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
22 struct ppc4xx_hsta_msi {
23 struct device *dev;
24
25 /* The ioremapped HSTA MSI IO space */
26 u32 __iomem *data;
27
28 /* Physical address of HSTA MSI IO space */
29 u64 address;
30 struct msi_bitmap bmp;
31
32 /* An array mapping offsets to hardware IRQs */
33 int *irq_map;
34
35 /* Number of hwirqs supported */
36 int irq_count;
37 };
38 static struct ppc4xx_hsta_msi ppc4xx_hsta_msi;
39
hsta_setup_msi_irqs(struct pci_dev * dev,int nvec,int type)40 static int hsta_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
41 {
42 struct msi_msg msg;
43 struct msi_desc *entry;
44 int irq, hwirq;
45 u64 addr;
46
47 /* We don't support MSI-X */
48 if (type == PCI_CAP_ID_MSIX) {
49 pr_debug("%s: MSI-X not supported.\n", __func__);
50 return -EINVAL;
51 }
52
53 list_for_each_entry(entry, &dev->msi_list, list) {
54 irq = msi_bitmap_alloc_hwirqs(&ppc4xx_hsta_msi.bmp, 1);
55 if (irq < 0) {
56 pr_debug("%s: Failed to allocate msi interrupt\n",
57 __func__);
58 return irq;
59 }
60
61 hwirq = ppc4xx_hsta_msi.irq_map[irq];
62 if (hwirq == NO_IRQ) {
63 pr_err("%s: Failed mapping irq %d\n", __func__, irq);
64 return -EINVAL;
65 }
66
67 /*
68 * HSTA generates interrupts on writes to 128-bit aligned
69 * addresses.
70 */
71 addr = ppc4xx_hsta_msi.address + irq*0x10;
72 msg.address_hi = upper_32_bits(addr);
73 msg.address_lo = lower_32_bits(addr);
74
75 /* Data is not used by the HSTA. */
76 msg.data = 0;
77
78 pr_debug("%s: Setup irq %d (0x%0llx)\n", __func__, hwirq,
79 (((u64) msg.address_hi) << 32) | msg.address_lo);
80
81 if (irq_set_msi_desc(hwirq, entry)) {
82 pr_err(
83 "%s: Invalid hwirq %d specified in device tree\n",
84 __func__, hwirq);
85 msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1);
86 return -EINVAL;
87 }
88 pci_write_msi_msg(hwirq, &msg);
89 }
90
91 return 0;
92 }
93
hsta_find_hwirq_offset(int hwirq)94 static int hsta_find_hwirq_offset(int hwirq)
95 {
96 int irq;
97
98 /* Find the offset given the hwirq */
99 for (irq = 0; irq < ppc4xx_hsta_msi.irq_count; irq++)
100 if (ppc4xx_hsta_msi.irq_map[irq] == hwirq)
101 return irq;
102
103 return -EINVAL;
104 }
105
hsta_teardown_msi_irqs(struct pci_dev * dev)106 static void hsta_teardown_msi_irqs(struct pci_dev *dev)
107 {
108 struct msi_desc *entry;
109 int irq;
110
111 list_for_each_entry(entry, &dev->msi_list, list) {
112 if (entry->irq == NO_IRQ)
113 continue;
114
115 irq = hsta_find_hwirq_offset(entry->irq);
116
117 /* entry->irq should always be in irq_map */
118 BUG_ON(irq < 0);
119 irq_set_msi_desc(entry->irq, NULL);
120 msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1);
121 pr_debug("%s: Teardown IRQ %u (index %u)\n", __func__,
122 entry->irq, irq);
123 }
124 }
125
hsta_msi_probe(struct platform_device * pdev)126 static int hsta_msi_probe(struct platform_device *pdev)
127 {
128 struct device *dev = &pdev->dev;
129 struct resource *mem;
130 int irq, ret, irq_count;
131
132 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
133 if (IS_ERR(mem)) {
134 dev_err(dev, "Unable to get mmio space\n");
135 return -EINVAL;
136 }
137
138 irq_count = of_irq_count(dev->of_node);
139 if (!irq_count) {
140 dev_err(dev, "Unable to find IRQ range\n");
141 return -EINVAL;
142 }
143
144 ppc4xx_hsta_msi.dev = dev;
145 ppc4xx_hsta_msi.address = mem->start;
146 ppc4xx_hsta_msi.data = ioremap(mem->start, resource_size(mem));
147 ppc4xx_hsta_msi.irq_count = irq_count;
148 if (!ppc4xx_hsta_msi.data) {
149 dev_err(dev, "Unable to map memory\n");
150 return -ENOMEM;
151 }
152
153 ret = msi_bitmap_alloc(&ppc4xx_hsta_msi.bmp, irq_count, dev->of_node);
154 if (ret)
155 goto out;
156
157 ppc4xx_hsta_msi.irq_map = kmalloc(sizeof(int) * irq_count, GFP_KERNEL);
158 if (IS_ERR(ppc4xx_hsta_msi.irq_map)) {
159 ret = -ENOMEM;
160 goto out1;
161 }
162
163 /* Setup a mapping from irq offsets to hardware irq numbers */
164 for (irq = 0; irq < irq_count; irq++) {
165 ppc4xx_hsta_msi.irq_map[irq] =
166 irq_of_parse_and_map(dev->of_node, irq);
167 if (ppc4xx_hsta_msi.irq_map[irq] == NO_IRQ) {
168 dev_err(dev, "Unable to map IRQ\n");
169 ret = -EINVAL;
170 goto out2;
171 }
172 }
173
174 ppc_md.setup_msi_irqs = hsta_setup_msi_irqs;
175 ppc_md.teardown_msi_irqs = hsta_teardown_msi_irqs;
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