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
40struct uic *primary_uic;
41
42struct 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
52static 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
70static 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
84static 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
95static 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
120static 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
166static 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
175static 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
191static const struct irq_domain_ops uic_host_ops = {
192	.map	= uic_host_map,
193	.xlate	= irq_domain_xlate_twocell,
194};
195
196static 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
219uic_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
228static 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
275void __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. */
320unsigned 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