xref: /openbmc/linux/drivers/sh/intc/irqdomain.c (revision 55fd7e02)
1 /*
2  * IRQ domain support for SH INTC subsystem
3  *
4  * Copyright (C) 2012  Paul Mundt
5  *
6  * This file is subject to the terms and conditions of the GNU General Public
7  * License.  See the file "COPYING" in the main directory of this archive
8  * for more details.
9  */
10 #define pr_fmt(fmt) "intc: " fmt
11 
12 #include <linux/irqdomain.h>
13 #include <linux/sh_intc.h>
14 #include <linux/export.h>
15 #include "internals.h"
16 
17 /**
18  * intc_irq_domain_evt_xlate() - Generic xlate for vectored IRQs.
19  *
20  * This takes care of exception vector to hwirq translation through
21  * by way of evt2irq() translation.
22  *
23  * Note: For platforms that use a flat vector space without INTEVT this
24  * basically just mimics irq_domain_xlate_onecell() by way of a nopped
25  * out evt2irq() implementation.
26  */
27 static int intc_evt_xlate(struct irq_domain *d, struct device_node *ctrlr,
28 			  const u32 *intspec, unsigned int intsize,
29 			  unsigned long *out_hwirq, unsigned int *out_type)
30 {
31 	if (WARN_ON(intsize < 1))
32 		return -EINVAL;
33 
34 	*out_hwirq = evt2irq(intspec[0]);
35 	*out_type = IRQ_TYPE_NONE;
36 
37 	return 0;
38 }
39 
40 static const struct irq_domain_ops intc_evt_ops = {
41 	.xlate		= intc_evt_xlate,
42 };
43 
44 void __init intc_irq_domain_init(struct intc_desc_int *d,
45 				 struct intc_hw_desc *hw)
46 {
47 	unsigned int irq_base, irq_end;
48 
49 	/*
50 	 * Quick linear revmap check
51 	 */
52 	irq_base = evt2irq(hw->vectors[0].vect);
53 	irq_end = evt2irq(hw->vectors[hw->nr_vectors - 1].vect);
54 
55 	/*
56 	 * Linear domains have a hard-wired assertion that IRQs start at
57 	 * 0 in order to make some performance optimizations. Lamely
58 	 * restrict the linear case to these conditions here, taking the
59 	 * tree penalty for linear cases with non-zero hwirq bases.
60 	 */
61 	if (irq_base == 0 && irq_end == (irq_base + hw->nr_vectors - 1))
62 		d->domain = irq_domain_add_linear(NULL, hw->nr_vectors,
63 						  &intc_evt_ops, NULL);
64 	else
65 		d->domain = irq_domain_add_tree(NULL, &intc_evt_ops, NULL);
66 
67 	BUG_ON(!d->domain);
68 }
69