/* * Copyright 2002 Momentum Computer * Author: mdharm@momenco.com * * arch/mips/momentum/ocelot_c/cpci-irq.c *     Interrupt routines for cpci.  Interrupt numbers are assigned from *     CPCI_IRQ_BASE to CPCI_IRQ_BASE+8 (8 interrupt sources). * * Note that the high-level software will need to be careful about using * these interrupts.  If this board is asserting a cPCI interrupt, it will * also see the asserted interrupt.  Care must be taken to avoid an * interrupt flood. * * 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/module.h>#include <linux/interrupt.h>#include <linux/irq.h>#include <linux/kernel.h>#include <asm/ptrace.h>#include <linux/sched.h>#include <linux/kernel_stat.h>#include <asm/io.h>#include "ocelot_c_fpga.h"#define CPCI_IRQ_BASE	8static inline int ls1bit8(unsigned int x){        int b = 7, s;        s =  4; if (((unsigned char)(x <<  4)) == 0) s = 0; b -= s; x <<= s;        s =  2; if (((unsigned char)(x <<  2)) == 0) s = 0; b -= s; x <<= s;        s =  1; if (((unsigned char)(x <<  1)) == 0) s = 0; b -= s;        return b;}/* mask off an interrupt -- 0 is enable, 1 is disable */static inline void mask_cpci_irq(unsigned int irq){	uint32_t value;	value = OCELOT_FPGA_READ(INTMASK);	value |= 1 << (irq - CPCI_IRQ_BASE);	OCELOT_FPGA_WRITE(value, INTMASK);	/* read the value back to assure that it's really been written */	value = OCELOT_FPGA_READ(INTMASK);}/* unmask an interrupt -- 0 is enable, 1 is disable */static inline void unmask_cpci_irq(unsigned int irq){	uint32_t value;	value = OCELOT_FPGA_READ(INTMASK);	value &= ~(1 << (irq - CPCI_IRQ_BASE));	OCELOT_FPGA_WRITE(value, INTMASK);	/* read the value back to assure that it's really been written */	value = OCELOT_FPGA_READ(INTMASK);}/* * Enables the IRQ in the FPGA */static void enable_cpci_irq(unsigned int irq){	unmask_cpci_irq(irq);}/* * Initialize the IRQ in the FPGA */static unsigned int startup_cpci_irq(unsigned int irq){	unmask_cpci_irq(irq);	return 0;}/* * Disables the IRQ in the FPGA */static void disable_cpci_irq(unsigned int irq){	mask_cpci_irq(irq);}/* * Masks and ACKs an IRQ */static void mask_and_ack_cpci_irq(unsigned int irq){	mask_cpci_irq(irq);}/* * End IRQ processing */static void end_cpci_irq(unsigned int irq){	if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))		unmask_cpci_irq(irq);}/* * Interrupt handler for interrupts coming from the FPGA chip. * It could be built in ethernet ports etc... */void ll_cpci_irq(struct pt_regs *regs){	unsigned int irq_src, irq_mask;	/* read the interrupt status registers */	irq_src = OCELOT_FPGA_READ(INTSTAT);	irq_mask = OCELOT_FPGA_READ(INTMASK);	/* mask for just the interrupts we want */	irq_src &= ~irq_mask;	do_IRQ(ls1bit8(irq_src) + CPCI_IRQ_BASE, regs);}#define shutdown_cpci_irq	disable_cpci_irqstruct hw_interrupt_type cpci_irq_type = {	"CPCI/FPGA",	startup_cpci_irq,	shutdown_cpci_irq,	enable_cpci_irq,	disable_cpci_irq,	mask_and_ack_cpci_irq,	end_cpci_irq,	NULL};void cpci_irq_init(void){	int i;	/* Reset irq handlers pointers to NULL */	for (i = CPCI_IRQ_BASE; i < (CPCI_IRQ_BASE + 8); i++) {		irq_desc[i].status = IRQ_DISABLED;		irq_desc[i].action = 0;		irq_desc[i].depth = 2;		irq_desc[i].handler = &cpci_irq_type;	}}