1 /*
2 * linux/arch/arm/mach-omap1/fpga.c
3 *
4 * Interrupt handler for OMAP-1510 Innovator FPGA
5 *
6 * Copyright (C) 2001 RidgeRun, Inc.
7 * Author: Greg Lonnon <glonnon@ridgerun.com>
8 *
9 * Copyright (C) 2002 MontaVista Software, Inc.
10 *
11 * Separated FPGA interrupts from innovator1510.c and cleaned up for 2.6
12 * Copyright (C) 2004 Nokia Corporation by Tony Lindrgen <tony@atomide.com>
13 *
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License version 2 as
16 * published by the Free Software Foundation.
17 */
18
19 #include <linux/types.h>
20 #include <linux/init.h>
21 #include <linux/kernel.h>
22 #include <linux/device.h>
23 #include <linux/errno.h>
24 #include <linux/io.h>
25
26 #include <mach/hardware.h>
27 #include <asm/irq.h>
28 #include <asm/mach/irq.h>
29
30 #include <mach/fpga.h>
31 #include <mach/gpio.h>
32
33 static void fpga_mask_irq(unsigned int irq)
34 {
35 irq -= OMAP_FPGA_IRQ_BASE;
36
37 if (irq < 8)
38 __raw_writeb((__raw_readb(OMAP1510_FPGA_IMR_LO)
39 & ~(1 << irq)), OMAP1510_FPGA_IMR_LO);
40 else if (irq < 16)
41 __raw_writeb((__raw_readb(OMAP1510_FPGA_IMR_HI)
42 & ~(1 << (irq - 8))), OMAP1510_FPGA_IMR_HI);
43 else
44 __raw_writeb((__raw_readb(INNOVATOR_FPGA_IMR2)
45 & ~(1 << (irq - 16))), INNOVATOR_FPGA_IMR2);
46 }
47
48
49 static inline u32 get_fpga_unmasked_irqs(void)
50 {
51 return
52 ((__raw_readb(OMAP1510_FPGA_ISR_LO) &
53 __raw_readb(OMAP1510_FPGA_IMR_LO))) |
54 ((__raw_readb(OMAP1510_FPGA_ISR_HI) &
55 __raw_readb(OMAP1510_FPGA_IMR_HI)) << 8) |
56 ((__raw_readb(INNOVATOR_FPGA_ISR2) &
57 __raw_readb(INNOVATOR_FPGA_IMR2)) << 16);
58 }
59
60
61 static void fpga_ack_irq(unsigned int irq)
62 {
63 /* Don't need to explicitly ACK FPGA interrupts */
64 }
65
66 static void fpga_unmask_irq(unsigned int irq)
67 {
68 irq -= OMAP_FPGA_IRQ_BASE;
69
70 if (irq < 8)
71 __raw_writeb((__raw_readb(OMAP1510_FPGA_IMR_LO) | (1 << irq)),
72 OMAP1510_FPGA_IMR_LO);
73 else if (irq < 16)
74 __raw_writeb((__raw_readb(OMAP1510_FPGA_IMR_HI)
75 | (1 << (irq - 8))), OMAP1510_FPGA_IMR_HI);
76 else
77 __raw_writeb((__raw_readb(INNOVATOR_FPGA_IMR2)
78 | (1 << (irq - 16))), INNOVATOR_FPGA_IMR2);
79 }
80
81 static void fpga_mask_ack_irq(unsigned int irq)
82 {
83 fpga_mask_irq(irq);
84 fpga_ack_irq(irq);
85 }
86
87 void innovator_fpga_IRQ_demux(unsigned int irq, struct irq_desc *desc)
88 {
89 u32 stat;
90 int fpga_irq;
91
92 stat = get_fpga_unmasked_irqs();
93
94 if (!stat)
95 return;
96
97 for (fpga_irq = OMAP_FPGA_IRQ_BASE;
98 (fpga_irq < OMAP_FPGA_IRQ_END) && stat;
99 fpga_irq++, stat >>= 1) {
100 if (stat & 1) {
101 generic_handle_irq(fpga_irq);
102 }
103 }
104 }
105
106 static struct irq_chip omap_fpga_irq_ack = {
107 .name = "FPGA-ack",
108 .ack = fpga_mask_ack_irq,
109 .mask = fpga_mask_irq,
110 .unmask = fpga_unmask_irq,
111 };
112
113
114 static struct irq_chip omap_fpga_irq = {
115 .name = "FPGA",
116 .ack = fpga_ack_irq,
117 .mask = fpga_mask_irq,
118 .unmask = fpga_unmask_irq,
119 };
120
121 /*
122 * All of the FPGA interrupt request inputs except for the touchscreen are
123 * edge-sensitive; the touchscreen is level-sensitive. The edge-sensitive
124 * interrupts are acknowledged as a side-effect of reading the interrupt
125 * status register from the FPGA. The edge-sensitive interrupt inputs
126 * cause a problem with level interrupt requests, such as Ethernet. The
127 * problem occurs when a level interrupt request is asserted while its
128 * interrupt input is masked in the FPGA, which results in a missed
129 * interrupt.
130 *
131 * In an attempt to workaround the problem with missed interrupts, the
132 * mask_ack routine for all of the FPGA interrupts has been changed from
133 * fpga_mask_ack_irq() to fpga_ack_irq() so that the specific FPGA interrupt
134 * being serviced is left unmasked. We can do this because the FPGA cascade
135 * interrupt is installed with the IRQF_DISABLED flag, which leaves all
136 * interrupts masked at the CPU while an FPGA interrupt handler executes.
137 *
138 * Limited testing indicates that this workaround appears to be effective
139 * for the smc9194 Ethernet driver used on the Innovator. It should work
140 * on other FPGA interrupts as well, but any drivers that explicitly mask
141 * interrupts at the interrupt controller via disable_irq/enable_irq
142 * could pose a problem.
143 */
144 void omap1510_fpga_init_irq(void)
145 {
146 int i;
147
148 __raw_writeb(0, OMAP1510_FPGA_IMR_LO);
149 __raw_writeb(0, OMAP1510_FPGA_IMR_HI);
150 __raw_writeb(0, INNOVATOR_FPGA_IMR2);
151
152 for (i = OMAP_FPGA_IRQ_BASE; i < OMAP_FPGA_IRQ_END; i++) {
153
154 if (i == OMAP1510_INT_FPGA_TS) {
155 /*
156 * The touchscreen interrupt is level-sensitive, so
157 * we'll use the regular mask_ack routine for it.
158 */
159 set_irq_chip(i, &omap_fpga_irq_ack);
160 }
161 else {
162 /*
163 * All FPGA interrupts except the touchscreen are
164 * edge-sensitive, so we won't mask them.
165 */
166 set_irq_chip(i, &omap_fpga_irq);
167 }
168
169 set_irq_handler(i, handle_edge_irq);
170 set_irq_flags(i, IRQF_VALID);
171 }
172
173 /*
174 * The FPGA interrupt line is connected to GPIO13. Claim this pin for
175 * the ARM.
176 *
177 * NOTE: For general GPIO/MPUIO access and interrupts, please see
178 * gpio.[ch]
179 */
180 gpio_request(13, "FPGA irq");
181 gpio_direction_input(13);
182 set_irq_type(gpio_to_irq(13), IRQ_TYPE_EDGE_RISING);
183 set_irq_chained_handler(OMAP1510_INT_FPGA, innovator_fpga_IRQ_demux);
184 }
185
186 EXPORT_SYMBOL(omap1510_fpga_init_irq);
187
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