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1 | // SPDX-License-Identifier: GPL-2.0-or-later | |
2 | /* | |
3 | * MSI support for PPC4xx SoCs using High Speed Transfer Assist (HSTA) for | |
4 | * generation of the interrupt. | |
5 | * | |
6 | * Copyright © 2013 Alistair Popple <alistair@popple.id.au> IBM Corporation | |
7 | */ | |
8 | ||
9 | #include <linux/kernel.h> | |
10 | #include <linux/interrupt.h> | |
11 | #include <linux/msi.h> | |
12 | #include <linux/of.h> | |
13 | #include <linux/of_platform.h> | |
14 | #include <linux/pci.h> | |
15 | #include <linux/semaphore.h> | |
16 | #include <asm/msi_bitmap.h> | |
17 | #include <asm/ppc-pci.h> | |
18 | ||
19 | struct ppc4xx_hsta_msi { | |
20 | struct device *dev; | |
21 | ||
22 | /* The ioremapped HSTA MSI IO space */ | |
23 | u32 __iomem *data; | |
24 | ||
25 | /* Physical address of HSTA MSI IO space */ | |
26 | u64 address; | |
27 | struct msi_bitmap bmp; | |
28 | ||
29 | /* An array mapping offsets to hardware IRQs */ | |
30 | int *irq_map; | |
31 | ||
32 | /* Number of hwirqs supported */ | |
33 | int irq_count; | |
34 | }; | |
35 | static struct ppc4xx_hsta_msi ppc4xx_hsta_msi; | |
36 | ||
37 | static int hsta_setup_msi_irqs(struct pci_dev *dev, int nvec, int type) | |
38 | { | |
39 | struct msi_msg msg; | |
40 | struct msi_desc *entry; | |
41 | int irq, hwirq; | |
42 | u64 addr; | |
43 | ||
44 | /* We don't support MSI-X */ | |
45 | if (type == PCI_CAP_ID_MSIX) { | |
46 | pr_debug("%s: MSI-X not supported.\n", __func__); | |
47 | return -EINVAL; | |
48 | } | |
49 | ||
50 | for_each_pci_msi_entry(entry, dev) { | |
51 | irq = msi_bitmap_alloc_hwirqs(&ppc4xx_hsta_msi.bmp, 1); | |
52 | if (irq < 0) { | |
53 | pr_debug("%s: Failed to allocate msi interrupt\n", | |
54 | __func__); | |
55 | return irq; | |
56 | } | |
57 | ||
58 | hwirq = ppc4xx_hsta_msi.irq_map[irq]; | |
59 | if (!hwirq) { | |
60 | pr_err("%s: Failed mapping irq %d\n", __func__, irq); | |
61 | return -EINVAL; | |
62 | } | |
63 | ||
64 | /* | |
65 | * HSTA generates interrupts on writes to 128-bit aligned | |
66 | * addresses. | |
67 | */ | |
68 | addr = ppc4xx_hsta_msi.address + irq*0x10; | |
69 | msg.address_hi = upper_32_bits(addr); | |
70 | msg.address_lo = lower_32_bits(addr); | |
71 | ||
72 | /* Data is not used by the HSTA. */ | |
73 | msg.data = 0; | |
74 | ||
75 | pr_debug("%s: Setup irq %d (0x%0llx)\n", __func__, hwirq, | |
76 | (((u64) msg.address_hi) << 32) | msg.address_lo); | |
77 | ||
78 | if (irq_set_msi_desc(hwirq, entry)) { | |
79 | pr_err( | |
80 | "%s: Invalid hwirq %d specified in device tree\n", | |
81 | __func__, hwirq); | |
82 | msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1); | |
83 | return -EINVAL; | |
84 | } | |
85 | pci_write_msi_msg(hwirq, &msg); | |
86 | } | |
87 | ||
88 | return 0; | |
89 | } | |
90 | ||
91 | static int hsta_find_hwirq_offset(int hwirq) | |
92 | { | |
93 | int irq; | |
94 | ||
95 | /* Find the offset given the hwirq */ | |
96 | for (irq = 0; irq < ppc4xx_hsta_msi.irq_count; irq++) | |
97 | if (ppc4xx_hsta_msi.irq_map[irq] == hwirq) | |
98 | return irq; | |
99 | ||
100 | return -EINVAL; | |
101 | } | |
102 | ||
103 | static void hsta_teardown_msi_irqs(struct pci_dev *dev) | |
104 | { | |
105 | struct msi_desc *entry; | |
106 | int irq; | |
107 | ||
108 | for_each_pci_msi_entry(entry, dev) { | |
109 | if (!entry->irq) | |
110 | continue; | |
111 | ||
112 | irq = hsta_find_hwirq_offset(entry->irq); | |
113 | ||
114 | /* entry->irq should always be in irq_map */ | |
115 | BUG_ON(irq < 0); | |
116 | irq_set_msi_desc(entry->irq, NULL); | |
117 | msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1); | |
118 | pr_debug("%s: Teardown IRQ %u (index %u)\n", __func__, | |
119 | entry->irq, irq); | |
120 | } | |
121 | } | |
122 | ||
123 | static int hsta_msi_probe(struct platform_device *pdev) | |
124 | { | |
125 | struct device *dev = &pdev->dev; | |
126 | struct resource *mem; | |
127 | int irq, ret, irq_count; | |
128 | struct pci_controller *phb; | |
129 | ||
130 | mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
131 | if (!mem) { | |
132 | dev_err(dev, "Unable to get mmio space\n"); | |
133 | return -EINVAL; | |
134 | } | |
135 | ||
136 | irq_count = of_irq_count(dev->of_node); | |
137 | if (!irq_count) { | |
138 | dev_err(dev, "Unable to find IRQ range\n"); | |
139 | return -EINVAL; | |
140 | } | |
141 | ||
142 | ppc4xx_hsta_msi.dev = dev; | |
143 | ppc4xx_hsta_msi.address = mem->start; | |
144 | ppc4xx_hsta_msi.data = ioremap(mem->start, resource_size(mem)); | |
145 | ppc4xx_hsta_msi.irq_count = irq_count; | |
146 | if (!ppc4xx_hsta_msi.data) { | |
147 | dev_err(dev, "Unable to map memory\n"); | |
148 | return -ENOMEM; | |
149 | } | |
150 | ||
151 | ret = msi_bitmap_alloc(&ppc4xx_hsta_msi.bmp, irq_count, dev->of_node); | |
152 | if (ret) | |
153 | goto out; | |
154 | ||
155 | ppc4xx_hsta_msi.irq_map = kmalloc_array(irq_count, sizeof(int), | |
156 | GFP_KERNEL); | |
157 | if (!ppc4xx_hsta_msi.irq_map) { | |
158 | ret = -ENOMEM; | |
159 | goto out1; | |
160 | } | |
161 | ||
162 | /* Setup a mapping from irq offsets to hardware irq numbers */ | |
163 | for (irq = 0; irq < irq_count; irq++) { | |
164 | ppc4xx_hsta_msi.irq_map[irq] = | |
165 | irq_of_parse_and_map(dev->of_node, irq); | |
166 | if (!ppc4xx_hsta_msi.irq_map[irq]) { | |
167 | dev_err(dev, "Unable to map IRQ\n"); | |
168 | ret = -EINVAL; | |
169 | goto out2; | |
170 | } | |
171 | } | |
172 | ||
173 | list_for_each_entry(phb, &hose_list, list_node) { | |
174 | phb->controller_ops.setup_msi_irqs = hsta_setup_msi_irqs; | |
175 | phb->controller_ops.teardown_msi_irqs = hsta_teardown_msi_irqs; | |
176 | } | |
177 | return 0; | |
178 | ||
179 | out2: | |
180 | kfree(ppc4xx_hsta_msi.irq_map); | |
181 | ||
182 | out1: | |
183 | msi_bitmap_free(&ppc4xx_hsta_msi.bmp); | |
184 | ||
185 | out: | |
186 | iounmap(ppc4xx_hsta_msi.data); | |
187 | return ret; | |
188 | } | |
189 | ||
190 | static const struct of_device_id hsta_msi_ids[] = { | |
191 | { | |
192 | .compatible = "ibm,hsta-msi", | |
193 | }, | |
194 | {} | |
195 | }; | |
196 | ||
197 | static struct platform_driver hsta_msi_driver = { | |
198 | .probe = hsta_msi_probe, | |
199 | .driver = { | |
200 | .name = "hsta-msi", | |
201 | .of_match_table = hsta_msi_ids, | |
202 | }, | |
203 | }; | |
204 | ||
205 | static int hsta_msi_init(void) | |
206 | { | |
207 | return platform_driver_register(&hsta_msi_driver); | |
208 | } | |
209 | subsys_initcall(hsta_msi_init); |