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beat_interrupt.c

/*
 * Celleb/Beat Interrupt controller
 *
 * (C) Copyright 2006-2007 TOSHIBA CORPORATION
 *
 * 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.
 *
 * 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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/percpu.h>
#include <linux/types.h>

#include <asm/machdep.h>

#include "beat_interrupt.h"
#include "beat_wrapper.h"

#define     MAX_IRQS    NR_IRQS
static DEFINE_SPINLOCK(beatic_irq_mask_lock);
static uint64_t   beatic_irq_mask_enable[(MAX_IRQS+255)/64];
static uint64_t   beatic_irq_mask_ack[(MAX_IRQS+255)/64];

static struct irq_host *beatic_host;

/*
 * In this implementation, "virq" == "IRQ plug number",
 * "(irq_hw_number_t)hwirq" == "IRQ outlet number".
 */

/* assumption: locked */
static inline void beatic_update_irq_mask(unsigned int irq_plug)
{
      int off;
      unsigned long masks[4];

      off = (irq_plug / 256) * 4;
      masks[0] = beatic_irq_mask_enable[off + 0]
            & beatic_irq_mask_ack[off + 0];
      masks[1] = beatic_irq_mask_enable[off + 1]
            & beatic_irq_mask_ack[off + 1];
      masks[2] = beatic_irq_mask_enable[off + 2]
            & beatic_irq_mask_ack[off + 2];
      masks[3] = beatic_irq_mask_enable[off + 3]
            & beatic_irq_mask_ack[off + 3];
      if (beat_set_interrupt_mask(irq_plug&~255UL,
            masks[0], masks[1], masks[2], masks[3]) != 0)
            panic("Failed to set mask IRQ!");
}

static void beatic_mask_irq(unsigned int irq_plug)
{
      unsigned long flags;

      spin_lock_irqsave(&beatic_irq_mask_lock, flags);
      beatic_irq_mask_enable[irq_plug/64] &= ~(1UL << (63 - (irq_plug%64)));
      beatic_update_irq_mask(irq_plug);
      spin_unlock_irqrestore(&beatic_irq_mask_lock, flags);
}

static void beatic_unmask_irq(unsigned int irq_plug)
{
      unsigned long flags;

      spin_lock_irqsave(&beatic_irq_mask_lock, flags);
      beatic_irq_mask_enable[irq_plug/64] |= 1UL << (63 - (irq_plug%64));
      beatic_update_irq_mask(irq_plug);
      spin_unlock_irqrestore(&beatic_irq_mask_lock, flags);
}

static void beatic_ack_irq(unsigned int irq_plug)
{
      unsigned long flags;

      spin_lock_irqsave(&beatic_irq_mask_lock, flags);
      beatic_irq_mask_ack[irq_plug/64] &= ~(1UL << (63 - (irq_plug%64)));
      beatic_update_irq_mask(irq_plug);
      spin_unlock_irqrestore(&beatic_irq_mask_lock, flags);
}

static void beatic_end_irq(unsigned int irq_plug)
{
      s64 err;
      unsigned long flags;

      err = beat_downcount_of_interrupt(irq_plug);
      if (err != 0) {
            if ((err & 0xFFFFFFFF) != 0xFFFFFFF5) /* -11: wrong state */
                  panic("Failed to downcount IRQ! Error = %16lx", err);

            printk(KERN_ERR "IRQ over-downcounted, plug %d\n", irq_plug);
      }
      spin_lock_irqsave(&beatic_irq_mask_lock, flags);
      beatic_irq_mask_ack[irq_plug/64] |= 1UL << (63 - (irq_plug%64));
      beatic_update_irq_mask(irq_plug);
      spin_unlock_irqrestore(&beatic_irq_mask_lock, flags);
}

static struct irq_chip beatic_pic = {
      .typename = " CELL-BEAT ",
      .unmask = beatic_unmask_irq,
      .mask = beatic_mask_irq,
      .eoi = beatic_end_irq,
};

/*
 * Dispose binding hardware IRQ number (hw) and Virtuql IRQ number (virq),
 * update flags.
 *
 * Note that the number (virq) is already assigned at upper layer.
 */
static void beatic_pic_host_unmap(struct irq_host *h, unsigned int virq)
{
      beat_destruct_irq_plug(virq);
}

/*
 * Create or update binding hardware IRQ number (hw) and Virtuql
 * IRQ number (virq). This is called only once for a given mapping.
 *
 * Note that the number (virq) is already assigned at upper layer.
 */
static int beatic_pic_host_map(struct irq_host *h, unsigned int virq,
                         irq_hw_number_t hw)
{
      struct irq_desc *desc = get_irq_desc(virq);
      int64_t     err;

      err = beat_construct_and_connect_irq_plug(virq, hw);
      if (err < 0)
            return -EIO;

      desc->status |= IRQ_LEVEL;
      set_irq_chip_and_handler(virq, &beatic_pic, handle_fasteoi_irq);
      return 0;
}

/*
 * Update binding hardware IRQ number (hw) and Virtuql
 * IRQ number (virq). This is called only once for a given mapping.
 */
static void beatic_pic_host_remap(struct irq_host *h, unsigned int virq,
                         irq_hw_number_t hw)
{
      beat_construct_and_connect_irq_plug(virq, hw);
}

/*
 * Translate device-tree interrupt spec to irq_hw_number_t style (ulong),
 * to pass away to irq_create_mapping().
 *
 * Called from irq_create_of_mapping() only.
 * Note: We have only 1 entry to translate.
 */
static int beatic_pic_host_xlate(struct irq_host *h, struct device_node *ct,
                         u32 *intspec, unsigned int intsize,
                         irq_hw_number_t *out_hwirq,
                         unsigned int *out_flags)
{
      u64 *intspec2 = (u64 *)intspec;

      *out_hwirq = *intspec2;
      *out_flags |= IRQ_TYPE_LEVEL_LOW;
      return 0;
}

static int beatic_pic_host_match(struct irq_host *h, struct device_node *np)
{
      /* Match all */
      return 1;
}

static struct irq_host_ops beatic_pic_host_ops = {
      .map = beatic_pic_host_map,
      .remap = beatic_pic_host_remap,
      .unmap = beatic_pic_host_unmap,
      .xlate = beatic_pic_host_xlate,
      .match = beatic_pic_host_match,
};

/*
 * Get an IRQ number
 * Note: returns VIRQ
 */
static inline unsigned int beatic_get_irq_plug(void)
{
      int i;
      uint64_t    pending[4], ub;

      for (i = 0; i < MAX_IRQS; i += 256) {
            beat_detect_pending_interrupts(i, pending);
            __asm__ ("cntlzd %0,%1":"=r"(ub):
                  "r"(pending[0] & beatic_irq_mask_enable[i/64+0]
                               & beatic_irq_mask_ack[i/64+0]));
            if (ub != 64)
                  return i + ub + 0;
            __asm__ ("cntlzd %0,%1":"=r"(ub):
                  "r"(pending[1] & beatic_irq_mask_enable[i/64+1]
                               & beatic_irq_mask_ack[i/64+1]));
            if (ub != 64)
                  return i + ub + 64;
            __asm__ ("cntlzd %0,%1":"=r"(ub):
                  "r"(pending[2] & beatic_irq_mask_enable[i/64+2]
                               & beatic_irq_mask_ack[i/64+2]));
            if (ub != 64)
                  return i + ub + 128;
            __asm__ ("cntlzd %0,%1":"=r"(ub):
                  "r"(pending[3] & beatic_irq_mask_enable[i/64+3]
                               & beatic_irq_mask_ack[i/64+3]));
            if (ub != 64)
                  return i + ub + 192;
      }

      return NO_IRQ;
}
unsigned int beatic_get_irq(void)
{
      unsigned int ret;

      ret = beatic_get_irq_plug();
      if (ret != NO_IRQ)
            beatic_ack_irq(ret);
      return ret;
}

/*
 */
void __init beatic_init_IRQ(void)
{
      int   i;

      memset(beatic_irq_mask_enable, 0, sizeof(beatic_irq_mask_enable));
      memset(beatic_irq_mask_ack, 255, sizeof(beatic_irq_mask_ack));
      for (i = 0; i < MAX_IRQS; i += 256)
            beat_set_interrupt_mask(i, 0L, 0L, 0L, 0L);

      /* Set out get_irq function */
      ppc_md.get_irq = beatic_get_irq;

      /* Allocate an irq host */
      beatic_host = irq_alloc_host(NULL, IRQ_HOST_MAP_NOMAP, 0,
                             &beatic_pic_host_ops,
                               0);
      BUG_ON(beatic_host == NULL);
      irq_set_default_host(beatic_host);
}

#ifdef CONFIG_SMP

/* Nullified to compile with SMP mode */
void beatic_setup_cpu(int cpu)
{
}

void beatic_cause_IPI(int cpu, int mesg)
{
}

void beatic_request_IPIs(void)
{
}
#endif /* CONFIG_SMP */

void beatic_deinit_IRQ(void)
{
      int   i;

      for (i = 1; i < NR_IRQS; i++)
            beat_destruct_irq_plug(i);
}

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