Loading...
Note: File does not exist in v3.5.6.
1// SPDX-License-Identifier: GPL-2.0-only OR MIT
2/*
3 * Apple SART device driver
4 * Copyright (C) The Asahi Linux Contributors
5 *
6 * Apple SART is a simple address filter for some DMA transactions.
7 * Regions of physical memory must be added to the SART's allow
8 * list before any DMA can target these. Unlike a proper
9 * IOMMU no remapping can be done and special support in the
10 * consumer driver is required since not all DMA transactions of
11 * a single device are subject to SART filtering.
12 */
13
14#include <linux/soc/apple/sart.h>
15#include <linux/atomic.h>
16#include <linux/bits.h>
17#include <linux/bitfield.h>
18#include <linux/device.h>
19#include <linux/io.h>
20#include <linux/module.h>
21#include <linux/of.h>
22#include <linux/of_platform.h>
23#include <linux/platform_device.h>
24#include <linux/types.h>
25
26#define APPLE_SART_MAX_ENTRIES 16
27
28/* This is probably a bitfield but the exact meaning of each bit is unknown. */
29#define APPLE_SART_FLAGS_ALLOW 0xff
30
31/* SARTv2 registers */
32#define APPLE_SART2_CONFIG(idx) (0x00 + 4 * (idx))
33#define APPLE_SART2_CONFIG_FLAGS GENMASK(31, 24)
34#define APPLE_SART2_CONFIG_SIZE GENMASK(23, 0)
35#define APPLE_SART2_CONFIG_SIZE_SHIFT 12
36#define APPLE_SART2_CONFIG_SIZE_MAX GENMASK(23, 0)
37
38#define APPLE_SART2_PADDR(idx) (0x40 + 4 * (idx))
39#define APPLE_SART2_PADDR_SHIFT 12
40
41/* SARTv3 registers */
42#define APPLE_SART3_CONFIG(idx) (0x00 + 4 * (idx))
43
44#define APPLE_SART3_PADDR(idx) (0x40 + 4 * (idx))
45#define APPLE_SART3_PADDR_SHIFT 12
46
47#define APPLE_SART3_SIZE(idx) (0x80 + 4 * (idx))
48#define APPLE_SART3_SIZE_SHIFT 12
49#define APPLE_SART3_SIZE_MAX GENMASK(29, 0)
50
51struct apple_sart_ops {
52 void (*get_entry)(struct apple_sart *sart, int index, u8 *flags,
53 phys_addr_t *paddr, size_t *size);
54 void (*set_entry)(struct apple_sart *sart, int index, u8 flags,
55 phys_addr_t paddr_shifted, size_t size_shifted);
56 unsigned int size_shift;
57 unsigned int paddr_shift;
58 size_t size_max;
59};
60
61struct apple_sart {
62 struct device *dev;
63 void __iomem *regs;
64
65 const struct apple_sart_ops *ops;
66
67 unsigned long protected_entries;
68 unsigned long used_entries;
69};
70
71static void sart2_get_entry(struct apple_sart *sart, int index, u8 *flags,
72 phys_addr_t *paddr, size_t *size)
73{
74 u32 cfg = readl(sart->regs + APPLE_SART2_CONFIG(index));
75 phys_addr_t paddr_ = readl(sart->regs + APPLE_SART2_PADDR(index));
76 size_t size_ = FIELD_GET(APPLE_SART2_CONFIG_SIZE, cfg);
77
78 *flags = FIELD_GET(APPLE_SART2_CONFIG_FLAGS, cfg);
79 *size = size_ << APPLE_SART2_CONFIG_SIZE_SHIFT;
80 *paddr = paddr_ << APPLE_SART2_PADDR_SHIFT;
81}
82
83static void sart2_set_entry(struct apple_sart *sart, int index, u8 flags,
84 phys_addr_t paddr_shifted, size_t size_shifted)
85{
86 u32 cfg;
87
88 cfg = FIELD_PREP(APPLE_SART2_CONFIG_FLAGS, flags);
89 cfg |= FIELD_PREP(APPLE_SART2_CONFIG_SIZE, size_shifted);
90
91 writel(paddr_shifted, sart->regs + APPLE_SART2_PADDR(index));
92 writel(cfg, sart->regs + APPLE_SART2_CONFIG(index));
93}
94
95static struct apple_sart_ops sart_ops_v2 = {
96 .get_entry = sart2_get_entry,
97 .set_entry = sart2_set_entry,
98 .size_shift = APPLE_SART2_CONFIG_SIZE_SHIFT,
99 .paddr_shift = APPLE_SART2_PADDR_SHIFT,
100 .size_max = APPLE_SART2_CONFIG_SIZE_MAX,
101};
102
103static void sart3_get_entry(struct apple_sart *sart, int index, u8 *flags,
104 phys_addr_t *paddr, size_t *size)
105{
106 phys_addr_t paddr_ = readl(sart->regs + APPLE_SART3_PADDR(index));
107 size_t size_ = readl(sart->regs + APPLE_SART3_SIZE(index));
108
109 *flags = readl(sart->regs + APPLE_SART3_CONFIG(index));
110 *size = size_ << APPLE_SART3_SIZE_SHIFT;
111 *paddr = paddr_ << APPLE_SART3_PADDR_SHIFT;
112}
113
114static void sart3_set_entry(struct apple_sart *sart, int index, u8 flags,
115 phys_addr_t paddr_shifted, size_t size_shifted)
116{
117 writel(paddr_shifted, sart->regs + APPLE_SART3_PADDR(index));
118 writel(size_shifted, sart->regs + APPLE_SART3_SIZE(index));
119 writel(flags, sart->regs + APPLE_SART3_CONFIG(index));
120}
121
122static struct apple_sart_ops sart_ops_v3 = {
123 .get_entry = sart3_get_entry,
124 .set_entry = sart3_set_entry,
125 .size_shift = APPLE_SART3_SIZE_SHIFT,
126 .paddr_shift = APPLE_SART3_PADDR_SHIFT,
127 .size_max = APPLE_SART3_SIZE_MAX,
128};
129
130static int apple_sart_probe(struct platform_device *pdev)
131{
132 int i;
133 struct apple_sart *sart;
134 struct device *dev = &pdev->dev;
135
136 sart = devm_kzalloc(dev, sizeof(*sart), GFP_KERNEL);
137 if (!sart)
138 return -ENOMEM;
139
140 sart->dev = dev;
141 sart->ops = of_device_get_match_data(dev);
142
143 sart->regs = devm_platform_ioremap_resource(pdev, 0);
144 if (IS_ERR(sart->regs))
145 return PTR_ERR(sart->regs);
146
147 for (i = 0; i < APPLE_SART_MAX_ENTRIES; ++i) {
148 u8 flags;
149 size_t size;
150 phys_addr_t paddr;
151
152 sart->ops->get_entry(sart, i, &flags, &paddr, &size);
153
154 if (!flags)
155 continue;
156
157 dev_dbg(sart->dev,
158 "SART bootloader entry: index %02d; flags: 0x%02x; paddr: %pa; size: 0x%zx\n",
159 i, flags, &paddr, size);
160 set_bit(i, &sart->protected_entries);
161 }
162
163 platform_set_drvdata(pdev, sart);
164 return 0;
165}
166
167static void apple_sart_put_device(void *dev)
168{
169 put_device(dev);
170}
171
172struct apple_sart *devm_apple_sart_get(struct device *dev)
173{
174 struct device_node *sart_node;
175 struct platform_device *sart_pdev;
176 struct apple_sart *sart;
177 int ret;
178
179 sart_node = of_parse_phandle(dev->of_node, "apple,sart", 0);
180 if (!sart_node)
181 return ERR_PTR(-ENODEV);
182
183 sart_pdev = of_find_device_by_node(sart_node);
184 of_node_put(sart_node);
185
186 if (!sart_pdev)
187 return ERR_PTR(-ENODEV);
188
189 sart = dev_get_drvdata(&sart_pdev->dev);
190 if (!sart) {
191 put_device(&sart_pdev->dev);
192 return ERR_PTR(-EPROBE_DEFER);
193 }
194
195 ret = devm_add_action_or_reset(dev, apple_sart_put_device,
196 &sart_pdev->dev);
197 if (ret)
198 return ERR_PTR(ret);
199
200 device_link_add(dev, &sart_pdev->dev,
201 DL_FLAG_PM_RUNTIME | DL_FLAG_AUTOREMOVE_SUPPLIER);
202
203 return sart;
204}
205EXPORT_SYMBOL_GPL(devm_apple_sart_get);
206
207static int sart_set_entry(struct apple_sart *sart, int index, u8 flags,
208 phys_addr_t paddr, size_t size)
209{
210 if (size & ((1 << sart->ops->size_shift) - 1))
211 return -EINVAL;
212 if (paddr & ((1 << sart->ops->paddr_shift) - 1))
213 return -EINVAL;
214
215 paddr >>= sart->ops->size_shift;
216 size >>= sart->ops->paddr_shift;
217
218 if (size > sart->ops->size_max)
219 return -EINVAL;
220
221 sart->ops->set_entry(sart, index, flags, paddr, size);
222 return 0;
223}
224
225int apple_sart_add_allowed_region(struct apple_sart *sart, phys_addr_t paddr,
226 size_t size)
227{
228 int i, ret;
229
230 for (i = 0; i < APPLE_SART_MAX_ENTRIES; ++i) {
231 if (test_bit(i, &sart->protected_entries))
232 continue;
233 if (test_and_set_bit(i, &sart->used_entries))
234 continue;
235
236 ret = sart_set_entry(sart, i, APPLE_SART_FLAGS_ALLOW, paddr,
237 size);
238 if (ret) {
239 dev_dbg(sart->dev,
240 "unable to set entry %d to [%pa, 0x%zx]\n",
241 i, &paddr, size);
242 clear_bit(i, &sart->used_entries);
243 return ret;
244 }
245
246 dev_dbg(sart->dev, "wrote [%pa, 0x%zx] to %d\n", &paddr, size,
247 i);
248 return 0;
249 }
250
251 dev_warn(sart->dev,
252 "no free entries left to add [paddr: 0x%pa, size: 0x%zx]\n",
253 &paddr, size);
254
255 return -EBUSY;
256}
257EXPORT_SYMBOL_GPL(apple_sart_add_allowed_region);
258
259int apple_sart_remove_allowed_region(struct apple_sart *sart, phys_addr_t paddr,
260 size_t size)
261{
262 int i;
263
264 dev_dbg(sart->dev,
265 "will remove [paddr: %pa, size: 0x%zx] from allowed regions\n",
266 &paddr, size);
267
268 for (i = 0; i < APPLE_SART_MAX_ENTRIES; ++i) {
269 u8 eflags;
270 size_t esize;
271 phys_addr_t epaddr;
272
273 if (test_bit(i, &sart->protected_entries))
274 continue;
275
276 sart->ops->get_entry(sart, i, &eflags, &epaddr, &esize);
277
278 if (epaddr != paddr || esize != size)
279 continue;
280
281 sart->ops->set_entry(sart, i, 0, 0, 0);
282
283 clear_bit(i, &sart->used_entries);
284 dev_dbg(sart->dev, "cleared entry %d\n", i);
285 return 0;
286 }
287
288 dev_warn(sart->dev, "entry [paddr: 0x%pa, size: 0x%zx] not found\n",
289 &paddr, size);
290
291 return -EINVAL;
292}
293EXPORT_SYMBOL_GPL(apple_sart_remove_allowed_region);
294
295static void apple_sart_shutdown(struct platform_device *pdev)
296{
297 struct apple_sart *sart = dev_get_drvdata(&pdev->dev);
298 int i;
299
300 for (i = 0; i < APPLE_SART_MAX_ENTRIES; ++i) {
301 if (test_bit(i, &sart->protected_entries))
302 continue;
303
304 sart->ops->set_entry(sart, i, 0, 0, 0);
305 }
306}
307
308static const struct of_device_id apple_sart_of_match[] = {
309 {
310 .compatible = "apple,t6000-sart",
311 .data = &sart_ops_v3,
312 },
313 {
314 .compatible = "apple,t8103-sart",
315 .data = &sart_ops_v2,
316 },
317 {}
318};
319MODULE_DEVICE_TABLE(of, apple_sart_of_match);
320
321static struct platform_driver apple_sart_driver = {
322 .driver = {
323 .name = "apple-sart",
324 .of_match_table = apple_sart_of_match,
325 },
326 .probe = apple_sart_probe,
327 .shutdown = apple_sart_shutdown,
328};
329module_platform_driver(apple_sart_driver);
330
331MODULE_LICENSE("Dual MIT/GPL");
332MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>");
333MODULE_DESCRIPTION("Apple SART driver");