1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * arch/powerpc/sysdev/uic.c
4 *
5 * IBM PowerPC 4xx Universal Interrupt Controller
6 *
7 * Copyright 2007 David Gibson <dwg@au1.ibm.com>, IBM Corporation.
8 */
9 #include <linux/kernel.h>
10 #include <linux/init.h>
11 #include <linux/errno.h>
12 #include <linux/reboot.h>
13 #include <linux/slab.h>
14 #include <linux/stddef.h>
15 #include <linux/sched.h>
16 #include <linux/signal.h>
17 #include <linux/device.h>
18 #include <linux/spinlock.h>
19 #include <linux/irq.h>
20 #include <linux/interrupt.h>
21 #include <linux/kernel_stat.h>
22 #include <linux/of.h>
23 #include <linux/of_irq.h>
24 #include <asm/irq.h>
25 #include <asm/io.h>
26 #include <asm/dcr.h>
27 #include <asm/uic.h>
28
29 #define NR_UIC_INTS 32
30
31 #define UIC_SR 0x0
32 #define UIC_ER 0x2
33 #define UIC_CR 0x3
34 #define UIC_PR 0x4
35 #define UIC_TR 0x5
36 #define UIC_MSR 0x6
37 #define UIC_VR 0x7
38 #define UIC_VCR 0x8
39
40 struct uic *primary_uic;
41
42 struct uic {
43 int index;
44 int dcrbase;
45
46 raw_spinlock_t lock;
47
48 /* The remapper for this UIC */
49 struct irq_domain *irqhost;
50 };
51
52 static void uic_unmask_irq(struct irq_data *d)
53 {
54 struct uic *uic = irq_data_get_irq_chip_data(d);
55 unsigned int src = irqd_to_hwirq(d);
56 unsigned long flags;
57 u32 er, sr;
58
59 sr = 1 << (31-src);
60 raw_spin_lock_irqsave(&uic->lock, flags);
61 /* ack level-triggered interrupts here */
62 if (irqd_is_level_type(d))
63 mtdcr(uic->dcrbase + UIC_SR, sr);
64 er = mfdcr(uic->dcrbase + UIC_ER);
65 er |= sr;
66 mtdcr(uic->dcrbase + UIC_ER, er);
67 raw_spin_unlock_irqrestore(&uic->lock, flags);
68 }
69
70 static void uic_mask_irq(struct irq_data *d)
71 {
72 struct uic *uic = irq_data_get_irq_chip_data(d);
73 unsigned int src = irqd_to_hwirq(d);
74 unsigned long flags;
75 u32 er;
76
77 raw_spin_lock_irqsave(&uic->lock, flags);
78 er = mfdcr(uic->dcrbase + UIC_ER);
79 er &= ~(1 << (31 - src));
80 mtdcr(uic->dcrbase + UIC_ER, er);
81 raw_spin_unlock_irqrestore(&uic->lock, flags);
82 }
83
84 static void uic_ack_irq(struct irq_data *d)
85 {
86 struct uic *uic = irq_data_get_irq_chip_data(d);
87 unsigned int src = irqd_to_hwirq(d);
88 unsigned long flags;
89
90 raw_spin_lock_irqsave(&uic->lock, flags);
91 mtdcr(uic->dcrbase + UIC_SR, 1 << (31-src));
92 raw_spin_unlock_irqrestore(&uic->lock, flags);
93 }
94
95 static void uic_mask_ack_irq(struct irq_data *d)
96 {
97 struct uic *uic = irq_data_get_irq_chip_data(d);
98 unsigned int src = irqd_to_hwirq(d);
99 unsigned long flags;
100 u32 er, sr;
101
102 sr = 1 << (31-src);
103 raw_spin_lock_irqsave(&uic->lock, flags);
104 er = mfdcr(uic->dcrbase + UIC_ER);
105 er &= ~sr;
106 mtdcr(uic->dcrbase + UIC_ER, er);
107 /* On the UIC, acking (i.e. clearing the SR bit)
108 * a level irq will have no effect if the interrupt
109 * is still asserted by the device, even if
110 * the interrupt is already masked. Therefore
111 * we only ack the egde interrupts here, while
112 * level interrupts are ack'ed after the actual
113 * isr call in the uic_unmask_irq()
114 */
115 if (!irqd_is_level_type(d))
116 mtdcr(uic->dcrbase + UIC_SR, sr);
117 raw_spin_unlock_irqrestore(&uic->lock, flags);
118 }
119
120 static int uic_set_irq_type(struct irq_data *d, unsigned int flow_type)
121 {
122 struct uic *uic = irq_data_get_irq_chip_data(d);
123 unsigned int src = irqd_to_hwirq(d);
124 unsigned long flags;
125 int trigger, polarity;
126 u32 tr, pr, mask;
127
128 switch (flow_type & IRQ_TYPE_SENSE_MASK) {
129 case IRQ_TYPE_NONE:
130 uic_mask_irq(d);
131 return 0;
132
133 case IRQ_TYPE_EDGE_RISING:
134 trigger = 1; polarity = 1;
135 break;
136 case IRQ_TYPE_EDGE_FALLING:
137 trigger = 1; polarity = 0;
138 break;
139 case IRQ_TYPE_LEVEL_HIGH:
140 trigger = 0; polarity = 1;
141 break;
142 case IRQ_TYPE_LEVEL_LOW:
143 trigger = 0; polarity = 0;
144 break;
145 default:
146 return -EINVAL;
147 }
148
149 mask = ~(1 << (31 - src));
150
151 raw_spin_lock_irqsave(&uic->lock, flags);
152 tr = mfdcr(uic->dcrbase + UIC_TR);
153 pr = mfdcr(uic->dcrbase + UIC_PR);
154 tr = (tr & mask) | (trigger << (31-src));
155 pr = (pr & mask) | (polarity << (31-src));
156
157 mtdcr(uic->dcrbase + UIC_PR, pr);
158 mtdcr(uic->dcrbase + UIC_TR, tr);
159 mtdcr(uic->dcrbase + UIC_SR, ~mask);
160
161 raw_spin_unlock_irqrestore(&uic->lock, flags);
162
163 return 0;
164 }
165
166 static struct irq_chip uic_irq_chip = {
167 .name = "UIC",
168 .irq_unmask = uic_unmask_irq,
169 .irq_mask = uic_mask_irq,
170 .irq_mask_ack = uic_mask_ack_irq,
171 .irq_ack = uic_ack_irq,
172 .irq_set_type = uic_set_irq_type,
173 };
174
175 static int uic_host_map(struct irq_domain *h, unsigned int virq,
176 irq_hw_number_t hw)
177 {
178 struct uic *uic = h->host_data;
179
180 irq_set_chip_data(virq, uic);
181 /* Despite the name, handle_level_irq() works for both level
182 * and edge irqs on UIC. FIXME: check this is correct */
183 irq_set_chip_and_handler(virq, &uic_irq_chip, handle_level_irq);
184
185 /* Set default irq type */
186 irq_set_irq_type(virq, IRQ_TYPE_NONE);
187
188 return 0;
189 }
190
191 static const struct irq_domain_ops uic_host_ops = {
192 .map = uic_host_map,
193 .xlate = irq_domain_xlate_twocell,
194 };
195
196 static void uic_irq_cascade(struct irq_desc *desc)
197 {
198 struct irq_chip *chip = irq_desc_get_chip(desc);
199 struct irq_data *idata = irq_desc_get_irq_data(desc);
200 struct uic *uic = irq_desc_get_handler_data(desc);
201 u32 msr;
202 int src;
203
204 raw_spin_lock(&desc->lock);
205 if (irqd_is_level_type(idata))
206 chip->irq_mask(idata);
207 else
208 chip->irq_mask_ack(idata);
209 raw_spin_unlock(&desc->lock);
210
211 msr = mfdcr(uic->dcrbase + UIC_MSR);
212 if (!msr) /* spurious interrupt */
213 goto uic_irq_ret;
214
215 src = 32 - ffs(msr);
216
217 generic_handle_domain_irq(uic->irqhost, src);
218
219 uic_irq_ret:
220 raw_spin_lock(&desc->lock);
221 if (irqd_is_level_type(idata))
222 chip->irq_ack(idata);
223 if (!irqd_irq_disabled(idata) && chip->irq_unmask)
224 chip->irq_unmask(idata);
225 raw_spin_unlock(&desc->lock);
226 }
227
228 static struct uic * __init uic_init_one(struct device_node *node)
229 {
230 struct uic *uic;
231 const u32 *indexp, *dcrreg;
232 int len;
233
234 BUG_ON(! of_device_is_compatible(node, "ibm,uic"));
235
236 uic = kzalloc(sizeof(*uic), GFP_KERNEL);
237 if (! uic)
238 return NULL; /* FIXME: panic? */
239
240 raw_spin_lock_init(&uic->lock);
241 indexp = of_get_property(node, "cell-index", &len);
242 if (!indexp || (len != sizeof(u32))) {
243 printk(KERN_ERR "uic: Device node %pOF has missing or invalid "
244 "cell-index property\n", node);
245 return NULL;
246 }
247 uic->index = *indexp;
248
249 dcrreg = of_get_property(node, "dcr-reg", &len);
250 if (!dcrreg || (len != 2*sizeof(u32))) {
251 printk(KERN_ERR "uic: Device node %pOF has missing or invalid "
252 "dcr-reg property\n", node);
253 return NULL;
254 }
255 uic->dcrbase = *dcrreg;
256
257 uic->irqhost = irq_domain_add_linear(node, NR_UIC_INTS, &uic_host_ops,
258 uic);
259 if (! uic->irqhost)
260 return NULL; /* FIXME: panic? */
261
262 /* Start with all interrupts disabled, level and non-critical */
263 mtdcr(uic->dcrbase + UIC_ER, 0);
264 mtdcr(uic->dcrbase + UIC_CR, 0);
265 mtdcr(uic->dcrbase + UIC_TR, 0);
266 /* Clear any pending interrupts, in case the firmware left some */
267 mtdcr(uic->dcrbase + UIC_SR, 0xffffffff);
268
269 printk ("UIC%d (%d IRQ sources) at DCR 0x%x\n", uic->index,
270 NR_UIC_INTS, uic->dcrbase);
271
272 return uic;
273 }
274
275 void __init uic_init_tree(void)
276 {
277 struct device_node *np;
278 struct uic *uic;
279 const u32 *interrupts;
280
281 /* First locate and initialize the top-level UIC */
282 for_each_compatible_node(np, NULL, "ibm,uic") {
283 interrupts = of_get_property(np, "interrupts", NULL);
284 if (!interrupts)
285 break;
286 }
287
288 BUG_ON(!np); /* uic_init_tree() assumes there's a UIC as the
289 * top-level interrupt controller */
290 primary_uic = uic_init_one(np);
291 if (!primary_uic)
292 panic("Unable to initialize primary UIC %pOF\n", np);
293
294 irq_set_default_host(primary_uic->irqhost);
295 of_node_put(np);
296
297 /* The scan again for cascaded UICs */
298 for_each_compatible_node(np, NULL, "ibm,uic") {
299 interrupts = of_get_property(np, "interrupts", NULL);
300 if (interrupts) {
301 /* Secondary UIC */
302 int cascade_virq;
303
304 uic = uic_init_one(np);
305 if (! uic)
306 panic("Unable to initialize a secondary UIC %pOF\n",
307 np);
308
309 cascade_virq = irq_of_parse_and_map(np, 0);
310
311 irq_set_handler_data(cascade_virq, uic);
312 irq_set_chained_handler(cascade_virq, uic_irq_cascade);
313
314 /* FIXME: setup critical cascade?? */
315 }
316 }
317 }
318
319 /* Return an interrupt vector or 0 if no interrupt is pending. */
320 unsigned int uic_get_irq(void)
321 {
322 u32 msr;
323 int src;
324
325 BUG_ON(! primary_uic);
326
327 msr = mfdcr(primary_uic->dcrbase + UIC_MSR);
328 src = 32 - ffs(msr);
329
330 return irq_linear_revmap(primary_uic->irqhost, src);
331 }
332
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