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1/*
2 * Interrupt controller driver for Xilinx Virtex FPGAs
3 *
4 * Copyright (C) 2007 Secret Lab Technologies Ltd.
5 *
6 * This file is licensed under the terms of the GNU General Public License
7 * version 2. This program is licensed "as is" without any warranty of any
8 * kind, whether express or implied.
9 *
10 */
11
12/*
13 * This is a driver for the interrupt controller typically found in
14 * Xilinx Virtex FPGA designs.
15 *
16 * The interrupt sense levels are hard coded into the FPGA design with
17 * typically a 1:1 relationship between irq lines and devices (no shared
18 * irq lines). Therefore, this driver does not attempt to handle edge
19 * and level interrupts differently.
20 */
21#undef DEBUG
22
23#include <linux/kernel.h>
24#include <linux/irq.h>
25#include <linux/of.h>
26#include <asm/io.h>
27#include <asm/processor.h>
28#include <asm/i8259.h>
29#include <asm/irq.h>
30
31/*
32 * INTC Registers
33 */
34#define XINTC_ISR 0 /* Interrupt Status */
35#define XINTC_IPR 4 /* Interrupt Pending */
36#define XINTC_IER 8 /* Interrupt Enable */
37#define XINTC_IAR 12 /* Interrupt Acknowledge */
38#define XINTC_SIE 16 /* Set Interrupt Enable bits */
39#define XINTC_CIE 20 /* Clear Interrupt Enable bits */
40#define XINTC_IVR 24 /* Interrupt Vector */
41#define XINTC_MER 28 /* Master Enable */
42
43static struct irq_host *master_irqhost;
44
45#define XILINX_INTC_MAXIRQS (32)
46
47/* The following table allows the interrupt type, edge or level,
48 * to be cached after being read from the device tree until the interrupt
49 * is mapped
50 */
51static int xilinx_intc_typetable[XILINX_INTC_MAXIRQS];
52
53/* Map the interrupt type from the device tree to the interrupt types
54 * used by the interrupt subsystem
55 */
56static unsigned char xilinx_intc_map_senses[] = {
57 IRQ_TYPE_EDGE_RISING,
58 IRQ_TYPE_EDGE_FALLING,
59 IRQ_TYPE_LEVEL_HIGH,
60 IRQ_TYPE_LEVEL_LOW,
61};
62
63/*
64 * The interrupt controller is setup such that it doesn't work well with
65 * the level interrupt handler in the kernel because the handler acks the
66 * interrupt before calling the application interrupt handler. To deal with
67 * that, we use 2 different irq chips so that different functions can be
68 * used for level and edge type interrupts.
69 *
70 * IRQ Chip common (across level and edge) operations
71 */
72static void xilinx_intc_mask(struct irq_data *d)
73{
74 int irq = irqd_to_hwirq(d);
75 void * regs = irq_data_get_irq_chip_data(d);
76 pr_debug("mask: %d\n", irq);
77 out_be32(regs + XINTC_CIE, 1 << irq);
78}
79
80static int xilinx_intc_set_type(struct irq_data *d, unsigned int flow_type)
81{
82 return 0;
83}
84
85/*
86 * IRQ Chip level operations
87 */
88static void xilinx_intc_level_unmask(struct irq_data *d)
89{
90 int irq = irqd_to_hwirq(d);
91 void * regs = irq_data_get_irq_chip_data(d);
92 pr_debug("unmask: %d\n", irq);
93 out_be32(regs + XINTC_SIE, 1 << irq);
94
95 /* ack level irqs because they can't be acked during
96 * ack function since the handle_level_irq function
97 * acks the irq before calling the inerrupt handler
98 */
99 out_be32(regs + XINTC_IAR, 1 << irq);
100}
101
102static struct irq_chip xilinx_intc_level_irqchip = {
103 .name = "Xilinx Level INTC",
104 .irq_mask = xilinx_intc_mask,
105 .irq_mask_ack = xilinx_intc_mask,
106 .irq_unmask = xilinx_intc_level_unmask,
107 .irq_set_type = xilinx_intc_set_type,
108};
109
110/*
111 * IRQ Chip edge operations
112 */
113static void xilinx_intc_edge_unmask(struct irq_data *d)
114{
115 int irq = irqd_to_hwirq(d);
116 void *regs = irq_data_get_irq_chip_data(d);
117 pr_debug("unmask: %d\n", irq);
118 out_be32(regs + XINTC_SIE, 1 << irq);
119}
120
121static void xilinx_intc_edge_ack(struct irq_data *d)
122{
123 int irq = irqd_to_hwirq(d);
124 void * regs = irq_data_get_irq_chip_data(d);
125 pr_debug("ack: %d\n", irq);
126 out_be32(regs + XINTC_IAR, 1 << irq);
127}
128
129static struct irq_chip xilinx_intc_edge_irqchip = {
130 .name = "Xilinx Edge INTC",
131 .irq_mask = xilinx_intc_mask,
132 .irq_unmask = xilinx_intc_edge_unmask,
133 .irq_ack = xilinx_intc_edge_ack,
134 .irq_set_type = xilinx_intc_set_type,
135};
136
137/*
138 * IRQ Host operations
139 */
140
141/**
142 * xilinx_intc_xlate - translate virq# from device tree interrupts property
143 */
144static int xilinx_intc_xlate(struct irq_host *h, struct device_node *ct,
145 const u32 *intspec, unsigned int intsize,
146 irq_hw_number_t *out_hwirq,
147 unsigned int *out_flags)
148{
149 if ((intsize < 2) || (intspec[0] >= XILINX_INTC_MAXIRQS))
150 return -EINVAL;
151
152 /* keep a copy of the interrupt type til the interrupt is mapped
153 */
154 xilinx_intc_typetable[intspec[0]] = xilinx_intc_map_senses[intspec[1]];
155
156 /* Xilinx uses 2 interrupt entries, the 1st being the h/w
157 * interrupt number, the 2nd being the interrupt type, edge or level
158 */
159 *out_hwirq = intspec[0];
160 *out_flags = xilinx_intc_map_senses[intspec[1]];
161
162 return 0;
163}
164static int xilinx_intc_map(struct irq_host *h, unsigned int virq,
165 irq_hw_number_t irq)
166{
167 irq_set_chip_data(virq, h->host_data);
168
169 if (xilinx_intc_typetable[irq] == IRQ_TYPE_LEVEL_HIGH ||
170 xilinx_intc_typetable[irq] == IRQ_TYPE_LEVEL_LOW) {
171 irq_set_chip_and_handler(virq, &xilinx_intc_level_irqchip,
172 handle_level_irq);
173 } else {
174 irq_set_chip_and_handler(virq, &xilinx_intc_edge_irqchip,
175 handle_edge_irq);
176 }
177 return 0;
178}
179
180static struct irq_host_ops xilinx_intc_ops = {
181 .map = xilinx_intc_map,
182 .xlate = xilinx_intc_xlate,
183};
184
185struct irq_host * __init
186xilinx_intc_init(struct device_node *np)
187{
188 struct irq_host * irq;
189 void * regs;
190
191 /* Find and map the intc registers */
192 regs = of_iomap(np, 0);
193 if (!regs) {
194 pr_err("xilinx_intc: could not map registers\n");
195 return NULL;
196 }
197
198 /* Setup interrupt controller */
199 out_be32(regs + XINTC_IER, 0); /* disable all irqs */
200 out_be32(regs + XINTC_IAR, ~(u32) 0); /* Acknowledge pending irqs */
201 out_be32(regs + XINTC_MER, 0x3UL); /* Turn on the Master Enable. */
202
203 /* Allocate and initialize an irq_host structure. */
204 irq = irq_alloc_host(np, IRQ_HOST_MAP_LINEAR, XILINX_INTC_MAXIRQS,
205 &xilinx_intc_ops, -1);
206 if (!irq)
207 panic(__FILE__ ": Cannot allocate IRQ host\n");
208 irq->host_data = regs;
209
210 return irq;
211}
212
213int xilinx_intc_get_irq(void)
214{
215 void * regs = master_irqhost->host_data;
216 pr_debug("get_irq:\n");
217 return irq_linear_revmap(master_irqhost, in_be32(regs + XINTC_IVR));
218}
219
220#if defined(CONFIG_PPC_I8259)
221/*
222 * Support code for cascading to 8259 interrupt controllers
223 */
224static void xilinx_i8259_cascade(unsigned int irq, struct irq_desc *desc)
225{
226 struct irq_chip *chip = irq_desc_get_chip(desc);
227 unsigned int cascade_irq = i8259_irq();
228
229 if (cascade_irq)
230 generic_handle_irq(cascade_irq);
231
232 /* Let xilinx_intc end the interrupt */
233 chip->irq_unmask(&desc->irq_data);
234}
235
236static void __init xilinx_i8259_setup_cascade(void)
237{
238 struct device_node *cascade_node;
239 int cascade_irq;
240
241 /* Initialize i8259 controller */
242 cascade_node = of_find_compatible_node(NULL, NULL, "chrp,iic");
243 if (!cascade_node)
244 return;
245
246 cascade_irq = irq_of_parse_and_map(cascade_node, 0);
247 if (!cascade_irq) {
248 pr_err("virtex_ml510: Failed to map cascade interrupt\n");
249 goto out;
250 }
251
252 i8259_init(cascade_node, 0);
253 irq_set_chained_handler(cascade_irq, xilinx_i8259_cascade);
254
255 /* Program irq 7 (usb/audio), 14/15 (ide) to level sensitive */
256 /* This looks like a dirty hack to me --gcl */
257 outb(0xc0, 0x4d0);
258 outb(0xc0, 0x4d1);
259
260 out:
261 of_node_put(cascade_node);
262}
263#else
264static inline void xilinx_i8259_setup_cascade(void) { return; }
265#endif /* defined(CONFIG_PPC_I8259) */
266
267static struct of_device_id xilinx_intc_match[] __initconst = {
268 { .compatible = "xlnx,opb-intc-1.00.c", },
269 { .compatible = "xlnx,xps-intc-1.00.a", },
270 {}
271};
272
273/*
274 * Initialize master Xilinx interrupt controller
275 */
276void __init xilinx_intc_init_tree(void)
277{
278 struct device_node *np;
279
280 /* find top level interrupt controller */
281 for_each_matching_node(np, xilinx_intc_match) {
282 if (!of_get_property(np, "interrupts", NULL))
283 break;
284 }
285 BUG_ON(!np);
286
287 master_irqhost = xilinx_intc_init(np);
288 BUG_ON(!master_irqhost);
289
290 irq_set_default_host(master_irqhost);
291 of_node_put(np);
292
293 xilinx_i8259_setup_cascade();
294}