ams-delta-fiq.c
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/*
* Amstrad E3 FIQ handling
*
* Copyright (C) 2009 Janusz Krzysztofik
* Copyright (c) 2006 Matt Callow
* Copyright (c) 2004 Amstrad Plc
* Copyright (C) 2001 RidgeRun, Inc.
*
* Parts of this code are taken from linux/arch/arm/mach-omap/irq.c
* in the MontaVista 2.4 kernel (and the Amstrad changes therein)
*
* 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/gpio.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/io.h>
#include <mach/board-ams-delta.h>
#include <asm/fiq.h>
#include <mach/ams-delta-fiq.h>
static struct fiq_handler fh = {
.name = "ams-delta-fiq"
};
/*
* This buffer is shared between FIQ and IRQ contexts.
* The FIQ and IRQ isrs can both read and write it.
* It is structured as a header section several 32bit slots,
* followed by the circular buffer where the FIQ isr stores
* keystrokes received from the qwerty keyboard.
* See ams-delta-fiq.h for details of offsets.
*/
unsigned int fiq_buffer[1024];
EXPORT_SYMBOL(fiq_buffer);
static unsigned int irq_counter[16];
static irqreturn_t deferred_fiq(int irq, void *dev_id)
{
struct irq_desc *irq_desc;
struct irq_chip *irq_chip = NULL;
int gpio, irq_num, fiq_count;
irq_desc = irq_to_desc(gpio_to_irq(AMS_DELTA_GPIO_PIN_KEYBRD_CLK));
if (irq_desc)
irq_chip = irq_desc->irq_data.chip;
/*
* For each handled GPIO interrupt, keep calling its interrupt handler
* until the IRQ counter catches the FIQ incremented interrupt counter.
*/
for (gpio = AMS_DELTA_GPIO_PIN_KEYBRD_CLK;
gpio <= AMS_DELTA_GPIO_PIN_HOOK_SWITCH; gpio++) {
irq_num = gpio_to_irq(gpio);
fiq_count = fiq_buffer[FIQ_CNT_INT_00 + gpio];
while (irq_counter[gpio] < fiq_count) {
if (gpio != AMS_DELTA_GPIO_PIN_KEYBRD_CLK) {
struct irq_data *d = irq_get_irq_data(irq_num);
/*
* It looks like handle_edge_irq() that
* OMAP GPIO edge interrupts default to,
* expects interrupt already unmasked.
*/
if (irq_chip && irq_chip->irq_unmask)
irq_chip->irq_unmask(d);
}
generic_handle_irq(irq_num);
irq_counter[gpio]++;
}
}
return IRQ_HANDLED;
}
void __init ams_delta_init_fiq(void)
{
void *fiqhandler_start;
unsigned int fiqhandler_length;
struct pt_regs FIQ_regs;
unsigned long val, offset;
int i, retval;
fiqhandler_start = &qwerty_fiqin_start;
fiqhandler_length = &qwerty_fiqin_end - &qwerty_fiqin_start;
pr_info("Installing fiq handler from %p, length 0x%x\n",
fiqhandler_start, fiqhandler_length);
retval = claim_fiq(&fh);
if (retval) {
pr_err("ams_delta_init_fiq(): couldn't claim FIQ, ret=%d\n",
retval);
return;
}
retval = request_irq(INT_DEFERRED_FIQ, deferred_fiq,
IRQ_TYPE_EDGE_RISING, "deferred_fiq", NULL);
if (retval < 0) {
pr_err("Failed to get deferred_fiq IRQ, ret=%d\n", retval);
release_fiq(&fh);
return;
}
/*
* Since no set_type() method is provided by OMAP irq chip,
* switch to edge triggered interrupt type manually.
*/
offset = IRQ_ILR0_REG_OFFSET + INT_DEFERRED_FIQ * 0x4;
val = omap_readl(DEFERRED_FIQ_IH_BASE + offset) & ~(1 << 1);
omap_writel(val, DEFERRED_FIQ_IH_BASE + offset);
set_fiq_handler(fiqhandler_start, fiqhandler_length);
/*
* Initialise the buffer which is shared
* between FIQ mode and IRQ mode
*/
fiq_buffer[FIQ_GPIO_INT_MASK] = 0;
fiq_buffer[FIQ_MASK] = 0;
fiq_buffer[FIQ_STATE] = 0;
fiq_buffer[FIQ_KEY] = 0;
fiq_buffer[FIQ_KEYS_CNT] = 0;
fiq_buffer[FIQ_KEYS_HICNT] = 0;
fiq_buffer[FIQ_TAIL_OFFSET] = 0;
fiq_buffer[FIQ_HEAD_OFFSET] = 0;
fiq_buffer[FIQ_BUF_LEN] = 256;
fiq_buffer[FIQ_MISSED_KEYS] = 0;
fiq_buffer[FIQ_BUFFER_START] =
(unsigned int) &fiq_buffer[FIQ_CIRC_BUFF];
for (i = FIQ_CNT_INT_00; i <= FIQ_CNT_INT_15; i++)
fiq_buffer[i] = 0;
/*
* FIQ mode r9 always points to the fiq_buffer, becauses the FIQ isr
* will run in an unpredictable context. The fiq_buffer is the FIQ isr's
* only means of communication with the IRQ level and other kernel
* context code.
*/
FIQ_regs.ARM_r9 = (unsigned int)fiq_buffer;
set_fiq_regs(&FIQ_regs);
pr_info("request_fiq(): fiq_buffer = %p\n", fiq_buffer);
/*
* Redirect GPIO interrupts to FIQ
*/
offset = IRQ_ILR0_REG_OFFSET + INT_GPIO_BANK1 * 0x4;
val = omap_readl(OMAP_IH1_BASE + offset) | 1;
omap_writel(val, OMAP_IH1_BASE + offset);
}