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c71bcdcb AG |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Nvidia GPU I2C controller Driver | |
4 | * | |
5 | * Copyright (C) 2018 NVIDIA Corporation. All rights reserved. | |
6 | * Author: Ajay Gupta <ajayg@nvidia.com> | |
7 | */ | |
8 | #include <linux/delay.h> | |
9 | #include <linux/i2c.h> | |
10 | #include <linux/interrupt.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/pci.h> | |
13 | #include <linux/platform_device.h> | |
14 | #include <linux/pm.h> | |
15 | #include <linux/pm_runtime.h> | |
16 | ||
17 | #include <asm/unaligned.h> | |
18 | ||
19 | /* I2C definitions */ | |
20 | #define I2C_MST_CNTL 0x00 | |
21 | #define I2C_MST_CNTL_GEN_START BIT(0) | |
22 | #define I2C_MST_CNTL_GEN_STOP BIT(1) | |
23 | #define I2C_MST_CNTL_CMD_READ (1 << 2) | |
24 | #define I2C_MST_CNTL_CMD_WRITE (2 << 2) | |
25 | #define I2C_MST_CNTL_BURST_SIZE_SHIFT 6 | |
26 | #define I2C_MST_CNTL_GEN_NACK BIT(28) | |
27 | #define I2C_MST_CNTL_STATUS GENMASK(30, 29) | |
28 | #define I2C_MST_CNTL_STATUS_OKAY (0 << 29) | |
29 | #define I2C_MST_CNTL_STATUS_NO_ACK (1 << 29) | |
30 | #define I2C_MST_CNTL_STATUS_TIMEOUT (2 << 29) | |
31 | #define I2C_MST_CNTL_STATUS_BUS_BUSY (3 << 29) | |
32 | #define I2C_MST_CNTL_CYCLE_TRIGGER BIT(31) | |
33 | ||
34 | #define I2C_MST_ADDR 0x04 | |
35 | ||
36 | #define I2C_MST_I2C0_TIMING 0x08 | |
37 | #define I2C_MST_I2C0_TIMING_SCL_PERIOD_100KHZ 0x10e | |
38 | #define I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT 16 | |
39 | #define I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT_MAX 255 | |
40 | #define I2C_MST_I2C0_TIMING_TIMEOUT_CHECK BIT(24) | |
41 | ||
42 | #define I2C_MST_DATA 0x0c | |
43 | ||
44 | #define I2C_MST_HYBRID_PADCTL 0x20 | |
45 | #define I2C_MST_HYBRID_PADCTL_MODE_I2C BIT(0) | |
46 | #define I2C_MST_HYBRID_PADCTL_I2C_SCL_INPUT_RCV BIT(14) | |
47 | #define I2C_MST_HYBRID_PADCTL_I2C_SDA_INPUT_RCV BIT(15) | |
48 | ||
49 | struct gpu_i2c_dev { | |
50 | struct device *dev; | |
51 | void __iomem *regs; | |
52 | struct i2c_adapter adapter; | |
53 | struct i2c_board_info *gpu_ccgx_ucsi; | |
54 | }; | |
55 | ||
56 | static void gpu_enable_i2c_bus(struct gpu_i2c_dev *i2cd) | |
57 | { | |
58 | u32 val; | |
59 | ||
60 | /* enable I2C */ | |
61 | val = readl(i2cd->regs + I2C_MST_HYBRID_PADCTL); | |
62 | val |= I2C_MST_HYBRID_PADCTL_MODE_I2C | | |
63 | I2C_MST_HYBRID_PADCTL_I2C_SCL_INPUT_RCV | | |
64 | I2C_MST_HYBRID_PADCTL_I2C_SDA_INPUT_RCV; | |
65 | writel(val, i2cd->regs + I2C_MST_HYBRID_PADCTL); | |
66 | ||
67 | /* enable 100KHZ mode */ | |
68 | val = I2C_MST_I2C0_TIMING_SCL_PERIOD_100KHZ; | |
69 | val |= (I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT_MAX | |
70 | << I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT); | |
71 | val |= I2C_MST_I2C0_TIMING_TIMEOUT_CHECK; | |
72 | writel(val, i2cd->regs + I2C_MST_I2C0_TIMING); | |
73 | } | |
74 | ||
75 | static int gpu_i2c_check_status(struct gpu_i2c_dev *i2cd) | |
76 | { | |
77 | unsigned long target = jiffies + msecs_to_jiffies(1000); | |
78 | u32 val; | |
79 | ||
80 | do { | |
81 | val = readl(i2cd->regs + I2C_MST_CNTL); | |
82 | if (!(val & I2C_MST_CNTL_CYCLE_TRIGGER)) | |
83 | break; | |
84 | if ((val & I2C_MST_CNTL_STATUS) != | |
85 | I2C_MST_CNTL_STATUS_BUS_BUSY) | |
86 | break; | |
87 | usleep_range(500, 600); | |
88 | } while (time_is_after_jiffies(target)); | |
89 | ||
90 | if (time_is_before_jiffies(target)) { | |
91 | dev_err(i2cd->dev, "i2c timeout error %x\n", val); | |
92 | return -ETIME; | |
93 | } | |
94 | ||
95 | val = readl(i2cd->regs + I2C_MST_CNTL); | |
96 | switch (val & I2C_MST_CNTL_STATUS) { | |
97 | case I2C_MST_CNTL_STATUS_OKAY: | |
98 | return 0; | |
99 | case I2C_MST_CNTL_STATUS_NO_ACK: | |
100 | return -EIO; | |
101 | case I2C_MST_CNTL_STATUS_TIMEOUT: | |
102 | return -ETIME; | |
103 | default: | |
104 | return 0; | |
105 | } | |
106 | } | |
107 | ||
108 | static int gpu_i2c_read(struct gpu_i2c_dev *i2cd, u8 *data, u16 len) | |
109 | { | |
110 | int status; | |
111 | u32 val; | |
112 | ||
113 | val = I2C_MST_CNTL_GEN_START | I2C_MST_CNTL_CMD_READ | | |
114 | (len << I2C_MST_CNTL_BURST_SIZE_SHIFT) | | |
115 | I2C_MST_CNTL_CYCLE_TRIGGER | I2C_MST_CNTL_GEN_NACK; | |
116 | writel(val, i2cd->regs + I2C_MST_CNTL); | |
117 | ||
118 | status = gpu_i2c_check_status(i2cd); | |
119 | if (status < 0) | |
120 | return status; | |
121 | ||
122 | val = readl(i2cd->regs + I2C_MST_DATA); | |
123 | switch (len) { | |
124 | case 1: | |
125 | data[0] = val; | |
126 | break; | |
127 | case 2: | |
128 | put_unaligned_be16(val, data); | |
129 | break; | |
130 | case 3: | |
131 | put_unaligned_be16(val >> 8, data); | |
132 | data[2] = val; | |
133 | break; | |
134 | case 4: | |
135 | put_unaligned_be32(val, data); | |
136 | break; | |
137 | default: | |
138 | break; | |
139 | } | |
140 | return status; | |
141 | } | |
142 | ||
143 | static int gpu_i2c_start(struct gpu_i2c_dev *i2cd) | |
144 | { | |
145 | writel(I2C_MST_CNTL_GEN_START, i2cd->regs + I2C_MST_CNTL); | |
146 | return gpu_i2c_check_status(i2cd); | |
147 | } | |
148 | ||
149 | static int gpu_i2c_stop(struct gpu_i2c_dev *i2cd) | |
150 | { | |
151 | writel(I2C_MST_CNTL_GEN_STOP, i2cd->regs + I2C_MST_CNTL); | |
152 | return gpu_i2c_check_status(i2cd); | |
153 | } | |
154 | ||
155 | static int gpu_i2c_write(struct gpu_i2c_dev *i2cd, u8 data) | |
156 | { | |
157 | u32 val; | |
158 | ||
159 | writel(data, i2cd->regs + I2C_MST_DATA); | |
160 | ||
161 | val = I2C_MST_CNTL_CMD_WRITE | (1 << I2C_MST_CNTL_BURST_SIZE_SHIFT); | |
162 | writel(val, i2cd->regs + I2C_MST_CNTL); | |
163 | ||
164 | return gpu_i2c_check_status(i2cd); | |
165 | } | |
166 | ||
167 | static int gpu_i2c_master_xfer(struct i2c_adapter *adap, | |
168 | struct i2c_msg *msgs, int num) | |
169 | { | |
170 | struct gpu_i2c_dev *i2cd = i2c_get_adapdata(adap); | |
171 | int status, status2; | |
172 | int i, j; | |
173 | ||
174 | /* | |
175 | * The controller supports maximum 4 byte read due to known | |
176 | * limitation of sending STOP after every read. | |
177 | */ | |
178 | for (i = 0; i < num; i++) { | |
179 | if (msgs[i].flags & I2C_M_RD) { | |
180 | /* program client address before starting read */ | |
181 | writel(msgs[i].addr, i2cd->regs + I2C_MST_ADDR); | |
182 | /* gpu_i2c_read has implicit start */ | |
183 | status = gpu_i2c_read(i2cd, msgs[i].buf, msgs[i].len); | |
184 | if (status < 0) | |
185 | goto stop; | |
186 | } else { | |
187 | u8 addr = i2c_8bit_addr_from_msg(msgs + i); | |
188 | ||
189 | status = gpu_i2c_start(i2cd); | |
190 | if (status < 0) { | |
191 | if (i == 0) | |
192 | return status; | |
193 | goto stop; | |
194 | } | |
195 | ||
196 | status = gpu_i2c_write(i2cd, addr); | |
197 | if (status < 0) | |
198 | goto stop; | |
199 | ||
200 | for (j = 0; j < msgs[i].len; j++) { | |
201 | status = gpu_i2c_write(i2cd, msgs[i].buf[j]); | |
202 | if (status < 0) | |
203 | goto stop; | |
204 | } | |
205 | } | |
206 | } | |
207 | status = gpu_i2c_stop(i2cd); | |
208 | if (status < 0) | |
209 | return status; | |
210 | ||
211 | return i; | |
212 | stop: | |
213 | status2 = gpu_i2c_stop(i2cd); | |
214 | if (status2 < 0) | |
215 | dev_err(i2cd->dev, "i2c stop failed %d\n", status2); | |
216 | return status; | |
217 | } | |
218 | ||
219 | static const struct i2c_adapter_quirks gpu_i2c_quirks = { | |
220 | .max_read_len = 4, | |
221 | .flags = I2C_AQ_COMB_WRITE_THEN_READ, | |
222 | }; | |
223 | ||
224 | static u32 gpu_i2c_functionality(struct i2c_adapter *adap) | |
225 | { | |
226 | return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; | |
227 | } | |
228 | ||
229 | static const struct i2c_algorithm gpu_i2c_algorithm = { | |
230 | .master_xfer = gpu_i2c_master_xfer, | |
231 | .functionality = gpu_i2c_functionality, | |
232 | }; | |
233 | ||
234 | /* | |
235 | * This driver is for Nvidia GPU cards with USB Type-C interface. | |
236 | * We want to identify the cards using vendor ID and class code only | |
237 | * to avoid dependency of adding product id for any new card which | |
238 | * requires this driver. | |
239 | * Currently there is no class code defined for UCSI device over PCI | |
240 | * so using UNKNOWN class for now and it will be updated when UCSI | |
241 | * over PCI gets a class code. | |
242 | * There is no other NVIDIA cards with UNKNOWN class code. Even if the | |
243 | * driver gets loaded for an undesired card then eventually i2c_read() | |
244 | * (initiated from UCSI i2c_client) will timeout or UCSI commands will | |
245 | * timeout. | |
246 | */ | |
247 | #define PCI_CLASS_SERIAL_UNKNOWN 0x0c80 | |
248 | static const struct pci_device_id gpu_i2c_ids[] = { | |
249 | { PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, | |
250 | PCI_CLASS_SERIAL_UNKNOWN << 8, 0xffffff00}, | |
251 | { } | |
252 | }; | |
253 | MODULE_DEVICE_TABLE(pci, gpu_i2c_ids); | |
254 | ||
255 | static int gpu_populate_client(struct gpu_i2c_dev *i2cd, int irq) | |
256 | { | |
257 | struct i2c_client *ccgx_client; | |
258 | ||
259 | i2cd->gpu_ccgx_ucsi = devm_kzalloc(i2cd->dev, | |
260 | sizeof(*i2cd->gpu_ccgx_ucsi), | |
261 | GFP_KERNEL); | |
262 | if (!i2cd->gpu_ccgx_ucsi) | |
263 | return -ENOMEM; | |
264 | ||
265 | strlcpy(i2cd->gpu_ccgx_ucsi->type, "ccgx-ucsi", | |
266 | sizeof(i2cd->gpu_ccgx_ucsi->type)); | |
267 | i2cd->gpu_ccgx_ucsi->addr = 0x8; | |
268 | i2cd->gpu_ccgx_ucsi->irq = irq; | |
269 | ccgx_client = i2c_new_device(&i2cd->adapter, i2cd->gpu_ccgx_ucsi); | |
270 | if (!ccgx_client) | |
271 | return -ENODEV; | |
272 | ||
273 | return 0; | |
274 | } | |
275 | ||
276 | static int gpu_i2c_probe(struct pci_dev *pdev, const struct pci_device_id *id) | |
277 | { | |
278 | struct gpu_i2c_dev *i2cd; | |
279 | int status; | |
280 | ||
281 | i2cd = devm_kzalloc(&pdev->dev, sizeof(*i2cd), GFP_KERNEL); | |
282 | if (!i2cd) | |
283 | return -ENOMEM; | |
284 | ||
285 | i2cd->dev = &pdev->dev; | |
286 | dev_set_drvdata(&pdev->dev, i2cd); | |
287 | ||
288 | status = pcim_enable_device(pdev); | |
289 | if (status < 0) { | |
290 | dev_err(&pdev->dev, "pcim_enable_device failed %d\n", status); | |
291 | return status; | |
292 | } | |
293 | ||
294 | pci_set_master(pdev); | |
295 | ||
296 | i2cd->regs = pcim_iomap(pdev, 0, 0); | |
297 | if (!i2cd->regs) { | |
298 | dev_err(&pdev->dev, "pcim_iomap failed\n"); | |
299 | return -ENOMEM; | |
300 | } | |
301 | ||
302 | status = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSI); | |
303 | if (status < 0) { | |
304 | dev_err(&pdev->dev, "pci_alloc_irq_vectors err %d\n", status); | |
305 | return status; | |
306 | } | |
307 | ||
308 | gpu_enable_i2c_bus(i2cd); | |
309 | ||
310 | i2c_set_adapdata(&i2cd->adapter, i2cd); | |
311 | i2cd->adapter.owner = THIS_MODULE; | |
312 | strlcpy(i2cd->adapter.name, "NVIDIA GPU I2C adapter", | |
313 | sizeof(i2cd->adapter.name)); | |
314 | i2cd->adapter.algo = &gpu_i2c_algorithm; | |
315 | i2cd->adapter.quirks = &gpu_i2c_quirks; | |
316 | i2cd->adapter.dev.parent = &pdev->dev; | |
317 | status = i2c_add_adapter(&i2cd->adapter); | |
318 | if (status < 0) | |
319 | goto free_irq_vectors; | |
320 | ||
321 | status = gpu_populate_client(i2cd, pdev->irq); | |
322 | if (status < 0) { | |
323 | dev_err(&pdev->dev, "gpu_populate_client failed %d\n", status); | |
324 | goto del_adapter; | |
325 | } | |
326 | ||
327 | return 0; | |
328 | ||
329 | del_adapter: | |
330 | i2c_del_adapter(&i2cd->adapter); | |
331 | free_irq_vectors: | |
332 | pci_free_irq_vectors(pdev); | |
333 | return status; | |
334 | } | |
335 | ||
336 | static void gpu_i2c_remove(struct pci_dev *pdev) | |
337 | { | |
338 | struct gpu_i2c_dev *i2cd = dev_get_drvdata(&pdev->dev); | |
339 | ||
340 | i2c_del_adapter(&i2cd->adapter); | |
341 | pci_free_irq_vectors(pdev); | |
342 | } | |
343 | ||
344 | static int gpu_i2c_resume(struct device *dev) | |
345 | { | |
346 | struct gpu_i2c_dev *i2cd = dev_get_drvdata(dev); | |
347 | ||
348 | gpu_enable_i2c_bus(i2cd); | |
349 | return 0; | |
350 | } | |
351 | ||
352 | UNIVERSAL_DEV_PM_OPS(gpu_i2c_driver_pm, NULL, gpu_i2c_resume, NULL); | |
353 | ||
354 | static struct pci_driver gpu_i2c_driver = { | |
355 | .name = "nvidia-gpu", | |
356 | .id_table = gpu_i2c_ids, | |
357 | .probe = gpu_i2c_probe, | |
358 | .remove = gpu_i2c_remove, | |
359 | .driver = { | |
360 | .pm = &gpu_i2c_driver_pm, | |
361 | }, | |
362 | }; | |
363 | ||
364 | module_pci_driver(gpu_i2c_driver); | |
365 | ||
366 | MODULE_AUTHOR("Ajay Gupta <ajayg@nvidia.com>"); | |
367 | MODULE_DESCRIPTION("Nvidia GPU I2C controller Driver"); | |
368 | MODULE_LICENSE("GPL v2"); |