1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Altera PCIe MSI support
4 *
5 * Author: Ley Foon Tan <lftan@altera.com>
6 *
7 * Copyright Altera Corporation (C) 2013-2015. All rights reserved
8 */
9
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
28 struct altera_msi {
29 DECLARE_BITMAP(used, MAX_MSI_VECTORS);
30 struct mutex lock; /* protect "used" bitmap */
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
msi_writel(struct altera_msi * msi,const u32 value,const u32 reg)41 static 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
msi_readl(struct altera_msi * msi,const u32 reg)47 static inline u32 msi_readl(struct altera_msi *msi, const u32 reg)
48 {
49 return readl_relaxed(msi->csr_base + reg);
50 }
51
altera_msi_isr(struct irq_desc * desc)52 static 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 u32 virq;
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 /* Dummy read from vector to clear the interrupt */
66 readl_relaxed(msi->vector_base + (bit * sizeof(u32)));
67
68 virq = irq_find_mapping(msi->inner_domain, bit);
69 if (virq)
70 generic_handle_irq(virq);
71 else
72 dev_err(&msi->pdev->dev, "unexpected MSI\n");
73 }
74 }
75
76 chained_irq_exit(chip, desc);
77 }
78
79 static struct irq_chip altera_msi_irq_chip = {
80 .name = "Altera PCIe MSI",
81 .irq_mask = pci_msi_mask_irq,
82 .irq_unmask = pci_msi_unmask_irq,
83 };
84
85 static struct msi_domain_info altera_msi_domain_info = {
86 .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
87 MSI_FLAG_PCI_MSIX),
88 .chip = &altera_msi_irq_chip,
89 };
90
altera_compose_msi_msg(struct irq_data * data,struct msi_msg * msg)91 static void altera_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
92 {
93 struct altera_msi *msi = irq_data_get_irq_chip_data(data);
94 phys_addr_t addr = msi->vector_phy + (data->hwirq * sizeof(u32));
95
96 msg->address_lo = lower_32_bits(addr);
97 msg->address_hi = upper_32_bits(addr);
98 msg->data = data->hwirq;
99
100 dev_dbg(&msi->pdev->dev, "msi#%d address_hi %#x address_lo %#x\n",
101 (int)data->hwirq, msg->address_hi, msg->address_lo);
102 }
103
altera_msi_set_affinity(struct irq_data * irq_data,const struct cpumask * mask,bool force)104 static int altera_msi_set_affinity(struct irq_data *irq_data,
105 const struct cpumask *mask, bool force)
106 {
107 return -EINVAL;
108 }
109
110 static struct irq_chip altera_msi_bottom_irq_chip = {
111 .name = "Altera MSI",
112 .irq_compose_msi_msg = altera_compose_msi_msg,
113 .irq_set_affinity = altera_msi_set_affinity,
114 };
115
altera_irq_domain_alloc(struct irq_domain * domain,unsigned int virq,unsigned int nr_irqs,void * args)116 static int altera_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
117 unsigned int nr_irqs, void *args)
118 {
119 struct altera_msi *msi = domain->host_data;
120 unsigned long bit;
121 u32 mask;
122
123 WARN_ON(nr_irqs != 1);
124 mutex_lock(&msi->lock);
125
126 bit = find_first_zero_bit(msi->used, msi->num_of_vectors);
127 if (bit >= msi->num_of_vectors) {
128 mutex_unlock(&msi->lock);
129 return -ENOSPC;
130 }
131
132 set_bit(bit, msi->used);
133
134 mutex_unlock(&msi->lock);
135
136 irq_domain_set_info(domain, virq, bit, &altera_msi_bottom_irq_chip,
137 domain->host_data, handle_simple_irq,
138 NULL, NULL);
139
140 mask = msi_readl(msi, MSI_INTMASK);
141 mask |= 1 << bit;
142 msi_writel(msi, mask, MSI_INTMASK);
143
144 return 0;
145 }
146
altera_irq_domain_free(struct irq_domain * domain,unsigned int virq,unsigned int nr_irqs)147 static void altera_irq_domain_free(struct irq_domain *domain,
148 unsigned int virq, unsigned int nr_irqs)
149 {
150 struct irq_data *d = irq_domain_get_irq_data(domain, virq);
151 struct altera_msi *msi = irq_data_get_irq_chip_data(d);
152 u32 mask;
153
154 mutex_lock(&msi->lock);
155
156 if (!test_bit(d->hwirq, msi->used)) {
157 dev_err(&msi->pdev->dev, "trying to free unused MSI#%lu\n",
158 d->hwirq);
159 } else {
160 __clear_bit(d->hwirq, msi->used);
161 mask = msi_readl(msi, MSI_INTMASK);
162 mask &= ~(1 << d->hwirq);
163 msi_writel(msi, mask, MSI_INTMASK);
164 }
165
166 mutex_unlock(&msi->lock);
167 }
168
169 static const struct irq_domain_ops msi_domain_ops = {
170 .alloc = altera_irq_domain_alloc,
171 .free = altera_irq_domain_free,
172 };
173
altera_allocate_domains(struct altera_msi * msi)174 static int altera_allocate_domains(struct altera_msi *msi)
175 {
176 struct fwnode_handle *fwnode = of_node_to_fwnode(msi->pdev->dev.of_node);
177
178 msi->inner_domain = irq_domain_add_linear(NULL, msi->num_of_vectors,
179 &msi_domain_ops, msi);
180 if (!msi->inner_domain) {
181 dev_err(&msi->pdev->dev, "failed to create IRQ domain\n");
182 return -ENOMEM;
183 }
184
185 msi->msi_domain = pci_msi_create_irq_domain(fwnode,
186 &altera_msi_domain_info, msi->inner_domain);
187 if (!msi->msi_domain) {
188 dev_err(&msi->pdev->dev, "failed to create MSI domain\n");
189 irq_domain_remove(msi->inner_domain);
190 return -ENOMEM;
191 }
192
193 return 0;
194 }
195
altera_free_domains(struct altera_msi * msi)196 static void altera_free_domains(struct altera_msi *msi)
197 {
198 irq_domain_remove(msi->msi_domain);
199 irq_domain_remove(msi->inner_domain);
200 }
201
altera_msi_remove(struct platform_device * pdev)202 static int altera_msi_remove(struct platform_device *pdev)
203 {
204 struct altera_msi *msi = platform_get_drvdata(pdev);
205
206 msi_writel(msi, 0, MSI_INTMASK);
207 irq_set_chained_handler(msi->irq, NULL);
208 irq_set_handler_data(msi->irq, NULL);
209
210 altera_free_domains(msi);
211
212 platform_set_drvdata(pdev, NULL);
213 return 0;
214 }
215
altera_msi_probe(struct platform_device * pdev)216 static int altera_msi_probe(struct platform_device *pdev)
217 {
218 struct altera_msi *msi;
219 struct device_node *np = pdev->dev.of_node;
220 struct resource *res;
221 int ret;
222
223 msi = devm_kzalloc(&pdev->dev, sizeof(struct altera_msi),
224 GFP_KERNEL);
225 if (!msi)
226 return -ENOMEM;
227
228 mutex_init(&msi->lock);
229 msi->pdev = pdev;
230
231 res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "csr");
232 msi->csr_base = devm_ioremap_resource(&pdev->dev, res);
233 if (IS_ERR(msi->csr_base)) {
234 dev_err(&pdev->dev, "failed to map csr memory\n");
235 return PTR_ERR(msi->csr_base);
236 }
237
238 res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
239 "vector_slave");
240 msi->vector_base = devm_ioremap_resource(&pdev->dev, res);
241 if (IS_ERR(msi->vector_base)) {
242 dev_err(&pdev->dev, "failed to map vector_slave memory\n");
243 return PTR_ERR(msi->vector_base);
244 }
245
246 msi->vector_phy = res->start;
247
248 if (of_property_read_u32(np, "num-vectors", &msi->num_of_vectors)) {
249 dev_err(&pdev->dev, "failed to parse the number of vectors\n");
250 return -EINVAL;
251 }
252
253 ret = altera_allocate_domains(msi);
254 if (ret)
255 return ret;
256
257 msi->irq = platform_get_irq(pdev, 0);
258 if (msi->irq < 0) {
259 dev_err(&pdev->dev, "failed to map IRQ: %d\n", msi->irq);
260 ret = msi->irq;
261 goto err;
262 }
263
264 irq_set_chained_handler_and_data(msi->irq, altera_msi_isr, msi);
265 platform_set_drvdata(pdev, msi);
266
267 return 0;
268
269 err:
270 altera_msi_remove(pdev);
271 return ret;
272 }
273
274 static const struct of_device_id altera_msi_of_match[] = {
275 { .compatible = "altr,msi-1.0", NULL },
276 { },
277 };
278
279 static struct platform_driver altera_msi_driver = {
280 .driver = {
281 .name = "altera-msi",
282 .of_match_table = altera_msi_of_match,
283 },
284 .probe = altera_msi_probe,
285 .remove = altera_msi_remove,
286 };
287
altera_msi_init(void)288 static int __init altera_msi_init(void)
289 {
290 return platform_driver_register(&altera_msi_driver);
291 }
292
altera_msi_exit(void)293 static void __exit altera_msi_exit(void)
294 {
295 platform_driver_unregister(&altera_msi_driver);
296 }
297
298 subsys_initcall(altera_msi_init);
299 MODULE_DEVICE_TABLE(of, altera_msi_of_match);
300 module_exit(altera_msi_exit);
301 MODULE_LICENSE("GPL v2");
302
