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10#include <linux/interrupt.h>
11#include <linux/irqchip/chained_irq.h>
12#include <linux/init.h>
13#include <linux/msi.h>
14#include <linux/of_address.h>
15#include <linux/of_irq.h>
16#include <linux/of_pci.h>
17#include <linux/pci.h>
18#include <linux/platform_device.h>
19#include <linux/slab.h>
20
21#define MSI_STATUS 0x0
22#define MSI_ERROR 0x4
23#define MSI_INTMASK 0x8
24
25#define MAX_MSI_VECTORS 32
26
27struct altera_msi {
28 DECLARE_BITMAP(used, MAX_MSI_VECTORS);
29 struct mutex lock;
30 struct platform_device *pdev;
31 struct irq_domain *msi_domain;
32 struct irq_domain *inner_domain;
33 void __iomem *csr_base;
34 void __iomem *vector_base;
35 phys_addr_t vector_phy;
36 u32 num_of_vectors;
37 int irq;
38};
39
40static inline void msi_writel(struct altera_msi *msi, const u32 value,
41 const u32 reg)
42{
43 writel_relaxed(value, msi->csr_base + reg);
44}
45
46static inline u32 msi_readl(struct altera_msi *msi, const u32 reg)
47{
48 return readl_relaxed(msi->csr_base + reg);
49}
50
51static void altera_msi_isr(struct irq_desc *desc)
52{
53 struct irq_chip *chip = irq_desc_get_chip(desc);
54 struct altera_msi *msi;
55 unsigned long status;
56 u32 bit;
57 u32 virq;
58
59 chained_irq_enter(chip, desc);
60 msi = irq_desc_get_handler_data(desc);
61
62 while ((status = msi_readl(msi, MSI_STATUS)) != 0) {
63 for_each_set_bit(bit, &status, msi->num_of_vectors) {
64
65 readl_relaxed(msi->vector_base + (bit * sizeof(u32)));
66
67 virq = irq_find_mapping(msi->inner_domain, bit);
68 if (virq)
69 generic_handle_irq(virq);
70 else
71 dev_err(&msi->pdev->dev, "unexpected MSI\n");
72 }
73 }
74
75 chained_irq_exit(chip, desc);
76}
77
78static struct irq_chip altera_msi_irq_chip = {
79 .name = "Altera PCIe MSI",
80 .irq_mask = pci_msi_mask_irq,
81 .irq_unmask = pci_msi_unmask_irq,
82};
83
84static struct msi_domain_info altera_msi_domain_info = {
85 .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
86 MSI_FLAG_PCI_MSIX),
87 .chip = &altera_msi_irq_chip,
88};
89
90static void altera_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
91{
92 struct altera_msi *msi = irq_data_get_irq_chip_data(data);
93 phys_addr_t addr = msi->vector_phy + (data->hwirq * sizeof(u32));
94
95 msg->address_lo = lower_32_bits(addr);
96 msg->address_hi = upper_32_bits(addr);
97 msg->data = data->hwirq;
98
99 dev_dbg(&msi->pdev->dev, "msi#%d address_hi %#x address_lo %#x\n",
100 (int)data->hwirq, msg->address_hi, msg->address_lo);
101}
102
103static int altera_msi_set_affinity(struct irq_data *irq_data,
104 const struct cpumask *mask, bool force)
105{
106 return -EINVAL;
107}
108
109static struct irq_chip altera_msi_bottom_irq_chip = {
110 .name = "Altera MSI",
111 .irq_compose_msi_msg = altera_compose_msi_msg,
112 .irq_set_affinity = altera_msi_set_affinity,
113};
114
115static int altera_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
116 unsigned int nr_irqs, void *args)
117{
118 struct altera_msi *msi = domain->host_data;
119 unsigned long bit;
120 u32 mask;
121
122 WARN_ON(nr_irqs != 1);
123 mutex_lock(&msi->lock);
124
125 bit = find_first_zero_bit(msi->used, msi->num_of_vectors);
126 if (bit >= msi->num_of_vectors) {
127 mutex_unlock(&msi->lock);
128 return -ENOSPC;
129 }
130
131 set_bit(bit, msi->used);
132
133 mutex_unlock(&msi->lock);
134
135 irq_domain_set_info(domain, virq, bit, &altera_msi_bottom_irq_chip,
136 domain->host_data, handle_simple_irq,
137 NULL, NULL);
138
139 mask = msi_readl(msi, MSI_INTMASK);
140 mask |= 1 << bit;
141 msi_writel(msi, mask, MSI_INTMASK);
142
143 return 0;
144}
145
146static void altera_irq_domain_free(struct irq_domain *domain,
147 unsigned int virq, unsigned int nr_irqs)
148{
149 struct irq_data *d = irq_domain_get_irq_data(domain, virq);
150 struct altera_msi *msi = irq_data_get_irq_chip_data(d);
151 u32 mask;
152
153 mutex_lock(&msi->lock);
154
155 if (!test_bit(d->hwirq, msi->used)) {
156 dev_err(&msi->pdev->dev, "trying to free unused MSI#%lu\n",
157 d->hwirq);
158 } else {
159 __clear_bit(d->hwirq, msi->used);
160 mask = msi_readl(msi, MSI_INTMASK);
161 mask &= ~(1 << d->hwirq);
162 msi_writel(msi, mask, MSI_INTMASK);
163 }
164
165 mutex_unlock(&msi->lock);
166}
167
168static const struct irq_domain_ops msi_domain_ops = {
169 .alloc = altera_irq_domain_alloc,
170 .free = altera_irq_domain_free,
171};
172
173static int altera_allocate_domains(struct altera_msi *msi)
174{
175 struct fwnode_handle *fwnode = of_node_to_fwnode(msi->pdev->dev.of_node);
176
177 msi->inner_domain = irq_domain_add_linear(NULL, msi->num_of_vectors,
178 &msi_domain_ops, msi);
179 if (!msi->inner_domain) {
180 dev_err(&msi->pdev->dev, "failed to create IRQ domain\n");
181 return -ENOMEM;
182 }
183
184 msi->msi_domain = pci_msi_create_irq_domain(fwnode,
185 &altera_msi_domain_info, msi->inner_domain);
186 if (!msi->msi_domain) {
187 dev_err(&msi->pdev->dev, "failed to create MSI domain\n");
188 irq_domain_remove(msi->inner_domain);
189 return -ENOMEM;
190 }
191
192 return 0;
193}
194
195static void altera_free_domains(struct altera_msi *msi)
196{
197 irq_domain_remove(msi->msi_domain);
198 irq_domain_remove(msi->inner_domain);
199}
200
201static int altera_msi_remove(struct platform_device *pdev)
202{
203 struct altera_msi *msi = platform_get_drvdata(pdev);
204
205 msi_writel(msi, 0, MSI_INTMASK);
206 irq_set_chained_handler(msi->irq, NULL);
207 irq_set_handler_data(msi->irq, NULL);
208
209 altera_free_domains(msi);
210
211 platform_set_drvdata(pdev, NULL);
212 return 0;
213}
214
215static int altera_msi_probe(struct platform_device *pdev)
216{
217 struct altera_msi *msi;
218 struct device_node *np = pdev->dev.of_node;
219 struct resource *res;
220 int ret;
221
222 msi = devm_kzalloc(&pdev->dev, sizeof(struct altera_msi),
223 GFP_KERNEL);
224 if (!msi)
225 return -ENOMEM;
226
227 mutex_init(&msi->lock);
228 msi->pdev = pdev;
229
230 res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "csr");
231 msi->csr_base = devm_ioremap_resource(&pdev->dev, res);
232 if (IS_ERR(msi->csr_base)) {
233 dev_err(&pdev->dev, "failed to map csr memory\n");
234 return PTR_ERR(msi->csr_base);
235 }
236
237 res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
238 "vector_slave");
239 msi->vector_base = devm_ioremap_resource(&pdev->dev, res);
240 if (IS_ERR(msi->vector_base)) {
241 dev_err(&pdev->dev, "failed to map vector_slave memory\n");
242 return PTR_ERR(msi->vector_base);
243 }
244
245 msi->vector_phy = res->start;
246
247 if (of_property_read_u32(np, "num-vectors", &msi->num_of_vectors)) {
248 dev_err(&pdev->dev, "failed to parse the number of vectors\n");
249 return -EINVAL;
250 }
251
252 ret = altera_allocate_domains(msi);
253 if (ret)
254 return ret;
255
256 msi->irq = platform_get_irq(pdev, 0);
257 if (msi->irq < 0) {
258 dev_err(&pdev->dev, "failed to map IRQ: %d\n", msi->irq);
259 ret = msi->irq;
260 goto err;
261 }
262
263 irq_set_chained_handler_and_data(msi->irq, altera_msi_isr, msi);
264 platform_set_drvdata(pdev, msi);
265
266 return 0;
267
268err:
269 altera_msi_remove(pdev);
270 return ret;
271}
272
273static const struct of_device_id altera_msi_of_match[] = {
274 { .compatible = "altr,msi-1.0", NULL },
275 { },
276};
277
278static struct platform_driver altera_msi_driver = {
279 .driver = {
280 .name = "altera-msi",
281 .of_match_table = altera_msi_of_match,
282 },
283 .probe = altera_msi_probe,
284 .remove = altera_msi_remove,
285};
286
287static int __init altera_msi_init(void)
288{
289 return platform_driver_register(&altera_msi_driver);
290}
291subsys_initcall(altera_msi_init);
292
