1 /*
2 * Annapurna Labs MSIX support services
3 *
4 * Copyright (C) 2016, Amazon.com, Inc. or its affiliates. All Rights Reserved.
5 *
6 * Antoine Tenart <antoine.tenart@free-electrons.com>
7 *
8 * This file is licensed under the terms of the GNU General Public
9 * License version 2. This program is licensed "as is" without any
10 * warranty of any kind, whether express or implied.
11 */
12
13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14
15 #include <linux/irqchip.h>
16 #include <linux/irqchip/arm-gic.h>
17 #include <linux/msi.h>
18 #include <linux/of.h>
19 #include <linux/of_address.h>
20 #include <linux/of_irq.h>
21 #include <linux/of_pci.h>
22 #include <linux/pci.h>
23 #include <linux/slab.h>
24
25 #include <asm/irq.h>
26 #include <asm/msi.h>
27
28 /* MSIX message address format: local GIC target */
29 #define ALPINE_MSIX_SPI_TARGET_CLUSTER0 BIT(16)
30
31 struct alpine_msix_data {
32 spinlock_t msi_map_lock;
33 phys_addr_t addr;
34 u32 spi_first; /* The SGI number that MSIs start */
35 u32 num_spis; /* The number of SGIs for MSIs */
36 unsigned long *msi_map;
37 };
38
alpine_msix_mask_msi_irq(struct irq_data * d)39 static void alpine_msix_mask_msi_irq(struct irq_data *d)
40 {
41 pci_msi_mask_irq(d);
42 irq_chip_mask_parent(d);
43 }
44
alpine_msix_unmask_msi_irq(struct irq_data * d)45 static void alpine_msix_unmask_msi_irq(struct irq_data *d)
46 {
47 pci_msi_unmask_irq(d);
48 irq_chip_unmask_parent(d);
49 }
50
51 static struct irq_chip alpine_msix_irq_chip = {
52 .name = "MSIx",
53 .irq_mask = alpine_msix_mask_msi_irq,
54 .irq_unmask = alpine_msix_unmask_msi_irq,
55 .irq_eoi = irq_chip_eoi_parent,
56 .irq_set_affinity = irq_chip_set_affinity_parent,
57 };
58
alpine_msix_allocate_sgi(struct alpine_msix_data * priv,int num_req)59 static int alpine_msix_allocate_sgi(struct alpine_msix_data *priv, int num_req)
60 {
61 int first;
62
63 spin_lock(&priv->msi_map_lock);
64
65 first = bitmap_find_next_zero_area(priv->msi_map, priv->num_spis, 0,
66 num_req, 0);
67 if (first >= priv->num_spis) {
68 spin_unlock(&priv->msi_map_lock);
69 return -ENOSPC;
70 }
71
72 bitmap_set(priv->msi_map, first, num_req);
73
74 spin_unlock(&priv->msi_map_lock);
75
76 return priv->spi_first + first;
77 }
78
alpine_msix_free_sgi(struct alpine_msix_data * priv,unsigned sgi,int num_req)79 static void alpine_msix_free_sgi(struct alpine_msix_data *priv, unsigned sgi,
80 int num_req)
81 {
82 int first = sgi - priv->spi_first;
83
84 spin_lock(&priv->msi_map_lock);
85
86 bitmap_clear(priv->msi_map, first, num_req);
87
88 spin_unlock(&priv->msi_map_lock);
89 }
90
alpine_msix_compose_msi_msg(struct irq_data * data,struct msi_msg * msg)91 static void alpine_msix_compose_msi_msg(struct irq_data *data,
92 struct msi_msg *msg)
93 {
94 struct alpine_msix_data *priv = irq_data_get_irq_chip_data(data);
95 phys_addr_t msg_addr = priv->addr;
96
97 msg_addr |= (data->hwirq << 3);
98
99 msg->address_hi = upper_32_bits(msg_addr);
100 msg->address_lo = lower_32_bits(msg_addr);
101 msg->data = 0;
102 }
103
104 static struct msi_domain_info alpine_msix_domain_info = {
105 .flags = MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
106 MSI_FLAG_PCI_MSIX,
107 .chip = &alpine_msix_irq_chip,
108 };
109
110 static struct irq_chip middle_irq_chip = {
111 .name = "alpine_msix_middle",
112 .irq_mask = irq_chip_mask_parent,
113 .irq_unmask = irq_chip_unmask_parent,
114 .irq_eoi = irq_chip_eoi_parent,
115 .irq_set_affinity = irq_chip_set_affinity_parent,
116 .irq_compose_msi_msg = alpine_msix_compose_msi_msg,
117 };
118
alpine_msix_gic_domain_alloc(struct irq_domain * domain,unsigned int virq,int sgi)119 static int alpine_msix_gic_domain_alloc(struct irq_domain *domain,
120 unsigned int virq, int sgi)
121 {
122 struct irq_fwspec fwspec;
123 struct irq_data *d;
124 int ret;
125
126 if (!is_of_node(domain->parent->fwnode))
127 return -EINVAL;
128
129 fwspec.fwnode = domain->parent->fwnode;
130 fwspec.param_count = 3;
131 fwspec.param[0] = 0;
132 fwspec.param[1] = sgi;
133 fwspec.param[2] = IRQ_TYPE_EDGE_RISING;
134
135 ret = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
136 if (ret)
137 return ret;
138
139 d = irq_domain_get_irq_data(domain->parent, virq);
140 d->chip->irq_set_type(d, IRQ_TYPE_EDGE_RISING);
141
142 return 0;
143 }
144
alpine_msix_middle_domain_alloc(struct irq_domain * domain,unsigned int virq,unsigned int nr_irqs,void * args)145 static int alpine_msix_middle_domain_alloc(struct irq_domain *domain,
146 unsigned int virq,
147 unsigned int nr_irqs, void *args)
148 {
149 struct alpine_msix_data *priv = domain->host_data;
150 int sgi, err, i;
151
152 sgi = alpine_msix_allocate_sgi(priv, nr_irqs);
153 if (sgi < 0)
154 return sgi;
155
156 for (i = 0; i < nr_irqs; i++) {
157 err = alpine_msix_gic_domain_alloc(domain, virq + i, sgi + i);
158 if (err)
159 goto err_sgi;
160
161 irq_domain_set_hwirq_and_chip(domain, virq + i, sgi + i,
162 &middle_irq_chip, priv);
163 }
164
165 return 0;
166
167 err_sgi:
168 while (--i >= 0)
169 irq_domain_free_irqs_parent(domain, virq, i);
170 alpine_msix_free_sgi(priv, sgi, nr_irqs);
171 return err;
172 }
173
alpine_msix_middle_domain_free(struct irq_domain * domain,unsigned int virq,unsigned int nr_irqs)174 static void alpine_msix_middle_domain_free(struct irq_domain *domain,
175 unsigned int virq,
176 unsigned int nr_irqs)
177 {
178 struct irq_data *d = irq_domain_get_irq_data(domain, virq);
179 struct alpine_msix_data *priv = irq_data_get_irq_chip_data(d);
180
181 irq_domain_free_irqs_parent(domain, virq, nr_irqs);
182 alpine_msix_free_sgi(priv, d->hwirq, nr_irqs);
183 }
184
185 static const struct irq_domain_ops alpine_msix_middle_domain_ops = {
186 .alloc = alpine_msix_middle_domain_alloc,
187 .free = alpine_msix_middle_domain_free,
188 };
189
alpine_msix_init_domains(struct alpine_msix_data * priv,struct device_node * node)190 static int alpine_msix_init_domains(struct alpine_msix_data *priv,
191 struct device_node *node)
192 {
193 struct irq_domain *middle_domain, *msi_domain, *gic_domain;
194 struct device_node *gic_node;
195
196 gic_node = of_irq_find_parent(node);
197 if (!gic_node) {
198 pr_err("Failed to find the GIC node\n");
199 return -ENODEV;
200 }
201
202 gic_domain = irq_find_host(gic_node);
203 if (!gic_domain) {
204 pr_err("Failed to find the GIC domain\n");
205 return -ENXIO;
206 }
207
208 middle_domain = irq_domain_add_tree(NULL,
209 &alpine_msix_middle_domain_ops,
210 priv);
211 if (!middle_domain) {
212 pr_err("Failed to create the MSIX middle domain\n");
213 return -ENOMEM;
214 }
215
216 middle_domain->parent = gic_domain;
217
218 msi_domain = pci_msi_create_irq_domain(of_node_to_fwnode(node),
219 &alpine_msix_domain_info,
220 middle_domain);
221 if (!msi_domain) {
222 pr_err("Failed to create MSI domain\n");
223 irq_domain_remove(middle_domain);
224 return -ENOMEM;
225 }
226
227 return 0;
228 }
229
alpine_msix_init(struct device_node * node,struct device_node * parent)230 static int alpine_msix_init(struct device_node *node,
231 struct device_node *parent)
232 {
233 struct alpine_msix_data *priv;
234 struct resource res;
235 int ret;
236
237 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
238 if (!priv)
239 return -ENOMEM;
240
241 spin_lock_init(&priv->msi_map_lock);
242
243 ret = of_address_to_resource(node, 0, &res);
244 if (ret) {
245 pr_err("Failed to allocate resource\n");
246 goto err_priv;
247 }
248
249 /*
250 * The 20 least significant bits of addr provide direct information
251 * regarding the interrupt destination.
252 *
253 * To select the primary GIC as the target GIC, bits [18:17] must be set
254 * to 0x0. In this case, bit 16 (SPI_TARGET_CLUSTER0) must be set.
255 */
256 priv->addr = res.start & GENMASK_ULL(63,20);
257 priv->addr |= ALPINE_MSIX_SPI_TARGET_CLUSTER0;
258
259 if (of_property_read_u32(node, "al,msi-base-spi", &priv->spi_first)) {
260 pr_err("Unable to parse MSI base\n");
261 ret = -EINVAL;
262 goto err_priv;
263 }
264
265 if (of_property_read_u32(node, "al,msi-num-spis", &priv->num_spis)) {
266 pr_err("Unable to parse MSI numbers\n");
267 ret = -EINVAL;
268 goto err_priv;
269 }
270
271 priv->msi_map = kcalloc(BITS_TO_LONGS(priv->num_spis),
272 sizeof(*priv->msi_map),
273 GFP_KERNEL);
274 if (!priv->msi_map) {
275 ret = -ENOMEM;
276 goto err_priv;
277 }
278
279 pr_debug("Registering %d msixs, starting at %d\n",
280 priv->num_spis, priv->spi_first);
281
282 ret = alpine_msix_init_domains(priv, node);
283 if (ret)
284 goto err_map;
285
286 return 0;
287
288 err_map:
289 kfree(priv->msi_map);
290 err_priv:
291 kfree(priv);
292 return ret;
293 }
294 IRQCHIP_DECLARE(alpine_msix, "al,alpine-msix", alpine_msix_init);
295
