summaryrefslogtreecommitdiff
path: root/drivers/soc/apple/sart.c
blob: 83804b16ad03db66bceb66e06b7bbc4cdb9b196a (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
315
316
317
318
319
320
321
322
323
324
325
326
327
328
// SPDX-License-Identifier: GPL-2.0-only OR MIT
/*
 * Apple SART device driver
 * Copyright (C) The Asahi Linux Contributors
 *
 * Apple SART is a simple address filter for some DMA transactions.
 * Regions of physical memory must be added to the SART's allow
 * list before any DMA can target these. Unlike a proper
 * IOMMU no remapping can be done and special support in the
 * consumer driver is required since not all DMA transactions of
 * a single device are subject to SART filtering.
 */

#include <linux/soc/apple/sart.h>
#include <linux/atomic.h>
#include <linux/bits.h>
#include <linux/bitfield.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/types.h>

#define APPLE_SART_MAX_ENTRIES 16

/* This is probably a bitfield but the exact meaning of each bit is unknown. */
#define APPLE_SART_FLAGS_ALLOW 0xff

/* SARTv2 registers */
#define APPLE_SART2_CONFIG(idx)	      (0x00 + 4 * (idx))
#define APPLE_SART2_CONFIG_FLAGS      GENMASK(31, 24)
#define APPLE_SART2_CONFIG_SIZE	      GENMASK(23, 0)
#define APPLE_SART2_CONFIG_SIZE_SHIFT 12
#define APPLE_SART2_CONFIG_SIZE_MAX   GENMASK(23, 0)

#define APPLE_SART2_PADDR(idx)	(0x40 + 4 * (idx))
#define APPLE_SART2_PADDR_SHIFT 12

/* SARTv3 registers */
#define APPLE_SART3_CONFIG(idx) (0x00 + 4 * (idx))

#define APPLE_SART3_PADDR(idx)	(0x40 + 4 * (idx))
#define APPLE_SART3_PADDR_SHIFT 12

#define APPLE_SART3_SIZE(idx)  (0x80 + 4 * (idx))
#define APPLE_SART3_SIZE_SHIFT 12
#define APPLE_SART3_SIZE_MAX   GENMASK(29, 0)

struct apple_sart_ops {
	void (*get_entry)(struct apple_sart *sart, int index, u8 *flags,
			  phys_addr_t *paddr, size_t *size);
	void (*set_entry)(struct apple_sart *sart, int index, u8 flags,
			  phys_addr_t paddr_shifted, size_t size_shifted);
	unsigned int size_shift;
	unsigned int paddr_shift;
	size_t size_max;
};

struct apple_sart {
	struct device *dev;
	void __iomem *regs;

	const struct apple_sart_ops *ops;

	unsigned long protected_entries;
	unsigned long used_entries;
};

static void sart2_get_entry(struct apple_sart *sart, int index, u8 *flags,
			    phys_addr_t *paddr, size_t *size)
{
	u32 cfg = readl(sart->regs + APPLE_SART2_CONFIG(index));
	phys_addr_t paddr_ = readl(sart->regs + APPLE_SART2_PADDR(index));
	size_t size_ = FIELD_GET(APPLE_SART2_CONFIG_SIZE, cfg);

	*flags = FIELD_GET(APPLE_SART2_CONFIG_FLAGS, cfg);
	*size = size_ << APPLE_SART2_CONFIG_SIZE_SHIFT;
	*paddr = paddr_ << APPLE_SART2_PADDR_SHIFT;
}

static void sart2_set_entry(struct apple_sart *sart, int index, u8 flags,
			    phys_addr_t paddr_shifted, size_t size_shifted)
{
	u32 cfg;

	cfg = FIELD_PREP(APPLE_SART2_CONFIG_FLAGS, flags);
	cfg |= FIELD_PREP(APPLE_SART2_CONFIG_SIZE, size_shifted);

	writel(paddr_shifted, sart->regs + APPLE_SART2_PADDR(index));
	writel(cfg, sart->regs + APPLE_SART2_CONFIG(index));
}

static struct apple_sart_ops sart_ops_v2 = {
	.get_entry = sart2_get_entry,
	.set_entry = sart2_set_entry,
	.size_shift = APPLE_SART2_CONFIG_SIZE_SHIFT,
	.paddr_shift = APPLE_SART2_PADDR_SHIFT,
	.size_max = APPLE_SART2_CONFIG_SIZE_MAX,
};

static void sart3_get_entry(struct apple_sart *sart, int index, u8 *flags,
			    phys_addr_t *paddr, size_t *size)
{
	phys_addr_t paddr_ = readl(sart->regs + APPLE_SART3_PADDR(index));
	size_t size_ = readl(sart->regs + APPLE_SART3_SIZE(index));

	*flags = readl(sart->regs + APPLE_SART3_CONFIG(index));
	*size = size_ << APPLE_SART3_SIZE_SHIFT;
	*paddr = paddr_ << APPLE_SART3_PADDR_SHIFT;
}

static void sart3_set_entry(struct apple_sart *sart, int index, u8 flags,
			    phys_addr_t paddr_shifted, size_t size_shifted)
{
	writel(paddr_shifted, sart->regs + APPLE_SART3_PADDR(index));
	writel(size_shifted, sart->regs + APPLE_SART3_SIZE(index));
	writel(flags, sart->regs + APPLE_SART3_CONFIG(index));
}

static struct apple_sart_ops sart_ops_v3 = {
	.get_entry = sart3_get_entry,
	.set_entry = sart3_set_entry,
	.size_shift = APPLE_SART3_SIZE_SHIFT,
	.paddr_shift = APPLE_SART3_PADDR_SHIFT,
	.size_max = APPLE_SART3_SIZE_MAX,
};

static int apple_sart_probe(struct platform_device *pdev)
{
	int i;
	struct apple_sart *sart;
	struct device *dev = &pdev->dev;

	sart = devm_kzalloc(dev, sizeof(*sart), GFP_KERNEL);
	if (!sart)
		return -ENOMEM;

	sart->dev = dev;
	sart->ops = of_device_get_match_data(dev);

	sart->regs = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(sart->regs))
		return PTR_ERR(sart->regs);

	for (i = 0; i < APPLE_SART_MAX_ENTRIES; ++i) {
		u8 flags;
		size_t size;
		phys_addr_t paddr;

		sart->ops->get_entry(sart, i, &flags, &paddr, &size);

		if (!flags)
			continue;

		dev_dbg(sart->dev,
			"SART bootloader entry: index %02d; flags: 0x%02x; paddr: %pa; size: 0x%zx\n",
			i, flags, &paddr, size);
		set_bit(i, &sart->protected_entries);
	}

	platform_set_drvdata(pdev, sart);
	return 0;
}

struct apple_sart *devm_apple_sart_get(struct device *dev)
{
	struct device_node *sart_node;
	struct platform_device *sart_pdev;
	struct apple_sart *sart;
	int ret;

	sart_node = of_parse_phandle(dev->of_node, "apple,sart", 0);
	if (!sart_node)
		return ERR_PTR(-ENODEV);

	sart_pdev = of_find_device_by_node(sart_node);
	of_node_put(sart_node);

	if (!sart_pdev)
		return ERR_PTR(-ENODEV);

	sart = dev_get_drvdata(&sart_pdev->dev);
	if (!sart) {
		put_device(&sart_pdev->dev);
		return ERR_PTR(-EPROBE_DEFER);
	}

	ret = devm_add_action_or_reset(dev, (void (*)(void *))put_device,
				       &sart_pdev->dev);
	if (ret)
		return ERR_PTR(ret);

	device_link_add(dev, &sart_pdev->dev,
			DL_FLAG_PM_RUNTIME | DL_FLAG_AUTOREMOVE_SUPPLIER);

	return sart;
}
EXPORT_SYMBOL_GPL(devm_apple_sart_get);

static int sart_set_entry(struct apple_sart *sart, int index, u8 flags,
			  phys_addr_t paddr, size_t size)
{
	if (size & ((1 << sart->ops->size_shift) - 1))
		return -EINVAL;
	if (paddr & ((1 << sart->ops->paddr_shift) - 1))
		return -EINVAL;

	paddr >>= sart->ops->size_shift;
	size >>= sart->ops->paddr_shift;

	if (size > sart->ops->size_max)
		return -EINVAL;

	sart->ops->set_entry(sart, index, flags, paddr, size);
	return 0;
}

int apple_sart_add_allowed_region(struct apple_sart *sart, phys_addr_t paddr,
				  size_t size)
{
	int i, ret;

	for (i = 0; i < APPLE_SART_MAX_ENTRIES; ++i) {
		if (test_bit(i, &sart->protected_entries))
			continue;
		if (test_and_set_bit(i, &sart->used_entries))
			continue;

		ret = sart_set_entry(sart, i, APPLE_SART_FLAGS_ALLOW, paddr,
				     size);
		if (ret) {
			dev_dbg(sart->dev,
				"unable to set entry %d to [%pa, 0x%zx]\n",
				i, &paddr, size);
			clear_bit(i, &sart->used_entries);
			return ret;
		}

		dev_dbg(sart->dev, "wrote [%pa, 0x%zx] to %d\n", &paddr, size,
			i);
		return 0;
	}

	dev_warn(sart->dev,
		 "no free entries left to add [paddr: 0x%pa, size: 0x%zx]\n",
		 &paddr, size);

	return -EBUSY;
}
EXPORT_SYMBOL_GPL(apple_sart_add_allowed_region);

int apple_sart_remove_allowed_region(struct apple_sart *sart, phys_addr_t paddr,
				     size_t size)
{
	int i;

	dev_dbg(sart->dev,
		"will remove [paddr: %pa, size: 0x%zx] from allowed regions\n",
		&paddr, size);

	for (i = 0; i < APPLE_SART_MAX_ENTRIES; ++i) {
		u8 eflags;
		size_t esize;
		phys_addr_t epaddr;

		if (test_bit(i, &sart->protected_entries))
			continue;

		sart->ops->get_entry(sart, i, &eflags, &epaddr, &esize);

		if (epaddr != paddr || esize != size)
			continue;

		sart->ops->set_entry(sart, i, 0, 0, 0);

		clear_bit(i, &sart->used_entries);
		dev_dbg(sart->dev, "cleared entry %d\n", i);
		return 0;
	}

	dev_warn(sart->dev, "entry [paddr: 0x%pa, size: 0x%zx] not found\n",
		 &paddr, size);

	return -EINVAL;
}
EXPORT_SYMBOL_GPL(apple_sart_remove_allowed_region);

static void apple_sart_shutdown(struct platform_device *pdev)
{
	struct apple_sart *sart = dev_get_drvdata(&pdev->dev);
	int i;

	for (i = 0; i < APPLE_SART_MAX_ENTRIES; ++i) {
		if (test_bit(i, &sart->protected_entries))
			continue;

		sart->ops->set_entry(sart, i, 0, 0, 0);
	}
}

static const struct of_device_id apple_sart_of_match[] = {
	{
		.compatible = "apple,t6000-sart",
		.data = &sart_ops_v3,
	},
	{
		.compatible = "apple,t8103-sart",
		.data = &sart_ops_v2,
	},
	{}
};
MODULE_DEVICE_TABLE(of, apple_sart_of_match);

static struct platform_driver apple_sart_driver = {
	.driver = {
		.name = "apple-sart",
		.of_match_table = apple_sart_of_match,
	},
	.probe = apple_sart_probe,
	.shutdown = apple_sart_shutdown,
};
module_platform_driver(apple_sart_driver);

MODULE_LICENSE("Dual MIT/GPL");
MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>");
MODULE_DESCRIPTION("Apple SART driver");