1 /* 2 * Amstrad E3 FIQ handling 3 * 4 * Copyright (C) 2009 Janusz Krzysztofik 5 * Copyright (c) 2006 Matt Callow 6 * Copyright (c) 2004 Amstrad Plc 7 * Copyright (C) 2001 RidgeRun, Inc. 8 * 9 * Parts of this code are taken from linux/arch/arm/mach-omap/irq.c 10 * in the MontaVista 2.4 kernel (and the Amstrad changes therein) 11 * 12 * This program is free software; you can redistribute it and/or modify it 13 * under the terms of the GNU General Public License version 2 as published by 14 * the Free Software Foundation. 15 */ 16 #include <linux/gpio.h> 17 #include <linux/interrupt.h> 18 #include <linux/irq.h> 19 #include <linux/module.h> 20 #include <linux/io.h> 21 22 #include <mach/board-ams-delta.h> 23 24 #include <asm/fiq.h> 25 26 #include <mach/ams-delta-fiq.h> 27 28 static struct fiq_handler fh = { 29 .name = "ams-delta-fiq" 30 }; 31 32 /* 33 * This buffer is shared between FIQ and IRQ contexts. 34 * The FIQ and IRQ isrs can both read and write it. 35 * It is structured as a header section several 32bit slots, 36 * followed by the circular buffer where the FIQ isr stores 37 * keystrokes received from the qwerty keyboard. 38 * See ams-delta-fiq.h for details of offsets. 39 */ 40 unsigned int fiq_buffer[1024]; 41 EXPORT_SYMBOL(fiq_buffer); 42 43 static unsigned int irq_counter[16]; 44 45 static irqreturn_t deferred_fiq(int irq, void *dev_id) 46 { 47 int gpio, irq_num, fiq_count; 48 struct irq_chip *irq_chip; 49 50 irq_chip = irq_get_chip(gpio_to_irq(AMS_DELTA_GPIO_PIN_KEYBRD_CLK)); 51 52 /* 53 * For each handled GPIO interrupt, keep calling its interrupt handler 54 * until the IRQ counter catches the FIQ incremented interrupt counter. 55 */ 56 for (gpio = AMS_DELTA_GPIO_PIN_KEYBRD_CLK; 57 gpio <= AMS_DELTA_GPIO_PIN_HOOK_SWITCH; gpio++) { 58 irq_num = gpio_to_irq(gpio); 59 fiq_count = fiq_buffer[FIQ_CNT_INT_00 + gpio]; 60 61 while (irq_counter[gpio] < fiq_count) { 62 if (gpio != AMS_DELTA_GPIO_PIN_KEYBRD_CLK) { 63 struct irq_data *d = irq_get_irq_data(irq_num); 64 65 /* 66 * It looks like handle_edge_irq() that 67 * OMAP GPIO edge interrupts default to, 68 * expects interrupt already unmasked. 69 */ 70 if (irq_chip && irq_chip->irq_unmask) 71 irq_chip->irq_unmask(d); 72 } 73 generic_handle_irq(irq_num); 74 75 irq_counter[gpio]++; 76 } 77 } 78 return IRQ_HANDLED; 79 } 80 81 void __init ams_delta_init_fiq(void) 82 { 83 void *fiqhandler_start; 84 unsigned int fiqhandler_length; 85 struct pt_regs FIQ_regs; 86 unsigned long val, offset; 87 int i, retval; 88 89 fiqhandler_start = &qwerty_fiqin_start; 90 fiqhandler_length = &qwerty_fiqin_end - &qwerty_fiqin_start; 91 pr_info("Installing fiq handler from %p, length 0x%x\n", 92 fiqhandler_start, fiqhandler_length); 93 94 retval = claim_fiq(&fh); 95 if (retval) { 96 pr_err("ams_delta_init_fiq(): couldn't claim FIQ, ret=%d\n", 97 retval); 98 return; 99 } 100 101 retval = request_irq(INT_DEFERRED_FIQ, deferred_fiq, 102 IRQ_TYPE_EDGE_RISING, "deferred_fiq", NULL); 103 if (retval < 0) { 104 pr_err("Failed to get deferred_fiq IRQ, ret=%d\n", retval); 105 release_fiq(&fh); 106 return; 107 } 108 /* 109 * Since no set_type() method is provided by OMAP irq chip, 110 * switch to edge triggered interrupt type manually. 111 */ 112 offset = IRQ_ILR0_REG_OFFSET + 113 ((INT_DEFERRED_FIQ - NR_IRQS_LEGACY) & 0x1f) * 0x4; 114 val = omap_readl(DEFERRED_FIQ_IH_BASE + offset) & ~(1 << 1); 115 omap_writel(val, DEFERRED_FIQ_IH_BASE + offset); 116 117 set_fiq_handler(fiqhandler_start, fiqhandler_length); 118 119 /* 120 * Initialise the buffer which is shared 121 * between FIQ mode and IRQ mode 122 */ 123 fiq_buffer[FIQ_GPIO_INT_MASK] = 0; 124 fiq_buffer[FIQ_MASK] = 0; 125 fiq_buffer[FIQ_STATE] = 0; 126 fiq_buffer[FIQ_KEY] = 0; 127 fiq_buffer[FIQ_KEYS_CNT] = 0; 128 fiq_buffer[FIQ_KEYS_HICNT] = 0; 129 fiq_buffer[FIQ_TAIL_OFFSET] = 0; 130 fiq_buffer[FIQ_HEAD_OFFSET] = 0; 131 fiq_buffer[FIQ_BUF_LEN] = 256; 132 fiq_buffer[FIQ_MISSED_KEYS] = 0; 133 fiq_buffer[FIQ_BUFFER_START] = 134 (unsigned int) &fiq_buffer[FIQ_CIRC_BUFF]; 135 136 for (i = FIQ_CNT_INT_00; i <= FIQ_CNT_INT_15; i++) 137 fiq_buffer[i] = 0; 138 139 /* 140 * FIQ mode r9 always points to the fiq_buffer, because the FIQ isr 141 * will run in an unpredictable context. The fiq_buffer is the FIQ isr's 142 * only means of communication with the IRQ level and other kernel 143 * context code. 144 */ 145 FIQ_regs.ARM_r9 = (unsigned int)fiq_buffer; 146 set_fiq_regs(&FIQ_regs); 147 148 pr_info("request_fiq(): fiq_buffer = %p\n", fiq_buffer); 149 150 /* 151 * Redirect GPIO interrupts to FIQ 152 */ 153 offset = IRQ_ILR0_REG_OFFSET + (INT_GPIO_BANK1 - NR_IRQS_LEGACY) * 0x4; 154 val = omap_readl(OMAP_IH1_BASE + offset) | 1; 155 omap_writel(val, OMAP_IH1_BASE + offset); 156 } 157