linux/arch/frv/kernel/irq-mb93091.c

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/* irq-mb93091.c: MB93091 FPGA interrupt handling
*
* Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* 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/ptrace.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/bitops.h>
#include <asm/io.h>
#include <asm/system.h>
#include <asm/delay.h>
#include <asm/irq.h>
#include <asm/irc-regs.h>
#define __reg16(ADDR) (*(volatile unsigned short *)(ADDR))
#define __get_IMR() ({ __reg16(0xffc00004); })
#define __set_IMR(M) do { __reg16(0xffc00004) = (M); wmb(); } while(0)
#define __get_IFR() ({ __reg16(0xffc0000c); })
#define __clr_IFR(M) do { __reg16(0xffc0000c) = ~(M); wmb(); } while(0)
/*
* on-motherboard FPGA PIC operations
*/
static void frv_fpga_mask(unsigned int irq)
{
uint16_t imr = __get_IMR();
imr |= 1 << (irq - IRQ_BASE_FPGA);
__set_IMR(imr);
}
static void frv_fpga_ack(unsigned int irq)
{
__clr_IFR(1 << (irq - IRQ_BASE_FPGA));
}
static void frv_fpga_mask_ack(unsigned int irq)
{
uint16_t imr = __get_IMR();
imr |= 1 << (irq - IRQ_BASE_FPGA);
__set_IMR(imr);
__clr_IFR(1 << (irq - IRQ_BASE_FPGA));
}
static void frv_fpga_unmask(unsigned int irq)
{
uint16_t imr = __get_IMR();
imr &= ~(1 << (irq - IRQ_BASE_FPGA));
__set_IMR(imr);
}
static struct irq_chip frv_fpga_pic = {
.name = "mb93091",
.ack = frv_fpga_ack,
.mask = frv_fpga_mask,
.mask_ack = frv_fpga_mask_ack,
.unmask = frv_fpga_unmask,
};
/*
* FPGA PIC interrupt handler
*/
IRQ: Maintain regs pointer globally rather than passing to IRQ handlers Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 15:55:46 +02:00
static irqreturn_t fpga_interrupt(int irq, void *_mask)
{
uint16_t imr, mask = (unsigned long) _mask;
imr = __get_IMR();
mask = mask & ~imr & __get_IFR();
/* poll all the triggered IRQs */
while (mask) {
int irq;
asm("scan %1,gr0,%0" : "=r"(irq) : "r"(mask));
irq = 31 - irq;
mask &= ~(1 << irq);
IRQ: Maintain regs pointer globally rather than passing to IRQ handlers Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 15:55:46 +02:00
generic_handle_irq(IRQ_BASE_FPGA + irq);
}
return IRQ_HANDLED;
}
/*
* define an interrupt action for each FPGA PIC output
* - use dev_id to indicate the FPGA PIC input to output mappings
*/
static struct irqaction fpga_irq[4] = {
[0] = {
.handler = fpga_interrupt,
.flags = IRQF_DISABLED | IRQF_SHARED,
.mask = CPU_MASK_NONE,
.name = "fpga.0",
.dev_id = (void *) 0x0028UL,
},
[1] = {
.handler = fpga_interrupt,
.flags = IRQF_DISABLED | IRQF_SHARED,
.mask = CPU_MASK_NONE,
.name = "fpga.1",
.dev_id = (void *) 0x0050UL,
},
[2] = {
.handler = fpga_interrupt,
.flags = IRQF_DISABLED | IRQF_SHARED,
.mask = CPU_MASK_NONE,
.name = "fpga.2",
.dev_id = (void *) 0x1c00UL,
},
[3] = {
.handler = fpga_interrupt,
.flags = IRQF_DISABLED | IRQF_SHARED,
.mask = CPU_MASK_NONE,
.name = "fpga.3",
.dev_id = (void *) 0x6386UL,
}
};
/*
* initialise the motherboard FPGA's PIC
*/
void __init fpga_init(void)
{
int irq;
/* all PIC inputs are all set to be low-level driven, apart from the
* NMI button (15) which is fixed at falling-edge
*/
__set_IMR(0x7ffe);
__clr_IFR(0x0000);
for (irq = IRQ_BASE_FPGA + 1; irq <= IRQ_BASE_FPGA + 14; irq++)
set_irq_chip_and_handler(irq, &frv_fpga_pic, handle_level_irq);
set_irq_chip_and_handler(IRQ_FPGA_NMI, &frv_fpga_pic, handle_edge_irq);
/* the FPGA drives the first four external IRQ inputs on the CPU PIC */
setup_irq(IRQ_CPU_EXTERNAL0, &fpga_irq[0]);
setup_irq(IRQ_CPU_EXTERNAL1, &fpga_irq[1]);
setup_irq(IRQ_CPU_EXTERNAL2, &fpga_irq[2]);
setup_irq(IRQ_CPU_EXTERNAL3, &fpga_irq[3]);
}