1 /*
2 * Copyright Altera Corporation (C) 2013-2015. All rights reserved
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms and conditions of the GNU General Public License,
6 * version 2, as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
11 * more details.
12 *
13 * You should have received a copy of the GNU General Public License along with
14 * this program. If not, see <http://www.gnu.org/licenses/>.
15 */
16
17 #include <linux/interrupt.h>
18 #include <linux/irqchip/chained_irq.h>
19 #include <linux/module.h>
20 #include <linux/msi.h>
21 #include <linux/of_address.h>
22 #include <linux/of_irq.h>
23 #include <linux/of_pci.h>
24 #include <linux/pci.h>
25 #include <linux/platform_device.h>
26 #include <linux/slab.h>
27
28 #define MSI_STATUS 0x0
29 #define MSI_ERROR 0x4
30 #define MSI_INTMASK 0x8
31
32 #define MAX_MSI_VECTORS 32
33
34 struct altera_msi {
35 DECLARE_BITMAP(used, MAX_MSI_VECTORS);
36 struct mutex lock; /* protect "used" bitmap */
37 struct platform_device *pdev;
38 struct irq_domain *msi_domain;
39 struct irq_domain *inner_domain;
40 void __iomem *csr_base;
41 void __iomem *vector_base;
42 phys_addr_t vector_phy;
43 u32 num_of_vectors;
44 int irq;
45 };
46
msi_writel(struct altera_msi * msi,const u32 value,const u32 reg)47 static inline void msi_writel(struct altera_msi *msi, const u32 value,
48 const u32 reg)
49 {
50 writel_relaxed(value, msi->csr_base + reg);
51 }
52
msi_readl(struct altera_msi * msi,const u32 reg)53 static inline u32 msi_readl(struct altera_msi *msi, const u32 reg)
54 {
55 return readl_relaxed(msi->csr_base + reg);
56 }
57
altera_msi_isr(struct irq_desc * desc)58 static void altera_msi_isr(struct irq_desc *desc)
59 {
60 struct irq_chip *chip = irq_desc_get_chip(desc);
61 struct altera_msi *msi;
62 unsigned long status;
63 u32 num_of_vectors;
64 u32 bit;
65 u32 virq;
66
67 chained_irq_enter(chip, desc);
68 msi = irq_desc_get_handler_data(desc);
69 num_of_vectors = msi->num_of_vectors;
70
71 while ((status = msi_readl(msi, MSI_STATUS)) != 0) {
72 for_each_set_bit(bit, &status, msi->num_of_vectors) {
73 /* Dummy read from vector to clear the interrupt */
74 readl_relaxed(msi->vector_base + (bit * sizeof(u32)));
75
76 virq = irq_find_mapping(msi->inner_domain, bit);
77 if (virq)
78 generic_handle_irq(virq);
79 else
80 dev_err(&msi->pdev->dev, "unexpected MSI\n");
81 }
82 }
83
84 chained_irq_exit(chip, desc);
85 }
86
87 static struct irq_chip altera_msi_irq_chip = {
88 .name = "Altera PCIe MSI",
89 .irq_mask = pci_msi_mask_irq,
90 .irq_unmask = pci_msi_unmask_irq,
91 };
92
93 static struct msi_domain_info altera_msi_domain_info = {
94 .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
95 MSI_FLAG_PCI_MSIX),
96 .chip = &altera_msi_irq_chip,
97 };
98
altera_compose_msi_msg(struct irq_data * data,struct msi_msg * msg)99 static void altera_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
100 {
101 struct altera_msi *msi = irq_data_get_irq_chip_data(data);
102 phys_addr_t addr = msi->vector_phy + (data->hwirq * sizeof(u32));
103
104 msg->address_lo = lower_32_bits(addr);
105 msg->address_hi = upper_32_bits(addr);
106 msg->data = data->hwirq;
107
108 dev_dbg(&msi->pdev->dev, "msi#%d address_hi %#x address_lo %#x\n",
109 (int)data->hwirq, msg->address_hi, msg->address_lo);
110 }
111
altera_msi_set_affinity(struct irq_data * irq_data,const struct cpumask * mask,bool force)112 static int altera_msi_set_affinity(struct irq_data *irq_data,
113 const struct cpumask *mask, bool force)
114 {
115 return -EINVAL;
116 }
117
118 static struct irq_chip altera_msi_bottom_irq_chip = {
119 .name = "Altera MSI",
120 .irq_compose_msi_msg = altera_compose_msi_msg,
121 .irq_set_affinity = altera_msi_set_affinity,
122 };
123
altera_irq_domain_alloc(struct irq_domain * domain,unsigned int virq,unsigned int nr_irqs,void * args)124 static int altera_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
125 unsigned int nr_irqs, void *args)
126 {
127 struct altera_msi *msi = domain->host_data;
128 unsigned long bit;
129 u32 mask;
130
131 WARN_ON(nr_irqs != 1);
132 mutex_lock(&msi->lock);
133
134 bit = find_first_zero_bit(msi->used, msi->num_of_vectors);
135 if (bit >= msi->num_of_vectors) {
136 mutex_unlock(&msi->lock);
137 return -ENOSPC;
138 }
139
140 set_bit(bit, msi->used);
141
142 mutex_unlock(&msi->lock);
143
144 irq_domain_set_info(domain, virq, bit, &altera_msi_bottom_irq_chip,
145 domain->host_data, handle_simple_irq,
146 NULL, NULL);
147
148 mask = msi_readl(msi, MSI_INTMASK);
149 mask |= 1 << bit;
150 msi_writel(msi, mask, MSI_INTMASK);
151
152 return 0;
153 }
154
altera_irq_domain_free(struct irq_domain * domain,unsigned int virq,unsigned int nr_irqs)155 static void altera_irq_domain_free(struct irq_domain *domain,
156 unsigned int virq, unsigned int nr_irqs)
157 {
158 struct irq_data *d = irq_domain_get_irq_data(domain, virq);
159 struct altera_msi *msi = irq_data_get_irq_chip_data(d);
160 u32 mask;
161
162 mutex_lock(&msi->lock);
163
164 if (!test_bit(d->hwirq, msi->used)) {
165 dev_err(&msi->pdev->dev, "trying to free unused MSI#%lu\n",
166 d->hwirq);
167 } else {
168 __clear_bit(d->hwirq, msi->used);
169 mask = msi_readl(msi, MSI_INTMASK);
170 mask &= ~(1 << d->hwirq);
171 msi_writel(msi, mask, MSI_INTMASK);
172 }
173
174 mutex_unlock(&msi->lock);
175 }
176
177 static const struct irq_domain_ops msi_domain_ops = {
178 .alloc = altera_irq_domain_alloc,
179 .free = altera_irq_domain_free,
180 };
181
altera_allocate_domains(struct altera_msi * msi)182 static int altera_allocate_domains(struct altera_msi *msi)
183 {
184 struct fwnode_handle *fwnode = of_node_to_fwnode(msi->pdev->dev.of_node);
185
186 msi->inner_domain = irq_domain_add_linear(NULL, msi->num_of_vectors,
187 &msi_domain_ops, msi);
188 if (!msi->inner_domain) {
189 dev_err(&msi->pdev->dev, "failed to create IRQ domain\n");
190 return -ENOMEM;
191 }
192
193 msi->msi_domain = pci_msi_create_irq_domain(fwnode,
194 &altera_msi_domain_info, msi->inner_domain);
195 if (!msi->msi_domain) {
196 dev_err(&msi->pdev->dev, "failed to create MSI domain\n");
197 irq_domain_remove(msi->inner_domain);
198 return -ENOMEM;
199 }
200
201 return 0;
202 }
203
altera_free_domains(struct altera_msi * msi)204 static void altera_free_domains(struct altera_msi *msi)
205 {
206 irq_domain_remove(msi->msi_domain);
207 irq_domain_remove(msi->inner_domain);
208 }
209
altera_msi_remove(struct platform_device * pdev)210 static int altera_msi_remove(struct platform_device *pdev)
211 {
212 struct altera_msi *msi = platform_get_drvdata(pdev);
213
214 msi_writel(msi, 0, MSI_INTMASK);
215 irq_set_chained_handler(msi->irq, NULL);
216 irq_set_handler_data(msi->irq, NULL);
217
218 altera_free_domains(msi);
219
220 platform_set_drvdata(pdev, NULL);
221 return 0;
222 }
223
altera_msi_probe(struct platform_device * pdev)224 static int altera_msi_probe(struct platform_device *pdev)
225 {
226 struct altera_msi *msi;
227 struct device_node *np = pdev->dev.of_node;
228 struct resource *res;
229 int ret;
230
231 msi = devm_kzalloc(&pdev->dev, sizeof(struct altera_msi),
232 GFP_KERNEL);
233 if (!msi)
234 return -ENOMEM;
235
236 mutex_init(&msi->lock);
237 msi->pdev = pdev;
238
239 res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "csr");
240 if (!res) {
241 dev_err(&pdev->dev, "no csr memory resource defined\n");
242 return -ENODEV;
243 }
244
245 msi->csr_base = devm_ioremap_resource(&pdev->dev, res);
246 if (IS_ERR(msi->csr_base)) {
247 dev_err(&pdev->dev, "failed to map csr memory\n");
248 return PTR_ERR(msi->csr_base);
249 }
250
251 res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
252 "vector_slave");
253 if (!res) {
254 dev_err(&pdev->dev, "no vector_slave memory resource defined\n");
255 return -ENODEV;
256 }
257
258 msi->vector_base = devm_ioremap_resource(&pdev->dev, res);
259 if (IS_ERR(msi->vector_base)) {
260 dev_err(&pdev->dev, "failed to map vector_slave memory\n");
261 return PTR_ERR(msi->vector_base);
262 }
263
264 msi->vector_phy = res->start;
265
266 if (of_property_read_u32(np, "num-vectors", &msi->num_of_vectors)) {
267 dev_err(&pdev->dev, "failed to parse the number of vectors\n");
268 return -EINVAL;
269 }
270
271 ret = altera_allocate_domains(msi);
272 if (ret)
273 return ret;
274
275 msi->irq = platform_get_irq(pdev, 0);
276 if (msi->irq <= 0) {
277 dev_err(&pdev->dev, "failed to map IRQ: %d\n", msi->irq);
278 ret = -ENODEV;
279 goto err;
280 }
281
282 irq_set_chained_handler_and_data(msi->irq, altera_msi_isr, msi);
283 platform_set_drvdata(pdev, msi);
284
285 return 0;
286
287 err:
288 altera_msi_remove(pdev);
289 return ret;
290 }
291
292 static const struct of_device_id altera_msi_of_match[] = {
293 { .compatible = "altr,msi-1.0", NULL },
294 { },
295 };
296
297 static struct platform_driver altera_msi_driver = {
298 .driver = {
299 .name = "altera-msi",
300 .of_match_table = altera_msi_of_match,
301 },
302 .probe = altera_msi_probe,
303 .remove = altera_msi_remove,
304 };
305
altera_msi_init(void)306 static int __init altera_msi_init(void)
307 {
308 return platform_driver_register(&altera_msi_driver);
309 }
310 subsys_initcall(altera_msi_init);
311
312 MODULE_AUTHOR("Ley Foon Tan <lftan@altera.com>");
313 MODULE_DESCRIPTION("Altera PCIe MSI support");
314 MODULE_LICENSE("GPL v2");
315