1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright 2007, Olof Johansson, PA Semi
4  *
5  * Based on arch/powerpc/sysdev/mpic_u3msi.c:
6  *
7  * Copyright 2006, Segher Boessenkool, IBM Corporation.
8  * Copyright 2006-2007, Michael Ellerman, IBM Corporation.
9  */
10 
11 #include <linux/irq.h>
12 #include <linux/irqdomain.h>
13 #include <linux/msi.h>
14 #include <asm/mpic.h>
15 #include <asm/hw_irq.h>
16 #include <asm/ppc-pci.h>
17 #include <asm/msi_bitmap.h>
18 
19 #include <sysdev/mpic.h>
20 
21 /* Allocate 16 interrupts per device, to give an alignment of 16,
22  * since that's the size of the grouping w.r.t. affinity. If someone
23  * needs more than 32 MSI's down the road we'll have to rethink this,
24  * but it should be OK for now.
25  */
26 #define ALLOC_CHUNK 16
27 
28 #define PASEMI_MSI_ADDR 0xfc080000
29 
30 /* A bit ugly, can we get this from the pci_dev somehow? */
31 static struct mpic *msi_mpic;
32 
33 
34 static void mpic_pasemi_msi_mask_irq(struct irq_data *data)
35 {
36 	pr_debug("mpic_pasemi_msi_mask_irq %d\n", data->irq);
37 	pci_msi_mask_irq(data);
38 	mpic_mask_irq(data);
39 }
40 
41 static void mpic_pasemi_msi_unmask_irq(struct irq_data *data)
42 {
43 	pr_debug("mpic_pasemi_msi_unmask_irq %d\n", data->irq);
44 	mpic_unmask_irq(data);
45 	pci_msi_unmask_irq(data);
46 }
47 
48 static struct irq_chip mpic_pasemi_msi_chip = {
49 	.irq_shutdown		= mpic_pasemi_msi_mask_irq,
50 	.irq_mask		= mpic_pasemi_msi_mask_irq,
51 	.irq_unmask		= mpic_pasemi_msi_unmask_irq,
52 	.irq_eoi		= mpic_end_irq,
53 	.irq_set_type		= mpic_set_irq_type,
54 	.irq_set_affinity	= mpic_set_affinity,
55 	.name			= "PASEMI-MSI",
56 };
57 
58 static void pasemi_msi_teardown_msi_irqs(struct pci_dev *pdev)
59 {
60 	struct msi_desc *entry;
61 	irq_hw_number_t hwirq;
62 
63 	pr_debug("pasemi_msi_teardown_msi_irqs, pdev %p\n", pdev);
64 
65 	msi_for_each_desc(entry, &pdev->dev, MSI_DESC_ASSOCIATED) {
66 		hwirq = virq_to_hw(entry->irq);
67 		irq_set_msi_desc(entry->irq, NULL);
68 		irq_dispose_mapping(entry->irq);
69 		msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap, hwirq, ALLOC_CHUNK);
70 	}
71 }
72 
73 static int pasemi_msi_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
74 {
75 	unsigned int virq;
76 	struct msi_desc *entry;
77 	struct msi_msg msg;
78 	int hwirq;
79 
80 	if (type == PCI_CAP_ID_MSIX)
81 		pr_debug("pasemi_msi: MSI-X untested, trying anyway\n");
82 	pr_debug("pasemi_msi_setup_msi_irqs, pdev %p nvec %d type %d\n",
83 		 pdev, nvec, type);
84 
85 	msg.address_hi = 0;
86 	msg.address_lo = PASEMI_MSI_ADDR;
87 
88 	msi_for_each_desc(entry, &pdev->dev, MSI_DESC_NOTASSOCIATED) {
89 		/* Allocate 16 interrupts for now, since that's the grouping for
90 		 * affinity. This can be changed later if it turns out 32 is too
91 		 * few MSIs for someone, but restrictions will apply to how the
92 		 * sources can be changed independently.
93 		 */
94 		hwirq = msi_bitmap_alloc_hwirqs(&msi_mpic->msi_bitmap,
95 						ALLOC_CHUNK);
96 		if (hwirq < 0) {
97 			pr_debug("pasemi_msi: failed allocating hwirq\n");
98 			return hwirq;
99 		}
100 
101 		virq = irq_create_mapping(msi_mpic->irqhost, hwirq);
102 		if (!virq) {
103 			pr_debug("pasemi_msi: failed mapping hwirq 0x%x\n",
104 				  hwirq);
105 			msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap, hwirq,
106 					       ALLOC_CHUNK);
107 			return -ENOSPC;
108 		}
109 
110 		/* Vector on MSI is really an offset, the hardware adds
111 		 * it to the value written at the magic address. So set
112 		 * it to 0 to remain sane.
113 		 */
114 		mpic_set_vector(virq, 0);
115 
116 		irq_set_msi_desc(virq, entry);
117 		irq_set_chip(virq, &mpic_pasemi_msi_chip);
118 		irq_set_irq_type(virq, IRQ_TYPE_EDGE_RISING);
119 
120 		pr_debug("pasemi_msi: allocated virq 0x%x (hw 0x%x) " \
121 			 "addr 0x%x\n", virq, hwirq, msg.address_lo);
122 
123 		/* Likewise, the device writes [0...511] into the target
124 		 * register to generate MSI [512...1023]
125 		 */
126 		msg.data = hwirq-0x200;
127 		pci_write_msi_msg(virq, &msg);
128 	}
129 
130 	return 0;
131 }
132 
133 int __init mpic_pasemi_msi_init(struct mpic *mpic)
134 {
135 	int rc;
136 	struct pci_controller *phb;
137 	struct device_node *of_node;
138 
139 	of_node = irq_domain_get_of_node(mpic->irqhost);
140 	if (!of_node ||
141 	    !of_device_is_compatible(of_node,
142 				     "pasemi,pwrficient-openpic"))
143 		return -ENODEV;
144 
145 	rc = mpic_msi_init_allocator(mpic);
146 	if (rc) {
147 		pr_debug("pasemi_msi: Error allocating bitmap!\n");
148 		return rc;
149 	}
150 
151 	pr_debug("pasemi_msi: Registering PA Semi MPIC MSI callbacks\n");
152 
153 	msi_mpic = mpic;
154 	list_for_each_entry(phb, &hose_list, list_node) {
155 		WARN_ON(phb->controller_ops.setup_msi_irqs);
156 		phb->controller_ops.setup_msi_irqs = pasemi_msi_setup_msi_irqs;
157 		phb->controller_ops.teardown_msi_irqs = pasemi_msi_teardown_msi_irqs;
158 	}
159 
160 	return 0;
161 }
162