1 /*
2  * Copyright (C) 2016 Marvell
3  *
4  * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
5  *
6  * This file is licensed under the terms of the GNU General Public
7  * License version 2.  This program is licensed "as is" without any
8  * warranty of any kind, whether express or implied.
9  */
10 
11 #define pr_fmt(fmt) "GIC-ODMI: " fmt
12 
13 #include <linux/irq.h>
14 #include <linux/irqchip.h>
15 #include <linux/irqdomain.h>
16 #include <linux/kernel.h>
17 #include <linux/msi.h>
18 #include <linux/of_address.h>
19 #include <linux/slab.h>
20 #include <dt-bindings/interrupt-controller/arm-gic.h>
21 
22 #define GICP_ODMIN_SET			0x40
23 #define   GICP_ODMI_INT_NUM_SHIFT	12
24 #define GICP_ODMIN_GM_EP_R0		0x110
25 #define GICP_ODMIN_GM_EP_R1		0x114
26 #define GICP_ODMIN_GM_EA_R0		0x108
27 #define GICP_ODMIN_GM_EA_R1		0x118
28 
29 /*
30  * We don't support the group events, so we simply have 8 interrupts
31  * per frame.
32  */
33 #define NODMIS_SHIFT		3
34 #define NODMIS_PER_FRAME	(1 << NODMIS_SHIFT)
35 #define NODMIS_MASK		(NODMIS_PER_FRAME - 1)
36 
37 struct odmi_data {
38 	struct resource res;
39 	void __iomem *base;
40 	unsigned int spi_base;
41 };
42 
43 static struct odmi_data *odmis;
44 static unsigned long *odmis_bm;
45 static unsigned int odmis_count;
46 
47 /* Protects odmis_bm */
48 static DEFINE_SPINLOCK(odmis_bm_lock);
49 
50 static void odmi_compose_msi_msg(struct irq_data *d, struct msi_msg *msg)
51 {
52 	struct odmi_data *odmi;
53 	phys_addr_t addr;
54 	unsigned int odmin;
55 
56 	if (WARN_ON(d->hwirq >= odmis_count * NODMIS_PER_FRAME))
57 		return;
58 
59 	odmi = &odmis[d->hwirq >> NODMIS_SHIFT];
60 	odmin = d->hwirq & NODMIS_MASK;
61 
62 	addr = odmi->res.start + GICP_ODMIN_SET;
63 
64 	msg->address_hi = upper_32_bits(addr);
65 	msg->address_lo = lower_32_bits(addr);
66 	msg->data = odmin << GICP_ODMI_INT_NUM_SHIFT;
67 }
68 
69 static struct irq_chip odmi_irq_chip = {
70 	.name			= "ODMI",
71 	.irq_mask		= irq_chip_mask_parent,
72 	.irq_unmask		= irq_chip_unmask_parent,
73 	.irq_eoi		= irq_chip_eoi_parent,
74 	.irq_set_affinity	= irq_chip_set_affinity_parent,
75 	.irq_compose_msi_msg	= odmi_compose_msi_msg,
76 };
77 
78 static int odmi_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
79 				 unsigned int nr_irqs, void *args)
80 {
81 	struct odmi_data *odmi = NULL;
82 	struct irq_fwspec fwspec;
83 	struct irq_data *d;
84 	unsigned int hwirq, odmin;
85 	int ret;
86 
87 	spin_lock(&odmis_bm_lock);
88 	hwirq = find_first_zero_bit(odmis_bm, NODMIS_PER_FRAME * odmis_count);
89 	if (hwirq >= NODMIS_PER_FRAME * odmis_count) {
90 		spin_unlock(&odmis_bm_lock);
91 		return -ENOSPC;
92 	}
93 
94 	__set_bit(hwirq, odmis_bm);
95 	spin_unlock(&odmis_bm_lock);
96 
97 	odmi = &odmis[hwirq >> NODMIS_SHIFT];
98 	odmin = hwirq & NODMIS_MASK;
99 
100 	fwspec.fwnode = domain->parent->fwnode;
101 	fwspec.param_count = 3;
102 	fwspec.param[0] = GIC_SPI;
103 	fwspec.param[1] = odmi->spi_base - 32 + odmin;
104 	fwspec.param[2] = IRQ_TYPE_EDGE_RISING;
105 
106 	ret = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
107 	if (ret) {
108 		pr_err("Cannot allocate parent IRQ\n");
109 		spin_lock(&odmis_bm_lock);
110 		__clear_bit(odmin, odmis_bm);
111 		spin_unlock(&odmis_bm_lock);
112 		return ret;
113 	}
114 
115 	/* Configure the interrupt line to be edge */
116 	d = irq_domain_get_irq_data(domain->parent, virq);
117 	d->chip->irq_set_type(d, IRQ_TYPE_EDGE_RISING);
118 
119 	irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
120 				      &odmi_irq_chip, NULL);
121 
122 	return 0;
123 }
124 
125 static void odmi_irq_domain_free(struct irq_domain *domain,
126 				 unsigned int virq, unsigned int nr_irqs)
127 {
128 	struct irq_data *d = irq_domain_get_irq_data(domain, virq);
129 
130 	if (d->hwirq >= odmis_count * NODMIS_PER_FRAME) {
131 		pr_err("Failed to teardown msi. Invalid hwirq %lu\n", d->hwirq);
132 		return;
133 	}
134 
135 	irq_domain_free_irqs_parent(domain, virq, nr_irqs);
136 
137 	/* Actually free the MSI */
138 	spin_lock(&odmis_bm_lock);
139 	__clear_bit(d->hwirq, odmis_bm);
140 	spin_unlock(&odmis_bm_lock);
141 }
142 
143 static const struct irq_domain_ops odmi_domain_ops = {
144 	.alloc	= odmi_irq_domain_alloc,
145 	.free	= odmi_irq_domain_free,
146 };
147 
148 static struct irq_chip odmi_msi_irq_chip = {
149 	.name	= "ODMI",
150 };
151 
152 static struct msi_domain_ops odmi_msi_ops = {
153 };
154 
155 static struct msi_domain_info odmi_msi_domain_info = {
156 	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS),
157 	.ops	= &odmi_msi_ops,
158 	.chip	= &odmi_msi_irq_chip,
159 };
160 
161 static int __init mvebu_odmi_init(struct device_node *node,
162 				  struct device_node *parent)
163 {
164 	struct irq_domain *inner_domain, *plat_domain;
165 	int ret, i;
166 
167 	if (of_property_read_u32(node, "marvell,odmi-frames", &odmis_count))
168 		return -EINVAL;
169 
170 	odmis = kcalloc(odmis_count, sizeof(struct odmi_data), GFP_KERNEL);
171 	if (!odmis)
172 		return -ENOMEM;
173 
174 	odmis_bm = kcalloc(BITS_TO_LONGS(odmis_count * NODMIS_PER_FRAME),
175 			   sizeof(long), GFP_KERNEL);
176 	if (!odmis_bm) {
177 		ret = -ENOMEM;
178 		goto err_alloc;
179 	}
180 
181 	for (i = 0; i < odmis_count; i++) {
182 		struct odmi_data *odmi = &odmis[i];
183 
184 		ret = of_address_to_resource(node, i, &odmi->res);
185 		if (ret)
186 			goto err_unmap;
187 
188 		odmi->base = of_io_request_and_map(node, i, "odmi");
189 		if (IS_ERR(odmi->base)) {
190 			ret = PTR_ERR(odmi->base);
191 			goto err_unmap;
192 		}
193 
194 		if (of_property_read_u32_index(node, "marvell,spi-base",
195 					       i, &odmi->spi_base)) {
196 			ret = -EINVAL;
197 			goto err_unmap;
198 		}
199 	}
200 
201 	inner_domain = irq_domain_create_linear(of_node_to_fwnode(node),
202 						odmis_count * NODMIS_PER_FRAME,
203 						&odmi_domain_ops, NULL);
204 	if (!inner_domain) {
205 		ret = -ENOMEM;
206 		goto err_unmap;
207 	}
208 
209 	inner_domain->parent = irq_find_host(parent);
210 
211 	plat_domain = platform_msi_create_irq_domain(of_node_to_fwnode(node),
212 						     &odmi_msi_domain_info,
213 						     inner_domain);
214 	if (!plat_domain) {
215 		ret = -ENOMEM;
216 		goto err_remove_inner;
217 	}
218 
219 	return 0;
220 
221 err_remove_inner:
222 	irq_domain_remove(inner_domain);
223 err_unmap:
224 	for (i = 0; i < odmis_count; i++) {
225 		struct odmi_data *odmi = &odmis[i];
226 
227 		if (odmi->base && !IS_ERR(odmi->base))
228 			iounmap(odmis[i].base);
229 	}
230 	kfree(odmis_bm);
231 err_alloc:
232 	kfree(odmis);
233 	return ret;
234 }
235 
236 IRQCHIP_DECLARE(mvebu_odmi, "marvell,odmi-controller", mvebu_odmi_init);
237