1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Cell Internal Interrupt Controller
4  *
5  * Copyright (C) 2006 Benjamin Herrenschmidt (benh@kernel.crashing.org)
6  *                    IBM, Corp.
7  *
8  * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
9  *
10  * Author: Arnd Bergmann <arndb@de.ibm.com>
11  *
12  * TODO:
13  * - Fix various assumptions related to HW CPU numbers vs. linux CPU numbers
14  *   vs node numbers in the setup code
15  * - Implement proper handling of maxcpus=1/2 (that is, routing of irqs from
16  *   a non-active node to the active node)
17  */
18 
19 #include <linux/interrupt.h>
20 #include <linux/irq.h>
21 #include <linux/export.h>
22 #include <linux/percpu.h>
23 #include <linux/types.h>
24 #include <linux/ioport.h>
25 #include <linux/kernel_stat.h>
26 #include <linux/pgtable.h>
27 
28 #include <asm/io.h>
29 #include <asm/prom.h>
30 #include <asm/ptrace.h>
31 #include <asm/machdep.h>
32 #include <asm/cell-regs.h>
33 
34 #include "interrupt.h"
35 
36 struct iic {
37 	struct cbe_iic_thread_regs __iomem *regs;
38 	u8 target_id;
39 	u8 eoi_stack[16];
40 	int eoi_ptr;
41 	struct device_node *node;
42 };
43 
44 static DEFINE_PER_CPU(struct iic, cpu_iic);
45 #define IIC_NODE_COUNT	2
46 static struct irq_domain *iic_host;
47 
48 /* Convert between "pending" bits and hw irq number */
49 static irq_hw_number_t iic_pending_to_hwnum(struct cbe_iic_pending_bits bits)
50 {
51 	unsigned char unit = bits.source & 0xf;
52 	unsigned char node = bits.source >> 4;
53 	unsigned char class = bits.class & 3;
54 
55 	/* Decode IPIs */
56 	if (bits.flags & CBE_IIC_IRQ_IPI)
57 		return IIC_IRQ_TYPE_IPI | (bits.prio >> 4);
58 	else
59 		return (node << IIC_IRQ_NODE_SHIFT) | (class << 4) | unit;
60 }
61 
62 static void iic_mask(struct irq_data *d)
63 {
64 }
65 
66 static void iic_unmask(struct irq_data *d)
67 {
68 }
69 
70 static void iic_eoi(struct irq_data *d)
71 {
72 	struct iic *iic = this_cpu_ptr(&cpu_iic);
73 	out_be64(&iic->regs->prio, iic->eoi_stack[--iic->eoi_ptr]);
74 	BUG_ON(iic->eoi_ptr < 0);
75 }
76 
77 static struct irq_chip iic_chip = {
78 	.name = "CELL-IIC",
79 	.irq_mask = iic_mask,
80 	.irq_unmask = iic_unmask,
81 	.irq_eoi = iic_eoi,
82 };
83 
84 
85 static void iic_ioexc_eoi(struct irq_data *d)
86 {
87 }
88 
89 static void iic_ioexc_cascade(struct irq_desc *desc)
90 {
91 	struct irq_chip *chip = irq_desc_get_chip(desc);
92 	struct cbe_iic_regs __iomem *node_iic =
93 		(void __iomem *)irq_desc_get_handler_data(desc);
94 	unsigned int irq = irq_desc_get_irq(desc);
95 	unsigned int base = (irq & 0xffffff00) | IIC_IRQ_TYPE_IOEXC;
96 	unsigned long bits, ack;
97 	int cascade;
98 
99 	for (;;) {
100 		bits = in_be64(&node_iic->iic_is);
101 		if (bits == 0)
102 			break;
103 		/* pre-ack edge interrupts */
104 		ack = bits & IIC_ISR_EDGE_MASK;
105 		if (ack)
106 			out_be64(&node_iic->iic_is, ack);
107 		/* handle them */
108 		for (cascade = 63; cascade >= 0; cascade--)
109 			if (bits & (0x8000000000000000UL >> cascade)) {
110 				unsigned int cirq =
111 					irq_linear_revmap(iic_host,
112 							  base | cascade);
113 				if (cirq)
114 					generic_handle_irq(cirq);
115 			}
116 		/* post-ack level interrupts */
117 		ack = bits & ~IIC_ISR_EDGE_MASK;
118 		if (ack)
119 			out_be64(&node_iic->iic_is, ack);
120 	}
121 	chip->irq_eoi(&desc->irq_data);
122 }
123 
124 
125 static struct irq_chip iic_ioexc_chip = {
126 	.name = "CELL-IOEX",
127 	.irq_mask = iic_mask,
128 	.irq_unmask = iic_unmask,
129 	.irq_eoi = iic_ioexc_eoi,
130 };
131 
132 /* Get an IRQ number from the pending state register of the IIC */
133 static unsigned int iic_get_irq(void)
134 {
135 	struct cbe_iic_pending_bits pending;
136 	struct iic *iic;
137 	unsigned int virq;
138 
139 	iic = this_cpu_ptr(&cpu_iic);
140 	*(unsigned long *) &pending =
141 		in_be64((u64 __iomem *) &iic->regs->pending_destr);
142 	if (!(pending.flags & CBE_IIC_IRQ_VALID))
143 		return 0;
144 	virq = irq_linear_revmap(iic_host, iic_pending_to_hwnum(pending));
145 	if (!virq)
146 		return 0;
147 	iic->eoi_stack[++iic->eoi_ptr] = pending.prio;
148 	BUG_ON(iic->eoi_ptr > 15);
149 	return virq;
150 }
151 
152 void iic_setup_cpu(void)
153 {
154 	out_be64(&this_cpu_ptr(&cpu_iic)->regs->prio, 0xff);
155 }
156 
157 u8 iic_get_target_id(int cpu)
158 {
159 	return per_cpu(cpu_iic, cpu).target_id;
160 }
161 
162 EXPORT_SYMBOL_GPL(iic_get_target_id);
163 
164 #ifdef CONFIG_SMP
165 
166 /* Use the highest interrupt priorities for IPI */
167 static inline int iic_msg_to_irq(int msg)
168 {
169 	return IIC_IRQ_TYPE_IPI + 0xf - msg;
170 }
171 
172 void iic_message_pass(int cpu, int msg)
173 {
174 	out_be64(&per_cpu(cpu_iic, cpu).regs->generate, (0xf - msg) << 4);
175 }
176 
177 static void iic_request_ipi(int msg)
178 {
179 	int virq;
180 
181 	virq = irq_create_mapping(iic_host, iic_msg_to_irq(msg));
182 	if (!virq) {
183 		printk(KERN_ERR
184 		       "iic: failed to map IPI %s\n", smp_ipi_name[msg]);
185 		return;
186 	}
187 
188 	/*
189 	 * If smp_request_message_ipi encounters an error it will notify
190 	 * the error.  If a message is not needed it will return non-zero.
191 	 */
192 	if (smp_request_message_ipi(virq, msg))
193 		irq_dispose_mapping(virq);
194 }
195 
196 void iic_request_IPIs(void)
197 {
198 	iic_request_ipi(PPC_MSG_CALL_FUNCTION);
199 	iic_request_ipi(PPC_MSG_RESCHEDULE);
200 	iic_request_ipi(PPC_MSG_TICK_BROADCAST);
201 	iic_request_ipi(PPC_MSG_NMI_IPI);
202 }
203 
204 #endif /* CONFIG_SMP */
205 
206 
207 static int iic_host_match(struct irq_domain *h, struct device_node *node,
208 			  enum irq_domain_bus_token bus_token)
209 {
210 	return of_device_is_compatible(node,
211 				    "IBM,CBEA-Internal-Interrupt-Controller");
212 }
213 
214 static int iic_host_map(struct irq_domain *h, unsigned int virq,
215 			irq_hw_number_t hw)
216 {
217 	switch (hw & IIC_IRQ_TYPE_MASK) {
218 	case IIC_IRQ_TYPE_IPI:
219 		irq_set_chip_and_handler(virq, &iic_chip, handle_percpu_irq);
220 		break;
221 	case IIC_IRQ_TYPE_IOEXC:
222 		irq_set_chip_and_handler(virq, &iic_ioexc_chip,
223 					 handle_edge_eoi_irq);
224 		break;
225 	default:
226 		irq_set_chip_and_handler(virq, &iic_chip, handle_edge_eoi_irq);
227 	}
228 	return 0;
229 }
230 
231 static int iic_host_xlate(struct irq_domain *h, struct device_node *ct,
232 			   const u32 *intspec, unsigned int intsize,
233 			   irq_hw_number_t *out_hwirq, unsigned int *out_flags)
234 
235 {
236 	unsigned int node, ext, unit, class;
237 	const u32 *val;
238 
239 	if (!of_device_is_compatible(ct,
240 				     "IBM,CBEA-Internal-Interrupt-Controller"))
241 		return -ENODEV;
242 	if (intsize != 1)
243 		return -ENODEV;
244 	val = of_get_property(ct, "#interrupt-cells", NULL);
245 	if (val == NULL || *val != 1)
246 		return -ENODEV;
247 
248 	node = intspec[0] >> 24;
249 	ext = (intspec[0] >> 16) & 0xff;
250 	class = (intspec[0] >> 8) & 0xff;
251 	unit = intspec[0] & 0xff;
252 
253 	/* Check if node is in supported range */
254 	if (node > 1)
255 		return -EINVAL;
256 
257 	/* Build up interrupt number, special case for IO exceptions */
258 	*out_hwirq = (node << IIC_IRQ_NODE_SHIFT);
259 	if (unit == IIC_UNIT_IIC && class == 1)
260 		*out_hwirq |= IIC_IRQ_TYPE_IOEXC | ext;
261 	else
262 		*out_hwirq |= IIC_IRQ_TYPE_NORMAL |
263 			(class << IIC_IRQ_CLASS_SHIFT) | unit;
264 
265 	/* Dummy flags, ignored by iic code */
266 	*out_flags = IRQ_TYPE_EDGE_RISING;
267 
268 	return 0;
269 }
270 
271 static const struct irq_domain_ops iic_host_ops = {
272 	.match = iic_host_match,
273 	.map = iic_host_map,
274 	.xlate = iic_host_xlate,
275 };
276 
277 static void __init init_one_iic(unsigned int hw_cpu, unsigned long addr,
278 				struct device_node *node)
279 {
280 	/* XXX FIXME: should locate the linux CPU number from the HW cpu
281 	 * number properly. We are lucky for now
282 	 */
283 	struct iic *iic = &per_cpu(cpu_iic, hw_cpu);
284 
285 	iic->regs = ioremap(addr, sizeof(struct cbe_iic_thread_regs));
286 	BUG_ON(iic->regs == NULL);
287 
288 	iic->target_id = ((hw_cpu & 2) << 3) | ((hw_cpu & 1) ? 0xf : 0xe);
289 	iic->eoi_stack[0] = 0xff;
290 	iic->node = of_node_get(node);
291 	out_be64(&iic->regs->prio, 0);
292 
293 	printk(KERN_INFO "IIC for CPU %d target id 0x%x : %pOF\n",
294 	       hw_cpu, iic->target_id, node);
295 }
296 
297 static int __init setup_iic(void)
298 {
299 	struct device_node *dn;
300 	struct resource r0, r1;
301 	unsigned int node, cascade, found = 0;
302 	struct cbe_iic_regs __iomem *node_iic;
303 	const u32 *np;
304 
305 	for_each_node_by_name(dn, "interrupt-controller") {
306 		if (!of_device_is_compatible(dn,
307 				     "IBM,CBEA-Internal-Interrupt-Controller"))
308 			continue;
309 		np = of_get_property(dn, "ibm,interrupt-server-ranges", NULL);
310 		if (np == NULL) {
311 			printk(KERN_WARNING "IIC: CPU association not found\n");
312 			of_node_put(dn);
313 			return -ENODEV;
314 		}
315 		if (of_address_to_resource(dn, 0, &r0) ||
316 		    of_address_to_resource(dn, 1, &r1)) {
317 			printk(KERN_WARNING "IIC: Can't resolve addresses\n");
318 			of_node_put(dn);
319 			return -ENODEV;
320 		}
321 		found++;
322 		init_one_iic(np[0], r0.start, dn);
323 		init_one_iic(np[1], r1.start, dn);
324 
325 		/* Setup cascade for IO exceptions. XXX cleanup tricks to get
326 		 * node vs CPU etc...
327 		 * Note that we configure the IIC_IRR here with a hard coded
328 		 * priority of 1. We might want to improve that later.
329 		 */
330 		node = np[0] >> 1;
331 		node_iic = cbe_get_cpu_iic_regs(np[0]);
332 		cascade = node << IIC_IRQ_NODE_SHIFT;
333 		cascade |= 1 << IIC_IRQ_CLASS_SHIFT;
334 		cascade |= IIC_UNIT_IIC;
335 		cascade = irq_create_mapping(iic_host, cascade);
336 		if (!cascade)
337 			continue;
338 		/*
339 		 * irq_data is a generic pointer that gets passed back
340 		 * to us later, so the forced cast is fine.
341 		 */
342 		irq_set_handler_data(cascade, (void __force *)node_iic);
343 		irq_set_chained_handler(cascade, iic_ioexc_cascade);
344 		out_be64(&node_iic->iic_ir,
345 			 (1 << 12)		/* priority */ |
346 			 (node << 4)		/* dest node */ |
347 			 IIC_UNIT_THREAD_0	/* route them to thread 0 */);
348 		/* Flush pending (make sure it triggers if there is
349 		 * anything pending
350 		 */
351 		out_be64(&node_iic->iic_is, 0xfffffffffffffffful);
352 	}
353 
354 	if (found)
355 		return 0;
356 	else
357 		return -ENODEV;
358 }
359 
360 void __init iic_init_IRQ(void)
361 {
362 	/* Setup an irq host data structure */
363 	iic_host = irq_domain_add_linear(NULL, IIC_SOURCE_COUNT, &iic_host_ops,
364 					 NULL);
365 	BUG_ON(iic_host == NULL);
366 	irq_set_default_host(iic_host);
367 
368 	/* Discover and initialize iics */
369 	if (setup_iic() < 0)
370 		panic("IIC: Failed to initialize !\n");
371 
372 	/* Set master interrupt handling function */
373 	ppc_md.get_irq = iic_get_irq;
374 
375 	/* Enable on current CPU */
376 	iic_setup_cpu();
377 }
378 
379 void iic_set_interrupt_routing(int cpu, int thread, int priority)
380 {
381 	struct cbe_iic_regs __iomem *iic_regs = cbe_get_cpu_iic_regs(cpu);
382 	u64 iic_ir = 0;
383 	int node = cpu >> 1;
384 
385 	/* Set which node and thread will handle the next interrupt */
386 	iic_ir |= CBE_IIC_IR_PRIO(priority) |
387 		  CBE_IIC_IR_DEST_NODE(node);
388 	if (thread == 0)
389 		iic_ir |= CBE_IIC_IR_DEST_UNIT(CBE_IIC_IR_PT_0);
390 	else
391 		iic_ir |= CBE_IIC_IR_DEST_UNIT(CBE_IIC_IR_PT_1);
392 	out_be64(&iic_regs->iic_ir, iic_ir);
393 }
394