1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * linux/arch/arm/mach-omap1/fpga.c
4 *
5 * Interrupt handler for OMAP-1510 Innovator FPGA
6 *
7 * Copyright (C) 2001 RidgeRun, Inc.
8 * Author: Greg Lonnon <glonnon@ridgerun.com>
9 *
10 * Copyright (C) 2002 MontaVista Software, Inc.
11 *
12 * Separated FPGA interrupts from innovator1510.c and cleaned up for 2.6
13 * Copyright (C) 2004 Nokia Corporation by Tony Lindrgen <tony@atomide.com>
14 */
15
16 #include <linux/types.h>
17 #include <linux/gpio.h>
18 #include <linux/init.h>
19 #include <linux/kernel.h>
20 #include <linux/device.h>
21 #include <linux/errno.h>
22 #include <linux/io.h>
23
24 #include <asm/irq.h>
25 #include <asm/mach/irq.h>
26
27 #include <mach/hardware.h>
28
29 #include "iomap.h"
30 #include "common.h"
31 #include "fpga.h"
32
fpga_mask_irq(struct irq_data * d)33 static void fpga_mask_irq(struct irq_data *d)
34 {
35 unsigned int irq = d->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
get_fpga_unmasked_irqs(void)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
fpga_ack_irq(struct irq_data * d)61 static void fpga_ack_irq(struct irq_data *d)
62 {
63 /* Don't need to explicitly ACK FPGA interrupts */
64 }
65
fpga_unmask_irq(struct irq_data * d)66 static void fpga_unmask_irq(struct irq_data *d)
67 {
68 unsigned int irq = d->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
fpga_mask_ack_irq(struct irq_data * d)81 static void fpga_mask_ack_irq(struct irq_data *d)
82 {
83 fpga_mask_irq(d);
84 fpga_ack_irq(d);
85 }
86
innovator_fpga_IRQ_demux(struct irq_desc * desc)87 static void innovator_fpga_IRQ_demux(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 .irq_ack = fpga_mask_ack_irq,
109 .irq_mask = fpga_mask_irq,
110 .irq_unmask = fpga_unmask_irq,
111 };
112
113
114 static struct irq_chip omap_fpga_irq = {
115 .name = "FPGA",
116 .irq_ack = fpga_ack_irq,
117 .irq_mask = fpga_mask_irq,
118 .irq_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 run with all interrupts masked.
136 *
137 * Limited testing indicates that this workaround appears to be effective
138 * for the smc9194 Ethernet driver used on the Innovator. It should work
139 * on other FPGA interrupts as well, but any drivers that explicitly mask
140 * interrupts at the interrupt controller via disable_irq/enable_irq
141 * could pose a problem.
142 */
omap1510_fpga_init_irq(void)143 void omap1510_fpga_init_irq(void)
144 {
145 int i, res;
146
147 __raw_writeb(0, OMAP1510_FPGA_IMR_LO);
148 __raw_writeb(0, OMAP1510_FPGA_IMR_HI);
149 __raw_writeb(0, INNOVATOR_FPGA_IMR2);
150
151 for (i = OMAP_FPGA_IRQ_BASE; i < OMAP_FPGA_IRQ_END; i++) {
152
153 if (i == OMAP1510_INT_FPGA_TS) {
154 /*
155 * The touchscreen interrupt is level-sensitive, so
156 * we'll use the regular mask_ack routine for it.
157 */
158 irq_set_chip(i, &omap_fpga_irq_ack);
159 }
160 else {
161 /*
162 * All FPGA interrupts except the touchscreen are
163 * edge-sensitive, so we won't mask them.
164 */
165 irq_set_chip(i, &omap_fpga_irq);
166 }
167
168 irq_set_handler(i, handle_edge_irq);
169 irq_clear_status_flags(i, IRQ_NOREQUEST);
170 }
171
172 /*
173 * The FPGA interrupt line is connected to GPIO13. Claim this pin for
174 * the ARM.
175 *
176 * NOTE: For general GPIO/MPUIO access and interrupts, please see
177 * gpio.[ch]
178 */
179 res = gpio_request(13, "FPGA irq");
180 if (res) {
181 pr_err("%s failed to get gpio\n", __func__);
182 return;
183 }
184 gpio_direction_input(13);
185 irq_set_irq_type(gpio_to_irq(13), IRQ_TYPE_EDGE_RISING);
186 irq_set_chained_handler(OMAP1510_INT_FPGA, innovator_fpga_IRQ_demux);
187 }
188