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/*
* linux/arch/arm/mach-omap1/fpga.c
*
* Interrupt handler for OMAP-1510 Innovator FPGA
*
* Copyright (C) 2001 RidgeRun, Inc.
* Author: Greg Lonnon <glonnon@ridgerun.com>
*
* Copyright (C) 2002 MontaVista Software, Inc.
*
* Separated FPGA interrupts from innovator1510.c and cleaned up for 2.6
* Copyright (C) 2004 Nokia Corporation by Tony Lindrgen <tony@atomide.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/types.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/io.h>
#include <mach/hardware.h>
#include <asm/irq.h>
#include <asm/mach/irq.h>
#include <mach/fpga.h>
#include <mach/gpio.h>
static void fpga_mask_irq(unsigned int irq)
{
irq -= OMAP_FPGA_IRQ_BASE;
if (irq < 8)
__raw_writeb((__raw_readb(OMAP1510_FPGA_IMR_LO)
& ~(1 << irq)), OMAP1510_FPGA_IMR_LO);
else if (irq < 16)
__raw_writeb((__raw_readb(OMAP1510_FPGA_IMR_HI)
& ~(1 << (irq - 8))), OMAP1510_FPGA_IMR_HI);
else
__raw_writeb((__raw_readb(INNOVATOR_FPGA_IMR2)
& ~(1 << (irq - 16))), INNOVATOR_FPGA_IMR2);
}
static inline u32 get_fpga_unmasked_irqs(void)
{
return
((__raw_readb(OMAP1510_FPGA_ISR_LO) &
__raw_readb(OMAP1510_FPGA_IMR_LO))) |
((__raw_readb(OMAP1510_FPGA_ISR_HI) &
__raw_readb(OMAP1510_FPGA_IMR_HI)) << 8) |
((__raw_readb(INNOVATOR_FPGA_ISR2) &
__raw_readb(INNOVATOR_FPGA_IMR2)) << 16);
}
static void fpga_ack_irq(unsigned int irq)
{
/* Don't need to explicitly ACK FPGA interrupts */
}
static void fpga_unmask_irq(unsigned int irq)
{
irq -= OMAP_FPGA_IRQ_BASE;
if (irq < 8)
__raw_writeb((__raw_readb(OMAP1510_FPGA_IMR_LO) | (1 << irq)),
OMAP1510_FPGA_IMR_LO);
else if (irq < 16)
__raw_writeb((__raw_readb(OMAP1510_FPGA_IMR_HI)
| (1 << (irq - 8))), OMAP1510_FPGA_IMR_HI);
else
__raw_writeb((__raw_readb(INNOVATOR_FPGA_IMR2)
| (1 << (irq - 16))), INNOVATOR_FPGA_IMR2);
}
static void fpga_mask_ack_irq(unsigned int irq)
{
fpga_mask_irq(irq);
fpga_ack_irq(irq);
}
void innovator_fpga_IRQ_demux(unsigned int irq, struct irq_desc *desc)
{
u32 stat;
int fpga_irq;
stat = get_fpga_unmasked_irqs();
if (!stat)
return;
for (fpga_irq = OMAP_FPGA_IRQ_BASE;
(fpga_irq < OMAP_FPGA_IRQ_END) && stat;
fpga_irq++, stat >>= 1) {
if (stat & 1) {
generic_handle_irq(fpga_irq);
}
}
}
static struct irq_chip omap_fpga_irq_ack = {
.name = "FPGA-ack",
.ack = fpga_mask_ack_irq,
.mask = fpga_mask_irq,
.unmask = fpga_unmask_irq,
};
static struct irq_chip omap_fpga_irq = {
.name = "FPGA",
.ack = fpga_ack_irq,
.mask = fpga_mask_irq,
.unmask = fpga_unmask_irq,
};
/*
* All of the FPGA interrupt request inputs except for the touchscreen are
* edge-sensitive; the touchscreen is level-sensitive. The edge-sensitive
* interrupts are acknowledged as a side-effect of reading the interrupt
* status register from the FPGA. The edge-sensitive interrupt inputs
* cause a problem with level interrupt requests, such as Ethernet. The
* problem occurs when a level interrupt request is asserted while its
* interrupt input is masked in the FPGA, which results in a missed
* interrupt.
*
* In an attempt to workaround the problem with missed interrupts, the
* mask_ack routine for all of the FPGA interrupts has been changed from
* fpga_mask_ack_irq() to fpga_ack_irq() so that the specific FPGA interrupt
* being serviced is left unmasked. We can do this because the FPGA cascade
* interrupt is installed with the IRQF_DISABLED flag, which leaves all
* interrupts masked at the CPU while an FPGA interrupt handler executes.
*
* Limited testing indicates that this workaround appears to be effective
* for the smc9194 Ethernet driver used on the Innovator. It should work
* on other FPGA interrupts as well, but any drivers that explicitly mask
* interrupts at the interrupt controller via disable_irq/enable_irq
* could pose a problem.
*/
void omap1510_fpga_init_irq(void)
{
int i;
__raw_writeb(0, OMAP1510_FPGA_IMR_LO);
__raw_writeb(0, OMAP1510_FPGA_IMR_HI);
__raw_writeb(0, INNOVATOR_FPGA_IMR2);
for (i = OMAP_FPGA_IRQ_BASE; i < OMAP_FPGA_IRQ_END; i++) {
if (i == OMAP1510_INT_FPGA_TS) {
/*
* The touchscreen interrupt is level-sensitive, so
* we'll use the regular mask_ack routine for it.
*/
set_irq_chip(i, &omap_fpga_irq_ack);
}
else {
/*
* All FPGA interrupts except the touchscreen are
* edge-sensitive, so we won't mask them.
*/
set_irq_chip(i, &omap_fpga_irq);
}
set_irq_handler(i, handle_edge_irq);
set_irq_flags(i, IRQF_VALID);
}
/*
* The FPGA interrupt line is connected to GPIO13. Claim this pin for
* the ARM.
*
* NOTE: For general GPIO/MPUIO access and interrupts, please see
* gpio.[ch]
*/
gpio_request(13, "FPGA irq");
gpio_direction_input(13);
set_irq_type(gpio_to_irq(13), IRQ_TYPE_EDGE_RISING);
set_irq_chained_handler(OMAP1510_INT_FPGA, innovator_fpga_IRQ_demux);
}
EXPORT_SYMBOL(omap1510_fpga_init_irq);
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