1 /*
2  * Marvell Armada 370 and Armada XP SoC IRQ handling
3  *
4  * Copyright (C) 2012 Marvell
5  *
6  * Lior Amsalem <alior@marvell.com>
7  * Gregory CLEMENT <gregory.clement@free-electrons.com>
8  * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
9  * Ben Dooks <ben.dooks@codethink.co.uk>
10  *
11  * This file is licensed under the terms of the GNU General Public
12  * License version 2.  This program is licensed "as is" without any
13  * warranty of any kind, whether express or implied.
14  */
15 
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/init.h>
19 #include <linux/irq.h>
20 #include <linux/interrupt.h>
21 #include <linux/irqchip/chained_irq.h>
22 #include <linux/cpu.h>
23 #include <linux/io.h>
24 #include <linux/of_address.h>
25 #include <linux/of_irq.h>
26 #include <linux/of_pci.h>
27 #include <linux/irqdomain.h>
28 #include <linux/slab.h>
29 #include <linux/msi.h>
30 #include <asm/mach/arch.h>
31 #include <asm/exception.h>
32 #include <asm/smp_plat.h>
33 #include <asm/mach/irq.h>
34 
35 #include "irqchip.h"
36 
37 /* Interrupt Controller Registers Map */
38 #define ARMADA_370_XP_INT_SET_MASK_OFFS		(0x48)
39 #define ARMADA_370_XP_INT_CLEAR_MASK_OFFS	(0x4C)
40 
41 #define ARMADA_370_XP_INT_CONTROL		(0x00)
42 #define ARMADA_370_XP_INT_SET_ENABLE_OFFS	(0x30)
43 #define ARMADA_370_XP_INT_CLEAR_ENABLE_OFFS	(0x34)
44 #define ARMADA_370_XP_INT_SOURCE_CTL(irq)	(0x100 + irq*4)
45 #define ARMADA_370_XP_INT_SOURCE_CPU_MASK	0xF
46 
47 #define ARMADA_370_XP_CPU_INTACK_OFFS		(0x44)
48 #define ARMADA_375_PPI_CAUSE			(0x10)
49 
50 #define ARMADA_370_XP_SW_TRIG_INT_OFFS           (0x4)
51 #define ARMADA_370_XP_IN_DRBEL_MSK_OFFS          (0xc)
52 #define ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS        (0x8)
53 
54 #define ARMADA_370_XP_MAX_PER_CPU_IRQS		(28)
55 
56 #define ARMADA_370_XP_TIMER0_PER_CPU_IRQ	(5)
57 
58 #define IPI_DOORBELL_START                      (0)
59 #define IPI_DOORBELL_END                        (8)
60 #define IPI_DOORBELL_MASK                       0xFF
61 #define PCI_MSI_DOORBELL_START                  (16)
62 #define PCI_MSI_DOORBELL_NR                     (16)
63 #define PCI_MSI_DOORBELL_END                    (32)
64 #define PCI_MSI_DOORBELL_MASK                   0xFFFF0000
65 
66 static void __iomem *per_cpu_int_base;
67 static void __iomem *main_int_base;
68 static struct irq_domain *armada_370_xp_mpic_domain;
69 #ifdef CONFIG_PCI_MSI
70 static struct irq_domain *armada_370_xp_msi_domain;
71 static DECLARE_BITMAP(msi_used, PCI_MSI_DOORBELL_NR);
72 static DEFINE_MUTEX(msi_used_lock);
73 static phys_addr_t msi_doorbell_addr;
74 #endif
75 
76 /*
77  * In SMP mode:
78  * For shared global interrupts, mask/unmask global enable bit
79  * For CPU interrupts, mask/unmask the calling CPU's bit
80  */
81 static void armada_370_xp_irq_mask(struct irq_data *d)
82 {
83 	irq_hw_number_t hwirq = irqd_to_hwirq(d);
84 
85 	if (hwirq != ARMADA_370_XP_TIMER0_PER_CPU_IRQ)
86 		writel(hwirq, main_int_base +
87 				ARMADA_370_XP_INT_CLEAR_ENABLE_OFFS);
88 	else
89 		writel(hwirq, per_cpu_int_base +
90 				ARMADA_370_XP_INT_SET_MASK_OFFS);
91 }
92 
93 static void armada_370_xp_irq_unmask(struct irq_data *d)
94 {
95 	irq_hw_number_t hwirq = irqd_to_hwirq(d);
96 
97 	if (hwirq != ARMADA_370_XP_TIMER0_PER_CPU_IRQ)
98 		writel(hwirq, main_int_base +
99 				ARMADA_370_XP_INT_SET_ENABLE_OFFS);
100 	else
101 		writel(hwirq, per_cpu_int_base +
102 				ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
103 }
104 
105 #ifdef CONFIG_PCI_MSI
106 
107 static int armada_370_xp_alloc_msi(void)
108 {
109 	int hwirq;
110 
111 	mutex_lock(&msi_used_lock);
112 	hwirq = find_first_zero_bit(&msi_used, PCI_MSI_DOORBELL_NR);
113 	if (hwirq >= PCI_MSI_DOORBELL_NR)
114 		hwirq = -ENOSPC;
115 	else
116 		set_bit(hwirq, msi_used);
117 	mutex_unlock(&msi_used_lock);
118 
119 	return hwirq;
120 }
121 
122 static void armada_370_xp_free_msi(int hwirq)
123 {
124 	mutex_lock(&msi_used_lock);
125 	if (!test_bit(hwirq, msi_used))
126 		pr_err("trying to free unused MSI#%d\n", hwirq);
127 	else
128 		clear_bit(hwirq, msi_used);
129 	mutex_unlock(&msi_used_lock);
130 }
131 
132 static int armada_370_xp_setup_msi_irq(struct msi_chip *chip,
133 				       struct pci_dev *pdev,
134 				       struct msi_desc *desc)
135 {
136 	struct msi_msg msg;
137 	int virq, hwirq;
138 
139 	hwirq = armada_370_xp_alloc_msi();
140 	if (hwirq < 0)
141 		return hwirq;
142 
143 	virq = irq_create_mapping(armada_370_xp_msi_domain, hwirq);
144 	if (!virq) {
145 		armada_370_xp_free_msi(hwirq);
146 		return -EINVAL;
147 	}
148 
149 	irq_set_msi_desc(virq, desc);
150 
151 	msg.address_lo = msi_doorbell_addr;
152 	msg.address_hi = 0;
153 	msg.data = 0xf00 | (hwirq + 16);
154 
155 	write_msi_msg(virq, &msg);
156 	return 0;
157 }
158 
159 static void armada_370_xp_teardown_msi_irq(struct msi_chip *chip,
160 					   unsigned int irq)
161 {
162 	struct irq_data *d = irq_get_irq_data(irq);
163 	unsigned long hwirq = d->hwirq;
164 
165 	irq_dispose_mapping(irq);
166 	armada_370_xp_free_msi(hwirq);
167 }
168 
169 static int armada_370_xp_check_msi_device(struct msi_chip *chip, struct pci_dev *dev,
170 					  int nvec, int type)
171 {
172 	/* We support MSI, but not MSI-X */
173 	if (type == PCI_CAP_ID_MSI)
174 		return 0;
175 	return -EINVAL;
176 }
177 
178 static struct irq_chip armada_370_xp_msi_irq_chip = {
179 	.name = "armada_370_xp_msi_irq",
180 	.irq_enable = unmask_msi_irq,
181 	.irq_disable = mask_msi_irq,
182 	.irq_mask = mask_msi_irq,
183 	.irq_unmask = unmask_msi_irq,
184 };
185 
186 static int armada_370_xp_msi_map(struct irq_domain *domain, unsigned int virq,
187 				 irq_hw_number_t hw)
188 {
189 	irq_set_chip_and_handler(virq, &armada_370_xp_msi_irq_chip,
190 				 handle_simple_irq);
191 	set_irq_flags(virq, IRQF_VALID);
192 
193 	return 0;
194 }
195 
196 static const struct irq_domain_ops armada_370_xp_msi_irq_ops = {
197 	.map = armada_370_xp_msi_map,
198 };
199 
200 static int armada_370_xp_msi_init(struct device_node *node,
201 				  phys_addr_t main_int_phys_base)
202 {
203 	struct msi_chip *msi_chip;
204 	u32 reg;
205 	int ret;
206 
207 	msi_doorbell_addr = main_int_phys_base +
208 		ARMADA_370_XP_SW_TRIG_INT_OFFS;
209 
210 	msi_chip = kzalloc(sizeof(*msi_chip), GFP_KERNEL);
211 	if (!msi_chip)
212 		return -ENOMEM;
213 
214 	msi_chip->setup_irq = armada_370_xp_setup_msi_irq;
215 	msi_chip->teardown_irq = armada_370_xp_teardown_msi_irq;
216 	msi_chip->check_device = armada_370_xp_check_msi_device;
217 	msi_chip->of_node = node;
218 
219 	armada_370_xp_msi_domain =
220 		irq_domain_add_linear(NULL, PCI_MSI_DOORBELL_NR,
221 				      &armada_370_xp_msi_irq_ops,
222 				      NULL);
223 	if (!armada_370_xp_msi_domain) {
224 		kfree(msi_chip);
225 		return -ENOMEM;
226 	}
227 
228 	ret = of_pci_msi_chip_add(msi_chip);
229 	if (ret < 0) {
230 		irq_domain_remove(armada_370_xp_msi_domain);
231 		kfree(msi_chip);
232 		return ret;
233 	}
234 
235 	reg = readl(per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_MSK_OFFS)
236 		| PCI_MSI_DOORBELL_MASK;
237 
238 	writel(reg, per_cpu_int_base +
239 	       ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
240 
241 	/* Unmask IPI interrupt */
242 	writel(1, per_cpu_int_base + ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
243 
244 	return 0;
245 }
246 #else
247 static inline int armada_370_xp_msi_init(struct device_node *node,
248 					 phys_addr_t main_int_phys_base)
249 {
250 	return 0;
251 }
252 #endif
253 
254 #ifdef CONFIG_SMP
255 static DEFINE_RAW_SPINLOCK(irq_controller_lock);
256 
257 static int armada_xp_set_affinity(struct irq_data *d,
258 				  const struct cpumask *mask_val, bool force)
259 {
260 	irq_hw_number_t hwirq = irqd_to_hwirq(d);
261 	unsigned long reg, mask;
262 	int cpu;
263 
264 	/* Select a single core from the affinity mask which is online */
265 	cpu = cpumask_any_and(mask_val, cpu_online_mask);
266 	mask = 1UL << cpu_logical_map(cpu);
267 
268 	raw_spin_lock(&irq_controller_lock);
269 	reg = readl(main_int_base + ARMADA_370_XP_INT_SOURCE_CTL(hwirq));
270 	reg = (reg & (~ARMADA_370_XP_INT_SOURCE_CPU_MASK)) | mask;
271 	writel(reg, main_int_base + ARMADA_370_XP_INT_SOURCE_CTL(hwirq));
272 	raw_spin_unlock(&irq_controller_lock);
273 
274 	return 0;
275 }
276 #endif
277 
278 static struct irq_chip armada_370_xp_irq_chip = {
279 	.name		= "armada_370_xp_irq",
280 	.irq_mask       = armada_370_xp_irq_mask,
281 	.irq_mask_ack   = armada_370_xp_irq_mask,
282 	.irq_unmask     = armada_370_xp_irq_unmask,
283 #ifdef CONFIG_SMP
284 	.irq_set_affinity = armada_xp_set_affinity,
285 #endif
286 };
287 
288 static int armada_370_xp_mpic_irq_map(struct irq_domain *h,
289 				      unsigned int virq, irq_hw_number_t hw)
290 {
291 	armada_370_xp_irq_mask(irq_get_irq_data(virq));
292 	if (hw != ARMADA_370_XP_TIMER0_PER_CPU_IRQ)
293 		writel(hw, per_cpu_int_base +
294 			ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
295 	else
296 		writel(hw, main_int_base + ARMADA_370_XP_INT_SET_ENABLE_OFFS);
297 	irq_set_status_flags(virq, IRQ_LEVEL);
298 
299 	if (hw == ARMADA_370_XP_TIMER0_PER_CPU_IRQ) {
300 		irq_set_percpu_devid(virq);
301 		irq_set_chip_and_handler(virq, &armada_370_xp_irq_chip,
302 					handle_percpu_devid_irq);
303 
304 	} else {
305 		irq_set_chip_and_handler(virq, &armada_370_xp_irq_chip,
306 					handle_level_irq);
307 	}
308 	set_irq_flags(virq, IRQF_VALID | IRQF_PROBE);
309 
310 	return 0;
311 }
312 
313 #ifdef CONFIG_SMP
314 static void armada_mpic_send_doorbell(const struct cpumask *mask,
315 				      unsigned int irq)
316 {
317 	int cpu;
318 	unsigned long map = 0;
319 
320 	/* Convert our logical CPU mask into a physical one. */
321 	for_each_cpu(cpu, mask)
322 		map |= 1 << cpu_logical_map(cpu);
323 
324 	/*
325 	 * Ensure that stores to Normal memory are visible to the
326 	 * other CPUs before issuing the IPI.
327 	 */
328 	dsb();
329 
330 	/* submit softirq */
331 	writel((map << 8) | irq, main_int_base +
332 		ARMADA_370_XP_SW_TRIG_INT_OFFS);
333 }
334 
335 static void armada_xp_mpic_smp_cpu_init(void)
336 {
337 	/* Clear pending IPIs */
338 	writel(0, per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS);
339 
340 	/* Enable first 8 IPIs */
341 	writel(IPI_DOORBELL_MASK, per_cpu_int_base +
342 		ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
343 
344 	/* Unmask IPI interrupt */
345 	writel(0, per_cpu_int_base + ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
346 }
347 
348 static int armada_xp_mpic_secondary_init(struct notifier_block *nfb,
349 					 unsigned long action, void *hcpu)
350 {
351 	if (action == CPU_STARTING || action == CPU_STARTING_FROZEN)
352 		armada_xp_mpic_smp_cpu_init();
353 	return NOTIFY_OK;
354 }
355 
356 static struct notifier_block armada_370_xp_mpic_cpu_notifier = {
357 	.notifier_call = armada_xp_mpic_secondary_init,
358 	.priority = 100,
359 };
360 
361 #endif /* CONFIG_SMP */
362 
363 static struct irq_domain_ops armada_370_xp_mpic_irq_ops = {
364 	.map = armada_370_xp_mpic_irq_map,
365 	.xlate = irq_domain_xlate_onecell,
366 };
367 
368 #ifdef CONFIG_PCI_MSI
369 static void armada_370_xp_handle_msi_irq(struct pt_regs *regs, bool is_chained)
370 {
371 	u32 msimask, msinr;
372 
373 	msimask = readl_relaxed(per_cpu_int_base +
374 				ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS)
375 		& PCI_MSI_DOORBELL_MASK;
376 
377 	writel(~msimask, per_cpu_int_base +
378 	       ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS);
379 
380 	for (msinr = PCI_MSI_DOORBELL_START;
381 	     msinr < PCI_MSI_DOORBELL_END; msinr++) {
382 		int irq;
383 
384 		if (!(msimask & BIT(msinr)))
385 			continue;
386 
387 		irq = irq_find_mapping(armada_370_xp_msi_domain,
388 				       msinr - 16);
389 
390 		if (is_chained)
391 			generic_handle_irq(irq);
392 		else
393 			handle_IRQ(irq, regs);
394 	}
395 }
396 #else
397 static void armada_370_xp_handle_msi_irq(struct pt_regs *r, bool b) {}
398 #endif
399 
400 static void armada_370_xp_mpic_handle_cascade_irq(unsigned int irq,
401 						  struct irq_desc *desc)
402 {
403 	struct irq_chip *chip = irq_get_chip(irq);
404 	unsigned long irqmap, irqn;
405 	unsigned int cascade_irq;
406 
407 	chained_irq_enter(chip, desc);
408 
409 	irqmap = readl_relaxed(per_cpu_int_base + ARMADA_375_PPI_CAUSE);
410 
411 	if (irqmap & BIT(0)) {
412 		armada_370_xp_handle_msi_irq(NULL, true);
413 		irqmap &= ~BIT(0);
414 	}
415 
416 	for_each_set_bit(irqn, &irqmap, BITS_PER_LONG) {
417 		cascade_irq = irq_find_mapping(armada_370_xp_mpic_domain, irqn);
418 		generic_handle_irq(cascade_irq);
419 	}
420 
421 	chained_irq_exit(chip, desc);
422 }
423 
424 static void __exception_irq_entry
425 armada_370_xp_handle_irq(struct pt_regs *regs)
426 {
427 	u32 irqstat, irqnr;
428 
429 	do {
430 		irqstat = readl_relaxed(per_cpu_int_base +
431 					ARMADA_370_XP_CPU_INTACK_OFFS);
432 		irqnr = irqstat & 0x3FF;
433 
434 		if (irqnr > 1022)
435 			break;
436 
437 		if (irqnr > 1) {
438 			irqnr =	irq_find_mapping(armada_370_xp_mpic_domain,
439 					irqnr);
440 			handle_IRQ(irqnr, regs);
441 			continue;
442 		}
443 
444 		/* MSI handling */
445 		if (irqnr == 1)
446 			armada_370_xp_handle_msi_irq(regs, false);
447 
448 #ifdef CONFIG_SMP
449 		/* IPI Handling */
450 		if (irqnr == 0) {
451 			u32 ipimask, ipinr;
452 
453 			ipimask = readl_relaxed(per_cpu_int_base +
454 						ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS)
455 				& IPI_DOORBELL_MASK;
456 
457 			writel(~ipimask, per_cpu_int_base +
458 				ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS);
459 
460 			/* Handle all pending doorbells */
461 			for (ipinr = IPI_DOORBELL_START;
462 			     ipinr < IPI_DOORBELL_END; ipinr++) {
463 				if (ipimask & (0x1 << ipinr))
464 					handle_IPI(ipinr, regs);
465 			}
466 			continue;
467 		}
468 #endif
469 
470 	} while (1);
471 }
472 
473 static int __init armada_370_xp_mpic_of_init(struct device_node *node,
474 					     struct device_node *parent)
475 {
476 	struct resource main_int_res, per_cpu_int_res;
477 	int parent_irq;
478 	u32 control;
479 
480 	BUG_ON(of_address_to_resource(node, 0, &main_int_res));
481 	BUG_ON(of_address_to_resource(node, 1, &per_cpu_int_res));
482 
483 	BUG_ON(!request_mem_region(main_int_res.start,
484 				   resource_size(&main_int_res),
485 				   node->full_name));
486 	BUG_ON(!request_mem_region(per_cpu_int_res.start,
487 				   resource_size(&per_cpu_int_res),
488 				   node->full_name));
489 
490 	main_int_base = ioremap(main_int_res.start,
491 				resource_size(&main_int_res));
492 	BUG_ON(!main_int_base);
493 
494 	per_cpu_int_base = ioremap(per_cpu_int_res.start,
495 				   resource_size(&per_cpu_int_res));
496 	BUG_ON(!per_cpu_int_base);
497 
498 	control = readl(main_int_base + ARMADA_370_XP_INT_CONTROL);
499 
500 	armada_370_xp_mpic_domain =
501 		irq_domain_add_linear(node, (control >> 2) & 0x3ff,
502 				&armada_370_xp_mpic_irq_ops, NULL);
503 
504 	BUG_ON(!armada_370_xp_mpic_domain);
505 
506 #ifdef CONFIG_SMP
507 	armada_xp_mpic_smp_cpu_init();
508 #endif
509 
510 	armada_370_xp_msi_init(node, main_int_res.start);
511 
512 	parent_irq = irq_of_parse_and_map(node, 0);
513 	if (parent_irq <= 0) {
514 		irq_set_default_host(armada_370_xp_mpic_domain);
515 		set_handle_irq(armada_370_xp_handle_irq);
516 #ifdef CONFIG_SMP
517 		set_smp_cross_call(armada_mpic_send_doorbell);
518 		register_cpu_notifier(&armada_370_xp_mpic_cpu_notifier);
519 #endif
520 	} else {
521 		irq_set_chained_handler(parent_irq,
522 					armada_370_xp_mpic_handle_cascade_irq);
523 	}
524 
525 	return 0;
526 }
527 
528 IRQCHIP_DECLARE(armada_370_xp_mpic, "marvell,mpic", armada_370_xp_mpic_of_init);
529