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 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(msg->flags, &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(i2c->bpmp, &msg); 194 else 195 err = tegra_bpmp_transfer(i2c->bpmp, &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(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, msgs, num); 244 err = tegra_bpmp_i2c_msg_xfer(i2c, &request, &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, 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, 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, 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(&pdev->dev, sizeof(*i2c), GFP_KERNEL); 290 if (!i2c) 291 return -ENOMEM; 292 293 i2c->dev = &pdev->dev; 294 295 i2c->bpmp = dev_get_drvdata(pdev->dev.parent); 296 if (!i2c->bpmp) 297 return -ENODEV; 298 299 err = of_property_read_u32(pdev->dev.of_node, "nvidia,bpmp-bus-id", 300 &value); 301 if (err < 0) 302 return err; 303 304 i2c->bus = value; 305 306 i2c_set_adapdata(&i2c->adapter, i2c); 307 i2c->adapter.owner = THIS_MODULE; 308 strlcpy(i2c->adapter.name, "Tegra BPMP I2C adapter", 309 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, i2c); 315 316 return i2c_add_adapter(&i2c->adapter); 317 } 318 319 static int tegra_bpmp_i2c_remove(struct platform_device *pdev) 320 { 321 struct tegra_bpmp_i2c *i2c = platform_get_drvdata(pdev); 322 323 i2c_del_adapter(&i2c->adapter); 324 325 return 0; 326 } 327 328 static const struct of_device_id tegra_bpmp_i2c_of_match[] = { 329 { .compatible = "nvidia,tegra186-bpmp-i2c", }, 330 { } 331 }; 332 MODULE_DEVICE_TABLE(of, tegra_bpmp_i2c_of_match); 333 334 static struct platform_driver tegra_bpmp_i2c_driver = { 335 .driver = { 336 .name = "tegra-bpmp-i2c", 337 .of_match_table = tegra_bpmp_i2c_of_match, 338 }, 339 .probe = tegra_bpmp_i2c_probe, 340 .remove = tegra_bpmp_i2c_remove, 341 }; 342 module_platform_driver(tegra_bpmp_i2c_driver); 343 344 MODULE_DESCRIPTION("NVIDIA Tegra BPMP I2C bus controller driver"); 345 MODULE_AUTHOR("Shardar Shariff Md <smohammed@nvidia.com>"); 346 MODULE_AUTHOR("Juha-Matti Tilli"); 347 MODULE_LICENSE("GPL v2"); 348