1 /*
2  * Cell Internal Interrupt Controller
3  *
4  * Copyright (C) 2006 Benjamin Herrenschmidt (benh@kernel.crashing.org)
5  *                    IBM, Corp.
6  *
7  * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
8  *
9  * Author: Arnd Bergmann <arndb@de.ibm.com>
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2, or (at your option)
14  * any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program; if not, write to the Free Software
23  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24  *
25  * TODO:
26  * - Fix various assumptions related to HW CPU numbers vs. linux CPU numbers
27  *   vs node numbers in the setup code
28  * - Implement proper handling of maxcpus=1/2 (that is, routing of irqs from
29  *   a non-active node to the active node)
30  */
31 
32 #include <linux/interrupt.h>
33 #include <linux/irq.h>
34 #include <linux/export.h>
35 #include <linux/percpu.h>
36 #include <linux/types.h>
37 #include <linux/ioport.h>
38 #include <linux/kernel_stat.h>
39 
40 #include <asm/io.h>
41 #include <asm/pgtable.h>
42 #include <asm/prom.h>
43 #include <asm/ptrace.h>
44 #include <asm/machdep.h>
45 #include <asm/cell-regs.h>
46 
47 #include "interrupt.h"
48 
49 struct iic {
50 	struct cbe_iic_thread_regs __iomem *regs;
51 	u8 target_id;
52 	u8 eoi_stack[16];
53 	int eoi_ptr;
54 	struct device_node *node;
55 };
56 
57 static DEFINE_PER_CPU(struct iic, cpu_iic);
58 #define IIC_NODE_COUNT	2
59 static struct irq_domain *iic_host;
60 
61 /* Convert between "pending" bits and hw irq number */
62 static irq_hw_number_t iic_pending_to_hwnum(struct cbe_iic_pending_bits bits)
63 {
64 	unsigned char unit = bits.source & 0xf;
65 	unsigned char node = bits.source >> 4;
66 	unsigned char class = bits.class & 3;
67 
68 	/* Decode IPIs */
69 	if (bits.flags & CBE_IIC_IRQ_IPI)
70 		return IIC_IRQ_TYPE_IPI | (bits.prio >> 4);
71 	else
72 		return (node << IIC_IRQ_NODE_SHIFT) | (class << 4) | unit;
73 }
74 
75 static void iic_mask(struct irq_data *d)
76 {
77 }
78 
79 static void iic_unmask(struct irq_data *d)
80 {
81 }
82 
83 static void iic_eoi(struct irq_data *d)
84 {
85 	struct iic *iic = this_cpu_ptr(&cpu_iic);
86 	out_be64(&iic->regs->prio, iic->eoi_stack[--iic->eoi_ptr]);
87 	BUG_ON(iic->eoi_ptr < 0);
88 }
89 
90 static struct irq_chip iic_chip = {
91 	.name = "CELL-IIC",
92 	.irq_mask = iic_mask,
93 	.irq_unmask = iic_unmask,
94 	.irq_eoi = iic_eoi,
95 };
96 
97 
98 static void iic_ioexc_eoi(struct irq_data *d)
99 {
100 }
101 
102 static void iic_ioexc_cascade(unsigned int irq, struct irq_desc *desc)
103 {
104 	struct irq_chip *chip = irq_desc_get_chip(desc);
105 	struct cbe_iic_regs __iomem *node_iic =
106 		(void __iomem *)irq_desc_get_handler_data(desc);
107 	unsigned int base = (irq & 0xffffff00) | IIC_IRQ_TYPE_IOEXC;
108 	unsigned long bits, ack;
109 	int cascade;
110 
111 	for (;;) {
112 		bits = in_be64(&node_iic->iic_is);
113 		if (bits == 0)
114 			break;
115 		/* pre-ack edge interrupts */
116 		ack = bits & IIC_ISR_EDGE_MASK;
117 		if (ack)
118 			out_be64(&node_iic->iic_is, ack);
119 		/* handle them */
120 		for (cascade = 63; cascade >= 0; cascade--)
121 			if (bits & (0x8000000000000000UL >> cascade)) {
122 				unsigned int cirq =
123 					irq_linear_revmap(iic_host,
124 							  base | cascade);
125 				if (cirq != NO_IRQ)
126 					generic_handle_irq(cirq);
127 			}
128 		/* post-ack level interrupts */
129 		ack = bits & ~IIC_ISR_EDGE_MASK;
130 		if (ack)
131 			out_be64(&node_iic->iic_is, ack);
132 	}
133 	chip->irq_eoi(&desc->irq_data);
134 }
135 
136 
137 static struct irq_chip iic_ioexc_chip = {
138 	.name = "CELL-IOEX",
139 	.irq_mask = iic_mask,
140 	.irq_unmask = iic_unmask,
141 	.irq_eoi = iic_ioexc_eoi,
142 };
143 
144 /* Get an IRQ number from the pending state register of the IIC */
145 static unsigned int iic_get_irq(void)
146 {
147 	struct cbe_iic_pending_bits pending;
148 	struct iic *iic;
149 	unsigned int virq;
150 
151 	iic = this_cpu_ptr(&cpu_iic);
152 	*(unsigned long *) &pending =
153 		in_be64((u64 __iomem *) &iic->regs->pending_destr);
154 	if (!(pending.flags & CBE_IIC_IRQ_VALID))
155 		return NO_IRQ;
156 	virq = irq_linear_revmap(iic_host, iic_pending_to_hwnum(pending));
157 	if (virq == NO_IRQ)
158 		return NO_IRQ;
159 	iic->eoi_stack[++iic->eoi_ptr] = pending.prio;
160 	BUG_ON(iic->eoi_ptr > 15);
161 	return virq;
162 }
163 
164 void iic_setup_cpu(void)
165 {
166 	out_be64(&this_cpu_ptr(&cpu_iic)->regs->prio, 0xff);
167 }
168 
169 u8 iic_get_target_id(int cpu)
170 {
171 	return per_cpu(cpu_iic, cpu).target_id;
172 }
173 
174 EXPORT_SYMBOL_GPL(iic_get_target_id);
175 
176 #ifdef CONFIG_SMP
177 
178 /* Use the highest interrupt priorities for IPI */
179 static inline int iic_msg_to_irq(int msg)
180 {
181 	return IIC_IRQ_TYPE_IPI + 0xf - msg;
182 }
183 
184 void iic_message_pass(int cpu, int msg)
185 {
186 	out_be64(&per_cpu(cpu_iic, cpu).regs->generate, (0xf - msg) << 4);
187 }
188 
189 struct irq_domain *iic_get_irq_host(int node)
190 {
191 	return iic_host;
192 }
193 EXPORT_SYMBOL_GPL(iic_get_irq_host);
194 
195 static void iic_request_ipi(int msg)
196 {
197 	int virq;
198 
199 	virq = irq_create_mapping(iic_host, iic_msg_to_irq(msg));
200 	if (virq == NO_IRQ) {
201 		printk(KERN_ERR
202 		       "iic: failed to map IPI %s\n", smp_ipi_name[msg]);
203 		return;
204 	}
205 
206 	/*
207 	 * If smp_request_message_ipi encounters an error it will notify
208 	 * the error.  If a message is not needed it will return non-zero.
209 	 */
210 	if (smp_request_message_ipi(virq, msg))
211 		irq_dispose_mapping(virq);
212 }
213 
214 void iic_request_IPIs(void)
215 {
216 	iic_request_ipi(PPC_MSG_CALL_FUNCTION);
217 	iic_request_ipi(PPC_MSG_RESCHEDULE);
218 	iic_request_ipi(PPC_MSG_TICK_BROADCAST);
219 	iic_request_ipi(PPC_MSG_DEBUGGER_BREAK);
220 }
221 
222 #endif /* CONFIG_SMP */
223 
224 
225 static int iic_host_match(struct irq_domain *h, struct device_node *node)
226 {
227 	return of_device_is_compatible(node,
228 				    "IBM,CBEA-Internal-Interrupt-Controller");
229 }
230 
231 static int iic_host_map(struct irq_domain *h, unsigned int virq,
232 			irq_hw_number_t hw)
233 {
234 	switch (hw & IIC_IRQ_TYPE_MASK) {
235 	case IIC_IRQ_TYPE_IPI:
236 		irq_set_chip_and_handler(virq, &iic_chip, handle_percpu_irq);
237 		break;
238 	case IIC_IRQ_TYPE_IOEXC:
239 		irq_set_chip_and_handler(virq, &iic_ioexc_chip,
240 					 handle_edge_eoi_irq);
241 		break;
242 	default:
243 		irq_set_chip_and_handler(virq, &iic_chip, handle_edge_eoi_irq);
244 	}
245 	return 0;
246 }
247 
248 static int iic_host_xlate(struct irq_domain *h, struct device_node *ct,
249 			   const u32 *intspec, unsigned int intsize,
250 			   irq_hw_number_t *out_hwirq, unsigned int *out_flags)
251 
252 {
253 	unsigned int node, ext, unit, class;
254 	const u32 *val;
255 
256 	if (!of_device_is_compatible(ct,
257 				     "IBM,CBEA-Internal-Interrupt-Controller"))
258 		return -ENODEV;
259 	if (intsize != 1)
260 		return -ENODEV;
261 	val = of_get_property(ct, "#interrupt-cells", NULL);
262 	if (val == NULL || *val != 1)
263 		return -ENODEV;
264 
265 	node = intspec[0] >> 24;
266 	ext = (intspec[0] >> 16) & 0xff;
267 	class = (intspec[0] >> 8) & 0xff;
268 	unit = intspec[0] & 0xff;
269 
270 	/* Check if node is in supported range */
271 	if (node > 1)
272 		return -EINVAL;
273 
274 	/* Build up interrupt number, special case for IO exceptions */
275 	*out_hwirq = (node << IIC_IRQ_NODE_SHIFT);
276 	if (unit == IIC_UNIT_IIC && class == 1)
277 		*out_hwirq |= IIC_IRQ_TYPE_IOEXC | ext;
278 	else
279 		*out_hwirq |= IIC_IRQ_TYPE_NORMAL |
280 			(class << IIC_IRQ_CLASS_SHIFT) | unit;
281 
282 	/* Dummy flags, ignored by iic code */
283 	*out_flags = IRQ_TYPE_EDGE_RISING;
284 
285 	return 0;
286 }
287 
288 static const struct irq_domain_ops iic_host_ops = {
289 	.match = iic_host_match,
290 	.map = iic_host_map,
291 	.xlate = iic_host_xlate,
292 };
293 
294 static void __init init_one_iic(unsigned int hw_cpu, unsigned long addr,
295 				struct device_node *node)
296 {
297 	/* XXX FIXME: should locate the linux CPU number from the HW cpu
298 	 * number properly. We are lucky for now
299 	 */
300 	struct iic *iic = &per_cpu(cpu_iic, hw_cpu);
301 
302 	iic->regs = ioremap(addr, sizeof(struct cbe_iic_thread_regs));
303 	BUG_ON(iic->regs == NULL);
304 
305 	iic->target_id = ((hw_cpu & 2) << 3) | ((hw_cpu & 1) ? 0xf : 0xe);
306 	iic->eoi_stack[0] = 0xff;
307 	iic->node = of_node_get(node);
308 	out_be64(&iic->regs->prio, 0);
309 
310 	printk(KERN_INFO "IIC for CPU %d target id 0x%x : %s\n",
311 	       hw_cpu, iic->target_id, node->full_name);
312 }
313 
314 static int __init setup_iic(void)
315 {
316 	struct device_node *dn;
317 	struct resource r0, r1;
318 	unsigned int node, cascade, found = 0;
319 	struct cbe_iic_regs __iomem *node_iic;
320 	const u32 *np;
321 
322 	for (dn = NULL;
323 	     (dn = of_find_node_by_name(dn,"interrupt-controller")) != NULL;) {
324 		if (!of_device_is_compatible(dn,
325 				     "IBM,CBEA-Internal-Interrupt-Controller"))
326 			continue;
327 		np = of_get_property(dn, "ibm,interrupt-server-ranges", NULL);
328 		if (np == NULL) {
329 			printk(KERN_WARNING "IIC: CPU association not found\n");
330 			of_node_put(dn);
331 			return -ENODEV;
332 		}
333 		if (of_address_to_resource(dn, 0, &r0) ||
334 		    of_address_to_resource(dn, 1, &r1)) {
335 			printk(KERN_WARNING "IIC: Can't resolve addresses\n");
336 			of_node_put(dn);
337 			return -ENODEV;
338 		}
339 		found++;
340 		init_one_iic(np[0], r0.start, dn);
341 		init_one_iic(np[1], r1.start, dn);
342 
343 		/* Setup cascade for IO exceptions. XXX cleanup tricks to get
344 		 * node vs CPU etc...
345 		 * Note that we configure the IIC_IRR here with a hard coded
346 		 * priority of 1. We might want to improve that later.
347 		 */
348 		node = np[0] >> 1;
349 		node_iic = cbe_get_cpu_iic_regs(np[0]);
350 		cascade = node << IIC_IRQ_NODE_SHIFT;
351 		cascade |= 1 << IIC_IRQ_CLASS_SHIFT;
352 		cascade |= IIC_UNIT_IIC;
353 		cascade = irq_create_mapping(iic_host, cascade);
354 		if (cascade == NO_IRQ)
355 			continue;
356 		/*
357 		 * irq_data is a generic pointer that gets passed back
358 		 * to us later, so the forced cast is fine.
359 		 */
360 		irq_set_handler_data(cascade, (void __force *)node_iic);
361 		irq_set_chained_handler(cascade, iic_ioexc_cascade);
362 		out_be64(&node_iic->iic_ir,
363 			 (1 << 12)		/* priority */ |
364 			 (node << 4)		/* dest node */ |
365 			 IIC_UNIT_THREAD_0	/* route them to thread 0 */);
366 		/* Flush pending (make sure it triggers if there is
367 		 * anything pending
368 		 */
369 		out_be64(&node_iic->iic_is, 0xfffffffffffffffful);
370 	}
371 
372 	if (found)
373 		return 0;
374 	else
375 		return -ENODEV;
376 }
377 
378 void __init iic_init_IRQ(void)
379 {
380 	/* Setup an irq host data structure */
381 	iic_host = irq_domain_add_linear(NULL, IIC_SOURCE_COUNT, &iic_host_ops,
382 					 NULL);
383 	BUG_ON(iic_host == NULL);
384 	irq_set_default_host(iic_host);
385 
386 	/* Discover and initialize iics */
387 	if (setup_iic() < 0)
388 		panic("IIC: Failed to initialize !\n");
389 
390 	/* Set master interrupt handling function */
391 	ppc_md.get_irq = iic_get_irq;
392 
393 	/* Enable on current CPU */
394 	iic_setup_cpu();
395 }
396 
397 void iic_set_interrupt_routing(int cpu, int thread, int priority)
398 {
399 	struct cbe_iic_regs __iomem *iic_regs = cbe_get_cpu_iic_regs(cpu);
400 	u64 iic_ir = 0;
401 	int node = cpu >> 1;
402 
403 	/* Set which node and thread will handle the next interrupt */
404 	iic_ir |= CBE_IIC_IR_PRIO(priority) |
405 		  CBE_IIC_IR_DEST_NODE(node);
406 	if (thread == 0)
407 		iic_ir |= CBE_IIC_IR_DEST_UNIT(CBE_IIC_IR_PT_0);
408 	else
409 		iic_ir |= CBE_IIC_IR_DEST_UNIT(CBE_IIC_IR_PT_1);
410 	out_be64(&iic_regs->iic_ir, iic_ir);
411 }
412