156 lines
4.3 KiB
C
156 lines
4.3 KiB
C
/*
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* Amstrad E3 FIQ handling
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*
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* Copyright (C) 2009 Janusz Krzysztofik
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* Copyright (c) 2006 Matt Callow
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* Copyright (c) 2004 Amstrad Plc
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* Copyright (C) 2001 RidgeRun, Inc.
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*
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* Parts of this code are taken from linux/arch/arm/mach-omap/irq.c
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* in the MontaVista 2.4 kernel (and the Amstrad changes therein)
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*/
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#include <linux/gpio.h>
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#include <linux/module.h>
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#include <linux/io.h>
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#include <plat/board-ams-delta.h>
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#include <asm/fiq.h>
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#include <mach/ams-delta-fiq.h>
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static struct fiq_handler fh = {
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.name = "ams-delta-fiq"
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};
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/*
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* This buffer is shared between FIQ and IRQ contexts.
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* The FIQ and IRQ isrs can both read and write it.
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* It is structured as a header section several 32bit slots,
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* followed by the circular buffer where the FIQ isr stores
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* keystrokes received from the qwerty keyboard.
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* See ams-delta-fiq.h for details of offsets.
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*/
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unsigned int fiq_buffer[1024];
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EXPORT_SYMBOL(fiq_buffer);
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static unsigned int irq_counter[16];
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static irqreturn_t deferred_fiq(int irq, void *dev_id)
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{
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struct irq_desc *irq_desc;
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struct irq_chip *irq_chip = NULL;
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int gpio, irq_num, fiq_count;
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irq_desc = irq_to_desc(IH_GPIO_BASE);
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if (irq_desc)
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irq_chip = irq_desc->chip;
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/*
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* For each handled GPIO interrupt, keep calling its interrupt handler
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* until the IRQ counter catches the FIQ incremented interrupt counter.
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*/
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for (gpio = AMS_DELTA_GPIO_PIN_KEYBRD_CLK;
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gpio <= AMS_DELTA_GPIO_PIN_HOOK_SWITCH; gpio++) {
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irq_num = gpio_to_irq(gpio);
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fiq_count = fiq_buffer[FIQ_CNT_INT_00 + gpio];
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while (irq_counter[gpio] < fiq_count) {
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if (gpio != AMS_DELTA_GPIO_PIN_KEYBRD_CLK) {
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/*
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* It looks like handle_edge_irq() that
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* OMAP GPIO edge interrupts default to,
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* expects interrupt already unmasked.
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*/
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if (irq_chip && irq_chip->unmask)
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irq_chip->unmask(irq_num);
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}
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generic_handle_irq(irq_num);
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irq_counter[gpio]++;
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}
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}
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return IRQ_HANDLED;
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}
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void __init ams_delta_init_fiq(void)
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{
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void *fiqhandler_start;
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unsigned int fiqhandler_length;
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struct pt_regs FIQ_regs;
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unsigned long val, offset;
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int i, retval;
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fiqhandler_start = &qwerty_fiqin_start;
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fiqhandler_length = &qwerty_fiqin_end - &qwerty_fiqin_start;
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pr_info("Installing fiq handler from %p, length 0x%x\n",
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fiqhandler_start, fiqhandler_length);
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retval = claim_fiq(&fh);
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if (retval) {
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pr_err("ams_delta_init_fiq(): couldn't claim FIQ, ret=%d\n",
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retval);
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return;
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}
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retval = request_irq(INT_DEFERRED_FIQ, deferred_fiq,
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IRQ_TYPE_EDGE_RISING, "deferred_fiq", 0);
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if (retval < 0) {
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pr_err("Failed to get deferred_fiq IRQ, ret=%d\n", retval);
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release_fiq(&fh);
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return;
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}
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/*
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* Since no set_type() method is provided by OMAP irq chip,
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* switch to edge triggered interrupt type manually.
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*/
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offset = IRQ_ILR0_REG_OFFSET + INT_DEFERRED_FIQ * 0x4;
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val = omap_readl(DEFERRED_FIQ_IH_BASE + offset) & ~(1 << 1);
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omap_writel(val, DEFERRED_FIQ_IH_BASE + offset);
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set_fiq_handler(fiqhandler_start, fiqhandler_length);
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/*
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* Initialise the buffer which is shared
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* between FIQ mode and IRQ mode
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*/
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fiq_buffer[FIQ_GPIO_INT_MASK] = 0;
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fiq_buffer[FIQ_MASK] = 0;
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fiq_buffer[FIQ_STATE] = 0;
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fiq_buffer[FIQ_KEY] = 0;
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fiq_buffer[FIQ_KEYS_CNT] = 0;
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fiq_buffer[FIQ_KEYS_HICNT] = 0;
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fiq_buffer[FIQ_TAIL_OFFSET] = 0;
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fiq_buffer[FIQ_HEAD_OFFSET] = 0;
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fiq_buffer[FIQ_BUF_LEN] = 256;
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fiq_buffer[FIQ_MISSED_KEYS] = 0;
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fiq_buffer[FIQ_BUFFER_START] =
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(unsigned int) &fiq_buffer[FIQ_CIRC_BUFF];
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for (i = FIQ_CNT_INT_00; i <= FIQ_CNT_INT_15; i++)
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fiq_buffer[i] = 0;
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/*
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* FIQ mode r9 always points to the fiq_buffer, becauses the FIQ isr
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* will run in an unpredictable context. The fiq_buffer is the FIQ isr's
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* only means of communication with the IRQ level and other kernel
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* context code.
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*/
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FIQ_regs.ARM_r9 = (unsigned int)fiq_buffer;
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set_fiq_regs(&FIQ_regs);
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pr_info("request_fiq(): fiq_buffer = %p\n", fiq_buffer);
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/*
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* Redirect GPIO interrupts to FIQ
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*/
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offset = IRQ_ILR0_REG_OFFSET + INT_GPIO_BANK1 * 0x4;
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val = omap_readl(OMAP_IH1_BASE + offset) | 1;
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omap_writel(val, OMAP_IH1_BASE + offset);
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}
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