1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Support for C64x+ Megamodule Interrupt Controller
4 *
5 * Copyright (C) 2010, 2011 Texas Instruments Incorporated
6 * Contributed by: Mark Salter <msalter@redhat.com>
7 */
8 #include <linux/module.h>
9 #include <linux/interrupt.h>
10 #include <linux/io.h>
11 #include <linux/of.h>
12 #include <linux/of_irq.h>
13 #include <linux/of_address.h>
14 #include <linux/slab.h>
15 #include <asm/soc.h>
16 #include <asm/megamod-pic.h>
17
18 #define NR_COMBINERS 4
19 #define NR_MUX_OUTPUTS 12
20
21 #define IRQ_UNMAPPED 0xffff
22
23 /*
24 * Megamodule Interrupt Controller register layout
25 */
26 struct megamod_regs {
27 u32 evtflag[8];
28 u32 evtset[8];
29 u32 evtclr[8];
30 u32 reserved0[8];
31 u32 evtmask[8];
32 u32 mevtflag[8];
33 u32 expmask[8];
34 u32 mexpflag[8];
35 u32 intmux_unused;
36 u32 intmux[7];
37 u32 reserved1[8];
38 u32 aegmux[2];
39 u32 reserved2[14];
40 u32 intxstat;
41 u32 intxclr;
42 u32 intdmask;
43 u32 reserved3[13];
44 u32 evtasrt;
45 };
46
47 struct megamod_pic {
48 struct irq_domain *irqhost;
49 struct megamod_regs __iomem *regs;
50 raw_spinlock_t lock;
51
52 /* hw mux mapping */
53 unsigned int output_to_irq[NR_MUX_OUTPUTS];
54 };
55
56 static struct megamod_pic *mm_pic;
57
58 struct megamod_cascade_data {
59 struct megamod_pic *pic;
60 int index;
61 };
62
63 static struct megamod_cascade_data cascade_data[NR_COMBINERS];
64
mask_megamod(struct irq_data * data)65 static void mask_megamod(struct irq_data *data)
66 {
67 struct megamod_pic *pic = irq_data_get_irq_chip_data(data);
68 irq_hw_number_t src = irqd_to_hwirq(data);
69 u32 __iomem *evtmask = &pic->regs->evtmask[src / 32];
70
71 raw_spin_lock(&pic->lock);
72 soc_writel(soc_readl(evtmask) | (1 << (src & 31)), evtmask);
73 raw_spin_unlock(&pic->lock);
74 }
75
unmask_megamod(struct irq_data * data)76 static void unmask_megamod(struct irq_data *data)
77 {
78 struct megamod_pic *pic = irq_data_get_irq_chip_data(data);
79 irq_hw_number_t src = irqd_to_hwirq(data);
80 u32 __iomem *evtmask = &pic->regs->evtmask[src / 32];
81
82 raw_spin_lock(&pic->lock);
83 soc_writel(soc_readl(evtmask) & ~(1 << (src & 31)), evtmask);
84 raw_spin_unlock(&pic->lock);
85 }
86
87 static struct irq_chip megamod_chip = {
88 .name = "megamod",
89 .irq_mask = mask_megamod,
90 .irq_unmask = unmask_megamod,
91 };
92
megamod_irq_cascade(struct irq_desc * desc)93 static void megamod_irq_cascade(struct irq_desc *desc)
94 {
95 struct megamod_cascade_data *cascade;
96 struct megamod_pic *pic;
97 unsigned int irq;
98 u32 events;
99 int n, idx;
100
101 cascade = irq_desc_get_handler_data(desc);
102
103 pic = cascade->pic;
104 idx = cascade->index;
105
106 while ((events = soc_readl(&pic->regs->mevtflag[idx])) != 0) {
107 n = __ffs(events);
108
109 irq = irq_linear_revmap(pic->irqhost, idx * 32 + n);
110
111 soc_writel(1 << n, &pic->regs->evtclr[idx]);
112
113 generic_handle_irq(irq);
114 }
115 }
116
megamod_map(struct irq_domain * h,unsigned int virq,irq_hw_number_t hw)117 static int megamod_map(struct irq_domain *h, unsigned int virq,
118 irq_hw_number_t hw)
119 {
120 struct megamod_pic *pic = h->host_data;
121 int i;
122
123 /* We shouldn't see a hwirq which is muxed to core controller */
124 for (i = 0; i < NR_MUX_OUTPUTS; i++)
125 if (pic->output_to_irq[i] == hw)
126 return -1;
127
128 irq_set_chip_data(virq, pic);
129 irq_set_chip_and_handler(virq, &megamod_chip, handle_level_irq);
130
131 /* Set default irq type */
132 irq_set_irq_type(virq, IRQ_TYPE_NONE);
133
134 return 0;
135 }
136
137 static const struct irq_domain_ops megamod_domain_ops = {
138 .map = megamod_map,
139 .xlate = irq_domain_xlate_onecell,
140 };
141
set_megamod_mux(struct megamod_pic * pic,int src,int output)142 static void __init set_megamod_mux(struct megamod_pic *pic, int src, int output)
143 {
144 int index, offset;
145 u32 val;
146
147 if (src < 0 || src >= (NR_COMBINERS * 32)) {
148 pic->output_to_irq[output] = IRQ_UNMAPPED;
149 return;
150 }
151
152 /* four mappings per mux register */
153 index = output / 4;
154 offset = (output & 3) * 8;
155
156 val = soc_readl(&pic->regs->intmux[index]);
157 val &= ~(0xff << offset);
158 val |= src << offset;
159 soc_writel(val, &pic->regs->intmux[index]);
160 }
161
162 /*
163 * Parse the MUX mapping, if one exists.
164 *
165 * The MUX map is an array of up to 12 cells; one for each usable core priority
166 * interrupt. The value of a given cell is the megamodule interrupt source
167 * which is to me MUXed to the output corresponding to the cell position
168 * withing the array. The first cell in the array corresponds to priority
169 * 4 and the last (12th) cell corresponds to priority 15. The allowed
170 * values are 4 - ((NR_COMBINERS * 32) - 1). Note that the combined interrupt
171 * sources (0 - 3) are not allowed to be mapped through this property. They
172 * are handled through the "interrupts" property. This allows us to use a
173 * value of zero as a "do not map" placeholder.
174 */
parse_priority_map(struct megamod_pic * pic,int * mapping,int size)175 static void __init parse_priority_map(struct megamod_pic *pic,
176 int *mapping, int size)
177 {
178 struct device_node *np = irq_domain_get_of_node(pic->irqhost);
179 const __be32 *map;
180 int i, maplen;
181 u32 val;
182
183 map = of_get_property(np, "ti,c64x+megamod-pic-mux", &maplen);
184 if (map) {
185 maplen /= 4;
186 if (maplen > size)
187 maplen = size;
188
189 for (i = 0; i < maplen; i++) {
190 val = be32_to_cpup(map);
191 if (val && val >= 4)
192 mapping[i] = val;
193 ++map;
194 }
195 }
196 }
197
init_megamod_pic(struct device_node * np)198 static struct megamod_pic * __init init_megamod_pic(struct device_node *np)
199 {
200 struct megamod_pic *pic;
201 int i, irq;
202 int mapping[NR_MUX_OUTPUTS];
203
204 pr_info("Initializing C64x+ Megamodule PIC\n");
205
206 pic = kzalloc(sizeof(struct megamod_pic), GFP_KERNEL);
207 if (!pic) {
208 pr_err("%pOF: Could not alloc PIC structure.\n", np);
209 return NULL;
210 }
211
212 pic->irqhost = irq_domain_add_linear(np, NR_COMBINERS * 32,
213 &megamod_domain_ops, pic);
214 if (!pic->irqhost) {
215 pr_err("%pOF: Could not alloc host.\n", np);
216 goto error_free;
217 }
218
219 pic->irqhost->host_data = pic;
220
221 raw_spin_lock_init(&pic->lock);
222
223 pic->regs = of_iomap(np, 0);
224 if (!pic->regs) {
225 pr_err("%pOF: Could not map registers.\n", np);
226 goto error_free;
227 }
228
229 /* Initialize MUX map */
230 for (i = 0; i < ARRAY_SIZE(mapping); i++)
231 mapping[i] = IRQ_UNMAPPED;
232
233 parse_priority_map(pic, mapping, ARRAY_SIZE(mapping));
234
235 /*
236 * We can have up to 12 interrupts cascading to the core controller.
237 * These cascades can be from the combined interrupt sources or for
238 * individual interrupt sources. The "interrupts" property only
239 * deals with the cascaded combined interrupts. The individual
240 * interrupts muxed to the core controller use the core controller
241 * as their interrupt parent.
242 */
243 for (i = 0; i < NR_COMBINERS; i++) {
244 struct irq_data *irq_data;
245 irq_hw_number_t hwirq;
246
247 irq = irq_of_parse_and_map(np, i);
248 if (irq == NO_IRQ)
249 continue;
250
251 irq_data = irq_get_irq_data(irq);
252 if (!irq_data) {
253 pr_err("%pOF: combiner-%d no irq_data for virq %d!\n",
254 np, i, irq);
255 continue;
256 }
257
258 hwirq = irq_data->hwirq;
259
260 /*
261 * Check that device tree provided something in the range
262 * of the core priority interrupts (4 - 15).
263 */
264 if (hwirq < 4 || hwirq >= NR_PRIORITY_IRQS) {
265 pr_err("%pOF: combiner-%d core irq %ld out of range!\n",
266 np, i, hwirq);
267 continue;
268 }
269
270 /* record the mapping */
271 mapping[hwirq - 4] = i;
272
273 pr_debug("%pOF: combiner-%d cascading to hwirq %ld\n",
274 np, i, hwirq);
275
276 cascade_data[i].pic = pic;
277 cascade_data[i].index = i;
278
279 /* mask and clear all events in combiner */
280 soc_writel(~0, &pic->regs->evtmask[i]);
281 soc_writel(~0, &pic->regs->evtclr[i]);
282
283 irq_set_chained_handler_and_data(irq, megamod_irq_cascade,
284 &cascade_data[i]);
285 }
286
287 /* Finally, set up the MUX registers */
288 for (i = 0; i < NR_MUX_OUTPUTS; i++) {
289 if (mapping[i] != IRQ_UNMAPPED) {
290 pr_debug("%pOF: setting mux %d to priority %d\n",
291 np, mapping[i], i + 4);
292 set_megamod_mux(pic, mapping[i], i);
293 }
294 }
295
296 return pic;
297
298 error_free:
299 kfree(pic);
300
301 return NULL;
302 }
303
304 /*
305 * Return next active event after ACK'ing it.
306 * Return -1 if no events active.
307 */
get_exception(void)308 static int get_exception(void)
309 {
310 int i, bit;
311 u32 mask;
312
313 for (i = 0; i < NR_COMBINERS; i++) {
314 mask = soc_readl(&mm_pic->regs->mexpflag[i]);
315 if (mask) {
316 bit = __ffs(mask);
317 soc_writel(1 << bit, &mm_pic->regs->evtclr[i]);
318 return (i * 32) + bit;
319 }
320 }
321 return -1;
322 }
323
assert_event(unsigned int val)324 static void assert_event(unsigned int val)
325 {
326 soc_writel(val, &mm_pic->regs->evtasrt);
327 }
328
megamod_pic_init(void)329 void __init megamod_pic_init(void)
330 {
331 struct device_node *np;
332
333 np = of_find_compatible_node(NULL, NULL, "ti,c64x+megamod-pic");
334 if (!np)
335 return;
336
337 mm_pic = init_megamod_pic(np);
338 of_node_put(np);
339
340 soc_ops.get_exception = get_exception;
341 soc_ops.assert_event = assert_event;
342
343 return;
344 }
345