kernel-fxtec-pro1x/arch/arm/mach-imx/irq.c
Matt Reimer e2f04e1894 [ARM] 3546/1: PATCH: subtle lost interrupts bug on i.MX
Patch from Matt Reimer

There is a subtle bug in the GPIO interrupt status register
handling in arch/arm/mach-imx/irq.c:imx_gpio_ack_irq(). The
documentation states that a 1 should be written to the relevant bit to
acknowledge a GPIO interrupt, but that is not what the code does.

The problem is that the |= writes back 1s for all the *other*
interrupts represented in the register, so interrupts could get lost.
For example, if interrupts are pending for GPIO B10 and B12, ISR_B
would have the value 0x00001400. Then when the interrupt code handles
GPIO B10, it eventually calls imx_gpio_ack_irq(IRQ_GPIOB(10)), which
effectively does this:

ISR_B |= 1 << 10;

with the result that (0x00001400 | 0x00000400) is written, clearing
the interrupt status bits for *both* GPIO B10 and B12.

The fix is to write 1s only for the interrupts we want to clear.

The same problem seems to be occurring in the DMA code; this patch
does not address those issues.

Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Matt Reimer <mreimer@vpop.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-06-08 22:46:48 +01:00

252 lines
6 KiB
C

/*
* linux/arch/arm/mach-imx/irq.c
*
* Copyright (C) 1999 ARM Limited
* Copyright (C) 2002 Shane Nay (shane@minirl.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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* 03/03/2004 Sascha Hauer <sascha@saschahauer.de>
* Copied from the motorola bsp package and added gpio demux
* interrupt handler
*/
#include <linux/init.h>
#include <linux/list.h>
#include <linux/timer.h>
#include <asm/hardware.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/mach/irq.h>
/*
*
* We simply use the ENABLE DISABLE registers inside of the IMX
* to turn on/off specific interrupts. FIXME- We should
* also add support for the accelerated interrupt controller
* by putting offets to irq jump code in the appropriate
* places.
*
*/
#define INTENNUM_OFF 0x8
#define INTDISNUM_OFF 0xC
#define VA_AITC_BASE IO_ADDRESS(IMX_AITC_BASE)
#define IMX_AITC_INTDISNUM (VA_AITC_BASE + INTDISNUM_OFF)
#define IMX_AITC_INTENNUM (VA_AITC_BASE + INTENNUM_OFF)
#if 0
#define DEBUG_IRQ(fmt...) printk(fmt)
#else
#define DEBUG_IRQ(fmt...) do { } while (0)
#endif
static void
imx_mask_irq(unsigned int irq)
{
__raw_writel(irq, IMX_AITC_INTDISNUM);
}
static void
imx_unmask_irq(unsigned int irq)
{
__raw_writel(irq, IMX_AITC_INTENNUM);
}
static int
imx_gpio_irq_type(unsigned int _irq, unsigned int type)
{
unsigned int irq_type = 0, irq, reg, bit;
irq = _irq - IRQ_GPIOA(0);
reg = irq >> 5;
bit = 1 << (irq % 32);
if (type == IRQT_PROBE) {
/* Don't mess with enabled GPIOs using preconfigured edges or
GPIOs set to alternate function during probe */
/* TODO: support probe */
// if ((GPIO_IRQ_rising_edge[idx] | GPIO_IRQ_falling_edge[idx]) &
// GPIO_bit(gpio))
// return 0;
// if (GAFR(gpio) & (0x3 << (((gpio) & 0xf)*2)))
// return 0;
// type = __IRQT_RISEDGE | __IRQT_FALEDGE;
}
GIUS(reg) |= bit;
DDIR(reg) &= ~(bit);
DEBUG_IRQ("setting type of irq %d to ", _irq);
if (type & __IRQT_RISEDGE) {
DEBUG_IRQ("rising edges\n");
irq_type = 0x0;
}
if (type & __IRQT_FALEDGE) {
DEBUG_IRQ("falling edges\n");
irq_type = 0x1;
}
if (type & __IRQT_LOWLVL) {
DEBUG_IRQ("low level\n");
irq_type = 0x3;
}
if (type & __IRQT_HIGHLVL) {
DEBUG_IRQ("high level\n");
irq_type = 0x2;
}
if (irq % 32 < 16) {
ICR1(reg) = (ICR1(reg) & ~(0x3 << ((irq % 16) * 2))) |
(irq_type << ((irq % 16) * 2));
} else {
ICR2(reg) = (ICR2(reg) & ~(0x3 << ((irq % 16) * 2))) |
(irq_type << ((irq % 16) * 2));
}
return 0;
}
static void
imx_gpio_ack_irq(unsigned int irq)
{
DEBUG_IRQ("%s: irq %d\n", __FUNCTION__, irq);
ISR(IRQ_TO_REG(irq)) = 1 << ((irq - IRQ_GPIOA(0)) % 32);
}
static void
imx_gpio_mask_irq(unsigned int irq)
{
DEBUG_IRQ("%s: irq %d\n", __FUNCTION__, irq);
IMR(IRQ_TO_REG(irq)) &= ~( 1 << ((irq - IRQ_GPIOA(0)) % 32));
}
static void
imx_gpio_unmask_irq(unsigned int irq)
{
DEBUG_IRQ("%s: irq %d\n", __FUNCTION__, irq);
IMR(IRQ_TO_REG(irq)) |= 1 << ((irq - IRQ_GPIOA(0)) % 32);
}
static void
imx_gpio_handler(unsigned int mask, unsigned int irq,
struct irqdesc *desc, struct pt_regs *regs)
{
desc = irq_desc + irq;
while (mask) {
if (mask & 1) {
DEBUG_IRQ("handling irq %d\n", irq);
desc_handle_irq(irq, desc, regs);
}
irq++;
desc++;
mask >>= 1;
}
}
static void
imx_gpioa_demux_handler(unsigned int irq_unused, struct irqdesc *desc,
struct pt_regs *regs)
{
unsigned int mask, irq;
mask = ISR(0);
irq = IRQ_GPIOA(0);
imx_gpio_handler(mask, irq, desc, regs);
}
static void
imx_gpiob_demux_handler(unsigned int irq_unused, struct irqdesc *desc,
struct pt_regs *regs)
{
unsigned int mask, irq;
mask = ISR(1);
irq = IRQ_GPIOB(0);
imx_gpio_handler(mask, irq, desc, regs);
}
static void
imx_gpioc_demux_handler(unsigned int irq_unused, struct irqdesc *desc,
struct pt_regs *regs)
{
unsigned int mask, irq;
mask = ISR(2);
irq = IRQ_GPIOC(0);
imx_gpio_handler(mask, irq, desc, regs);
}
static void
imx_gpiod_demux_handler(unsigned int irq_unused, struct irqdesc *desc,
struct pt_regs *regs)
{
unsigned int mask, irq;
mask = ISR(3);
irq = IRQ_GPIOD(0);
imx_gpio_handler(mask, irq, desc, regs);
}
static struct irqchip imx_internal_chip = {
.ack = imx_mask_irq,
.mask = imx_mask_irq,
.unmask = imx_unmask_irq,
};
static struct irqchip imx_gpio_chip = {
.ack = imx_gpio_ack_irq,
.mask = imx_gpio_mask_irq,
.unmask = imx_gpio_unmask_irq,
.set_type = imx_gpio_irq_type,
};
void __init
imx_init_irq(void)
{
unsigned int irq;
DEBUG_IRQ("Initializing imx interrupts\n");
/* Mask all interrupts initially */
IMR(0) = 0;
IMR(1) = 0;
IMR(2) = 0;
IMR(3) = 0;
for (irq = 0; irq < IMX_IRQS; irq++) {
set_irq_chip(irq, &imx_internal_chip);
set_irq_handler(irq, do_level_IRQ);
set_irq_flags(irq, IRQF_VALID);
}
for (irq = IRQ_GPIOA(0); irq < IRQ_GPIOD(32); irq++) {
set_irq_chip(irq, &imx_gpio_chip);
set_irq_handler(irq, do_edge_IRQ);
set_irq_flags(irq, IRQF_VALID);
}
set_irq_chained_handler(GPIO_INT_PORTA, imx_gpioa_demux_handler);
set_irq_chained_handler(GPIO_INT_PORTB, imx_gpiob_demux_handler);
set_irq_chained_handler(GPIO_INT_PORTC, imx_gpioc_demux_handler);
set_irq_chained_handler(GPIO_INT_PORTD, imx_gpiod_demux_handler);
/* Disable all interrupts initially. */
/* In IMX this is done in the bootloader. */
}