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
hsta_setup_msi_irqs(struct pci_dev * dev,int nvec,int type)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
hsta_find_hwirq_offset(int hwirq)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
hsta_teardown_msi_irqs(struct pci_dev * dev)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
hsta_msi_probe(struct platform_device * pdev)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
hsta_msi_init(void)205 static int hsta_msi_init(void)
206 {
207 return platform_driver_register(&hsta_msi_driver);
208 }
209 subsys_initcall(hsta_msi_init);
210