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_device.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 int tegra_bpmp_xlate_flags(u16 flags, u16 *out) 42 { 43 if (flags & I2C_M_TEN) { 44 *out |= SERIALI2C_TEN; 45 flags &= ~I2C_M_TEN; 46 } 47 48 if (flags & I2C_M_RD) { 49 *out |= SERIALI2C_RD; 50 flags &= ~I2C_M_RD; 51 } 52 53 if (flags & I2C_M_STOP) { 54 *out |= SERIALI2C_STOP; 55 flags &= ~I2C_M_STOP; 56 } 57 58 if (flags & I2C_M_NOSTART) { 59 *out |= SERIALI2C_NOSTART; 60 flags &= ~I2C_M_NOSTART; 61 } 62 63 if (flags & I2C_M_REV_DIR_ADDR) { 64 *out |= SERIALI2C_REV_DIR_ADDR; 65 flags &= ~I2C_M_REV_DIR_ADDR; 66 } 67 68 if (flags & I2C_M_IGNORE_NAK) { 69 *out |= SERIALI2C_IGNORE_NAK; 70 flags &= ~I2C_M_IGNORE_NAK; 71 } 72 73 if (flags & I2C_M_NO_RD_ACK) { 74 *out |= SERIALI2C_NO_RD_ACK; 75 flags &= ~I2C_M_NO_RD_ACK; 76 } 77 78 if (flags & I2C_M_RECV_LEN) { 79 *out |= SERIALI2C_RECV_LEN; 80 flags &= ~I2C_M_RECV_LEN; 81 } 82 83 return (flags != 0) ? -EINVAL : 0; 84 } 85 86 /** 87 * The serialized I2C format is simply the following: 88 * [addr little-endian][flags little-endian][len little-endian][data if write] 89 * [addr little-endian][flags little-endian][len little-endian][data if write] 90 * ... 91 * 92 * The flags are translated from Linux kernel representation to seriali2c 93 * representation. Any undefined flag being set causes an error. 94 * 95 * The data is there only for writes. Reads have the data transferred in the 96 * other direction, and thus data is not present. 97 * 98 * See deserialize_i2c documentation for the data format in the other direction. 99 */ 100 static int tegra_bpmp_serialize_i2c_msg(struct tegra_bpmp_i2c *i2c, 101 struct mrq_i2c_request *request, 102 struct i2c_msg *msgs, 103 unsigned int num) 104 { 105 char *buf = request->xfer.data_buf; 106 unsigned int i, j, pos = 0; 107 int err; 108 109 for (i = 0; i < num; i++) { 110 struct i2c_msg *msg = &msgs[i]; 111 u16 flags = 0; 112 113 err = tegra_bpmp_xlate_flags(msg->flags, &flags); 114 if (err < 0) 115 return err; 116 117 buf[pos++] = msg->addr & 0xff; 118 buf[pos++] = (msg->addr & 0xff00) >> 8; 119 buf[pos++] = flags & 0xff; 120 buf[pos++] = (flags & 0xff00) >> 8; 121 buf[pos++] = msg->len & 0xff; 122 buf[pos++] = (msg->len & 0xff00) >> 8; 123 124 if ((flags & SERIALI2C_RD) == 0) { 125 for (j = 0; j < msg->len; j++) 126 buf[pos++] = msg->buf[j]; 127 } 128 } 129 130 request->xfer.data_size = pos; 131 132 return 0; 133 } 134 135 /** 136 * The data in the BPMP -> CPU direction is composed of sequential blocks for 137 * those messages that have I2C_M_RD. So, for example, if you have: 138 * 139 * - !I2C_M_RD, len == 5, data == a0 01 02 03 04 140 * - !I2C_M_RD, len == 1, data == a0 141 * - I2C_M_RD, len == 2, data == [uninitialized buffer 1] 142 * - !I2C_M_RD, len == 1, data == a2 143 * - I2C_M_RD, len == 2, data == [uninitialized buffer 2] 144 * 145 * ...then the data in the BPMP -> CPU direction would be 4 bytes total, and 146 * would contain 2 bytes that will go to uninitialized buffer 1, and 2 bytes 147 * that will go to uninitialized buffer 2. 148 */ 149 static int tegra_bpmp_i2c_deserialize(struct tegra_bpmp_i2c *i2c, 150 struct mrq_i2c_response *response, 151 struct i2c_msg *msgs, 152 unsigned int num) 153 { 154 size_t size = response->xfer.data_size, len = 0, pos = 0; 155 char *buf = response->xfer.data_buf; 156 unsigned int i; 157 158 for (i = 0; i < num; i++) 159 if (msgs[i].flags & I2C_M_RD) 160 len += msgs[i].len; 161 162 if (len != size) 163 return -EINVAL; 164 165 for (i = 0; i < num; i++) { 166 if (msgs[i].flags & I2C_M_RD) { 167 memcpy(msgs[i].buf, buf + pos, msgs[i].len); 168 pos += msgs[i].len; 169 } 170 } 171 172 return 0; 173 } 174 175 static int tegra_bpmp_i2c_msg_len_check(struct i2c_msg *msgs, unsigned int num) 176 { 177 size_t tx_len = 0, rx_len = 0; 178 unsigned int i; 179 180 for (i = 0; i < num; i++) 181 if (!(msgs[i].flags & I2C_M_RD)) 182 tx_len += SERIALI2C_HDR_SIZE + msgs[i].len; 183 184 if (tx_len > TEGRA_I2C_IPC_MAX_IN_BUF_SIZE) 185 return -EINVAL; 186 187 for (i = 0; i < num; i++) 188 if ((msgs[i].flags & I2C_M_RD)) 189 rx_len += msgs[i].len; 190 191 if (rx_len > TEGRA_I2C_IPC_MAX_OUT_BUF_SIZE) 192 return -EINVAL; 193 194 return 0; 195 } 196 197 static int tegra_bpmp_i2c_msg_xfer(struct tegra_bpmp_i2c *i2c, 198 struct mrq_i2c_request *request, 199 struct mrq_i2c_response *response, 200 bool atomic) 201 { 202 struct tegra_bpmp_message msg; 203 int err; 204 205 request->cmd = CMD_I2C_XFER; 206 request->xfer.bus_id = i2c->bus; 207 208 memset(&msg, 0, sizeof(msg)); 209 msg.mrq = MRQ_I2C; 210 msg.tx.data = request; 211 msg.tx.size = sizeof(*request); 212 msg.rx.data = response; 213 msg.rx.size = sizeof(*response); 214 215 if (atomic) 216 err = tegra_bpmp_transfer_atomic(i2c->bpmp, &msg); 217 else 218 err = tegra_bpmp_transfer(i2c->bpmp, &msg); 219 220 return err; 221 } 222 223 static int tegra_bpmp_i2c_xfer_common(struct i2c_adapter *adapter, 224 struct i2c_msg *msgs, int num, 225 bool atomic) 226 { 227 struct tegra_bpmp_i2c *i2c = i2c_get_adapdata(adapter); 228 struct mrq_i2c_response response; 229 struct mrq_i2c_request request; 230 int err; 231 232 err = tegra_bpmp_i2c_msg_len_check(msgs, num); 233 if (err < 0) { 234 dev_err(i2c->dev, "unsupported message length\n"); 235 return err; 236 } 237 238 memset(&request, 0, sizeof(request)); 239 memset(&response, 0, sizeof(response)); 240 241 err = tegra_bpmp_serialize_i2c_msg(i2c, &request, msgs, num); 242 if (err < 0) { 243 dev_err(i2c->dev, "failed to serialize message: %d\n", err); 244 return err; 245 } 246 247 err = tegra_bpmp_i2c_msg_xfer(i2c, &request, &response, atomic); 248 if (err < 0) { 249 dev_err(i2c->dev, "failed to transfer message: %d\n", err); 250 return err; 251 } 252 253 err = tegra_bpmp_i2c_deserialize(i2c, &response, msgs, num); 254 if (err < 0) { 255 dev_err(i2c->dev, "failed to deserialize message: %d\n", err); 256 return err; 257 } 258 259 return num; 260 } 261 262 static int tegra_bpmp_i2c_xfer(struct i2c_adapter *adapter, 263 struct i2c_msg *msgs, int num) 264 { 265 return tegra_bpmp_i2c_xfer_common(adapter, msgs, num, false); 266 } 267 268 static int tegra_bpmp_i2c_xfer_atomic(struct i2c_adapter *adapter, 269 struct i2c_msg *msgs, int num) 270 { 271 return tegra_bpmp_i2c_xfer_common(adapter, msgs, num, true); 272 } 273 274 static u32 tegra_bpmp_i2c_func(struct i2c_adapter *adapter) 275 { 276 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR | 277 I2C_FUNC_PROTOCOL_MANGLING | I2C_FUNC_NOSTART; 278 } 279 280 static const struct i2c_algorithm tegra_bpmp_i2c_algo = { 281 .master_xfer = tegra_bpmp_i2c_xfer, 282 .master_xfer_atomic = tegra_bpmp_i2c_xfer_atomic, 283 .functionality = tegra_bpmp_i2c_func, 284 }; 285 286 static int tegra_bpmp_i2c_probe(struct platform_device *pdev) 287 { 288 struct tegra_bpmp_i2c *i2c; 289 u32 value; 290 int err; 291 292 i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL); 293 if (!i2c) 294 return -ENOMEM; 295 296 i2c->dev = &pdev->dev; 297 298 i2c->bpmp = dev_get_drvdata(pdev->dev.parent); 299 if (!i2c->bpmp) 300 return -ENODEV; 301 302 err = of_property_read_u32(pdev->dev.of_node, "nvidia,bpmp-bus-id", 303 &value); 304 if (err < 0) 305 return err; 306 307 i2c->bus = value; 308 309 i2c_set_adapdata(&i2c->adapter, i2c); 310 i2c->adapter.owner = THIS_MODULE; 311 strlcpy(i2c->adapter.name, "Tegra BPMP I2C adapter", 312 sizeof(i2c->adapter.name)); 313 i2c->adapter.algo = &tegra_bpmp_i2c_algo; 314 i2c->adapter.dev.parent = &pdev->dev; 315 i2c->adapter.dev.of_node = pdev->dev.of_node; 316 317 platform_set_drvdata(pdev, i2c); 318 319 return i2c_add_adapter(&i2c->adapter); 320 } 321 322 static int tegra_bpmp_i2c_remove(struct platform_device *pdev) 323 { 324 struct tegra_bpmp_i2c *i2c = platform_get_drvdata(pdev); 325 326 i2c_del_adapter(&i2c->adapter); 327 328 return 0; 329 } 330 331 static const struct of_device_id tegra_bpmp_i2c_of_match[] = { 332 { .compatible = "nvidia,tegra186-bpmp-i2c", }, 333 { } 334 }; 335 MODULE_DEVICE_TABLE(of, tegra_bpmp_i2c_of_match); 336 337 static struct platform_driver tegra_bpmp_i2c_driver = { 338 .driver = { 339 .name = "tegra-bpmp-i2c", 340 .of_match_table = tegra_bpmp_i2c_of_match, 341 }, 342 .probe = tegra_bpmp_i2c_probe, 343 .remove = tegra_bpmp_i2c_remove, 344 }; 345 module_platform_driver(tegra_bpmp_i2c_driver); 346 347 MODULE_DESCRIPTION("NVIDIA Tegra BPMP I2C bus controller driver"); 348 MODULE_AUTHOR("Shardar Shariff Md <smohammed@nvidia.com>"); 349 MODULE_AUTHOR("Juha-Matti Tilli"); 350 MODULE_LICENSE("GPL v2"); 351