1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * drivers/i2c/busses/i2c-tegra-bpmp.c |
4 | * |
5 | * Copyright (c) 2016 NVIDIA Corporation. All rights reserved. |
6 | * |
7 | * Author: Shardar Shariff Md <smohammed@nvidia.com> |
8 | */ |
9 | |
10 | #include <linux/err.h> |
11 | #include <linux/i2c.h> |
12 | #include <linux/init.h> |
13 | #include <linux/kernel.h> |
14 | #include <linux/module.h> |
15 | #include <linux/of.h> |
16 | #include <linux/platform_device.h> |
17 | #include <linux/pm_runtime.h> |
18 | |
19 | #include <soc/tegra/bpmp-abi.h> |
20 | #include <soc/tegra/bpmp.h> |
21 | |
22 | /* |
23 | * Serialized I2C message header size is 6 bytes and includes address, flags |
24 | * and length |
25 | */ |
26 | #define SERIALI2C_HDR_SIZE 6 |
27 | |
28 | struct tegra_bpmp_i2c { |
29 | struct i2c_adapter adapter; |
30 | struct device *dev; |
31 | |
32 | struct tegra_bpmp *bpmp; |
33 | unsigned int bus; |
34 | }; |
35 | |
36 | /* |
37 | * Linux flags are translated to BPMP defined I2C flags that are used in BPMP |
38 | * firmware I2C driver to avoid any issues in future if Linux I2C flags are |
39 | * changed. |
40 | */ |
41 | static void tegra_bpmp_xlate_flags(u16 flags, u16 *out) |
42 | { |
43 | if (flags & I2C_M_TEN) |
44 | *out |= SERIALI2C_TEN; |
45 | |
46 | if (flags & I2C_M_RD) |
47 | *out |= SERIALI2C_RD; |
48 | |
49 | if (flags & I2C_M_STOP) |
50 | *out |= SERIALI2C_STOP; |
51 | |
52 | if (flags & I2C_M_NOSTART) |
53 | *out |= SERIALI2C_NOSTART; |
54 | |
55 | if (flags & I2C_M_REV_DIR_ADDR) |
56 | *out |= SERIALI2C_REV_DIR_ADDR; |
57 | |
58 | if (flags & I2C_M_IGNORE_NAK) |
59 | *out |= SERIALI2C_IGNORE_NAK; |
60 | |
61 | if (flags & I2C_M_NO_RD_ACK) |
62 | *out |= SERIALI2C_NO_RD_ACK; |
63 | |
64 | if (flags & I2C_M_RECV_LEN) |
65 | *out |= SERIALI2C_RECV_LEN; |
66 | } |
67 | |
68 | /* |
69 | * The serialized I2C format is simply the following: |
70 | * [addr little-endian][flags little-endian][len little-endian][data if write] |
71 | * [addr little-endian][flags little-endian][len little-endian][data if write] |
72 | * ... |
73 | * |
74 | * The flags are translated from Linux kernel representation to seriali2c |
75 | * representation. Any undefined flag being set causes an error. |
76 | * |
77 | * The data is there only for writes. Reads have the data transferred in the |
78 | * other direction, and thus data is not present. |
79 | * |
80 | * See deserialize_i2c documentation for the data format in the other direction. |
81 | */ |
82 | static void tegra_bpmp_serialize_i2c_msg(struct tegra_bpmp_i2c *i2c, |
83 | struct mrq_i2c_request *request, |
84 | struct i2c_msg *msgs, |
85 | unsigned int num) |
86 | { |
87 | char *buf = request->xfer.data_buf; |
88 | unsigned int i, j, pos = 0; |
89 | |
90 | for (i = 0; i < num; i++) { |
91 | struct i2c_msg *msg = &msgs[i]; |
92 | u16 flags = 0; |
93 | |
94 | tegra_bpmp_xlate_flags(flags: msg->flags, out: &flags); |
95 | |
96 | buf[pos++] = msg->addr & 0xff; |
97 | buf[pos++] = (msg->addr & 0xff00) >> 8; |
98 | buf[pos++] = flags & 0xff; |
99 | buf[pos++] = (flags & 0xff00) >> 8; |
100 | buf[pos++] = msg->len & 0xff; |
101 | buf[pos++] = (msg->len & 0xff00) >> 8; |
102 | |
103 | if ((flags & SERIALI2C_RD) == 0) { |
104 | for (j = 0; j < msg->len; j++) |
105 | buf[pos++] = msg->buf[j]; |
106 | } |
107 | } |
108 | |
109 | request->xfer.data_size = pos; |
110 | } |
111 | |
112 | /* |
113 | * The data in the BPMP -> CPU direction is composed of sequential blocks for |
114 | * those messages that have I2C_M_RD. So, for example, if you have: |
115 | * |
116 | * - !I2C_M_RD, len == 5, data == a0 01 02 03 04 |
117 | * - !I2C_M_RD, len == 1, data == a0 |
118 | * - I2C_M_RD, len == 2, data == [uninitialized buffer 1] |
119 | * - !I2C_M_RD, len == 1, data == a2 |
120 | * - I2C_M_RD, len == 2, data == [uninitialized buffer 2] |
121 | * |
122 | * ...then the data in the BPMP -> CPU direction would be 4 bytes total, and |
123 | * would contain 2 bytes that will go to uninitialized buffer 1, and 2 bytes |
124 | * that will go to uninitialized buffer 2. |
125 | */ |
126 | static int tegra_bpmp_i2c_deserialize(struct tegra_bpmp_i2c *i2c, |
127 | struct mrq_i2c_response *response, |
128 | struct i2c_msg *msgs, |
129 | unsigned int num) |
130 | { |
131 | size_t size = response->xfer.data_size, len = 0, pos = 0; |
132 | char *buf = response->xfer.data_buf; |
133 | unsigned int i; |
134 | |
135 | for (i = 0; i < num; i++) |
136 | if (msgs[i].flags & I2C_M_RD) |
137 | len += msgs[i].len; |
138 | |
139 | if (len != size) |
140 | return -EINVAL; |
141 | |
142 | for (i = 0; i < num; i++) { |
143 | if (msgs[i].flags & I2C_M_RD) { |
144 | memcpy(msgs[i].buf, buf + pos, msgs[i].len); |
145 | pos += msgs[i].len; |
146 | } |
147 | } |
148 | |
149 | return 0; |
150 | } |
151 | |
152 | static int tegra_bpmp_i2c_msg_len_check(struct i2c_msg *msgs, unsigned int num) |
153 | { |
154 | size_t tx_len = 0, rx_len = 0; |
155 | unsigned int i; |
156 | |
157 | for (i = 0; i < num; i++) |
158 | if (!(msgs[i].flags & I2C_M_RD)) |
159 | tx_len += SERIALI2C_HDR_SIZE + msgs[i].len; |
160 | |
161 | if (tx_len > TEGRA_I2C_IPC_MAX_IN_BUF_SIZE) |
162 | return -EINVAL; |
163 | |
164 | for (i = 0; i < num; i++) |
165 | if ((msgs[i].flags & I2C_M_RD)) |
166 | rx_len += msgs[i].len; |
167 | |
168 | if (rx_len > TEGRA_I2C_IPC_MAX_OUT_BUF_SIZE) |
169 | return -EINVAL; |
170 | |
171 | return 0; |
172 | } |
173 | |
174 | static int tegra_bpmp_i2c_msg_xfer(struct tegra_bpmp_i2c *i2c, |
175 | struct mrq_i2c_request *request, |
176 | struct mrq_i2c_response *response, |
177 | bool atomic) |
178 | { |
179 | struct tegra_bpmp_message msg; |
180 | int err; |
181 | |
182 | request->cmd = CMD_I2C_XFER; |
183 | request->xfer.bus_id = i2c->bus; |
184 | |
185 | memset(&msg, 0, sizeof(msg)); |
186 | msg.mrq = MRQ_I2C; |
187 | msg.tx.data = request; |
188 | msg.tx.size = sizeof(*request); |
189 | msg.rx.data = response; |
190 | msg.rx.size = sizeof(*response); |
191 | |
192 | if (atomic) |
193 | err = tegra_bpmp_transfer_atomic(bpmp: i2c->bpmp, msg: &msg); |
194 | else |
195 | err = tegra_bpmp_transfer(bpmp: i2c->bpmp, msg: &msg); |
196 | |
197 | if (err < 0) { |
198 | dev_err(i2c->dev, "failed to transfer message: %d\n" , err); |
199 | return err; |
200 | } |
201 | |
202 | if (msg.rx.ret != 0) { |
203 | if (msg.rx.ret == -BPMP_EAGAIN) { |
204 | dev_dbg(i2c->dev, "arbitration lost\n" ); |
205 | return -EAGAIN; |
206 | } |
207 | |
208 | if (msg.rx.ret == -BPMP_ETIMEDOUT) { |
209 | dev_dbg(i2c->dev, "timeout\n" ); |
210 | return -ETIMEDOUT; |
211 | } |
212 | |
213 | if (msg.rx.ret == -BPMP_ENXIO) { |
214 | dev_dbg(i2c->dev, "NAK\n" ); |
215 | return -ENXIO; |
216 | } |
217 | |
218 | dev_err(i2c->dev, "transaction failed: %d\n" , msg.rx.ret); |
219 | return -EIO; |
220 | } |
221 | |
222 | return 0; |
223 | } |
224 | |
225 | static int tegra_bpmp_i2c_xfer_common(struct i2c_adapter *adapter, |
226 | struct i2c_msg *msgs, int num, |
227 | bool atomic) |
228 | { |
229 | struct tegra_bpmp_i2c *i2c = i2c_get_adapdata(adap: adapter); |
230 | struct mrq_i2c_response response; |
231 | struct mrq_i2c_request request; |
232 | int err; |
233 | |
234 | err = tegra_bpmp_i2c_msg_len_check(msgs, num); |
235 | if (err < 0) { |
236 | dev_err(i2c->dev, "unsupported message length\n" ); |
237 | return err; |
238 | } |
239 | |
240 | memset(&request, 0, sizeof(request)); |
241 | memset(&response, 0, sizeof(response)); |
242 | |
243 | tegra_bpmp_serialize_i2c_msg(i2c, request: &request, msgs, num); |
244 | err = tegra_bpmp_i2c_msg_xfer(i2c, request: &request, response: &response, atomic); |
245 | if (err < 0) { |
246 | dev_err(i2c->dev, "failed to transfer message: %d\n" , err); |
247 | return err; |
248 | } |
249 | |
250 | err = tegra_bpmp_i2c_deserialize(i2c, response: &response, msgs, num); |
251 | if (err < 0) { |
252 | dev_err(i2c->dev, "failed to deserialize message: %d\n" , err); |
253 | return err; |
254 | } |
255 | |
256 | return num; |
257 | } |
258 | |
259 | static int tegra_bpmp_i2c_xfer(struct i2c_adapter *adapter, |
260 | struct i2c_msg *msgs, int num) |
261 | { |
262 | return tegra_bpmp_i2c_xfer_common(adapter, msgs, num, atomic: false); |
263 | } |
264 | |
265 | static int tegra_bpmp_i2c_xfer_atomic(struct i2c_adapter *adapter, |
266 | struct i2c_msg *msgs, int num) |
267 | { |
268 | return tegra_bpmp_i2c_xfer_common(adapter, msgs, num, atomic: true); |
269 | } |
270 | |
271 | static u32 tegra_bpmp_i2c_func(struct i2c_adapter *adapter) |
272 | { |
273 | return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR | |
274 | I2C_FUNC_PROTOCOL_MANGLING | I2C_FUNC_NOSTART; |
275 | } |
276 | |
277 | static const struct i2c_algorithm tegra_bpmp_i2c_algo = { |
278 | .master_xfer = tegra_bpmp_i2c_xfer, |
279 | .master_xfer_atomic = tegra_bpmp_i2c_xfer_atomic, |
280 | .functionality = tegra_bpmp_i2c_func, |
281 | }; |
282 | |
283 | static int tegra_bpmp_i2c_probe(struct platform_device *pdev) |
284 | { |
285 | struct tegra_bpmp_i2c *i2c; |
286 | u32 value; |
287 | int err; |
288 | |
289 | i2c = devm_kzalloc(dev: &pdev->dev, size: sizeof(*i2c), GFP_KERNEL); |
290 | if (!i2c) |
291 | return -ENOMEM; |
292 | |
293 | i2c->dev = &pdev->dev; |
294 | |
295 | i2c->bpmp = dev_get_drvdata(dev: pdev->dev.parent); |
296 | if (!i2c->bpmp) |
297 | return -ENODEV; |
298 | |
299 | err = of_property_read_u32(np: pdev->dev.of_node, propname: "nvidia,bpmp-bus-id" , |
300 | out_value: &value); |
301 | if (err < 0) |
302 | return err; |
303 | |
304 | i2c->bus = value; |
305 | |
306 | i2c_set_adapdata(adap: &i2c->adapter, data: i2c); |
307 | i2c->adapter.owner = THIS_MODULE; |
308 | strscpy(p: i2c->adapter.name, q: "Tegra BPMP I2C adapter" , |
309 | size: sizeof(i2c->adapter.name)); |
310 | i2c->adapter.algo = &tegra_bpmp_i2c_algo; |
311 | i2c->adapter.dev.parent = &pdev->dev; |
312 | i2c->adapter.dev.of_node = pdev->dev.of_node; |
313 | |
314 | platform_set_drvdata(pdev, data: i2c); |
315 | |
316 | return i2c_add_adapter(adap: &i2c->adapter); |
317 | } |
318 | |
319 | static void tegra_bpmp_i2c_remove(struct platform_device *pdev) |
320 | { |
321 | struct tegra_bpmp_i2c *i2c = platform_get_drvdata(pdev); |
322 | |
323 | i2c_del_adapter(adap: &i2c->adapter); |
324 | } |
325 | |
326 | static const struct of_device_id tegra_bpmp_i2c_of_match[] = { |
327 | { .compatible = "nvidia,tegra186-bpmp-i2c" , }, |
328 | { } |
329 | }; |
330 | MODULE_DEVICE_TABLE(of, tegra_bpmp_i2c_of_match); |
331 | |
332 | static struct platform_driver tegra_bpmp_i2c_driver = { |
333 | .driver = { |
334 | .name = "tegra-bpmp-i2c" , |
335 | .of_match_table = tegra_bpmp_i2c_of_match, |
336 | }, |
337 | .probe = tegra_bpmp_i2c_probe, |
338 | .remove_new = tegra_bpmp_i2c_remove, |
339 | }; |
340 | module_platform_driver(tegra_bpmp_i2c_driver); |
341 | |
342 | MODULE_DESCRIPTION("NVIDIA Tegra BPMP I2C bus controller driver" ); |
343 | MODULE_AUTHOR("Shardar Shariff Md <smohammed@nvidia.com>" ); |
344 | MODULE_AUTHOR("Juha-Matti Tilli" ); |
345 | MODULE_LICENSE("GPL v2" ); |
346 | |