1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * External Interrupt Controller on Spider South Bridge
4  *
5  * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
6  *
7  * Author: Arnd Bergmann <arndb@de.ibm.com>
8  */
9 
10 #include <linux/interrupt.h>
11 #include <linux/irq.h>
12 #include <linux/ioport.h>
13 #include <linux/of_address.h>
14 #include <linux/of_irq.h>
15 #include <linux/pgtable.h>
16 
17 #include <asm/io.h>
18 
19 #include "interrupt.h"
20 
21 /* register layout taken from Spider spec, table 7.4-4 */
22 enum {
23 	TIR_DEN		= 0x004, /* Detection Enable Register */
24 	TIR_MSK		= 0x084, /* Mask Level Register */
25 	TIR_EDC		= 0x0c0, /* Edge Detection Clear Register */
26 	TIR_PNDA	= 0x100, /* Pending Register A */
27 	TIR_PNDB	= 0x104, /* Pending Register B */
28 	TIR_CS		= 0x144, /* Current Status Register */
29 	TIR_LCSA	= 0x150, /* Level Current Status Register A */
30 	TIR_LCSB	= 0x154, /* Level Current Status Register B */
31 	TIR_LCSC	= 0x158, /* Level Current Status Register C */
32 	TIR_LCSD	= 0x15c, /* Level Current Status Register D */
33 	TIR_CFGA	= 0x200, /* Setting Register A0 */
34 	TIR_CFGB	= 0x204, /* Setting Register B0 */
35 			/* 0x208 ... 0x3ff Setting Register An/Bn */
36 	TIR_PPNDA	= 0x400, /* Packet Pending Register A */
37 	TIR_PPNDB	= 0x404, /* Packet Pending Register B */
38 	TIR_PIERA	= 0x408, /* Packet Output Error Register A */
39 	TIR_PIERB	= 0x40c, /* Packet Output Error Register B */
40 	TIR_PIEN	= 0x444, /* Packet Output Enable Register */
41 	TIR_PIPND	= 0x454, /* Packet Output Pending Register */
42 	TIRDID		= 0x484, /* Spider Device ID Register */
43 	REISTIM		= 0x500, /* Reissue Command Timeout Time Setting */
44 	REISTIMEN	= 0x504, /* Reissue Command Timeout Setting */
45 	REISWAITEN	= 0x508, /* Reissue Wait Control*/
46 };
47 
48 #define SPIDER_CHIP_COUNT	4
49 #define SPIDER_SRC_COUNT	64
50 #define SPIDER_IRQ_INVALID	63
51 
52 struct spider_pic {
53 	struct irq_domain		*host;
54 	void __iomem		*regs;
55 	unsigned int		node_id;
56 };
57 static struct spider_pic spider_pics[SPIDER_CHIP_COUNT];
58 
59 static struct spider_pic *spider_irq_data_to_pic(struct irq_data *d)
60 {
61 	return irq_data_get_irq_chip_data(d);
62 }
63 
64 static void __iomem *spider_get_irq_config(struct spider_pic *pic,
65 					   unsigned int src)
66 {
67 	return pic->regs + TIR_CFGA + 8 * src;
68 }
69 
70 static void spider_unmask_irq(struct irq_data *d)
71 {
72 	struct spider_pic *pic = spider_irq_data_to_pic(d);
73 	void __iomem *cfg = spider_get_irq_config(pic, irqd_to_hwirq(d));
74 
75 	out_be32(cfg, in_be32(cfg) | 0x30000000u);
76 }
77 
78 static void spider_mask_irq(struct irq_data *d)
79 {
80 	struct spider_pic *pic = spider_irq_data_to_pic(d);
81 	void __iomem *cfg = spider_get_irq_config(pic, irqd_to_hwirq(d));
82 
83 	out_be32(cfg, in_be32(cfg) & ~0x30000000u);
84 }
85 
86 static void spider_ack_irq(struct irq_data *d)
87 {
88 	struct spider_pic *pic = spider_irq_data_to_pic(d);
89 	unsigned int src = irqd_to_hwirq(d);
90 
91 	/* Reset edge detection logic if necessary
92 	 */
93 	if (irqd_is_level_type(d))
94 		return;
95 
96 	/* Only interrupts 47 to 50 can be set to edge */
97 	if (src < 47 || src > 50)
98 		return;
99 
100 	/* Perform the clear of the edge logic */
101 	out_be32(pic->regs + TIR_EDC, 0x100 | (src & 0xf));
102 }
103 
104 static int spider_set_irq_type(struct irq_data *d, unsigned int type)
105 {
106 	unsigned int sense = type & IRQ_TYPE_SENSE_MASK;
107 	struct spider_pic *pic = spider_irq_data_to_pic(d);
108 	unsigned int hw = irqd_to_hwirq(d);
109 	void __iomem *cfg = spider_get_irq_config(pic, hw);
110 	u32 old_mask;
111 	u32 ic;
112 
113 	/* Note that only level high is supported for most interrupts */
114 	if (sense != IRQ_TYPE_NONE && sense != IRQ_TYPE_LEVEL_HIGH &&
115 	    (hw < 47 || hw > 50))
116 		return -EINVAL;
117 
118 	/* Decode sense type */
119 	switch(sense) {
120 	case IRQ_TYPE_EDGE_RISING:
121 		ic = 0x3;
122 		break;
123 	case IRQ_TYPE_EDGE_FALLING:
124 		ic = 0x2;
125 		break;
126 	case IRQ_TYPE_LEVEL_LOW:
127 		ic = 0x0;
128 		break;
129 	case IRQ_TYPE_LEVEL_HIGH:
130 	case IRQ_TYPE_NONE:
131 		ic = 0x1;
132 		break;
133 	default:
134 		return -EINVAL;
135 	}
136 
137 	/* Configure the source. One gross hack that was there before and
138 	 * that I've kept around is the priority to the BE which I set to
139 	 * be the same as the interrupt source number. I don't know whether
140 	 * that's supposed to make any kind of sense however, we'll have to
141 	 * decide that, but for now, I'm not changing the behaviour.
142 	 */
143 	old_mask = in_be32(cfg) & 0x30000000u;
144 	out_be32(cfg, old_mask | (ic << 24) | (0x7 << 16) |
145 		 (pic->node_id << 4) | 0xe);
146 	out_be32(cfg + 4, (0x2 << 16) | (hw & 0xff));
147 
148 	return 0;
149 }
150 
151 static struct irq_chip spider_pic = {
152 	.name = "SPIDER",
153 	.irq_unmask = spider_unmask_irq,
154 	.irq_mask = spider_mask_irq,
155 	.irq_ack = spider_ack_irq,
156 	.irq_set_type = spider_set_irq_type,
157 };
158 
159 static int spider_host_map(struct irq_domain *h, unsigned int virq,
160 			irq_hw_number_t hw)
161 {
162 	irq_set_chip_data(virq, h->host_data);
163 	irq_set_chip_and_handler(virq, &spider_pic, handle_level_irq);
164 
165 	/* Set default irq type */
166 	irq_set_irq_type(virq, IRQ_TYPE_NONE);
167 
168 	return 0;
169 }
170 
171 static int spider_host_xlate(struct irq_domain *h, struct device_node *ct,
172 			   const u32 *intspec, unsigned int intsize,
173 			   irq_hw_number_t *out_hwirq, unsigned int *out_flags)
174 
175 {
176 	/* Spider interrupts have 2 cells, first is the interrupt source,
177 	 * second, well, I don't know for sure yet ... We mask the top bits
178 	 * because old device-trees encode a node number in there
179 	 */
180 	*out_hwirq = intspec[0] & 0x3f;
181 	*out_flags = IRQ_TYPE_LEVEL_HIGH;
182 	return 0;
183 }
184 
185 static const struct irq_domain_ops spider_host_ops = {
186 	.map = spider_host_map,
187 	.xlate = spider_host_xlate,
188 };
189 
190 static void spider_irq_cascade(struct irq_desc *desc)
191 {
192 	struct irq_chip *chip = irq_desc_get_chip(desc);
193 	struct spider_pic *pic = irq_desc_get_handler_data(desc);
194 	unsigned int cs;
195 
196 	cs = in_be32(pic->regs + TIR_CS) >> 24;
197 	if (cs != SPIDER_IRQ_INVALID)
198 		generic_handle_domain_irq(pic->host, cs);
199 
200 	chip->irq_eoi(&desc->irq_data);
201 }
202 
203 /* For hooking up the cascade we have a problem. Our device-tree is
204  * crap and we don't know on which BE iic interrupt we are hooked on at
205  * least not the "standard" way. We can reconstitute it based on two
206  * informations though: which BE node we are connected to and whether
207  * we are connected to IOIF0 or IOIF1. Right now, we really only care
208  * about the IBM cell blade and we know that its firmware gives us an
209  * interrupt-map property which is pretty strange.
210  */
211 static unsigned int __init spider_find_cascade_and_node(struct spider_pic *pic)
212 {
213 	unsigned int virq;
214 	const u32 *imap, *tmp;
215 	int imaplen, intsize, unit;
216 	struct device_node *iic;
217 	struct device_node *of_node;
218 
219 	of_node = irq_domain_get_of_node(pic->host);
220 
221 	/* First, we check whether we have a real "interrupts" in the device
222 	 * tree in case the device-tree is ever fixed
223 	 */
224 	virq = irq_of_parse_and_map(of_node, 0);
225 	if (virq)
226 		return virq;
227 
228 	/* Now do the horrible hacks */
229 	tmp = of_get_property(of_node, "#interrupt-cells", NULL);
230 	if (tmp == NULL)
231 		return 0;
232 	intsize = *tmp;
233 	imap = of_get_property(of_node, "interrupt-map", &imaplen);
234 	if (imap == NULL || imaplen < (intsize + 1))
235 		return 0;
236 	iic = of_find_node_by_phandle(imap[intsize]);
237 	if (iic == NULL)
238 		return 0;
239 	imap += intsize + 1;
240 	tmp = of_get_property(iic, "#interrupt-cells", NULL);
241 	if (tmp == NULL) {
242 		of_node_put(iic);
243 		return 0;
244 	}
245 	intsize = *tmp;
246 	/* Assume unit is last entry of interrupt specifier */
247 	unit = imap[intsize - 1];
248 	/* Ok, we have a unit, now let's try to get the node */
249 	tmp = of_get_property(iic, "ibm,interrupt-server-ranges", NULL);
250 	if (tmp == NULL) {
251 		of_node_put(iic);
252 		return 0;
253 	}
254 	/* ugly as hell but works for now */
255 	pic->node_id = (*tmp) >> 1;
256 	of_node_put(iic);
257 
258 	/* Ok, now let's get cracking. You may ask me why I just didn't match
259 	 * the iic host from the iic OF node, but that way I'm still compatible
260 	 * with really really old old firmwares for which we don't have a node
261 	 */
262 	/* Manufacture an IIC interrupt number of class 2 */
263 	virq = irq_create_mapping(NULL,
264 				  (pic->node_id << IIC_IRQ_NODE_SHIFT) |
265 				  (2 << IIC_IRQ_CLASS_SHIFT) |
266 				  unit);
267 	if (!virq)
268 		printk(KERN_ERR "spider_pic: failed to map cascade !");
269 	return virq;
270 }
271 
272 
273 static void __init spider_init_one(struct device_node *of_node, int chip,
274 				   unsigned long addr)
275 {
276 	struct spider_pic *pic = &spider_pics[chip];
277 	int i, virq;
278 
279 	/* Map registers */
280 	pic->regs = ioremap(addr, 0x1000);
281 	if (pic->regs == NULL)
282 		panic("spider_pic: can't map registers !");
283 
284 	/* Allocate a host */
285 	pic->host = irq_domain_add_linear(of_node, SPIDER_SRC_COUNT,
286 					  &spider_host_ops, pic);
287 	if (pic->host == NULL)
288 		panic("spider_pic: can't allocate irq host !");
289 
290 	/* Go through all sources and disable them */
291 	for (i = 0; i < SPIDER_SRC_COUNT; i++) {
292 		void __iomem *cfg = pic->regs + TIR_CFGA + 8 * i;
293 		out_be32(cfg, in_be32(cfg) & ~0x30000000u);
294 	}
295 
296 	/* do not mask any interrupts because of level */
297 	out_be32(pic->regs + TIR_MSK, 0x0);
298 
299 	/* enable interrupt packets to be output */
300 	out_be32(pic->regs + TIR_PIEN, in_be32(pic->regs + TIR_PIEN) | 0x1);
301 
302 	/* Hook up the cascade interrupt to the iic and nodeid */
303 	virq = spider_find_cascade_and_node(pic);
304 	if (!virq)
305 		return;
306 	irq_set_handler_data(virq, pic);
307 	irq_set_chained_handler(virq, spider_irq_cascade);
308 
309 	printk(KERN_INFO "spider_pic: node %d, addr: 0x%lx %pOF\n",
310 	       pic->node_id, addr, of_node);
311 
312 	/* Enable the interrupt detection enable bit. Do this last! */
313 	out_be32(pic->regs + TIR_DEN, in_be32(pic->regs + TIR_DEN) | 0x1);
314 }
315 
316 void __init spider_init_IRQ(void)
317 {
318 	struct resource r;
319 	struct device_node *dn;
320 	int chip = 0;
321 
322 	/* XXX node numbers are totally bogus. We _hope_ we get the device
323 	 * nodes in the right order here but that's definitely not guaranteed,
324 	 * we need to get the node from the device tree instead.
325 	 * There is currently no proper property for it (but our whole
326 	 * device-tree is bogus anyway) so all we can do is pray or maybe test
327 	 * the address and deduce the node-id
328 	 */
329 	for_each_node_by_name(dn, "interrupt-controller") {
330 		if (of_device_is_compatible(dn, "CBEA,platform-spider-pic")) {
331 			if (of_address_to_resource(dn, 0, &r)) {
332 				printk(KERN_WARNING "spider-pic: Failed\n");
333 				continue;
334 			}
335 		} else if (of_device_is_compatible(dn, "sti,platform-spider-pic")
336 			   && (chip < 2)) {
337 			static long hard_coded_pics[] =
338 				{ 0x24000008000ul, 0x34000008000ul};
339 			r.start = hard_coded_pics[chip];
340 		} else
341 			continue;
342 		spider_init_one(dn, chip++, r.start);
343 	}
344 }
345