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kernel/linux-imx6_3.14.28/arch/mips/sgi-ip27/ip27-irq.c 5.43 KB
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  /*
   * ip27-irq.c: Highlevel interrupt handling for IP27 architecture.
   *
   * Copyright (C) 1999, 2000 Ralf Baechle (ralf@gnu.org)
   * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
   * Copyright (C) 1999 - 2001 Kanoj Sarcar
   */
  
  #undef DEBUG
  
  #include <linux/init.h>
  #include <linux/irq.h>
  #include <linux/errno.h>
  #include <linux/signal.h>
  #include <linux/sched.h>
  #include <linux/types.h>
  #include <linux/interrupt.h>
  #include <linux/ioport.h>
  #include <linux/timex.h>
  #include <linux/smp.h>
  #include <linux/random.h>
  #include <linux/kernel.h>
  #include <linux/kernel_stat.h>
  #include <linux/delay.h>
  #include <linux/bitops.h>
  
  #include <asm/bootinfo.h>
  #include <asm/io.h>
  #include <asm/mipsregs.h>
  
  #include <asm/processor.h>
  #include <asm/sn/addrs.h>
  #include <asm/sn/agent.h>
  #include <asm/sn/arch.h>
  #include <asm/sn/hub.h>
  #include <asm/sn/intr.h>
  
  /*
   * Linux has a controller-independent x86 interrupt architecture.
   * every controller has a 'controller-template', that is used
   * by the main code to do the right thing. Each driver-visible
   * interrupt source is transparently wired to the appropriate
   * controller. Thus drivers need not be aware of the
   * interrupt-controller.
   *
   * Various interrupt controllers we handle: 8259 PIC, SMP IO-APIC,
   * PIIX4's internal 8259 PIC and SGI's Visual Workstation Cobalt (IO-)APIC.
   * (IO-APICs assumed to be messaging to Pentium local-APICs)
   *
   * the code is designed to be easily extended with new/different
   * interrupt controllers, without having to do assembly magic.
   */
  
  extern asmlinkage void ip27_irq(void);
  
  /*
   * Find first bit set
   */
  static int ms1bit(unsigned long x)
  {
  	int b = 0, s;
  
  	s = 16; if (x >> 16 == 0) s = 0; b += s; x >>= s;
  	s =  8; if (x >>  8 == 0) s = 0; b += s; x >>= s;
  	s =  4; if (x >>  4 == 0) s = 0; b += s; x >>= s;
  	s =  2; if (x >>  2 == 0) s = 0; b += s; x >>= s;
  	s =  1; if (x >>  1 == 0) s = 0; b += s;
  
  	return b;
  }
  
  /*
   * This code is unnecessarily complex, because we do
   * intr enabling. Basically, once we grab the set of intrs we need
   * to service, we must mask _all_ these interrupts; firstly, to make
   * sure the same intr does not intr again, causing recursion that
   * can lead to stack overflow. Secondly, we can not just mask the
   * one intr we are do_IRQing, because the non-masked intrs in the
   * first set might intr again, causing multiple servicings of the
   * same intr. This effect is mostly seen for intercpu intrs.
   * Kanoj 05.13.00
   */
  
  static void ip27_do_irq_mask0(void)
  {
  	int irq, swlevel;
  	hubreg_t pend0, mask0;
  	cpuid_t cpu = smp_processor_id();
  	int pi_int_mask0 =
  		(cputoslice(cpu) == 0) ?  PI_INT_MASK0_A : PI_INT_MASK0_B;
  
  	/* copied from Irix intpend0() */
  	pend0 = LOCAL_HUB_L(PI_INT_PEND0);
  	mask0 = LOCAL_HUB_L(pi_int_mask0);
  
  	pend0 &= mask0;		/* Pick intrs we should look at */
  	if (!pend0)
  		return;
  
  	swlevel = ms1bit(pend0);
  #ifdef CONFIG_SMP
  	if (pend0 & (1UL << CPU_RESCHED_A_IRQ)) {
  		LOCAL_HUB_CLR_INTR(CPU_RESCHED_A_IRQ);
  		scheduler_ipi();
  	} else if (pend0 & (1UL << CPU_RESCHED_B_IRQ)) {
  		LOCAL_HUB_CLR_INTR(CPU_RESCHED_B_IRQ);
  		scheduler_ipi();
  	} else if (pend0 & (1UL << CPU_CALL_A_IRQ)) {
  		LOCAL_HUB_CLR_INTR(CPU_CALL_A_IRQ);
  		smp_call_function_interrupt();
  	} else if (pend0 & (1UL << CPU_CALL_B_IRQ)) {
  		LOCAL_HUB_CLR_INTR(CPU_CALL_B_IRQ);
  		smp_call_function_interrupt();
  	} else
  #endif
  	{
  		/* "map" swlevel to irq */
  		struct slice_data *si = cpu_data[cpu].data;
  
  		irq = si->level_to_irq[swlevel];
  		do_IRQ(irq);
  	}
  
  	LOCAL_HUB_L(PI_INT_PEND0);
  }
  
  static void ip27_do_irq_mask1(void)
  {
  	int irq, swlevel;
  	hubreg_t pend1, mask1;
  	cpuid_t cpu = smp_processor_id();
  	int pi_int_mask1 = (cputoslice(cpu) == 0) ?  PI_INT_MASK1_A : PI_INT_MASK1_B;
  	struct slice_data *si = cpu_data[cpu].data;
  
  	/* copied from Irix intpend0() */
  	pend1 = LOCAL_HUB_L(PI_INT_PEND1);
  	mask1 = LOCAL_HUB_L(pi_int_mask1);
  
  	pend1 &= mask1;		/* Pick intrs we should look at */
  	if (!pend1)
  		return;
  
  	swlevel = ms1bit(pend1);
  	/* "map" swlevel to irq */
  	irq = si->level_to_irq[swlevel];
  	LOCAL_HUB_CLR_INTR(swlevel);
  	do_IRQ(irq);
  
  	LOCAL_HUB_L(PI_INT_PEND1);
  }
  
  static void ip27_prof_timer(void)
  {
  	panic("CPU %d got a profiling interrupt", smp_processor_id());
  }
  
  static void ip27_hub_error(void)
  {
  	panic("CPU %d got a hub error interrupt", smp_processor_id());
  }
  
  asmlinkage void plat_irq_dispatch(void)
  {
  	unsigned long pending = read_c0_cause() & read_c0_status();
  	extern unsigned int rt_timer_irq;
  
  	if (pending & CAUSEF_IP4)
  		do_IRQ(rt_timer_irq);
  	else if (pending & CAUSEF_IP2)	/* PI_INT_PEND_0 or CC_PEND_{A|B} */
  		ip27_do_irq_mask0();
  	else if (pending & CAUSEF_IP3)	/* PI_INT_PEND_1 */
  		ip27_do_irq_mask1();
  	else if (pending & CAUSEF_IP5)
  		ip27_prof_timer();
  	else if (pending & CAUSEF_IP6)
  		ip27_hub_error();
  }
  
  void __init arch_init_irq(void)
  {
  }
  
  void install_ipi(void)
  {
  	int slice = LOCAL_HUB_L(PI_CPU_NUM);
  	int cpu = smp_processor_id();
  	struct slice_data *si = cpu_data[cpu].data;
  	struct hub_data *hub = hub_data(cpu_to_node(cpu));
  	int resched, call;
  
  	resched = CPU_RESCHED_A_IRQ + slice;
  	__set_bit(resched, hub->irq_alloc_mask);
  	__set_bit(resched, si->irq_enable_mask);
  	LOCAL_HUB_CLR_INTR(resched);
  
  	call = CPU_CALL_A_IRQ + slice;
  	__set_bit(call, hub->irq_alloc_mask);
  	__set_bit(call, si->irq_enable_mask);
  	LOCAL_HUB_CLR_INTR(call);
  
  	if (slice == 0) {
  		LOCAL_HUB_S(PI_INT_MASK0_A, si->irq_enable_mask[0]);
  		LOCAL_HUB_S(PI_INT_MASK1_A, si->irq_enable_mask[1]);
  	} else {
  		LOCAL_HUB_S(PI_INT_MASK0_B, si->irq_enable_mask[0]);
  		LOCAL_HUB_S(PI_INT_MASK1_B, si->irq_enable_mask[1]);
  	}
  }