1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
2 /*
3 * AMD MP2 platform driver
4 *
5 * Setup the I2C adapters enumerated in the ACPI namespace.
6 * MP2 controllers have 2 separate busses, up to 2 I2C adapters may be listed.
7 *
8 * Authors: Nehal Bakulchandra Shah <Nehal-bakulchandra.shah@amd.com>
9 * Elie Morisse <syniurge@gmail.com>
10 */
11
12 #include <linux/acpi.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/platform_device.h>
16 #include <linux/slab.h>
17 #include <linux/types.h>
18
19 #include "i2c-amd-mp2.h"
20
21 #define AMD_MP2_I2C_MAX_RW_LENGTH ((1 << 12) - 1)
22 #define AMD_I2C_TIMEOUT (msecs_to_jiffies(250))
23
24 /**
25 * struct amd_i2c_dev - MP2 bus/i2c adapter context
26 * @common: shared context with the MP2 PCI driver
27 * @pdev: platform driver node
28 * @adap: i2c adapter
29 * @cmd_complete: xfer completion object
30 */
31 struct amd_i2c_dev {
32 struct amd_i2c_common common;
33 struct platform_device *pdev;
34 struct i2c_adapter adap;
35 struct completion cmd_complete;
36 };
37
38 #define amd_i2c_dev_common(__common) \
39 container_of(__common, struct amd_i2c_dev, common)
40
i2c_amd_dma_map(struct amd_i2c_common * i2c_common)41 static int i2c_amd_dma_map(struct amd_i2c_common *i2c_common)
42 {
43 struct device *dev_pci = &i2c_common->mp2_dev->pci_dev->dev;
44 struct amd_i2c_dev *i2c_dev = amd_i2c_dev_common(i2c_common);
45 enum dma_data_direction dma_direction =
46 i2c_common->msg->flags & I2C_M_RD ?
47 DMA_FROM_DEVICE : DMA_TO_DEVICE;
48
49 i2c_common->dma_buf = i2c_get_dma_safe_msg_buf(i2c_common->msg, 0);
50 i2c_common->dma_addr = dma_map_single(dev_pci, i2c_common->dma_buf,
51 i2c_common->msg->len,
52 dma_direction);
53
54 if (unlikely(dma_mapping_error(dev_pci, i2c_common->dma_addr))) {
55 dev_err(&i2c_dev->pdev->dev,
56 "Error while mapping dma buffer %p\n",
57 i2c_common->dma_buf);
58 return -EIO;
59 }
60
61 return 0;
62 }
63
i2c_amd_dma_unmap(struct amd_i2c_common * i2c_common)64 static void i2c_amd_dma_unmap(struct amd_i2c_common *i2c_common)
65 {
66 struct device *dev_pci = &i2c_common->mp2_dev->pci_dev->dev;
67 enum dma_data_direction dma_direction =
68 i2c_common->msg->flags & I2C_M_RD ?
69 DMA_FROM_DEVICE : DMA_TO_DEVICE;
70
71 dma_unmap_single(dev_pci, i2c_common->dma_addr,
72 i2c_common->msg->len, dma_direction);
73
74 i2c_put_dma_safe_msg_buf(i2c_common->dma_buf, i2c_common->msg, true);
75 }
76
i2c_amd_start_cmd(struct amd_i2c_dev * i2c_dev)77 static void i2c_amd_start_cmd(struct amd_i2c_dev *i2c_dev)
78 {
79 struct amd_i2c_common *i2c_common = &i2c_dev->common;
80
81 reinit_completion(&i2c_dev->cmd_complete);
82 i2c_common->cmd_success = false;
83 }
84
i2c_amd_cmd_completion(struct amd_i2c_common * i2c_common)85 static void i2c_amd_cmd_completion(struct amd_i2c_common *i2c_common)
86 {
87 struct amd_i2c_dev *i2c_dev = amd_i2c_dev_common(i2c_common);
88 union i2c_event *event = &i2c_common->eventval;
89
90 if (event->r.status == i2c_readcomplete_event)
91 dev_dbg(&i2c_dev->pdev->dev, "readdata:%*ph\n", event->r.length,
92 i2c_common->msg->buf);
93
94 complete(&i2c_dev->cmd_complete);
95 }
96
i2c_amd_check_cmd_completion(struct amd_i2c_dev * i2c_dev)97 static int i2c_amd_check_cmd_completion(struct amd_i2c_dev *i2c_dev)
98 {
99 struct amd_i2c_common *i2c_common = &i2c_dev->common;
100 unsigned long time_left;
101
102 time_left = wait_for_completion_timeout(&i2c_dev->cmd_complete,
103 i2c_dev->adap.timeout);
104
105 if ((i2c_common->reqcmd == i2c_read ||
106 i2c_common->reqcmd == i2c_write) &&
107 i2c_common->msg->len > 32)
108 i2c_amd_dma_unmap(i2c_common);
109
110 if (time_left == 0) {
111 amd_mp2_rw_timeout(i2c_common);
112 return -ETIMEDOUT;
113 }
114
115 amd_mp2_process_event(i2c_common);
116
117 if (!i2c_common->cmd_success)
118 return -EIO;
119
120 return 0;
121 }
122
i2c_amd_enable_set(struct amd_i2c_dev * i2c_dev,bool enable)123 static int i2c_amd_enable_set(struct amd_i2c_dev *i2c_dev, bool enable)
124 {
125 struct amd_i2c_common *i2c_common = &i2c_dev->common;
126
127 i2c_amd_start_cmd(i2c_dev);
128 amd_mp2_bus_enable_set(i2c_common, enable);
129
130 return i2c_amd_check_cmd_completion(i2c_dev);
131 }
132
i2c_amd_xfer_msg(struct amd_i2c_dev * i2c_dev,struct i2c_msg * pmsg)133 static int i2c_amd_xfer_msg(struct amd_i2c_dev *i2c_dev, struct i2c_msg *pmsg)
134 {
135 struct amd_i2c_common *i2c_common = &i2c_dev->common;
136
137 i2c_amd_start_cmd(i2c_dev);
138 i2c_common->msg = pmsg;
139
140 if (pmsg->len > 32)
141 if (i2c_amd_dma_map(i2c_common))
142 return -EIO;
143
144 if (pmsg->flags & I2C_M_RD)
145 amd_mp2_rw(i2c_common, i2c_read);
146 else
147 amd_mp2_rw(i2c_common, i2c_write);
148
149 return i2c_amd_check_cmd_completion(i2c_dev);
150 }
151
i2c_amd_xfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)152 static int i2c_amd_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
153 {
154 struct amd_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
155 int i;
156 struct i2c_msg *pmsg;
157 int err = 0;
158
159 /* the adapter might have been deleted while waiting for the bus lock */
160 if (unlikely(!i2c_dev->common.mp2_dev))
161 return -EINVAL;
162
163 amd_mp2_pm_runtime_get(i2c_dev->common.mp2_dev);
164
165 for (i = 0; i < num; i++) {
166 pmsg = &msgs[i];
167 err = i2c_amd_xfer_msg(i2c_dev, pmsg);
168 if (err)
169 break;
170 }
171
172 amd_mp2_pm_runtime_put(i2c_dev->common.mp2_dev);
173 return err ? err : num;
174 }
175
i2c_amd_func(struct i2c_adapter * a)176 static u32 i2c_amd_func(struct i2c_adapter *a)
177 {
178 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
179 }
180
181 static const struct i2c_algorithm i2c_amd_algorithm = {
182 .master_xfer = i2c_amd_xfer,
183 .functionality = i2c_amd_func,
184 };
185
186 #ifdef CONFIG_PM
i2c_amd_suspend(struct amd_i2c_common * i2c_common)187 static int i2c_amd_suspend(struct amd_i2c_common *i2c_common)
188 {
189 struct amd_i2c_dev *i2c_dev = amd_i2c_dev_common(i2c_common);
190
191 i2c_amd_enable_set(i2c_dev, false);
192 return 0;
193 }
194
i2c_amd_resume(struct amd_i2c_common * i2c_common)195 static int i2c_amd_resume(struct amd_i2c_common *i2c_common)
196 {
197 struct amd_i2c_dev *i2c_dev = amd_i2c_dev_common(i2c_common);
198
199 return i2c_amd_enable_set(i2c_dev, true);
200 }
201 #endif
202
203 static const u32 supported_speeds[] = {
204 I2C_MAX_HIGH_SPEED_MODE_FREQ,
205 I2C_MAX_TURBO_MODE_FREQ,
206 I2C_MAX_FAST_MODE_PLUS_FREQ,
207 I2C_MAX_FAST_MODE_FREQ,
208 I2C_MAX_STANDARD_MODE_FREQ,
209 };
210
i2c_amd_get_bus_speed(struct platform_device * pdev)211 static enum speed_enum i2c_amd_get_bus_speed(struct platform_device *pdev)
212 {
213 u32 acpi_speed;
214 int i;
215
216 acpi_speed = i2c_acpi_find_bus_speed(&pdev->dev);
217 /* round down to the lowest standard speed */
218 for (i = 0; i < ARRAY_SIZE(supported_speeds); i++) {
219 if (acpi_speed >= supported_speeds[i])
220 break;
221 }
222 acpi_speed = i < ARRAY_SIZE(supported_speeds) ? supported_speeds[i] : 0;
223
224 switch (acpi_speed) {
225 case I2C_MAX_STANDARD_MODE_FREQ:
226 return speed100k;
227 case I2C_MAX_FAST_MODE_FREQ:
228 return speed400k;
229 case I2C_MAX_FAST_MODE_PLUS_FREQ:
230 return speed1000k;
231 case I2C_MAX_TURBO_MODE_FREQ:
232 return speed1400k;
233 case I2C_MAX_HIGH_SPEED_MODE_FREQ:
234 return speed3400k;
235 default:
236 return speed400k;
237 }
238 }
239
240 static const struct i2c_adapter_quirks amd_i2c_dev_quirks = {
241 .max_read_len = AMD_MP2_I2C_MAX_RW_LENGTH,
242 .max_write_len = AMD_MP2_I2C_MAX_RW_LENGTH,
243 };
244
i2c_amd_probe(struct platform_device * pdev)245 static int i2c_amd_probe(struct platform_device *pdev)
246 {
247 struct device *dev = &pdev->dev;
248 int ret;
249 struct amd_i2c_dev *i2c_dev;
250 struct amd_mp2_dev *mp2_dev;
251 u64 uid;
252
253 ret = acpi_dev_uid_to_integer(ACPI_COMPANION(dev), &uid);
254 if (ret)
255 return dev_err_probe(dev, ret, "missing UID/bus id!\n");
256 if (uid >= 2)
257 return dev_err_probe(dev, -EINVAL, "incorrect UID/bus id \"%llu\"!\n", uid);
258 dev_dbg(dev, "bus id is %llu\n", uid);
259
260 /* The ACPI namespace doesn't contain information about which MP2 PCI
261 * device an AMDI0011 ACPI device is related to, so assume that there's
262 * only one MP2 PCI device per system.
263 */
264 mp2_dev = amd_mp2_find_device();
265 if (!mp2_dev || !mp2_dev->probed)
266 /* The MP2 PCI device should get probed later */
267 return -EPROBE_DEFER;
268
269 i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL);
270 if (!i2c_dev)
271 return -ENOMEM;
272
273 i2c_dev->common.bus_id = uid;
274 i2c_dev->common.mp2_dev = mp2_dev;
275 i2c_dev->pdev = pdev;
276 platform_set_drvdata(pdev, i2c_dev);
277
278 i2c_dev->common.cmd_completion = &i2c_amd_cmd_completion;
279 #ifdef CONFIG_PM
280 i2c_dev->common.suspend = &i2c_amd_suspend;
281 i2c_dev->common.resume = &i2c_amd_resume;
282 #endif
283
284 /* Register the adapter */
285 amd_mp2_pm_runtime_get(mp2_dev);
286
287 i2c_dev->common.reqcmd = i2c_none;
288 if (amd_mp2_register_cb(&i2c_dev->common))
289 return -EINVAL;
290 device_link_add(&i2c_dev->pdev->dev, &mp2_dev->pci_dev->dev,
291 DL_FLAG_AUTOREMOVE_CONSUMER);
292
293 i2c_dev->common.i2c_speed = i2c_amd_get_bus_speed(pdev);
294
295 /* Setup i2c adapter description */
296 i2c_dev->adap.owner = THIS_MODULE;
297 i2c_dev->adap.algo = &i2c_amd_algorithm;
298 i2c_dev->adap.quirks = &amd_i2c_dev_quirks;
299 i2c_dev->adap.dev.parent = &pdev->dev;
300 i2c_dev->adap.algo_data = i2c_dev;
301 i2c_dev->adap.timeout = AMD_I2C_TIMEOUT;
302 ACPI_COMPANION_SET(&i2c_dev->adap.dev, ACPI_COMPANION(&pdev->dev));
303 i2c_dev->adap.dev.of_node = pdev->dev.of_node;
304 snprintf(i2c_dev->adap.name, sizeof(i2c_dev->adap.name),
305 "AMD MP2 i2c bus %u", i2c_dev->common.bus_id);
306 i2c_set_adapdata(&i2c_dev->adap, i2c_dev);
307
308 init_completion(&i2c_dev->cmd_complete);
309
310 /* Enable the bus */
311 if (i2c_amd_enable_set(i2c_dev, true))
312 dev_err(&pdev->dev, "initial bus enable failed\n");
313
314 /* Attach to the i2c layer */
315 ret = i2c_add_adapter(&i2c_dev->adap);
316
317 amd_mp2_pm_runtime_put(mp2_dev);
318
319 if (ret < 0)
320 dev_err(&pdev->dev, "i2c add adapter failed = %d\n", ret);
321
322 return ret;
323 }
324
i2c_amd_remove(struct platform_device * pdev)325 static void i2c_amd_remove(struct platform_device *pdev)
326 {
327 struct amd_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
328 struct amd_i2c_common *i2c_common = &i2c_dev->common;
329
330 i2c_lock_bus(&i2c_dev->adap, I2C_LOCK_ROOT_ADAPTER);
331
332 i2c_amd_enable_set(i2c_dev, false);
333 amd_mp2_unregister_cb(i2c_common);
334 i2c_common->mp2_dev = NULL;
335
336 i2c_unlock_bus(&i2c_dev->adap, I2C_LOCK_ROOT_ADAPTER);
337
338 i2c_del_adapter(&i2c_dev->adap);
339 }
340
341 static const struct acpi_device_id i2c_amd_acpi_match[] = {
342 { "AMDI0011" },
343 { }
344 };
345 MODULE_DEVICE_TABLE(acpi, i2c_amd_acpi_match);
346
347 static struct platform_driver i2c_amd_plat_driver = {
348 .probe = i2c_amd_probe,
349 .remove_new = i2c_amd_remove,
350 .driver = {
351 .name = "i2c_amd_mp2",
352 .acpi_match_table = ACPI_PTR(i2c_amd_acpi_match),
353 },
354 };
355 module_platform_driver(i2c_amd_plat_driver);
356
357 MODULE_DESCRIPTION("AMD(R) MP2 I2C Platform Driver");
358 MODULE_AUTHOR("Nehal Shah <nehal-bakulchandra.shah@amd.com>");
359 MODULE_AUTHOR("Elie Morisse <syniurge@gmail.com>");
360 MODULE_LICENSE("Dual BSD/GPL");
361