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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
34struct altera_msi {
35 DECLARE_BITMAP(used, MAX_MSI_VECTORS);
36 struct mutex lock;
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
47static 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
53static inline u32 msi_readl(struct altera_msi *msi, const u32 reg)
54{
55 return readl_relaxed(msi->csr_base + reg);
56}
57
58static 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
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
87static 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
93static 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
99static 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
112static int altera_msi_set_affinity(struct irq_data *irq_data,
113 const struct cpumask *mask, bool force)
114{
115 return -EINVAL;
116}
117
118static 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
124static 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
155static 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
177static const struct irq_domain_ops msi_domain_ops = {
178 .alloc = altera_irq_domain_alloc,
179 .free = altera_irq_domain_free,
180};
181
182static 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
204static 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
210static 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
224static 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
287err:
288 altera_msi_remove(pdev);
289 return ret;
290}
291
292static const struct of_device_id altera_msi_of_match[] = {
293 { .compatible = "altr,msi-1.0", NULL },
294 { },
295};
296
297static 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
306static int __init altera_msi_init(void)
307{
308 return platform_driver_register(&altera_msi_driver);
309}
310subsys_initcall(altera_msi_init);
311
312MODULE_AUTHOR("Ley Foon Tan <lftan@altera.com>");
313MODULE_DESCRIPTION("Altera PCIe MSI support");
314MODULE_LICENSE("GPL v2");
315
