summaryrefslogtreecommitdiffstats
path: root/kernel/drivers/pci/host/pcie-altera-msi.c
blob: 99177f4ccde286b29ac7c61977fab444065f827a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
/*
 * Copyright Altera Corporation (C) 2013-2015. All rights reserved
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/interrupt.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/module.h>
#include <linux/msi.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_pci.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#define MSI_STATUS		0x0
#define MSI_ERROR		0x4
#define MSI_INTMASK		0x8

#define MAX_MSI_VECTORS		32

struct altera_msi {
	DECLARE_BITMAP(used, MAX_MSI_VECTORS);
	struct mutex		lock;	/* protect "used" bitmap */
	struct platform_device	*pdev;
	struct irq_domain	*msi_domain;
	struct irq_domain	*inner_domain;
	void __iomem		*csr_base;
	void __iomem		*vector_base;
	phys_addr_t		vector_phy;
	u32			num_of_vectors;
	int			irq;
};

static inline void msi_writel(struct altera_msi *msi, const u32 value,
			      const u32 reg)
{
	writel_relaxed(value, msi->csr_base + reg);
}

static inline u32 msi_readl(struct altera_msi *msi, const u32 reg)
{
	return readl_relaxed(msi->csr_base + reg);
}

static void altera_msi_isr(struct irq_desc *desc)
{
	struct irq_chip *chip = irq_desc_get_chip(desc);
	struct altera_msi *msi;
	unsigned long status;
	u32 num_of_vectors;
	u32 bit;
	u32 virq;

	chained_irq_enter(chip, desc);
	msi = irq_desc_get_handler_data(desc);
	num_of_vectors = msi->num_of_vectors;

	while ((status = msi_readl(msi, MSI_STATUS)) != 0) {
		for_each_set_bit(bit, &status, msi->num_of_vectors) {
			/* Dummy read from vector to clear the interrupt */
			readl_relaxed(msi->vector_base + (bit * sizeof(u32)));

			virq = irq_find_mapping(msi->inner_domain, bit);
			if (virq)
				generic_handle_irq(virq);
			else
				dev_err(&msi->pdev->dev, "unexpected MSI\n");
		}
	}

	chained_irq_exit(chip, desc);
}

static struct irq_chip altera_msi_irq_chip = {
	.name = "Altera PCIe MSI",
	.irq_mask = pci_msi_mask_irq,
	.irq_unmask = pci_msi_unmask_irq,
};

static struct msi_domain_info altera_msi_domain_info = {
	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
		     MSI_FLAG_PCI_MSIX),
	.chip	= &altera_msi_irq_chip,
};

static void altera_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
{
	struct altera_msi *msi = irq_data_get_irq_chip_data(data);
	phys_addr_t addr = msi->vector_phy + (data->hwirq * sizeof(u32));

	msg->address_lo = lower_32_bits(addr);
	msg->address_hi = upper_32_bits(addr);
	msg->data = data->hwirq;

	dev_dbg(&msi->pdev->dev, "msi#%d address_hi %#x address_lo %#x\n",
		(int)data->hwirq, msg->address_hi, msg->address_lo);
}

static int altera_msi_set_affinity(struct irq_data *irq_data,
				   const struct cpumask *mask, bool force)
{
	 return -EINVAL;
}

static struct irq_chip altera_msi_bottom_irq_chip = {
	.name			= "Altera MSI",
	.irq_compose_msi_msg	= altera_compose_msi_msg,
	.irq_set_affinity	= altera_msi_set_affinity,
};

static int altera_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
				   unsigned int nr_irqs, void *args)
{
	struct altera_msi *msi = domain->host_data;
	unsigned long bit;
	u32 mask;

	WARN_ON(nr_irqs != 1);
	mutex_lock(&msi->lock);

	bit = find_first_zero_bit(msi->used, msi->num_of_vectors);
	if (bit >= msi->num_of_vectors) {
		mutex_unlock(&msi->lock);
		return -ENOSPC;
	}

	set_bit(bit, msi->used);

	mutex_unlock(&msi->lock);

	irq_domain_set_info(domain, virq, bit, &altera_msi_bottom_irq_chip,
			    domain->host_data, handle_simple_irq,
			    NULL, NULL);

	mask = msi_readl(msi, MSI_INTMASK);
	mask |= 1 << bit;
	msi_writel(msi, mask, MSI_INTMASK);

	return 0;
}

static void altera_irq_domain_free(struct irq_domain *domain,
				   unsigned int virq, unsigned int nr_irqs)
{
	struct irq_data *d = irq_domain_get_irq_data(domain, virq);
	struct altera_msi *msi = irq_data_get_irq_chip_data(d);
	u32 mask;

	mutex_lock(&msi->lock);

	if (!test_bit(d->hwirq, msi->used)) {
		dev_err(&msi->pdev->dev, "trying to free unused MSI#%lu\n",
			d->hwirq);
	} else {
		__clear_bit(d->hwirq, msi->used);
		mask = msi_readl(msi, MSI_INTMASK);
		mask &= ~(1 << d->hwirq);
		msi_writel(msi, mask, MSI_INTMASK);
	}

	mutex_unlock(&msi->lock);
}

static const struct irq_domain_ops msi_domain_ops = {
	.alloc	= altera_irq_domain_alloc,
	.free	= altera_irq_domain_free,
};

static int altera_allocate_domains(struct altera_msi *msi)
{
	struct fwnode_handle *fwnode = of_node_to_fwnode(msi->pdev->dev.of_node);

	msi->inner_domain = irq_domain_add_linear(NULL, msi->num_of_vectors,
					     &msi_domain_ops, msi);
	if (!msi->inner_domain) {
		dev_err(&msi->pdev->dev, "failed to create IRQ domain\n");
		return -ENOMEM;
	}

	msi->msi_domain = pci_msi_create_irq_domain(fwnode,
				&altera_msi_domain_info, msi->inner_domain);
	if (!msi->msi_domain) {
		dev_err(&msi->pdev->dev, "failed to create MSI domain\n");
		irq_domain_remove(msi->inner_domain);
		return -ENOMEM;
	}

	return 0;
}

static void altera_free_domains(struct altera_msi *msi)
{
	irq_domain_remove(msi->msi_domain);
	irq_domain_remove(msi->inner_domain);
}

static int altera_msi_remove(struct platform_device *pdev)
{
	struct altera_msi *msi = platform_get_drvdata(pdev);

	msi_writel(msi, 0, MSI_INTMASK);
	irq_set_chained_handler(msi->irq, NULL);
	irq_set_handler_data(msi->irq, NULL);

	altera_free_domains(msi);

	platform_set_drvdata(pdev, NULL);
	return 0;
}

static int altera_msi_probe(struct platform_device *pdev)
{
	struct altera_msi *msi;
	struct device_node *np = pdev->dev.of_node;
	struct resource *res;
	int ret;

	msi = devm_kzalloc(&pdev->dev, sizeof(struct altera_msi),
			   GFP_KERNEL);
	if (!msi)
		return -ENOMEM;

	mutex_init(&msi->lock);
	msi->pdev = pdev;

	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "csr");
	if (!res) {
		dev_err(&pdev->dev, "no csr memory resource defined\n");
		return -ENODEV;
	}

	msi->csr_base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(msi->csr_base)) {
		dev_err(&pdev->dev, "failed to map csr memory\n");
		return PTR_ERR(msi->csr_base);
	}

	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
					   "vector_slave");
	if (!res) {
		dev_err(&pdev->dev, "no vector_slave memory resource defined\n");
		return -ENODEV;
	}

	msi->vector_base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(msi->vector_base)) {
		dev_err(&pdev->dev, "failed to map vector_slave memory\n");
		return PTR_ERR(msi->vector_base);
	}

	msi->vector_phy = res->start;

	if (of_property_read_u32(np, "num-vectors", &msi->num_of_vectors)) {
		dev_err(&pdev->dev, "failed to parse the number of vectors\n");
		return -EINVAL;
	}

	ret = altera_allocate_domains(msi);
	if (ret)
		return ret;

	msi->irq = platform_get_irq(pdev, 0);
	if (msi->irq <= 0) {
		dev_err(&pdev->dev, "failed to map IRQ: %d\n", msi->irq);
		ret = -ENODEV;
		goto err;
	}

	irq_set_chained_handler_and_data(msi->irq, altera_msi_isr, msi);
	platform_set_drvdata(pdev, msi);

	return 0;

err:
	altera_msi_remove(pdev);
	return ret;
}

static const struct of_device_id altera_msi_of_match[] = {
	{ .compatible = "altr,msi-1.0", NULL },
	{ },
};

static struct platform_driver altera_msi_driver = {
	.driver = {
		.name = "altera-msi",
		.of_match_table = altera_msi_of_match,
	},
	.probe = altera_msi_probe,
	.remove = altera_msi_remove,
};

static int __init altera_msi_init(void)
{
	return platform_driver_register(&altera_msi_driver);
}
subsys_initcall(altera_msi_init);

MODULE_AUTHOR("Ley Foon Tan <lftan@altera.com>");
MODULE_DESCRIPTION("Altera PCIe MSI support");
MODULE_LICENSE("GPL v2");