1 /*
2 * MSI support for PPC4xx SoCs using High Speed Transfer Assist (HSTA) for
3 * generation of the interrupt.
4 *
5 * Copyright © 2013 Alistair Popple <alistair@popple.id.au> IBM Corporation
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the
9 * Free Software Foundation; either version 2 of the License, or (at your
10 * option) any later version.
11 */
12
13 #include <linux/kernel.h>
14 #include <linux/interrupt.h>
15 #include <linux/msi.h>
16 #include <linux/of.h>
17 #include <linux/of_platform.h>
18 #include <linux/pci.h>
19 #include <linux/semaphore.h>
20 #include <asm/msi_bitmap.h>
21 #include <asm/ppc-pci.h>
22
23 struct ppc4xx_hsta_msi {
24 struct device *dev;
25
26 /* The ioremapped HSTA MSI IO space */
27 u32 __iomem *data;
28
29 /* Physical address of HSTA MSI IO space */
30 u64 address;
31 struct msi_bitmap bmp;
32
33 /* An array mapping offsets to hardware IRQs */
34 int *irq_map;
35
36 /* Number of hwirqs supported */
37 int irq_count;
38 };
39 static struct ppc4xx_hsta_msi ppc4xx_hsta_msi;
40
hsta_setup_msi_irqs(struct pci_dev * dev,int nvec,int type)41 static int hsta_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
42 {
43 struct msi_msg msg;
44 struct msi_desc *entry;
45 int irq, hwirq;
46 u64 addr;
47
48 /* We don't support MSI-X */
49 if (type == PCI_CAP_ID_MSIX) {
50 pr_debug("%s: MSI-X not supported.\n", __func__);
51 return -EINVAL;
52 }
53
54 for_each_pci_msi_entry(entry, dev) {
55 irq = msi_bitmap_alloc_hwirqs(&ppc4xx_hsta_msi.bmp, 1);
56 if (irq < 0) {
57 pr_debug("%s: Failed to allocate msi interrupt\n",
58 __func__);
59 return irq;
60 }
61
62 hwirq = ppc4xx_hsta_msi.irq_map[irq];
63 if (!hwirq) {
64 pr_err("%s: Failed mapping irq %d\n", __func__, irq);
65 return -EINVAL;
66 }
67
68 /*
69 * HSTA generates interrupts on writes to 128-bit aligned
70 * addresses.
71 */
72 addr = ppc4xx_hsta_msi.address + irq*0x10;
73 msg.address_hi = upper_32_bits(addr);
74 msg.address_lo = lower_32_bits(addr);
75
76 /* Data is not used by the HSTA. */
77 msg.data = 0;
78
79 pr_debug("%s: Setup irq %d (0x%0llx)\n", __func__, hwirq,
80 (((u64) msg.address_hi) << 32) | msg.address_lo);
81
82 if (irq_set_msi_desc(hwirq, entry)) {
83 pr_err(
84 "%s: Invalid hwirq %d specified in device tree\n",
85 __func__, hwirq);
86 msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1);
87 return -EINVAL;
88 }
89 pci_write_msi_msg(hwirq, &msg);
90 }
91
92 return 0;
93 }
94
hsta_find_hwirq_offset(int hwirq)95 static int hsta_find_hwirq_offset(int hwirq)
96 {
97 int irq;
98
99 /* Find the offset given the hwirq */
100 for (irq = 0; irq < ppc4xx_hsta_msi.irq_count; irq++)
101 if (ppc4xx_hsta_msi.irq_map[irq] == hwirq)
102 return irq;
103
104 return -EINVAL;
105 }
106
hsta_teardown_msi_irqs(struct pci_dev * dev)107 static void hsta_teardown_msi_irqs(struct pci_dev *dev)
108 {
109 struct msi_desc *entry;
110 int irq;
111
112 for_each_pci_msi_entry(entry, dev) {
113 if (!entry->irq)
114 continue;
115
116 irq = hsta_find_hwirq_offset(entry->irq);
117
118 /* entry->irq should always be in irq_map */
119 BUG_ON(irq < 0);
120 irq_set_msi_desc(entry->irq, NULL);
121 msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1);
122 pr_debug("%s: Teardown IRQ %u (index %u)\n", __func__,
123 entry->irq, irq);
124 }
125 }
126
hsta_msi_probe(struct platform_device * pdev)127 static int hsta_msi_probe(struct platform_device *pdev)
128 {
129 struct device *dev = &pdev->dev;
130 struct resource *mem;
131 int irq, ret, irq_count;
132 struct pci_controller *phb;
133
134 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
135 if (!mem) {
136 dev_err(dev, "Unable to get mmio space\n");
137 return -EINVAL;
138 }
139
140 irq_count = of_irq_count(dev->of_node);
141 if (!irq_count) {
142 dev_err(dev, "Unable to find IRQ range\n");
143 return -EINVAL;
144 }
145
146 ppc4xx_hsta_msi.dev = dev;
147 ppc4xx_hsta_msi.address = mem->start;
148 ppc4xx_hsta_msi.data = ioremap(mem->start, resource_size(mem));
149 ppc4xx_hsta_msi.irq_count = irq_count;
150 if (!ppc4xx_hsta_msi.data) {
151 dev_err(dev, "Unable to map memory\n");
152 return -ENOMEM;
153 }
154
155 ret = msi_bitmap_alloc(&ppc4xx_hsta_msi.bmp, irq_count, dev->of_node);
156 if (ret)
157 goto out;
158
159 ppc4xx_hsta_msi.irq_map = kmalloc(sizeof(int) * irq_count, GFP_KERNEL);
160 if (!ppc4xx_hsta_msi.irq_map) {
161 ret = -ENOMEM;
162 goto out1;
163 }
164
165 /* Setup a mapping from irq offsets to hardware irq numbers */
166 for (irq = 0; irq < irq_count; irq++) {
167 ppc4xx_hsta_msi.irq_map[irq] =
168 irq_of_parse_and_map(dev->of_node, irq);
169 if (!ppc4xx_hsta_msi.irq_map[irq]) {
170 dev_err(dev, "Unable to map IRQ\n");
171 ret = -EINVAL;
172 goto out2;
173 }
174 }
175
176 list_for_each_entry(phb, &hose_list, list_node) {
177 phb->controller_ops.setup_msi_irqs = hsta_setup_msi_irqs;
178 phb->controller_ops.teardown_msi_irqs = hsta_teardown_msi_irqs;
179 }
180 return 0;
181
182 out2:
183 kfree(ppc4xx_hsta_msi.irq_map);
184
185 out1:
186 msi_bitmap_free(&ppc4xx_hsta_msi.bmp);
187
188 out:
189 iounmap(ppc4xx_hsta_msi.data);
190 return ret;
191 }
192
193 static const struct of_device_id hsta_msi_ids[] = {
194 {
195 .compatible = "ibm,hsta-msi",
196 },
197 {}
198 };
199
200 static struct platform_driver hsta_msi_driver = {
201 .probe = hsta_msi_probe,
202 .driver = {
203 .name = "hsta-msi",
204 .of_match_table = hsta_msi_ids,
205 },
206 };
207
hsta_msi_init(void)208 static int hsta_msi_init(void)
209 {
210 return platform_driver_register(&hsta_msi_driver);
211 }
212 subsys_initcall(hsta_msi_init);
213