1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2018 ARM Limited, All Rights Reserved.
4  * Author: Marc Zyngier <marc.zyngier@arm.com>
5  */
6 
7 #define pr_fmt(fmt) "GICv3: " fmt
8 
9 #include <linux/dma-iommu.h>
10 #include <linux/irq.h>
11 #include <linux/irqdomain.h>
12 #include <linux/kernel.h>
13 #include <linux/msi.h>
14 #include <linux/of_address.h>
15 #include <linux/of_pci.h>
16 #include <linux/slab.h>
17 #include <linux/spinlock.h>
18 
19 #include <linux/irqchip/arm-gic-v3.h>
20 
21 struct mbi_range {
22 	u32			spi_start;
23 	u32			nr_spis;
24 	unsigned long		*bm;
25 };
26 
27 static struct mutex		mbi_lock;
28 static phys_addr_t		mbi_phys_base;
29 static struct mbi_range		*mbi_ranges;
30 static unsigned int		mbi_range_nr;
31 
32 static struct irq_chip mbi_irq_chip = {
33 	.name			= "MBI",
34 	.irq_mask		= irq_chip_mask_parent,
35 	.irq_unmask		= irq_chip_unmask_parent,
36 	.irq_eoi		= irq_chip_eoi_parent,
37 	.irq_set_type		= irq_chip_set_type_parent,
38 	.irq_set_affinity	= irq_chip_set_affinity_parent,
39 };
40 
41 static int mbi_irq_gic_domain_alloc(struct irq_domain *domain,
42 				       unsigned int virq,
43 				       irq_hw_number_t hwirq)
44 {
45 	struct irq_fwspec fwspec;
46 	struct irq_data *d;
47 	int err;
48 
49 	/*
50 	 * Using ACPI? There is no MBI support in the spec, you
51 	 * shouldn't even be here.
52 	 */
53 	if (!is_of_node(domain->parent->fwnode))
54 		return -EINVAL;
55 
56 	/*
57 	 * Let's default to edge. This is consistent with traditional
58 	 * MSIs, and systems requiring level signaling will just
59 	 * enforce the trigger on their own.
60 	 */
61 	fwspec.fwnode = domain->parent->fwnode;
62 	fwspec.param_count = 3;
63 	fwspec.param[0] = 0;
64 	fwspec.param[1] = hwirq - 32;
65 	fwspec.param[2] = IRQ_TYPE_EDGE_RISING;
66 
67 	err = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
68 	if (err)
69 		return err;
70 
71 	d = irq_domain_get_irq_data(domain->parent, virq);
72 	return d->chip->irq_set_type(d, IRQ_TYPE_EDGE_RISING);
73 }
74 
75 static void mbi_free_msi(struct mbi_range *mbi, unsigned int hwirq,
76 			 int nr_irqs)
77 {
78 	mutex_lock(&mbi_lock);
79 	bitmap_release_region(mbi->bm, hwirq - mbi->spi_start,
80 			      get_count_order(nr_irqs));
81 	mutex_unlock(&mbi_lock);
82 }
83 
84 static int mbi_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
85 				   unsigned int nr_irqs, void *args)
86 {
87 	struct mbi_range *mbi = NULL;
88 	int hwirq, offset, i, err = 0;
89 
90 	mutex_lock(&mbi_lock);
91 	for (i = 0; i < mbi_range_nr; i++) {
92 		offset = bitmap_find_free_region(mbi_ranges[i].bm,
93 						 mbi_ranges[i].nr_spis,
94 						 get_count_order(nr_irqs));
95 		if (offset >= 0) {
96 			mbi = &mbi_ranges[i];
97 			break;
98 		}
99 	}
100 	mutex_unlock(&mbi_lock);
101 
102 	if (!mbi)
103 		return -ENOSPC;
104 
105 	hwirq = mbi->spi_start + offset;
106 
107 	for (i = 0; i < nr_irqs; i++) {
108 		err = mbi_irq_gic_domain_alloc(domain, virq + i, hwirq + i);
109 		if (err)
110 			goto fail;
111 
112 		irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
113 					      &mbi_irq_chip, mbi);
114 	}
115 
116 	return 0;
117 
118 fail:
119 	irq_domain_free_irqs_parent(domain, virq, nr_irqs);
120 	mbi_free_msi(mbi, hwirq, nr_irqs);
121 	return err;
122 }
123 
124 static void mbi_irq_domain_free(struct irq_domain *domain,
125 				unsigned int virq, unsigned int nr_irqs)
126 {
127 	struct irq_data *d = irq_domain_get_irq_data(domain, virq);
128 	struct mbi_range *mbi = irq_data_get_irq_chip_data(d);
129 
130 	mbi_free_msi(mbi, d->hwirq, nr_irqs);
131 	irq_domain_free_irqs_parent(domain, virq, nr_irqs);
132 }
133 
134 static const struct irq_domain_ops mbi_domain_ops = {
135 	.alloc			= mbi_irq_domain_alloc,
136 	.free			= mbi_irq_domain_free,
137 };
138 
139 static void mbi_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
140 {
141 	msg[0].address_hi = upper_32_bits(mbi_phys_base + GICD_SETSPI_NSR);
142 	msg[0].address_lo = lower_32_bits(mbi_phys_base + GICD_SETSPI_NSR);
143 	msg[0].data = data->parent_data->hwirq;
144 
145 	iommu_dma_map_msi_msg(data->irq, msg);
146 }
147 
148 #ifdef CONFIG_PCI_MSI
149 /* PCI-specific irqchip */
150 static void mbi_mask_msi_irq(struct irq_data *d)
151 {
152 	pci_msi_mask_irq(d);
153 	irq_chip_mask_parent(d);
154 }
155 
156 static void mbi_unmask_msi_irq(struct irq_data *d)
157 {
158 	pci_msi_unmask_irq(d);
159 	irq_chip_unmask_parent(d);
160 }
161 
162 static struct irq_chip mbi_msi_irq_chip = {
163 	.name			= "MSI",
164 	.irq_mask		= mbi_mask_msi_irq,
165 	.irq_unmask		= mbi_unmask_msi_irq,
166 	.irq_eoi		= irq_chip_eoi_parent,
167 	.irq_compose_msi_msg	= mbi_compose_msi_msg,
168 	.irq_write_msi_msg	= pci_msi_domain_write_msg,
169 };
170 
171 static struct msi_domain_info mbi_msi_domain_info = {
172 	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
173 		   MSI_FLAG_PCI_MSIX | MSI_FLAG_MULTI_PCI_MSI),
174 	.chip	= &mbi_msi_irq_chip,
175 };
176 
177 static int mbi_allocate_pci_domain(struct irq_domain *nexus_domain,
178 				   struct irq_domain **pci_domain)
179 {
180 	*pci_domain = pci_msi_create_irq_domain(nexus_domain->parent->fwnode,
181 						&mbi_msi_domain_info,
182 						nexus_domain);
183 	if (!*pci_domain)
184 		return -ENOMEM;
185 
186 	return 0;
187 }
188 #else
189 static int mbi_allocate_pci_domain(struct irq_domain *nexus_domain,
190 				   struct irq_domain **pci_domain)
191 {
192 	*pci_domain = NULL;
193 	return 0;
194 }
195 #endif
196 
197 static void mbi_compose_mbi_msg(struct irq_data *data, struct msi_msg *msg)
198 {
199 	mbi_compose_msi_msg(data, msg);
200 
201 	msg[1].address_hi = upper_32_bits(mbi_phys_base + GICD_CLRSPI_NSR);
202 	msg[1].address_lo = lower_32_bits(mbi_phys_base + GICD_CLRSPI_NSR);
203 	msg[1].data = data->parent_data->hwirq;
204 
205 	iommu_dma_map_msi_msg(data->irq, &msg[1]);
206 }
207 
208 /* Platform-MSI specific irqchip */
209 static struct irq_chip mbi_pmsi_irq_chip = {
210 	.name			= "pMSI",
211 	.irq_set_type		= irq_chip_set_type_parent,
212 	.irq_compose_msi_msg	= mbi_compose_mbi_msg,
213 	.flags			= IRQCHIP_SUPPORTS_LEVEL_MSI,
214 };
215 
216 static struct msi_domain_ops mbi_pmsi_ops = {
217 };
218 
219 static struct msi_domain_info mbi_pmsi_domain_info = {
220 	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
221 		   MSI_FLAG_LEVEL_CAPABLE),
222 	.ops	= &mbi_pmsi_ops,
223 	.chip	= &mbi_pmsi_irq_chip,
224 };
225 
226 static int mbi_allocate_domains(struct irq_domain *parent)
227 {
228 	struct irq_domain *nexus_domain, *pci_domain, *plat_domain;
229 	int err;
230 
231 	nexus_domain = irq_domain_create_tree(parent->fwnode,
232 					      &mbi_domain_ops, NULL);
233 	if (!nexus_domain)
234 		return -ENOMEM;
235 
236 	irq_domain_update_bus_token(nexus_domain, DOMAIN_BUS_NEXUS);
237 	nexus_domain->parent = parent;
238 
239 	err = mbi_allocate_pci_domain(nexus_domain, &pci_domain);
240 
241 	plat_domain = platform_msi_create_irq_domain(parent->fwnode,
242 						     &mbi_pmsi_domain_info,
243 						     nexus_domain);
244 
245 	if (err || !plat_domain) {
246 		if (plat_domain)
247 			irq_domain_remove(plat_domain);
248 		if (pci_domain)
249 			irq_domain_remove(pci_domain);
250 		irq_domain_remove(nexus_domain);
251 		return -ENOMEM;
252 	}
253 
254 	return 0;
255 }
256 
257 int __init mbi_init(struct fwnode_handle *fwnode, struct irq_domain *parent)
258 {
259 	struct device_node *np;
260 	const __be32 *reg;
261 	int ret, n;
262 
263 	np = to_of_node(fwnode);
264 
265 	if (!of_property_read_bool(np, "msi-controller"))
266 		return 0;
267 
268 	n = of_property_count_elems_of_size(np, "mbi-ranges", sizeof(u32));
269 	if (n <= 0 || n % 2)
270 		return -EINVAL;
271 
272 	mbi_range_nr = n / 2;
273 	mbi_ranges = kcalloc(mbi_range_nr, sizeof(*mbi_ranges), GFP_KERNEL);
274 	if (!mbi_ranges)
275 		return -ENOMEM;
276 
277 	for (n = 0; n < mbi_range_nr; n++) {
278 		ret = of_property_read_u32_index(np, "mbi-ranges", n * 2,
279 						 &mbi_ranges[n].spi_start);
280 		if (ret)
281 			goto err_free_mbi;
282 		ret = of_property_read_u32_index(np, "mbi-ranges", n * 2 + 1,
283 						 &mbi_ranges[n].nr_spis);
284 		if (ret)
285 			goto err_free_mbi;
286 
287 		mbi_ranges[n].bm = kcalloc(BITS_TO_LONGS(mbi_ranges[n].nr_spis),
288 					   sizeof(long), GFP_KERNEL);
289 		if (!mbi_ranges[n].bm) {
290 			ret = -ENOMEM;
291 			goto err_free_mbi;
292 		}
293 		pr_info("MBI range [%d:%d]\n", mbi_ranges[n].spi_start,
294 			mbi_ranges[n].spi_start + mbi_ranges[n].nr_spis - 1);
295 	}
296 
297 	reg = of_get_property(np, "mbi-alias", NULL);
298 	if (reg) {
299 		mbi_phys_base = of_translate_address(np, reg);
300 		if (mbi_phys_base == OF_BAD_ADDR) {
301 			ret = -ENXIO;
302 			goto err_free_mbi;
303 		}
304 	} else {
305 		struct resource res;
306 
307 		if (of_address_to_resource(np, 0, &res)) {
308 			ret = -ENXIO;
309 			goto err_free_mbi;
310 		}
311 
312 		mbi_phys_base = res.start;
313 	}
314 
315 	pr_info("Using MBI frame %pa\n", &mbi_phys_base);
316 
317 	ret = mbi_allocate_domains(parent);
318 	if (ret)
319 		goto err_free_mbi;
320 
321 	return 0;
322 
323 err_free_mbi:
324 	if (mbi_ranges) {
325 		for (n = 0; n < mbi_range_nr; n++)
326 			kfree(mbi_ranges[n].bm);
327 		kfree(mbi_ranges);
328 	}
329 
330 	return ret;
331 }
332