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/irqdomain.h>
13 #include <linux/init.h>
14 #include <linux/module.h>
15 #include <linux/msi.h>
16 #include <linux/of_address.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 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 /* Dummy read from vector to clear the interrupt */
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
77 static 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
83 static 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_NO_AFFINITY | MSI_FLAG_PCI_MSIX,
86 .chip = &altera_msi_irq_chip,
87 };
88
altera_compose_msi_msg(struct irq_data * data,struct msi_msg * msg)89 static 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
102 static struct irq_chip altera_msi_bottom_irq_chip = {
103 .name = "Altera MSI",
104 .irq_compose_msi_msg = altera_compose_msi_msg,
105 };
106
altera_irq_domain_alloc(struct irq_domain * domain,unsigned int virq,unsigned int nr_irqs,void * args)107 static int altera_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
108 unsigned int nr_irqs, void *args)
109 {
110 struct altera_msi *msi = domain->host_data;
111 unsigned long bit;
112 u32 mask;
113
114 WARN_ON(nr_irqs != 1);
115 mutex_lock(&msi->lock);
116
117 bit = find_first_zero_bit(msi->used, msi->num_of_vectors);
118 if (bit >= msi->num_of_vectors) {
119 mutex_unlock(&msi->lock);
120 return -ENOSPC;
121 }
122
123 set_bit(bit, msi->used);
124
125 mutex_unlock(&msi->lock);
126
127 irq_domain_set_info(domain, virq, bit, &altera_msi_bottom_irq_chip,
128 domain->host_data, handle_simple_irq,
129 NULL, NULL);
130
131 mask = msi_readl(msi, MSI_INTMASK);
132 mask |= 1 << bit;
133 msi_writel(msi, mask, MSI_INTMASK);
134
135 return 0;
136 }
137
altera_irq_domain_free(struct irq_domain * domain,unsigned int virq,unsigned int nr_irqs)138 static void altera_irq_domain_free(struct irq_domain *domain,
139 unsigned int virq, unsigned int nr_irqs)
140 {
141 struct irq_data *d = irq_domain_get_irq_data(domain, virq);
142 struct altera_msi *msi = irq_data_get_irq_chip_data(d);
143 u32 mask;
144
145 mutex_lock(&msi->lock);
146
147 if (!test_bit(d->hwirq, msi->used)) {
148 dev_err(&msi->pdev->dev, "trying to free unused MSI#%lu\n",
149 d->hwirq);
150 } else {
151 __clear_bit(d->hwirq, msi->used);
152 mask = msi_readl(msi, MSI_INTMASK);
153 mask &= ~(1 << d->hwirq);
154 msi_writel(msi, mask, MSI_INTMASK);
155 }
156
157 mutex_unlock(&msi->lock);
158 }
159
160 static const struct irq_domain_ops msi_domain_ops = {
161 .alloc = altera_irq_domain_alloc,
162 .free = altera_irq_domain_free,
163 };
164
altera_allocate_domains(struct altera_msi * msi)165 static int altera_allocate_domains(struct altera_msi *msi)
166 {
167 struct fwnode_handle *fwnode = of_node_to_fwnode(msi->pdev->dev.of_node);
168
169 msi->inner_domain = irq_domain_add_linear(NULL, msi->num_of_vectors,
170 &msi_domain_ops, msi);
171 if (!msi->inner_domain) {
172 dev_err(&msi->pdev->dev, "failed to create IRQ domain\n");
173 return -ENOMEM;
174 }
175
176 msi->msi_domain = pci_msi_create_irq_domain(fwnode,
177 &altera_msi_domain_info, msi->inner_domain);
178 if (!msi->msi_domain) {
179 dev_err(&msi->pdev->dev, "failed to create MSI domain\n");
180 irq_domain_remove(msi->inner_domain);
181 return -ENOMEM;
182 }
183
184 return 0;
185 }
186
altera_free_domains(struct altera_msi * msi)187 static void altera_free_domains(struct altera_msi *msi)
188 {
189 irq_domain_remove(msi->msi_domain);
190 irq_domain_remove(msi->inner_domain);
191 }
192
altera_msi_remove(struct platform_device * pdev)193 static void altera_msi_remove(struct platform_device *pdev)
194 {
195 struct altera_msi *msi = platform_get_drvdata(pdev);
196
197 msi_writel(msi, 0, MSI_INTMASK);
198 irq_set_chained_handler_and_data(msi->irq, NULL, NULL);
199
200 altera_free_domains(msi);
201
202 platform_set_drvdata(pdev, NULL);
203 }
204
altera_msi_probe(struct platform_device * pdev)205 static int altera_msi_probe(struct platform_device *pdev)
206 {
207 struct altera_msi *msi;
208 struct device_node *np = pdev->dev.of_node;
209 struct resource *res;
210 int ret;
211
212 msi = devm_kzalloc(&pdev->dev, sizeof(struct altera_msi),
213 GFP_KERNEL);
214 if (!msi)
215 return -ENOMEM;
216
217 mutex_init(&msi->lock);
218 msi->pdev = pdev;
219
220 msi->csr_base = devm_platform_ioremap_resource_byname(pdev, "csr");
221 if (IS_ERR(msi->csr_base)) {
222 dev_err(&pdev->dev, "failed to map csr memory\n");
223 return PTR_ERR(msi->csr_base);
224 }
225
226 res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
227 "vector_slave");
228 msi->vector_base = devm_ioremap_resource(&pdev->dev, res);
229 if (IS_ERR(msi->vector_base))
230 return PTR_ERR(msi->vector_base);
231
232 msi->vector_phy = res->start;
233
234 if (of_property_read_u32(np, "num-vectors", &msi->num_of_vectors)) {
235 dev_err(&pdev->dev, "failed to parse the number of vectors\n");
236 return -EINVAL;
237 }
238
239 ret = altera_allocate_domains(msi);
240 if (ret)
241 return ret;
242
243 msi->irq = platform_get_irq(pdev, 0);
244 if (msi->irq < 0) {
245 ret = msi->irq;
246 goto err;
247 }
248
249 irq_set_chained_handler_and_data(msi->irq, altera_msi_isr, msi);
250 platform_set_drvdata(pdev, msi);
251
252 return 0;
253
254 err:
255 altera_msi_remove(pdev);
256 return ret;
257 }
258
259 static const struct of_device_id altera_msi_of_match[] = {
260 { .compatible = "altr,msi-1.0", NULL },
261 { },
262 };
263
264 static struct platform_driver altera_msi_driver = {
265 .driver = {
266 .name = "altera-msi",
267 .of_match_table = altera_msi_of_match,
268 },
269 .probe = altera_msi_probe,
270 .remove_new = altera_msi_remove,
271 };
272
altera_msi_init(void)273 static int __init altera_msi_init(void)
274 {
275 return platform_driver_register(&altera_msi_driver);
276 }
277
altera_msi_exit(void)278 static void __exit altera_msi_exit(void)
279 {
280 platform_driver_unregister(&altera_msi_driver);
281 }
282
283 subsys_initcall(altera_msi_init);
284 MODULE_DEVICE_TABLE(of, altera_msi_of_match);
285 module_exit(altera_msi_exit);
286 MODULE_DESCRIPTION("Altera PCIe MSI support driver");
287 MODULE_LICENSE("GPL v2");
288