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