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21#include <linux/interrupt.h>
22#include <linux/irqchip/chained_irq.h>
23#include <linux/init.h>
24#include <linux/msi.h>
25#include <linux/of_address.h>
26#include <linux/of_irq.h>
27#include <linux/of_pci.h>
28#include <linux/pci.h>
29#include <linux/platform_device.h>
30#include <linux/slab.h>
31
32#define MSI_STATUS 0x0
33#define MSI_ERROR 0x4
34#define MSI_INTMASK 0x8
35
36#define MAX_MSI_VECTORS 32
37
38struct altera_msi {
39 DECLARE_BITMAP(used, MAX_MSI_VECTORS);
40 struct mutex lock;
41 struct platform_device *pdev;
42 struct irq_domain *msi_domain;
43 struct irq_domain *inner_domain;
44 void __iomem *csr_base;
45 void __iomem *vector_base;
46 phys_addr_t vector_phy;
47 u32 num_of_vectors;
48 int irq;
49};
50
51static inline void msi_writel(struct altera_msi *msi, const u32 value,
52 const u32 reg)
53{
54 writel_relaxed(value, msi->csr_base + reg);
55}
56
57static inline u32 msi_readl(struct altera_msi *msi, const u32 reg)
58{
59 return readl_relaxed(msi->csr_base + reg);
60}
61
62static void altera_msi_isr(struct irq_desc *desc)
63{
64 struct irq_chip *chip = irq_desc_get_chip(desc);
65 struct altera_msi *msi;
66 unsigned long status;
67 u32 num_of_vectors;
68 u32 bit;
69 u32 virq;
70
71 chained_irq_enter(chip, desc);
72 msi = irq_desc_get_handler_data(desc);
73 num_of_vectors = msi->num_of_vectors;
74
75 while ((status = msi_readl(msi, MSI_STATUS)) != 0) {
76 for_each_set_bit(bit, &status, msi->num_of_vectors) {
77
78 readl_relaxed(msi->vector_base + (bit * sizeof(u32)));
79
80 virq = irq_find_mapping(msi->inner_domain, bit);
81 if (virq)
82 generic_handle_irq(virq);
83 else
84 dev_err(&msi->pdev->dev, "unexpected MSI\n");
85 }
86 }
87
88 chained_irq_exit(chip, desc);
89}
90
91static struct irq_chip altera_msi_irq_chip = {
92 .name = "Altera PCIe MSI",
93 .irq_mask = pci_msi_mask_irq,
94 .irq_unmask = pci_msi_unmask_irq,
95};
96
97static struct msi_domain_info altera_msi_domain_info = {
98 .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
99 MSI_FLAG_PCI_MSIX),
100 .chip = &altera_msi_irq_chip,
101};
102
103static void altera_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
104{
105 struct altera_msi *msi = irq_data_get_irq_chip_data(data);
106 phys_addr_t addr = msi->vector_phy + (data->hwirq * sizeof(u32));
107
108 msg->address_lo = lower_32_bits(addr);
109 msg->address_hi = upper_32_bits(addr);
110 msg->data = data->hwirq;
111
112 dev_dbg(&msi->pdev->dev, "msi#%d address_hi %#x address_lo %#x\n",
113 (int)data->hwirq, msg->address_hi, msg->address_lo);
114}
115
116static int altera_msi_set_affinity(struct irq_data *irq_data,
117 const struct cpumask *mask, bool force)
118{
119 return -EINVAL;
120}
121
122static struct irq_chip altera_msi_bottom_irq_chip = {
123 .name = "Altera MSI",
124 .irq_compose_msi_msg = altera_compose_msi_msg,
125 .irq_set_affinity = altera_msi_set_affinity,
126};
127
128static int altera_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
129 unsigned int nr_irqs, void *args)
130{
131 struct altera_msi *msi = domain->host_data;
132 unsigned long bit;
133 u32 mask;
134
135 WARN_ON(nr_irqs != 1);
136 mutex_lock(&msi->lock);
137
138 bit = find_first_zero_bit(msi->used, msi->num_of_vectors);
139 if (bit >= msi->num_of_vectors) {
140 mutex_unlock(&msi->lock);
141 return -ENOSPC;
142 }
143
144 set_bit(bit, msi->used);
145
146 mutex_unlock(&msi->lock);
147
148 irq_domain_set_info(domain, virq, bit, &altera_msi_bottom_irq_chip,
149 domain->host_data, handle_simple_irq,
150 NULL, NULL);
151
152 mask = msi_readl(msi, MSI_INTMASK);
153 mask |= 1 << bit;
154 msi_writel(msi, mask, MSI_INTMASK);
155
156 return 0;
157}
158
159static void altera_irq_domain_free(struct irq_domain *domain,
160 unsigned int virq, unsigned int nr_irqs)
161{
162 struct irq_data *d = irq_domain_get_irq_data(domain, virq);
163 struct altera_msi *msi = irq_data_get_irq_chip_data(d);
164 u32 mask;
165
166 mutex_lock(&msi->lock);
167
168 if (!test_bit(d->hwirq, msi->used)) {
169 dev_err(&msi->pdev->dev, "trying to free unused MSI#%lu\n",
170 d->hwirq);
171 } else {
172 __clear_bit(d->hwirq, msi->used);
173 mask = msi_readl(msi, MSI_INTMASK);
174 mask &= ~(1 << d->hwirq);
175 msi_writel(msi, mask, MSI_INTMASK);
176 }
177
178 mutex_unlock(&msi->lock);
179}
180
181static const struct irq_domain_ops msi_domain_ops = {
182 .alloc = altera_irq_domain_alloc,
183 .free = altera_irq_domain_free,
184};
185
186static int altera_allocate_domains(struct altera_msi *msi)
187{
188 struct fwnode_handle *fwnode = of_node_to_fwnode(msi->pdev->dev.of_node);
189
190 msi->inner_domain = irq_domain_add_linear(NULL, msi->num_of_vectors,
191 &msi_domain_ops, msi);
192 if (!msi->inner_domain) {
193 dev_err(&msi->pdev->dev, "failed to create IRQ domain\n");
194 return -ENOMEM;
195 }
196
197 msi->msi_domain = pci_msi_create_irq_domain(fwnode,
198 &altera_msi_domain_info, msi->inner_domain);
199 if (!msi->msi_domain) {
200 dev_err(&msi->pdev->dev, "failed to create MSI domain\n");
201 irq_domain_remove(msi->inner_domain);
202 return -ENOMEM;
203 }
204
205 return 0;
206}
207
208static void altera_free_domains(struct altera_msi *msi)
209{
210 irq_domain_remove(msi->msi_domain);
211 irq_domain_remove(msi->inner_domain);
212}
213
214static int altera_msi_remove(struct platform_device *pdev)
215{
216 struct altera_msi *msi = platform_get_drvdata(pdev);
217
218 msi_writel(msi, 0, MSI_INTMASK);
219 irq_set_chained_handler(msi->irq, NULL);
220 irq_set_handler_data(msi->irq, NULL);
221
222 altera_free_domains(msi);
223
224 platform_set_drvdata(pdev, NULL);
225 return 0;
226}
227
228static int altera_msi_probe(struct platform_device *pdev)
229{
230 struct altera_msi *msi;
231 struct device_node *np = pdev->dev.of_node;
232 struct resource *res;
233 int ret;
234
235 msi = devm_kzalloc(&pdev->dev, sizeof(struct altera_msi),
236 GFP_KERNEL);
237 if (!msi)
238 return -ENOMEM;
239
240 mutex_init(&msi->lock);
241 msi->pdev = pdev;
242
243 res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "csr");
244 msi->csr_base = devm_ioremap_resource(&pdev->dev, res);
245 if (IS_ERR(msi->csr_base)) {
246 dev_err(&pdev->dev, "failed to map csr memory\n");
247 return PTR_ERR(msi->csr_base);
248 }
249
250 res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
251 "vector_slave");
252 msi->vector_base = devm_ioremap_resource(&pdev->dev, res);
253 if (IS_ERR(msi->vector_base)) {
254 dev_err(&pdev->dev, "failed to map vector_slave memory\n");
255 return PTR_ERR(msi->vector_base);
256 }
257
258 msi->vector_phy = res->start;
259
260 if (of_property_read_u32(np, "num-vectors", &msi->num_of_vectors)) {
261 dev_err(&pdev->dev, "failed to parse the number of vectors\n");
262 return -EINVAL;
263 }
264
265 ret = altera_allocate_domains(msi);
266 if (ret)
267 return ret;
268
269 msi->irq = platform_get_irq(pdev, 0);
270 if (msi->irq <= 0) {
271 dev_err(&pdev->dev, "failed to map IRQ: %d\n", msi->irq);
272 ret = -ENODEV;
273 goto err;
274 }
275
276 irq_set_chained_handler_and_data(msi->irq, altera_msi_isr, msi);
277 platform_set_drvdata(pdev, msi);
278
279 return 0;
280
281err:
282 altera_msi_remove(pdev);
283 return ret;
284}
285
286static const struct of_device_id altera_msi_of_match[] = {
287 { .compatible = "altr,msi-1.0", NULL },
288 { },
289};
290
291static struct platform_driver altera_msi_driver = {
292 .driver = {
293 .name = "altera-msi",
294 .of_match_table = altera_msi_of_match,
295 },
296 .probe = altera_msi_probe,
297 .remove = altera_msi_remove,
298};
299
300static int __init altera_msi_init(void)
301{
302 return platform_driver_register(&altera_msi_driver);
303}
304subsys_initcall(altera_msi_init);
305
