xref: /openbmc/linux/arch/powerpc/sysdev/mpic_msi.c (revision 842ed298)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright 2006-2007, Michael Ellerman, IBM Corporation.
4  */
5 
6 #include <linux/irq.h>
7 #include <linux/bitmap.h>
8 #include <linux/msi.h>
9 #include <asm/mpic.h>
10 #include <asm/prom.h>
11 #include <asm/hw_irq.h>
12 #include <asm/ppc-pci.h>
13 #include <asm/msi_bitmap.h>
14 
15 #include <sysdev/mpic.h>
16 
17 void mpic_msi_reserve_hwirq(struct mpic *mpic, irq_hw_number_t hwirq)
18 {
19 	/* The mpic calls this even when there is no allocator setup */
20 	if (!mpic->msi_bitmap.bitmap)
21 		return;
22 
23 	msi_bitmap_reserve_hwirq(&mpic->msi_bitmap, hwirq);
24 }
25 
26 #ifdef CONFIG_MPIC_U3_HT_IRQS
27 static int mpic_msi_reserve_u3_hwirqs(struct mpic *mpic)
28 {
29 	irq_hw_number_t hwirq;
30 	const struct irq_domain_ops *ops = mpic->irqhost->ops;
31 	struct device_node *np;
32 	int flags, index, i;
33 	struct of_phandle_args oirq;
34 
35 	pr_debug("mpic: found U3, guessing msi allocator setup\n");
36 
37 	/* Reserve source numbers we know are reserved in the HW.
38 	 *
39 	 * This is a bit of a mix of U3 and U4 reserves but that's going
40 	 * to work fine, we have plenty enugh numbers left so let's just
41 	 * mark anything we don't like reserved.
42 	 */
43 	for (i = 0;   i < 8;   i++)
44 		msi_bitmap_reserve_hwirq(&mpic->msi_bitmap, i);
45 
46 	for (i = 42;  i < 46;  i++)
47 		msi_bitmap_reserve_hwirq(&mpic->msi_bitmap, i);
48 
49 	for (i = 100; i < 105; i++)
50 		msi_bitmap_reserve_hwirq(&mpic->msi_bitmap, i);
51 
52 	for (i = 124; i < mpic->num_sources; i++)
53 		msi_bitmap_reserve_hwirq(&mpic->msi_bitmap, i);
54 
55 
56 	np = NULL;
57 	while ((np = of_find_all_nodes(np))) {
58 		pr_debug("mpic: mapping hwirqs for %pOF\n", np);
59 
60 		index = 0;
61 		while (of_irq_parse_one(np, index++, &oirq) == 0) {
62 			ops->xlate(mpic->irqhost, NULL, oirq.args,
63 						oirq.args_count, &hwirq, &flags);
64 			msi_bitmap_reserve_hwirq(&mpic->msi_bitmap, hwirq);
65 		}
66 	}
67 
68 	return 0;
69 }
70 #else
71 static int mpic_msi_reserve_u3_hwirqs(struct mpic *mpic)
72 {
73 	return -1;
74 }
75 #endif
76 
77 int mpic_msi_init_allocator(struct mpic *mpic)
78 {
79 	int rc;
80 
81 	rc = msi_bitmap_alloc(&mpic->msi_bitmap, mpic->num_sources,
82 			      irq_domain_get_of_node(mpic->irqhost));
83 	if (rc)
84 		return rc;
85 
86 	rc = msi_bitmap_reserve_dt_hwirqs(&mpic->msi_bitmap);
87 	if (rc > 0) {
88 		if (mpic->flags & MPIC_U3_HT_IRQS)
89 			rc = mpic_msi_reserve_u3_hwirqs(mpic);
90 
91 		if (rc) {
92 			msi_bitmap_free(&mpic->msi_bitmap);
93 			return rc;
94 		}
95 	}
96 
97 	return 0;
98 }
99