xref: /openbmc/linux/arch/powerpc/sysdev/mpic_msi.c (revision 23c2b932)
1 /*
2  * Copyright 2006-2007, Michael Ellerman, IBM Corporation.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License
6  * as published by the Free Software Foundation; version 2 of the
7  * License.
8  *
9  */
10 
11 #include <linux/irq.h>
12 #include <linux/bitmap.h>
13 #include <linux/msi.h>
14 #include <asm/mpic.h>
15 #include <asm/prom.h>
16 #include <asm/hw_irq.h>
17 #include <asm/ppc-pci.h>
18 #include <asm/msi_bitmap.h>
19 
20 #include <sysdev/mpic.h>
21 
22 void mpic_msi_reserve_hwirq(struct mpic *mpic, irq_hw_number_t hwirq)
23 {
24 	/* The mpic calls this even when there is no allocator setup */
25 	if (!mpic->msi_bitmap.bitmap)
26 		return;
27 
28 	msi_bitmap_reserve_hwirq(&mpic->msi_bitmap, hwirq);
29 }
30 
31 #ifdef CONFIG_MPIC_U3_HT_IRQS
32 static int mpic_msi_reserve_u3_hwirqs(struct mpic *mpic)
33 {
34 	irq_hw_number_t hwirq;
35 	const struct irq_domain_ops *ops = mpic->irqhost->ops;
36 	struct device_node *np;
37 	int flags, index, i;
38 	struct of_phandle_args oirq;
39 
40 	pr_debug("mpic: found U3, guessing msi allocator setup\n");
41 
42 	/* Reserve source numbers we know are reserved in the HW.
43 	 *
44 	 * This is a bit of a mix of U3 and U4 reserves but that's going
45 	 * to work fine, we have plenty enugh numbers left so let's just
46 	 * mark anything we don't like reserved.
47 	 */
48 	for (i = 0;   i < 8;   i++)
49 		msi_bitmap_reserve_hwirq(&mpic->msi_bitmap, i);
50 
51 	for (i = 42;  i < 46;  i++)
52 		msi_bitmap_reserve_hwirq(&mpic->msi_bitmap, i);
53 
54 	for (i = 100; i < 105; i++)
55 		msi_bitmap_reserve_hwirq(&mpic->msi_bitmap, i);
56 
57 	for (i = 124; i < mpic->num_sources; i++)
58 		msi_bitmap_reserve_hwirq(&mpic->msi_bitmap, i);
59 
60 
61 	np = NULL;
62 	while ((np = of_find_all_nodes(np))) {
63 		pr_debug("mpic: mapping hwirqs for %s\n", np->full_name);
64 
65 		index = 0;
66 		while (of_irq_parse_one(np, index++, &oirq) == 0) {
67 			ops->xlate(mpic->irqhost, NULL, oirq.args,
68 						oirq.args_count, &hwirq, &flags);
69 			msi_bitmap_reserve_hwirq(&mpic->msi_bitmap, hwirq);
70 		}
71 	}
72 
73 	return 0;
74 }
75 #else
76 static int mpic_msi_reserve_u3_hwirqs(struct mpic *mpic)
77 {
78 	return -1;
79 }
80 #endif
81 
82 int mpic_msi_init_allocator(struct mpic *mpic)
83 {
84 	int rc;
85 
86 	rc = msi_bitmap_alloc(&mpic->msi_bitmap, mpic->num_sources,
87 			      irq_domain_get_of_node(mpic->irqhost));
88 	if (rc)
89 		return rc;
90 
91 	rc = msi_bitmap_reserve_dt_hwirqs(&mpic->msi_bitmap);
92 	if (rc > 0) {
93 		if (mpic->flags & MPIC_U3_HT_IRQS)
94 			rc = mpic_msi_reserve_u3_hwirqs(mpic);
95 
96 		if (rc) {
97 			msi_bitmap_free(&mpic->msi_bitmap);
98 			return rc;
99 		}
100 	}
101 
102 	return 0;
103 }
104