spi-topcliff-pch: supports a spi mode setup and bit order setup by IO control

[zen-stable.git] / arch / c6x / kernel / irq.c

/*
 *  Copyright (C) 2011 Texas Instruments Incorporated
 *
 *  This borrows heavily from powerpc version, which is:
 *
 *  Derived from arch/i386/kernel/irq.c
 *    Copyright (C) 1992 Linus Torvalds
 *  Adapted from arch/i386 by Gary Thomas
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *  Updated and modified by Cort Dougan <cort@fsmlabs.com>
 *    Copyright (C) 1996-2001 Cort Dougan
 *  Adapted for Power Macintosh by Paul Mackerras
 *    Copyright (C) 1996 Paul Mackerras (paulus@cs.anu.edu.au)
 *
 * 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.
 */
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/radix-tree.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>

#include <asm/megamod-pic.h>

unsigned long irq_err_count;

static DEFINE_RAW_SPINLOCK(core_irq_lock);

static void mask_core_irq(struct irq_data *data)
{
        unsigned int prio = data->irq;

        BUG_ON(prio < 4 || prio >= NR_PRIORITY_IRQS);

        raw_spin_lock(&core_irq_lock);
        and_creg(IER, ~(1 << prio));
        raw_spin_unlock(&core_irq_lock);
}

static void unmask_core_irq(struct irq_data *data)
{
        unsigned int prio = data->irq;

        raw_spin_lock(&core_irq_lock);
        or_creg(IER, 1 << prio);
        raw_spin_unlock(&core_irq_lock);
}

static struct irq_chip core_chip = {
        .name           = "core",
        .irq_mask       = mask_core_irq,
        .irq_unmask     = unmask_core_irq,
};

asmlinkage void c6x_do_IRQ(unsigned int prio, struct pt_regs *regs)
{
        struct pt_regs *old_regs = set_irq_regs(regs);

        irq_enter();

        BUG_ON(prio < 4 || prio >= NR_PRIORITY_IRQS);

        generic_handle_irq(prio);

        irq_exit();

        set_irq_regs(old_regs);
}

static struct irq_host *core_host;

static int core_host_map(struct irq_host *h, unsigned int virq,
                         irq_hw_number_t hw)
{
        if (hw < 4 || hw >= NR_PRIORITY_IRQS)
                return -EINVAL;

        irq_set_status_flags(virq, IRQ_LEVEL);
        irq_set_chip_and_handler(virq, &core_chip, handle_level_irq);
        return 0;
}

static struct irq_host_ops core_host_ops = {
        .map = core_host_map,
};

void __init init_IRQ(void)
{
        struct device_node *np;

        /* Mask all priority IRQs */
        and_creg(IER, ~0xfff0);

        np = of_find_compatible_node(NULL, NULL, "ti,c64x+core-pic");
        if (np != NULL) {
                /* create the core host */
                core_host = irq_alloc_host(np, IRQ_HOST_MAP_PRIORITY, 0,
                                           &core_host_ops, 0);
                if (core_host)
                        irq_set_default_host(core_host);
                of_node_put(np);
        }

        printk(KERN_INFO "Core interrupt controller initialized\n");

        /* now we're ready for other SoC controllers */
        megamod_pic_init();

        /* Clear all general IRQ flags */
        set_creg(ICR, 0xfff0);
}

void ack_bad_irq(int irq)
{
        printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq);
        irq_err_count++;
}

int arch_show_interrupts(struct seq_file *p, int prec)
{
        seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count);
        return 0;
}

/*
 * IRQ controller and virtual interrupts
 */

/* The main irq map itself is an array of NR_IRQ entries containing the
 * associate host and irq number. An entry with a host of NULL is free.
 * An entry can be allocated if it's free, the allocator always then sets
 * hwirq first to the host's invalid irq number and then fills ops.
 */
struct irq_map_entry {
        irq_hw_number_t hwirq;
        struct irq_host *host;
};

static LIST_HEAD(irq_hosts);
static DEFINE_RAW_SPINLOCK(irq_big_lock);
static DEFINE_MUTEX(revmap_trees_mutex);
static struct irq_map_entry irq_map[NR_IRQS];
static unsigned int irq_virq_count = NR_IRQS;
static struct irq_host *irq_default_host;

irq_hw_number_t irqd_to_hwirq(struct irq_data *d)
{
        return irq_map[d->irq].hwirq;
}
EXPORT_SYMBOL_GPL(irqd_to_hwirq);

irq_hw_number_t virq_to_hw(unsigned int virq)
{
        return irq_map[virq].hwirq;
}
EXPORT_SYMBOL_GPL(virq_to_hw);

bool virq_is_host(unsigned int virq, struct irq_host *host)
{
        return irq_map[virq].host == host;
}
EXPORT_SYMBOL_GPL(virq_is_host);

static int default_irq_host_match(struct irq_host *h, struct device_node *np)
{
        return h->of_node != NULL && h->of_node == np;
}

struct irq_host *irq_alloc_host(struct device_node *of_node,
                                unsigned int revmap_type,
                                unsigned int revmap_arg,
                                struct irq_host_ops *ops,
                                irq_hw_number_t inval_irq)
{
        struct irq_host *host;
        unsigned int size = sizeof(struct irq_host);
        unsigned int i;
        unsigned int *rmap;
        unsigned long flags;

        /* Allocate structure and revmap table if using linear mapping */
        if (revmap_type == IRQ_HOST_MAP_LINEAR)
                size += revmap_arg * sizeof(unsigned int);
        host = kzalloc(size, GFP_KERNEL);
        if (host == NULL)
                return NULL;

        /* Fill structure */
        host->revmap_type = revmap_type;
        host->inval_irq = inval_irq;
        host->ops = ops;
        host->of_node = of_node_get(of_node);

        if (host->ops->match == NULL)
                host->ops->match = default_irq_host_match;

        raw_spin_lock_irqsave(&irq_big_lock, flags);

        /* Check for the priority controller. */
        if (revmap_type == IRQ_HOST_MAP_PRIORITY) {
                if (irq_map[0].host != NULL) {
                        raw_spin_unlock_irqrestore(&irq_big_lock, flags);
                        of_node_put(host->of_node);
                        kfree(host);
                        return NULL;
                }
                irq_map[0].host = host;
        }

        list_add(&host->link, &irq_hosts);
        raw_spin_unlock_irqrestore(&irq_big_lock, flags);

        /* Additional setups per revmap type */
        switch (revmap_type) {
        case IRQ_HOST_MAP_PRIORITY:
                /* 0 is always the invalid number for priority */
                host->inval_irq = 0;
                /* setup us as the host for all priority interrupts */
                for (i = 1; i < NR_PRIORITY_IRQS; i++) {
                        irq_map[i].hwirq = i;
                        smp_wmb();
                        irq_map[i].host = host;
                        smp_wmb();

                        ops->map(host, i, i);
                }
                break;
        case IRQ_HOST_MAP_LINEAR:
                rmap = (unsigned int *)(host + 1);
                for (i = 0; i < revmap_arg; i++)
                        rmap[i] = NO_IRQ;
                host->revmap_data.linear.size = revmap_arg;
                smp_wmb();
                host->revmap_data.linear.revmap = rmap;
                break;
        case IRQ_HOST_MAP_TREE:
                INIT_RADIX_TREE(&host->revmap_data.tree, GFP_KERNEL);
                break;
        default:
                break;
        }

        pr_debug("irq: Allocated host of type %d @0x%p\n", revmap_type, host);

        return host;
}

struct irq_host *irq_find_host(struct device_node *node)
{
        struct irq_host *h, *found = NULL;
        unsigned long flags;

        /* We might want to match the legacy controller last since
         * it might potentially be set to match all interrupts in
         * the absence of a device node. This isn't a problem so far
         * yet though...
         */
        raw_spin_lock_irqsave(&irq_big_lock, flags);
        list_for_each_entry(h, &irq_hosts, link)
                if (h->ops->match(h, node)) {
                        found = h;
                        break;
                }
        raw_spin_unlock_irqrestore(&irq_big_lock, flags);
        return found;
}
EXPORT_SYMBOL_GPL(irq_find_host);

void irq_set_default_host(struct irq_host *host)
{
        pr_debug("irq: Default host set to @0x%p\n", host);

        irq_default_host = host;
}

void irq_set_virq_count(unsigned int count)
{
        pr_debug("irq: Trying to set virq count to %d\n", count);

        BUG_ON(count < NR_PRIORITY_IRQS);
        if (count < NR_IRQS)
                irq_virq_count = count;
}

static int irq_setup_virq(struct irq_host *host, unsigned int virq,
                            irq_hw_number_t hwirq)
{
        int res;

        res = irq_alloc_desc_at(virq, 0);
        if (res != virq) {
                pr_debug("irq: -> allocating desc failed\n");
                goto error;
        }

        /* map it */
        smp_wmb();
        irq_map[virq].hwirq = hwirq;
        smp_mb();

        if (host->ops->map(host, virq, hwirq)) {
                pr_debug("irq: -> mapping failed, freeing\n");
                goto errdesc;
        }

        irq_clear_status_flags(virq, IRQ_NOREQUEST);

        return 0;

errdesc:
        irq_free_descs(virq, 1);
error:
        irq_free_virt(virq, 1);
        return -1;
}

unsigned int irq_create_direct_mapping(struct irq_host *host)
{
        unsigned int virq;

        if (host == NULL)
                host = irq_default_host;

        BUG_ON(host == NULL);
        WARN_ON(host->revmap_type != IRQ_HOST_MAP_NOMAP);

        virq = irq_alloc_virt(host, 1, 0);
        if (virq == NO_IRQ) {
                pr_debug("irq: create_direct virq allocation failed\n");
                return NO_IRQ;
        }

        pr_debug("irq: create_direct obtained virq %d\n", virq);

        if (irq_setup_virq(host, virq, virq))
                return NO_IRQ;

        return virq;
}

unsigned int irq_create_mapping(struct irq_host *host,
                                irq_hw_number_t hwirq)
{
        unsigned int virq, hint;

        pr_debug("irq: irq_create_mapping(0x%p, 0x%lx)\n", host, hwirq);

        /* Look for default host if nececssary */
        if (host == NULL)
                host = irq_default_host;
        if (host == NULL) {
                printk(KERN_WARNING "irq_create_mapping called for"
                       " NULL host, hwirq=%lx\n", hwirq);
                WARN_ON(1);
                return NO_IRQ;
        }
        pr_debug("irq: -> using host @%p\n", host);

        /* Check if mapping already exists */
        virq = irq_find_mapping(host, hwirq);
        if (virq != NO_IRQ) {
                pr_debug("irq: -> existing mapping on virq %d\n", virq);
                return virq;
        }

        /* Allocate a virtual interrupt number */
        hint = hwirq % irq_virq_count;
        virq = irq_alloc_virt(host, 1, hint);
        if (virq == NO_IRQ) {
                pr_debug("irq: -> virq allocation failed\n");
                return NO_IRQ;
        }

        if (irq_setup_virq(host, virq, hwirq))
                return NO_IRQ;

        pr_debug("irq: irq %lu on host %s mapped to virtual irq %u\n",
                hwirq, host->of_node ? host->of_node->full_name : "null", virq);

        return virq;
}
EXPORT_SYMBOL_GPL(irq_create_mapping);

unsigned int irq_create_of_mapping(struct device_node *controller,
                                   const u32 *intspec, unsigned int intsize)
{
        struct irq_host *host;
        irq_hw_number_t hwirq;
        unsigned int type = IRQ_TYPE_NONE;
        unsigned int virq;

        if (controller == NULL)
                host = irq_default_host;
        else
                host = irq_find_host(controller);
        if (host == NULL) {
                printk(KERN_WARNING "irq: no irq host found for %s !\n",
                       controller->full_name);
                return NO_IRQ;
        }

        /* If host has no translation, then we assume interrupt line */
        if (host->ops->xlate == NULL)
                hwirq = intspec[0];
        else {
                if (host->ops->xlate(host, controller, intspec, intsize,
                                     &hwirq, &type))
                        return NO_IRQ;
        }

        /* Create mapping */
        virq = irq_create_mapping(host, hwirq);
        if (virq == NO_IRQ)
                return virq;

        /* Set type if specified and different than the current one */
        if (type != IRQ_TYPE_NONE &&
            type != (irqd_get_trigger_type(irq_get_irq_data(virq))))
                irq_set_irq_type(virq, type);
        return virq;
}
EXPORT_SYMBOL_GPL(irq_create_of_mapping);

void irq_dispose_mapping(unsigned int virq)
{
        struct irq_host *host;
        irq_hw_number_t hwirq;

        if (virq == NO_IRQ)
                return;

        /* Never unmap priority interrupts */
        if (virq < NR_PRIORITY_IRQS)
                return;

        host = irq_map[virq].host;
        if (WARN_ON(host == NULL))
                return;

        irq_set_status_flags(virq, IRQ_NOREQUEST);

        /* remove chip and handler */
        irq_set_chip_and_handler(virq, NULL, NULL);

        /* Make sure it's completed */
        synchronize_irq(virq);

        /* Tell the PIC about it */
        if (host->ops->unmap)
                host->ops->unmap(host, virq);
        smp_mb();

        /* Clear reverse map */
        hwirq = irq_map[virq].hwirq;
        switch (host->revmap_type) {
        case IRQ_HOST_MAP_LINEAR:
                if (hwirq < host->revmap_data.linear.size)
                        host->revmap_data.linear.revmap[hwirq] = NO_IRQ;
                break;
        case IRQ_HOST_MAP_TREE:
                mutex_lock(&revmap_trees_mutex);
                radix_tree_delete(&host->revmap_data.tree, hwirq);
                mutex_unlock(&revmap_trees_mutex);
                break;
        }

        /* Destroy map */
        smp_mb();
        irq_map[virq].hwirq = host->inval_irq;

        irq_free_descs(virq, 1);
        /* Free it */
        irq_free_virt(virq, 1);
}
EXPORT_SYMBOL_GPL(irq_dispose_mapping);

unsigned int irq_find_mapping(struct irq_host *host,
                              irq_hw_number_t hwirq)
{
        unsigned int i;
        unsigned int hint = hwirq % irq_virq_count;

        /* Look for default host if nececssary */
        if (host == NULL)
                host = irq_default_host;
        if (host == NULL)
                return NO_IRQ;

        /* Slow path does a linear search of the map */
        i = hint;
        do  {
                if (irq_map[i].host == host &&
                    irq_map[i].hwirq == hwirq)
                        return i;
                i++;
                if (i >= irq_virq_count)
                        i = 4;
        } while (i != hint);
        return NO_IRQ;
}
EXPORT_SYMBOL_GPL(irq_find_mapping);

unsigned int irq_radix_revmap_lookup(struct irq_host *host,
                                     irq_hw_number_t hwirq)
{
        struct irq_map_entry *ptr;
        unsigned int virq;

        if (WARN_ON_ONCE(host->revmap_type != IRQ_HOST_MAP_TREE))
                return irq_find_mapping(host, hwirq);

        /*
         * The ptr returned references the static global irq_map.
         * but freeing an irq can delete nodes along the path to
         * do the lookup via call_rcu.
         */
        rcu_read_lock();
        ptr = radix_tree_lookup(&host->revmap_data.tree, hwirq);
        rcu_read_unlock();

        /*
         * If found in radix tree, then fine.
         * Else fallback to linear lookup - this should not happen in practice
         * as it means that we failed to insert the node in the radix tree.
         */
        if (ptr)
                virq = ptr - irq_map;
        else
                virq = irq_find_mapping(host, hwirq);

        return virq;
}

void irq_radix_revmap_insert(struct irq_host *host, unsigned int virq,
                             irq_hw_number_t hwirq)
{
        if (WARN_ON(host->revmap_type != IRQ_HOST_MAP_TREE))
                return;

        if (virq != NO_IRQ) {
                mutex_lock(&revmap_trees_mutex);
                radix_tree_insert(&host->revmap_data.tree, hwirq,
                                  &irq_map[virq]);
                mutex_unlock(&revmap_trees_mutex);
        }
}

unsigned int irq_linear_revmap(struct irq_host *host,
                               irq_hw_number_t hwirq)
{
        unsigned int *revmap;

        if (WARN_ON_ONCE(host->revmap_type != IRQ_HOST_MAP_LINEAR))
                return irq_find_mapping(host, hwirq);

        /* Check revmap bounds */
        if (unlikely(hwirq >= host->revmap_data.linear.size))
                return irq_find_mapping(host, hwirq);

        /* Check if revmap was allocated */
        revmap = host->revmap_data.linear.revmap;
        if (unlikely(revmap == NULL))
                return irq_find_mapping(host, hwirq);

        /* Fill up revmap with slow path if no mapping found */
        if (unlikely(revmap[hwirq] == NO_IRQ))
                revmap[hwirq] = irq_find_mapping(host, hwirq);

        return revmap[hwirq];
}

unsigned int irq_alloc_virt(struct irq_host *host,
                            unsigned int count,
                            unsigned int hint)
{
        unsigned long flags;
        unsigned int i, j, found = NO_IRQ;

        if (count == 0 || count > (irq_virq_count - NR_PRIORITY_IRQS))
                return NO_IRQ;

        raw_spin_lock_irqsave(&irq_big_lock, flags);

        /* Use hint for 1 interrupt if any */
        if (count == 1 && hint >= NR_PRIORITY_IRQS &&
            hint < irq_virq_count && irq_map[hint].host == NULL) {
                found = hint;
                goto hint_found;
        }

        /* Look for count consecutive numbers in the allocatable
         * (non-legacy) space
         */
        for (i = NR_PRIORITY_IRQS, j = 0; i < irq_virq_count; i++) {
                if (irq_map[i].host != NULL)
                        j = 0;
                else
                        j++;

                if (j == count) {
                        found = i - count + 1;
                        break;
                }
        }
        if (found == NO_IRQ) {
                raw_spin_unlock_irqrestore(&irq_big_lock, flags);
                return NO_IRQ;
        }
 hint_found:
        for (i = found; i < (found + count); i++) {
                irq_map[i].hwirq = host->inval_irq;
                smp_wmb();
                irq_map[i].host = host;
        }
        raw_spin_unlock_irqrestore(&irq_big_lock, flags);
        return found;
}

void irq_free_virt(unsigned int virq, unsigned int count)
{
        unsigned long flags;
        unsigned int i;

        WARN_ON(virq < NR_PRIORITY_IRQS);
        WARN_ON(count == 0 || (virq + count) > irq_virq_count);

        if (virq < NR_PRIORITY_IRQS) {
                if (virq + count < NR_PRIORITY_IRQS)
                        return;
                count  -= NR_PRIORITY_IRQS - virq;
                virq = NR_PRIORITY_IRQS;
        }

        if (count > irq_virq_count || virq > irq_virq_count - count) {
                if (virq > irq_virq_count)
                        return;
                count = irq_virq_count - virq;
        }

        raw_spin_lock_irqsave(&irq_big_lock, flags);
        for (i = virq; i < (virq + count); i++) {
                struct irq_host *host;

                host = irq_map[i].host;
                irq_map[i].hwirq = host->inval_irq;
                smp_wmb();
                irq_map[i].host = NULL;
        }
        raw_spin_unlock_irqrestore(&irq_big_lock, flags);
}

#ifdef CONFIG_VIRQ_DEBUG
static int virq_debug_show(struct seq_file *m, void *private)
{
        unsigned long flags;
        struct irq_desc *desc;
        const char *p;
        static const char none[] = "none";
        void *data;
        int i;

        seq_printf(m, "%-5s  %-7s  %-15s  %-18s  %s\n", "virq", "hwirq",
                      "chip name", "chip data", "host name");

        for (i = 1; i < nr_irqs; i++) {
                desc = irq_to_desc(i);
                if (!desc)
                        continue;

                raw_spin_lock_irqsave(&desc->lock, flags);

                if (desc->action && desc->action->handler) {
                        struct irq_chip *chip;

                        seq_printf(m, "%5d  ", i);
                        seq_printf(m, "0x%05lx  ", irq_map[i].hwirq);

                        chip = irq_desc_get_chip(desc);
                        if (chip && chip->name)
                                p = chip->name;
                        else
                                p = none;
                        seq_printf(m, "%-15s  ", p);

                        data = irq_desc_get_chip_data(desc);
                        seq_printf(m, "0x%16p  ", data);

                        if (irq_map[i].host && irq_map[i].host->of_node)
                                p = irq_map[i].host->of_node->full_name;
                        else
                                p = none;
                        seq_printf(m, "%s\n", p);
                }

                raw_spin_unlock_irqrestore(&desc->lock, flags);
        }

        return 0;
}

static int virq_debug_open(struct inode *inode, struct file *file)
{
        return single_open(file, virq_debug_show, inode->i_private);
}

static const struct file_operations virq_debug_fops = {
        .open = virq_debug_open,
        .read = seq_read,
        .llseek = seq_lseek,
        .release = single_release,
};

static int __init irq_debugfs_init(void)
{
        if (debugfs_create_file("virq_mapping", S_IRUGO, powerpc_debugfs_root,
                                 NULL, &virq_debug_fops) == NULL)
                return -ENOMEM;

        return 0;
}
device_initcall(irq_debugfs_init);
#endif /* CONFIG_VIRQ_DEBUG */