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irq-gic.c

#undef DEBUG

#include <linux/bitmap.h>
#include <linux/init.h>
#include <linux/smp.h>

#include <asm/io.h>
#include <asm/gic.h>
#include <asm/gcmpregs.h>
#include <asm/mips-boards/maltaint.h>
#include <asm/irq.h>
#include <linux/hardirq.h>
#include <asm-generic/bitops/find.h>


static unsigned long _gic_base;
static unsigned int _irqbase;
static unsigned int gic_irq_flags[GIC_NUM_INTRS];
#define GIC_IRQ_FLAG_EDGE      0x0001

struct gic_pcpu_mask pcpu_masks[NR_CPUS];
static struct gic_pending_regs pending_regs[NR_CPUS];
static struct gic_intrmask_regs intrmask_regs[NR_CPUS];

void gic_send_ipi(unsigned int intr)
{
      pr_debug("CPU%d: %s status %08x\n", smp_processor_id(), __func__,
             read_c0_status());
      GICWRITE(GIC_REG(SHARED, GIC_SH_WEDGE), 0x80000000 | intr);
}

/* This is Malta specific and needs to be exported */
static void __init vpe_local_setup(unsigned int numvpes)
{
      int i;
      unsigned long timer_interrupt = 5, perf_interrupt = 5;
      unsigned int vpe_ctl;

      /*
       * Setup the default performance counter timer interrupts
       * for all VPEs
       */
      for (i = 0; i < numvpes; i++) {
            GICWRITE(GIC_REG(VPE_LOCAL, GIC_VPE_OTHER_ADDR), i);

            /* Are Interrupts locally routable? */
            GICREAD(GIC_REG(VPE_OTHER, GIC_VPE_CTL), vpe_ctl);
            if (vpe_ctl & GIC_VPE_CTL_TIMER_RTBL_MSK)
                  GICWRITE(GIC_REG(VPE_OTHER, GIC_VPE_TIMER_MAP),
                         GIC_MAP_TO_PIN_MSK | timer_interrupt);

            if (vpe_ctl & GIC_VPE_CTL_PERFCNT_RTBL_MSK)
                  GICWRITE(GIC_REG(VPE_OTHER, GIC_VPE_PERFCTR_MAP),
                         GIC_MAP_TO_PIN_MSK | perf_interrupt);
      }
}

unsigned int gic_get_int(void)
{
      unsigned int i;
      unsigned long *pending, *intrmask, *pcpu_mask;
      unsigned long *pending_abs, *intrmask_abs;

      /* Get per-cpu bitmaps */
      pending = pending_regs[smp_processor_id()].pending;
      intrmask = intrmask_regs[smp_processor_id()].intrmask;
      pcpu_mask = pcpu_masks[smp_processor_id()].pcpu_mask;

      pending_abs = (unsigned long *) GIC_REG_ABS_ADDR(SHARED,
                                           GIC_SH_PEND_31_0_OFS);
      intrmask_abs = (unsigned long *) GIC_REG_ABS_ADDR(SHARED,
                                            GIC_SH_MASK_31_0_OFS);

      for (i = 0; i < BITS_TO_LONGS(GIC_NUM_INTRS); i++) {
            GICREAD(*pending_abs, pending[i]);
            GICREAD(*intrmask_abs, intrmask[i]);
            pending_abs++;
            intrmask_abs++;
      }

      bitmap_and(pending, pending, intrmask, GIC_NUM_INTRS);
      bitmap_and(pending, pending, pcpu_mask, GIC_NUM_INTRS);

      i = find_first_bit(pending, GIC_NUM_INTRS);

      pr_debug("CPU%d: %s pend=%d\n", smp_processor_id(), __func__, i);

      return i;
}

static unsigned int gic_irq_startup(unsigned int irq)
{
      irq -= _irqbase;
      pr_debug("CPU%d: %s: irq%d\n", smp_processor_id(), __func__, irq);
      GIC_SET_INTR_MASK(irq);
      return 0;
}

static void gic_irq_ack(unsigned int irq)
{
      irq -= _irqbase;
      pr_debug("CPU%d: %s: irq%d\n", smp_processor_id(), __func__, irq);
      GIC_CLR_INTR_MASK(irq);

      if (gic_irq_flags[irq] & GIC_IRQ_FLAG_EDGE)
            GICWRITE(GIC_REG(SHARED, GIC_SH_WEDGE), irq);
}

static void gic_mask_irq(unsigned int irq)
{
      irq -= _irqbase;
      pr_debug("CPU%d: %s: irq%d\n", smp_processor_id(), __func__, irq);
      GIC_CLR_INTR_MASK(irq);
}

static void gic_unmask_irq(unsigned int irq)
{
      irq -= _irqbase;
      pr_debug("CPU%d: %s: irq%d\n", smp_processor_id(), __func__, irq);
      GIC_SET_INTR_MASK(irq);
}

#ifdef CONFIG_SMP

static DEFINE_SPINLOCK(gic_lock);

static int gic_set_affinity(unsigned int irq, const struct cpumask *cpumask)
{
      cpumask_t   tmp = CPU_MASK_NONE;
      unsigned long     flags;
      int         i;

      irq -= _irqbase;
      pr_debug(KERN_DEBUG "%s(%d) called\n", __func__, irq);
      cpumask_and(&tmp, cpumask, cpu_online_mask);
      if (cpus_empty(tmp))
            return -1;

      /* Assumption : cpumask refers to a single CPU */
      spin_lock_irqsave(&gic_lock, flags);
      for (;;) {
            /* Re-route this IRQ */
            GIC_SH_MAP_TO_VPE_SMASK(irq, first_cpu(tmp));

            /* Update the pcpu_masks */
            for (i = 0; i < NR_CPUS; i++)
                  clear_bit(irq, pcpu_masks[i].pcpu_mask);
            set_bit(irq, pcpu_masks[first_cpu(tmp)].pcpu_mask);

      }
      cpumask_copy(irq_desc[irq].affinity, cpumask);
      spin_unlock_irqrestore(&gic_lock, flags);

      return 0;
}
#endif

static struct irq_chip gic_irq_controller = {
      .name       =     "MIPS GIC",
      .startup    =     gic_irq_startup,
      .ack        =     gic_irq_ack,
      .mask       =     gic_mask_irq,
      .mask_ack   =     gic_mask_irq,
      .unmask           =     gic_unmask_irq,
      .eoi        =     gic_unmask_irq,
#ifdef CONFIG_SMP
      .set_affinity     =     gic_set_affinity,
#endif
};

static void __init gic_setup_intr(unsigned int intr, unsigned int cpu,
      unsigned int pin, unsigned int polarity, unsigned int trigtype,
      unsigned int flags)
{
      /* Setup Intr to Pin mapping */
      if (pin & GIC_MAP_TO_NMI_MSK) {
            GICWRITE(GIC_REG_ADDR(SHARED, GIC_SH_MAP_TO_PIN(intr)), pin);
            /* FIXME: hack to route NMI to all cpu's */
            for (cpu = 0; cpu < NR_CPUS; cpu += 32) {
                  GICWRITE(GIC_REG_ADDR(SHARED,
                                GIC_SH_MAP_TO_VPE_REG_OFF(intr, cpu)),
                         0xffffffff);
            }
      } else {
            GICWRITE(GIC_REG_ADDR(SHARED, GIC_SH_MAP_TO_PIN(intr)),
                   GIC_MAP_TO_PIN_MSK | pin);
            /* Setup Intr to CPU mapping */
            GIC_SH_MAP_TO_VPE_SMASK(intr, cpu);
      }

      /* Setup Intr Polarity */
      GIC_SET_POLARITY(intr, polarity);

      /* Setup Intr Trigger Type */
      GIC_SET_TRIGGER(intr, trigtype);

      /* Init Intr Masks */
      GIC_CLR_INTR_MASK(intr);
      /* Initialise per-cpu Interrupt software masks */
      if (flags & GIC_FLAG_IPI)
            set_bit(intr, pcpu_masks[cpu].pcpu_mask);
      if (flags & GIC_FLAG_TRANSPARENT)
            GIC_SET_INTR_MASK(intr);
      if (trigtype == GIC_TRIG_EDGE)
            gic_irq_flags[intr] |= GIC_IRQ_FLAG_EDGE;
}

static void __init gic_basic_init(int numintrs, int numvpes,
                  struct gic_intr_map *intrmap, int mapsize)
{
      unsigned int i, cpu;

      /* Setup defaults */
      for (i = 0; i < numintrs; i++) {
            GIC_SET_POLARITY(i, GIC_POL_POS);
            GIC_SET_TRIGGER(i, GIC_TRIG_LEVEL);
            GIC_CLR_INTR_MASK(i);
            if (i < GIC_NUM_INTRS)
                  gic_irq_flags[i] = 0;
      }

      /* Setup specifics */
      for (i = 0; i < mapsize; i++) {
            cpu = intrmap[i].cpunum;
            if (cpu == X)
                  continue;
            if (cpu == 0 && i != 0 && intrmap[i].flags == 0)
                  continue;
            gic_setup_intr(i,
                  intrmap[i].cpunum,
                  intrmap[i].pin,
                  intrmap[i].polarity,
                  intrmap[i].trigtype,
                  intrmap[i].flags);
      }

      vpe_local_setup(numvpes);

      for (i = _irqbase; i < (_irqbase + numintrs); i++)
            set_irq_chip(i, &gic_irq_controller);
}

void __init gic_init(unsigned long gic_base_addr,
                 unsigned long gic_addrspace_size,
                 struct gic_intr_map *intr_map, unsigned int intr_map_size,
                 unsigned int irqbase)
{
      unsigned int gicconfig;
      int numvpes, numintrs;

      _gic_base = (unsigned long) ioremap_nocache(gic_base_addr,
                                        gic_addrspace_size);
      _irqbase = irqbase;

      GICREAD(GIC_REG(SHARED, GIC_SH_CONFIG), gicconfig);
      numintrs = (gicconfig & GIC_SH_CONFIG_NUMINTRS_MSK) >>
               GIC_SH_CONFIG_NUMINTRS_SHF;
      numintrs = ((numintrs + 1) * 8);

      numvpes = (gicconfig & GIC_SH_CONFIG_NUMVPES_MSK) >>
              GIC_SH_CONFIG_NUMVPES_SHF;

      pr_debug("%s called\n", __func__);

      gic_basic_init(numintrs, numvpes, intr_map, intr_map_size);
}

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