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10#include <linux/interrupt.h>
11#include <linux/irqchip/chained_irq.h>
12#include <linux/init.h>
13#include <linux/module.h>
14#include <linux/msi.h>
15#include <linux/of_address.h>
16#include <linux/of_irq.h>
17#include <linux/of_pci.h>
18#include <linux/pci.h>
19#include <linux/platform_device.h>
20#include <linux/slab.h>
21
22#define MSI_STATUS 0x0
23#define MSI_ERROR 0x4
24#define MSI_INTMASK 0x8
25
26#define MAX_MSI_VECTORS 32
27
28struct altera_msi {
29 DECLARE_BITMAP(used, MAX_MSI_VECTORS);
30 struct mutex lock;
31 struct platform_device *pdev;
32 struct irq_domain *msi_domain;
33 struct irq_domain *inner_domain;
34 void __iomem *csr_base;
35 void __iomem *vector_base;
36 phys_addr_t vector_phy;
37 u32 num_of_vectors;
38 int irq;
39};
40
41static inline void msi_writel(struct altera_msi *msi, const u32 value,
42 const u32 reg)
43{
44 writel_relaxed(value, msi->csr_base + reg);
45}
46
47static inline u32 msi_readl(struct altera_msi *msi, const u32 reg)
48{
49 return readl_relaxed(msi->csr_base + reg);
50}
51
52static void altera_msi_isr(struct irq_desc *desc)
53{
54 struct irq_chip *chip = irq_desc_get_chip(desc);
55 struct altera_msi *msi;
56 unsigned long status;
57 u32 bit;
58 int ret;
59
60 chained_irq_enter(chip, desc);
61 msi = irq_desc_get_handler_data(desc);
62
63 while ((status = msi_readl(msi, MSI_STATUS)) != 0) {
64 for_each_set_bit(bit, &status, msi->num_of_vectors) {
65
66 readl_relaxed(msi->vector_base + (bit * sizeof(u32)));
67
68 ret = generic_handle_domain_irq(msi->inner_domain, bit);
69 if (ret)
70 dev_err_ratelimited(&msi->pdev->dev, "unexpected MSI\n");
71 }
72 }
73
74 chained_irq_exit(chip, desc);
75}
76
77static struct irq_chip altera_msi_irq_chip = {
78 .name = "Altera PCIe MSI",
79 .irq_mask = pci_msi_mask_irq,
80 .irq_unmask = pci_msi_unmask_irq,
81};
82
83static struct msi_domain_info altera_msi_domain_info = {
84 .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
85 MSI_FLAG_PCI_MSIX),
86 .chip = &altera_msi_irq_chip,
87};
88
89static void altera_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
90{
91 struct altera_msi *msi = irq_data_get_irq_chip_data(data);
92 phys_addr_t addr = msi->vector_phy + (data->hwirq * sizeof(u32));
93
94 msg->address_lo = lower_32_bits(addr);
95 msg->address_hi = upper_32_bits(addr);
96 msg->data = data->hwirq;
97
98 dev_dbg(&msi->pdev->dev, "msi#%d address_hi %#x address_lo %#x\n",
99 (int)data->hwirq, msg->address_hi, msg->address_lo);
100}
101
102static int altera_msi_set_affinity(struct irq_data *irq_data,
103 const struct cpumask *mask, bool force)
104{
105 return -EINVAL;
106}
107
108static struct irq_chip altera_msi_bottom_irq_chip = {
109 .name = "Altera MSI",
110 .irq_compose_msi_msg = altera_compose_msi_msg,
111 .irq_set_affinity = altera_msi_set_affinity,
112};
113
114static int altera_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
115 unsigned int nr_irqs, void *args)
116{
117 struct altera_msi *msi = domain->host_data;
118 unsigned long bit;
119 u32 mask;
120
121 WARN_ON(nr_irqs != 1);
122 mutex_lock(&msi->lock);
123
124 bit = find_first_zero_bit(msi->used, msi->num_of_vectors);
125 if (bit >= msi->num_of_vectors) {
126 mutex_unlock(&msi->lock);
127 return -ENOSPC;
128 }
129
130 set_bit(bit, msi->used);
131
132 mutex_unlock(&msi->lock);
133
134 irq_domain_set_info(domain, virq, bit, &altera_msi_bottom_irq_chip,
135 domain->host_data, handle_simple_irq,
136 NULL, NULL);
137
138 mask = msi_readl(msi, MSI_INTMASK);
139 mask |= 1 << bit;
140 msi_writel(msi, mask, MSI_INTMASK);
141
142 return 0;
143}
144
145static void altera_irq_domain_free(struct irq_domain *domain,
146 unsigned int virq, unsigned int nr_irqs)
147{
148 struct irq_data *d = irq_domain_get_irq_data(domain, virq);
149 struct altera_msi *msi = irq_data_get_irq_chip_data(d);
150 u32 mask;
151
152 mutex_lock(&msi->lock);
153
154 if (!test_bit(d->hwirq, msi->used)) {
155 dev_err(&msi->pdev->dev, "trying to free unused MSI#%lu\n",
156 d->hwirq);
157 } else {
158 __clear_bit(d->hwirq, msi->used);
159 mask = msi_readl(msi, MSI_INTMASK);
160 mask &= ~(1 << d->hwirq);
161 msi_writel(msi, mask, MSI_INTMASK);
162 }
163
164 mutex_unlock(&msi->lock);
165}
166
167static const struct irq_domain_ops msi_domain_ops = {
168 .alloc = altera_irq_domain_alloc,
169 .free = altera_irq_domain_free,
170};
171
172static int altera_allocate_domains(struct altera_msi *msi)
173{
174 struct fwnode_handle *fwnode = of_node_to_fwnode(msi->pdev->dev.of_node);
175
176 msi->inner_domain = irq_domain_add_linear(NULL, msi->num_of_vectors,
177 &msi_domain_ops, msi);
178 if (!msi->inner_domain) {
179 dev_err(&msi->pdev->dev, "failed to create IRQ domain\n");
180 return -ENOMEM;
181 }
182
183 msi->msi_domain = pci_msi_create_irq_domain(fwnode,
184 &altera_msi_domain_info, msi->inner_domain);
185 if (!msi->msi_domain) {
186 dev_err(&msi->pdev->dev, "failed to create MSI domain\n");
187 irq_domain_remove(msi->inner_domain);
188 return -ENOMEM;
189 }
190
191 return 0;
192}
193
194static void altera_free_domains(struct altera_msi *msi)
195{
196 irq_domain_remove(msi->msi_domain);
197 irq_domain_remove(msi->inner_domain);
198}
199
200static int altera_msi_remove(struct platform_device *pdev)
201{
202 struct altera_msi *msi = platform_get_drvdata(pdev);
203
204 msi_writel(msi, 0, MSI_INTMASK);
205 irq_set_chained_handler_and_data(msi->irq, NULL, NULL);
206
207 altera_free_domains(msi);
208
209 platform_set_drvdata(pdev, NULL);
210 return 0;
211}
212
213static int altera_msi_probe(struct platform_device *pdev)
214{
215 struct altera_msi *msi;
216 struct device_node *np = pdev->dev.of_node;
217 struct resource *res;
218 int ret;
219
220 msi = devm_kzalloc(&pdev->dev, sizeof(struct altera_msi),
221 GFP_KERNEL);
222 if (!msi)
223 return -ENOMEM;
224
225 mutex_init(&msi->lock);
226 msi->pdev = pdev;
227
228 msi->csr_base = devm_platform_ioremap_resource_byname(pdev, "csr");
229 if (IS_ERR(msi->csr_base)) {
230 dev_err(&pdev->dev, "failed to map csr memory\n");
231 return PTR_ERR(msi->csr_base);
232 }
233
234 res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
235 "vector_slave");
236 msi->vector_base = devm_ioremap_resource(&pdev->dev, res);
237 if (IS_ERR(msi->vector_base))
238 return PTR_ERR(msi->vector_base);
239
240 msi->vector_phy = res->start;
241
242 if (of_property_read_u32(np, "num-vectors", &msi->num_of_vectors)) {
243 dev_err(&pdev->dev, "failed to parse the number of vectors\n");
244 return -EINVAL;
245 }
246
247 ret = altera_allocate_domains(msi);
248 if (ret)
249 return ret;
250
251 msi->irq = platform_get_irq(pdev, 0);
252 if (msi->irq < 0) {
253 ret = msi->irq;
254 goto err;
255 }
256
257 irq_set_chained_handler_and_data(msi->irq, altera_msi_isr, msi);
258 platform_set_drvdata(pdev, msi);
259
260 return 0;
261
262err:
263 altera_msi_remove(pdev);
264 return ret;
265}
266
267static const struct of_device_id altera_msi_of_match[] = {
268 { .compatible = "altr,msi-1.0", NULL },
269 { },
270};
271
272static struct platform_driver altera_msi_driver = {
273 .driver = {
274 .name = "altera-msi",
275 .of_match_table = altera_msi_of_match,
276 },
277 .probe = altera_msi_probe,
278 .remove = altera_msi_remove,
279};
280
281static int __init altera_msi_init(void)
282{
283 return platform_driver_register(&altera_msi_driver);
284}
285
286static void __exit altera_msi_exit(void)
287{
288 platform_driver_unregister(&altera_msi_driver);
289}
290
291subsys_initcall(altera_msi_init);
292MODULE_DEVICE_TABLE(of, altera_msi_of_match);
293module_exit(altera_msi_exit);
294MODULE_LICENSE("GPL v2");
295
