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