timespec ts;

        ret = -ENOMEM;
        spu = kzalloc(sizeof (*spu), GFP_KERNEL);
        if (!spu)
                goto out;

        spu->alloc_state = SPU_FREE;

        spin_lock_init(&spu->register_lock);
        spin_lock(&spu_lock);
        spu->number = number++;
        spin_unlock(&spu_lock);

        ret = spu_create_spu(spu, data);

        if (ret)
                goto out_free;

        spu_mfc_sdr_setup(spu);
        spu_mfc_sr1_set(spu, 0x33);
        ret = spu_request_irqs(spu);
        if (ret)
                goto out_destroy;

        ret = spu_create_sysdev(spu);
        if (ret)
                goto out_free_irqs;

        mutex_lock(&cbe_spu_info[spu->node].list_mutex);
        list_add(&spu->cbe_list, &cbe_spu_info[spu->node].spus);
        cbe_spu_info[spu->node].n_spus++;
        mutex_unlock(&cbe_spu_info[spu->node].list_mutex);

        mutex_lock(&spu_full_list_mutex);
        spin_lock_irqsave(&spu_full_list_lock, flags);
        list_add(&spu->full_list, &spu_full_list);
        spin_unlock_irqrestore(&spu_full_list_lock, flags);
        mutex_unlock(&spu_full_list_mutex);

        spu->stats.util_state = SPU_UTIL_IDLE_LOADED;
        ktime_get_ts(&ts);
        spu->stats.tstamp = timespec_to_ns(&ts);

        INIT_LIST_HEAD(&spu->aff_list);

        goto out;

out_free_irqs:
        spu_free_irqs(spu);
out_destroy:
        spu_destroy_spu(spu);
out_free:
        kfree(spu);
out:
        return ret;
}

static const char *spu_state_names[] = {
        "user", "system", "iowait", "idle"
};

static unsigned long long spu_acct_time(struct spu *spu,
                enum spu_utilization_state state)
{
        struct timespec ts;
        unsigned long long time = spu->stats.times[state];

        /*
         * If the spu is idle or the context is stopped, utilization
         * statistics are not updated.  Apply the time delta from the
         * last recorded state of the spu.
         */
        if (spu->stats.util_state == state) {
                ktime_get_ts(&ts);
                time += timespec_to_ns(&ts) - spu->stats.tstamp;
        }

        return time / NSEC_PER_MSEC;
}


static ssize_t spu_stat_show(struct sys_device *sysdev, char *buf)
{
        struct spu *spu = container_of(sysdev, struct spu, sysdev);

        return sprintf(buf, "%s %llu %llu %llu %llu "
                      "%llu %llu %llu %llu %llu %llu %llu %llu\n",
                spu_state_names[spu->stats.util_state],
                spu_acct_time(spu, SPU_UTIL_USER),
                spu_acct_time(spu, SPU_UTIL_SYSTEM),
                spu_acct_time(spu, SPU_UTIL_IOWAIT),
                spu_acct_time(spu, SPU_UTIL_IDLE_LOADED),
                spu->stats.vol_ctx_switch,
                spu->stats.invol_ctx_switch,
                spu->stats.slb_flt,
                spu->stats.hash_flt,
                spu->stats.min_flt,
                spu->stats.maj_flt,
                spu->stats.class2_intr,
                spu->stats.libassist);
}

static SYSDEV_ATTR(stat, 0644, spu_stat_show, NULL);

static int __init init_spu_base(void)
{
        int i, ret = 0;

        for (i = 0; i < MAX_NUMNODES; i++) {
                mutex_init(&cbe_spu_info[i].list_mutex);
                INIT_LIST_HEAD(&cbe_spu_info[i].spus);
        }

        if (!spu_management_ops)
                goto out;

        /* create sysdev class for spus */
        ret = sysdev_class_register(&spu_sysdev_class);
        if (ret)
                goto out;

        ret = spu_enumerate_spus(create_spu);

        if (ret < 0) {
                printk(KERN_WARNING "%s: Error initializing spus\n",
                        __FUNCTION__);
                goto out_unregister_sysdev_class;
        }

        if (ret > 0) {
                /*
                 * We cannot put the forward declaration in
                 * <linux/linux_logo.h> because of conflicting session type
                 * conflicts for const and __initdata with different compiler
                 * versions
                 */
                extern const struct linux_logo logo_spe_clut224;

                fb_append_extra_logo(&logo_spe_clut224, ret);
        }

        mutex_lock(&spu_full_list_mutex);
        xmon_register_spus(&spu_full_list);
        crash_register_spus(&spu_full_list);
        mutex_unlock(&spu_full_list_mutex);
        spu_add_sysdev_attr(&attr_stat);

        spu_init_affinity();

        return 0;

 out_unregister_sysdev_class:
        sysdev_class_unregister(&spu_sysdev_class);
 out:
        return ret;
}
module_init(init_spu_base);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>");