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Janusz Krzysztofik11f95622010-04-28 01:03:59 +00001/*
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
Tony Lindgrene27e35e2012-09-19 10:33:43 -070022#include <mach/board-ams-delta.h>
Janusz Krzysztofik11f95622010-04-28 01:03:59 +000023
24#include <asm/fiq.h>
Tony Lindgren2e3ee9f2012-02-24 10:34:34 -080025
Janusz Krzysztofik11f95622010-04-28 01:03:59 +000026#include <mach/ams-delta-fiq.h>
27
28static 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 */
40unsigned int fiq_buffer[1024];
41EXPORT_SYMBOL(fiq_buffer);
42
43static unsigned int irq_counter[16];
44
45static irqreturn_t deferred_fiq(int irq, void *dev_id)
46{
47 struct irq_desc *irq_desc;
48 struct irq_chip *irq_chip = NULL;
49 int gpio, irq_num, fiq_count;
50
Janusz Krzysztofikb6392bd2012-04-30 19:26:09 +020051 irq_desc = irq_to_desc(gpio_to_irq(AMS_DELTA_GPIO_PIN_KEYBRD_CLK));
Janusz Krzysztofik11f95622010-04-28 01:03:59 +000052 if (irq_desc)
Lennert Buytenheka51eef72010-11-29 10:39:27 +010053 irq_chip = irq_desc->irq_data.chip;
Janusz Krzysztofik11f95622010-04-28 01:03:59 +000054
55 /*
56 * For each handled GPIO interrupt, keep calling its interrupt handler
57 * until the IRQ counter catches the FIQ incremented interrupt counter.
58 */
59 for (gpio = AMS_DELTA_GPIO_PIN_KEYBRD_CLK;
60 gpio <= AMS_DELTA_GPIO_PIN_HOOK_SWITCH; gpio++) {
61 irq_num = gpio_to_irq(gpio);
62 fiq_count = fiq_buffer[FIQ_CNT_INT_00 + gpio];
63
64 while (irq_counter[gpio] < fiq_count) {
65 if (gpio != AMS_DELTA_GPIO_PIN_KEYBRD_CLK) {
Lennert Buytenheka51eef72010-11-29 10:39:27 +010066 struct irq_data *d = irq_get_irq_data(irq_num);
67
Janusz Krzysztofik11f95622010-04-28 01:03:59 +000068 /*
69 * It looks like handle_edge_irq() that
70 * OMAP GPIO edge interrupts default to,
71 * expects interrupt already unmasked.
72 */
Lennert Buytenheka51eef72010-11-29 10:39:27 +010073 if (irq_chip && irq_chip->irq_unmask)
74 irq_chip->irq_unmask(d);
Janusz Krzysztofik11f95622010-04-28 01:03:59 +000075 }
76 generic_handle_irq(irq_num);
77
78 irq_counter[gpio]++;
79 }
80 }
81 return IRQ_HANDLED;
82}
83
84void __init ams_delta_init_fiq(void)
85{
86 void *fiqhandler_start;
87 unsigned int fiqhandler_length;
88 struct pt_regs FIQ_regs;
89 unsigned long val, offset;
90 int i, retval;
91
92 fiqhandler_start = &qwerty_fiqin_start;
93 fiqhandler_length = &qwerty_fiqin_end - &qwerty_fiqin_start;
94 pr_info("Installing fiq handler from %p, length 0x%x\n",
95 fiqhandler_start, fiqhandler_length);
96
97 retval = claim_fiq(&fh);
98 if (retval) {
99 pr_err("ams_delta_init_fiq(): couldn't claim FIQ, ret=%d\n",
100 retval);
101 return;
102 }
103
104 retval = request_irq(INT_DEFERRED_FIQ, deferred_fiq,
Paul Walmsleya7022d62012-04-13 06:34:28 -0600105 IRQ_TYPE_EDGE_RISING, "deferred_fiq", NULL);
Janusz Krzysztofik11f95622010-04-28 01:03:59 +0000106 if (retval < 0) {
107 pr_err("Failed to get deferred_fiq IRQ, ret=%d\n", retval);
108 release_fiq(&fh);
109 return;
110 }
111 /*
112 * Since no set_type() method is provided by OMAP irq chip,
113 * switch to edge triggered interrupt type manually.
114 */
115 offset = IRQ_ILR0_REG_OFFSET + INT_DEFERRED_FIQ * 0x4;
116 val = omap_readl(DEFERRED_FIQ_IH_BASE + offset) & ~(1 << 1);
117 omap_writel(val, DEFERRED_FIQ_IH_BASE + offset);
118
119 set_fiq_handler(fiqhandler_start, fiqhandler_length);
120
121 /*
122 * Initialise the buffer which is shared
123 * between FIQ mode and IRQ mode
124 */
125 fiq_buffer[FIQ_GPIO_INT_MASK] = 0;
126 fiq_buffer[FIQ_MASK] = 0;
127 fiq_buffer[FIQ_STATE] = 0;
128 fiq_buffer[FIQ_KEY] = 0;
129 fiq_buffer[FIQ_KEYS_CNT] = 0;
130 fiq_buffer[FIQ_KEYS_HICNT] = 0;
131 fiq_buffer[FIQ_TAIL_OFFSET] = 0;
132 fiq_buffer[FIQ_HEAD_OFFSET] = 0;
133 fiq_buffer[FIQ_BUF_LEN] = 256;
134 fiq_buffer[FIQ_MISSED_KEYS] = 0;
135 fiq_buffer[FIQ_BUFFER_START] =
136 (unsigned int) &fiq_buffer[FIQ_CIRC_BUFF];
137
138 for (i = FIQ_CNT_INT_00; i <= FIQ_CNT_INT_15; i++)
139 fiq_buffer[i] = 0;
140
141 /*
142 * FIQ mode r9 always points to the fiq_buffer, becauses the FIQ isr
143 * will run in an unpredictable context. The fiq_buffer is the FIQ isr's
144 * only means of communication with the IRQ level and other kernel
145 * context code.
146 */
147 FIQ_regs.ARM_r9 = (unsigned int)fiq_buffer;
148 set_fiq_regs(&FIQ_regs);
149
150 pr_info("request_fiq(): fiq_buffer = %p\n", fiq_buffer);
151
152 /*
153 * Redirect GPIO interrupts to FIQ
154 */
155 offset = IRQ_ILR0_REG_OFFSET + INT_GPIO_BANK1 * 0x4;
156 val = omap_readl(OMAP_IH1_BASE + offset) | 1;
157 omap_writel(val, OMAP_IH1_BASE + offset);
158}