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8cfab3cf | 1 | // SPDX-License-Identifier: GPL-2.0 |
af1169b4 | 2 | /* |
18224b3a PG |
3 | * Altera PCIe MSI support |
4 | * | |
5 | * Author: Ley Foon Tan <lftan@altera.com> | |
6 | * | |
af1169b4 | 7 | * Copyright Altera Corporation (C) 2013-2015. All rights reserved |
af1169b4 LFT |
8 | */ |
9 | ||
10 | #include <linux/interrupt.h> | |
11 | #include <linux/irqchip/chained_irq.h> | |
18224b3a | 12 | #include <linux/init.h> |
af1169b4 LFT |
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 | ||
27 | struct altera_msi { | |
28 | DECLARE_BITMAP(used, MAX_MSI_VECTORS); | |
29 | struct mutex lock; /* protect "used" bitmap */ | |
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 | ||
40 | static 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 | ||
46 | static inline u32 msi_readl(struct altera_msi *msi, const u32 reg) | |
47 | { | |
48 | return readl_relaxed(msi->csr_base + reg); | |
49 | } | |
50 | ||
51 | static 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; | |
af1169b4 LFT |
56 | u32 bit; |
57 | u32 virq; | |
58 | ||
59 | chained_irq_enter(chip, desc); | |
60 | msi = irq_desc_get_handler_data(desc); | |
af1169b4 LFT |
61 | |
62 | while ((status = msi_readl(msi, MSI_STATUS)) != 0) { | |
63 | for_each_set_bit(bit, &status, msi->num_of_vectors) { | |
64 | /* Dummy read from vector to clear the interrupt */ | |
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 | ||
78 | static 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 | ||
84 | static 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 | ||
90 | static 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 | ||
103 | static int altera_msi_set_affinity(struct irq_data *irq_data, | |
104 | const struct cpumask *mask, bool force) | |
105 | { | |
106 | return -EINVAL; | |
107 | } | |
108 | ||
109 | static 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 | ||
115 | static 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 | ||
146 | static 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 | ||
168 | static const struct irq_domain_ops msi_domain_ops = { | |
169 | .alloc = altera_irq_domain_alloc, | |
170 | .free = altera_irq_domain_free, | |
171 | }; | |
172 | ||
173 | static int altera_allocate_domains(struct altera_msi *msi) | |
174 | { | |
3c87b791 LT |
175 | struct fwnode_handle *fwnode = of_node_to_fwnode(msi->pdev->dev.of_node); |
176 | ||
af1169b4 LFT |
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 | ||
3c87b791 | 184 | msi->msi_domain = pci_msi_create_irq_domain(fwnode, |
af1169b4 LFT |
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 | ||
195 | static 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 | ||
201 | static 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 | ||
215 | static 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"); | |
af1169b4 LFT |
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"); | |
af1169b4 LFT |
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); | |
ef75369a | 257 | if (msi->irq < 0) { |
af1169b4 | 258 | dev_err(&pdev->dev, "failed to map IRQ: %d\n", msi->irq); |
ef75369a | 259 | ret = msi->irq; |
af1169b4 LFT |
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 | ||
268 | err: | |
269 | altera_msi_remove(pdev); | |
270 | return ret; | |
271 | } | |
272 | ||
273 | static const struct of_device_id altera_msi_of_match[] = { | |
274 | { .compatible = "altr,msi-1.0", NULL }, | |
275 | { }, | |
276 | }; | |
277 | ||
278 | static 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 | ||
287 | static int __init altera_msi_init(void) | |
288 | { | |
289 | return platform_driver_register(&altera_msi_driver); | |
290 | } | |
291 | subsys_initcall(altera_msi_init); |