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kernel/linux-imx6_3.14.28/arch/mips/dec/int-handler.S 6.87 KB
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  /*
   * Copyright (C) 1995, 1996, 1997 Paul M. Antoine and Harald Koerfgen
   * Copyright (C) 2000, 2001, 2002, 2003, 2005  Maciej W. Rozycki
   *
   * Written by Ralf Baechle and Andreas Busse, modified for DECstation
   * support by Paul Antoine and Harald Koerfgen.
   *
   * completly rewritten:
   * Copyright (C) 1998 Harald Koerfgen
   *
   * Rewritten extensively for controller-driven IRQ support
   * by Maciej W. Rozycki.
   */
  
  #include <asm/addrspace.h>
  #include <asm/asm.h>
  #include <asm/mipsregs.h>
  #include <asm/regdef.h>
  #include <asm/stackframe.h>
  
  #include <asm/dec/interrupts.h>
  #include <asm/dec/ioasic_addrs.h>
  #include <asm/dec/ioasic_ints.h>
  #include <asm/dec/kn01.h>
  #include <asm/dec/kn02.h>
  #include <asm/dec/kn02xa.h>
  #include <asm/dec/kn03.h>
  
  #define KN02_CSR_BASE		CKSEG1ADDR(KN02_SLOT_BASE + KN02_CSR)
  #define KN02XA_IOASIC_BASE	CKSEG1ADDR(KN02XA_SLOT_BASE + IOASIC_IOCTL)
  #define KN03_IOASIC_BASE	CKSEG1ADDR(KN03_SLOT_BASE + IOASIC_IOCTL)
  
  		.text
  		.set	noreorder
  /*
   * plat_irq_dispatch: Interrupt handler for DECstations
   *
   * We follow the model in the Indy interrupt code by David Miller, where he
   * says: a lot of complication here is taken away because:
   *
   * 1) We handle one interrupt and return, sitting in a loop
   *    and moving across all the pending IRQ bits in the cause
   *    register is _NOT_ the answer, the common case is one
   *    pending IRQ so optimize in that direction.
   *
   * 2) We need not check against bits in the status register
   *    IRQ mask, that would make this routine slow as hell.
   *
   * 3) Linux only thinks in terms of all IRQs on or all IRQs
   *    off, nothing in between like BSD spl() brain-damage.
   *
   * Furthermore, the IRQs on the DECstations look basically (barring
   * software IRQs which we don't use at all) like...
   *
   * DS2100/3100's, aka kn01, aka Pmax:
   *
   *	MIPS IRQ	Source
   *	--------	------
   *	       0	Software (ignored)
   *	       1	Software (ignored)
   *	       2	SCSI
   *	       3	Lance Ethernet
   *	       4	DZ11 serial
   *	       5	RTC
   *	       6	Memory Controller & Video
   *	       7	FPU
   *
   * DS5000/200, aka kn02, aka 3max:
   *
   *	MIPS IRQ	Source
   *	--------	------
   *	       0	Software (ignored)
   *	       1	Software (ignored)
   *	       2	TurboChannel
   *	       3	RTC
   *	       4	Reserved
   *	       5	Memory Controller
   *	       6	Reserved
   *	       7	FPU
   *
   * DS5000/1xx's, aka kn02ba, aka 3min:
   *
   *	MIPS IRQ	Source
   *	--------	------
   *	       0	Software (ignored)
   *	       1	Software (ignored)
   *	       2	TurboChannel Slot 0
   *	       3	TurboChannel Slot 1
   *	       4	TurboChannel Slot 2
   *	       5	TurboChannel Slot 3 (ASIC)
   *	       6	Halt button
   *	       7	FPU/R4k timer
   *
   * DS5000/2x's, aka kn02ca, aka maxine:
   *
   *	MIPS IRQ	Source
   *	--------	------
   *	       0	Software (ignored)
   *	       1	Software (ignored)
   *	       2	Periodic Interrupt (100usec)
   *	       3	RTC
   *	       4	I/O write timeout
   *	       5	TurboChannel (ASIC)
   *	       6	Halt Keycode from Access.Bus keyboard (CTRL-ALT-ENTER)
   *	       7	FPU/R4k timer
   *
   * DS5000/2xx's, aka kn03, aka 3maxplus:
   *
   *	MIPS IRQ	Source
   *	--------	------
   *	       0	Software (ignored)
   *	       1	Software (ignored)
   *	       2	System Board (ASIC)
   *	       3	RTC
   *	       4	Reserved
   *	       5	Memory
   *	       6	Halt Button
   *	       7	FPU/R4k timer
   *
   * We handle the IRQ according to _our_ priority (see setup.c),
   * then we just return.  If multiple IRQs are pending then we will
   * just take another exception, big deal.
   */
  		.align	5
  		NESTED(plat_irq_dispatch, PT_SIZE, ra)
  		.set	noreorder
  
  		/*
  		 * Get pending Interrupts
  		 */
  		mfc0	t0,CP0_CAUSE		# get pending interrupts
  		mfc0	t1,CP0_STATUS
  #ifdef CONFIG_32BIT
  		lw	t2,cpu_fpu_mask
  #endif
  		andi	t0,ST0_IM		# CAUSE.CE may be non-zero!
  		and	t0,t1			# isolate allowed ones
  
  		beqz	t0,spurious
  
  #ifdef CONFIG_32BIT
  		 and	t2,t0
  		bnez	t2,fpu			# handle FPU immediately
  #endif
  
  		/*
  		 * Find irq with highest priority
  		 */
  		 PTR_LA	t1,cpu_mask_nr_tbl
  1:		lw	t2,(t1)
  		nop
  		and	t2,t0
  		beqz	t2,1b
  		 addu	t1,2*PTRSIZE		# delay slot
  
  		/*
  		 * Do the low-level stuff
  		 */
  		lw	a0,(-PTRSIZE)(t1)
  		nop
  		bgez	a0,handle_it		# irq_nr >= 0?
  						# irq_nr < 0: it is an address
  		 nop
  		jr	a0
  						# a trick to save a branch:
  		 lui	t2,(KN03_IOASIC_BASE>>16)&0xffff
  						# upper part of IOASIC Address
  
  /*
   * Handle "IRQ Controller" Interrupts
   * Masked Interrupts are still visible and have to be masked "by hand".
   */
  		FEXPORT(kn02_io_int)		# 3max
  		lui	t0,(KN02_CSR_BASE>>16)&0xffff
  						# get interrupt status and mask
  		lw	t0,(t0)
  		nop
  		andi	t1,t0,KN02_IRQ_ALL
  		b	1f
  		 srl	t0,16			# shift interrupt mask
  
  		FEXPORT(kn02xa_io_int)		# 3min/maxine
  		lui	t2,(KN02XA_IOASIC_BASE>>16)&0xffff
  						# upper part of IOASIC Address
  
  		FEXPORT(kn03_io_int)		# 3max+ (t2 loaded earlier)
  		lw	t0,IO_REG_SIR(t2)	# get status: IOASIC sir
  		lw	t1,IO_REG_SIMR(t2)	# get mask:   IOASIC simr
  		nop
  
  1:		and	t0,t1			# mask out allowed ones
  
  		beqz	t0,spurious
  
  		/*
  		 * Find irq with highest priority
  		 */
  		 PTR_LA	t1,asic_mask_nr_tbl
  2:		lw	t2,(t1)
  		nop
  		and	t2,t0
  		beq	zero,t2,2b
  		 addu	t1,2*PTRSIZE		# delay slot
  
  		/*
  		 * Do the low-level stuff
  		 */
  		lw	a0,%lo(-PTRSIZE)(t1)
  		nop
  		bgez	a0,handle_it		# irq_nr >= 0?
  						# irq_nr < 0: it is an address
  		 nop
  		jr	a0
  		 nop				# delay slot
  
  /*
   * Dispatch low-priority interrupts.  We reconsider all status
   * bits again, which looks like a lose, but it makes the code
   * simple and O(log n), so it gets compensated.
   */
  		FEXPORT(cpu_all_int)		# HALT, timers, software junk
  		li	a0,DEC_CPU_IRQ_BASE
  		srl	t0,CAUSEB_IP
  		li	t1,CAUSEF_IP>>CAUSEB_IP	# mask
  		b	1f
  		 li	t2,4			# nr of bits / 2
  
  		FEXPORT(kn02_all_int)		# impossible ?
  		li	a0,KN02_IRQ_BASE
  		li	t1,KN02_IRQ_ALL		# mask
  		b	1f
  		 li	t2,4			# nr of bits / 2
  
  		FEXPORT(asic_all_int)		# various I/O ASIC junk
  		li	a0,IO_IRQ_BASE
  		li	t1,IO_IRQ_ALL		# mask
  		b	1f
  		 li	t2,8			# nr of bits / 2
  
  /*
   * Dispatch DMA interrupts -- O(log n).
   */
  		FEXPORT(asic_dma_int)		# I/O ASIC DMA events
  		li	a0,IO_IRQ_BASE+IO_INR_DMA
  		srl	t0,IO_INR_DMA
  		li	t1,IO_IRQ_DMA>>IO_INR_DMA # mask
  		li	t2,8			# nr of bits / 2
  
  		/*
  		 * Find irq with highest priority.
  		 * Highest irq number takes precedence.
  		 */
  1:		srlv	t3,t1,t2
  2:		xor	t1,t3
  		and	t3,t0,t1
  		beqz	t3,3f
  		 nop
  		move	t0,t3
  		addu	a0,t2
  3:		srl	t2,1
  		bnez	t2,2b
  		 srlv	t3,t1,t2
  
  handle_it:
  		j	dec_irq_dispatch
  		 nop
  
  #ifdef CONFIG_32BIT
  fpu:
  		j	handle_fpe_int
  		 nop
  #endif
  
  spurious:
  		j	spurious_interrupt
  		 nop
  		END(plat_irq_dispatch)
  
  /*
   * Generic unimplemented interrupt routines -- cpu_mask_nr_tbl
   * and asic_mask_nr_tbl are initialized to point all interrupts here.
   * The tables are then filled in by machine-specific initialisation
   * in dec_setup().
   */
  		FEXPORT(dec_intr_unimplemented)
  		move	a1,t0			# cheats way of printing an arg!
  		PANIC("Unimplemented cpu interrupt! CP0_CAUSE: 0x%08x");
  
  		FEXPORT(asic_intr_unimplemented)
  		move	a1,t0			# cheats way of printing an arg!
  		PANIC("Unimplemented asic interrupt! ASIC ISR: 0x%08x");