1 /* 2 * drivers/i2c/busses/i2c-tegra-bpmp.c 3 * 4 * Copyright (c) 2016 NVIDIA Corporation. All rights reserved. 5 * 6 * Author: Shardar Shariff Md <smohammed@nvidia.com> 7 * 8 * This program is free software; you can redistribute it and/or modify it 9 * under the terms and conditions of the GNU General Public License, 10 * version 2, as published by the Free Software Foundation. 11 * 12 * This program is distributed in the hope it will be useful, but WITHOUT 13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 15 * more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program. If not, see <http://www.gnu.org/licenses/>. 19 */ 20 21 #include <linux/err.h> 22 #include <linux/i2c.h> 23 #include <linux/init.h> 24 #include <linux/kernel.h> 25 #include <linux/module.h> 26 #include <linux/of_device.h> 27 #include <linux/platform_device.h> 28 #include <linux/pm_runtime.h> 29 30 #include <soc/tegra/bpmp-abi.h> 31 #include <soc/tegra/bpmp.h> 32 33 /* 34 * Serialized I2C message header size is 6 bytes and includes address, flags 35 * and length 36 */ 37 #define SERIALI2C_HDR_SIZE 6 38 39 struct tegra_bpmp_i2c { 40 struct i2c_adapter adapter; 41 struct device *dev; 42 43 struct tegra_bpmp *bpmp; 44 unsigned int bus; 45 }; 46 47 /* 48 * Linux flags are translated to BPMP defined I2C flags that are used in BPMP 49 * firmware I2C driver to avoid any issues in future if Linux I2C flags are 50 * changed. 51 */ 52 static int tegra_bpmp_xlate_flags(u16 flags, u16 *out) 53 { 54 if (flags & I2C_M_TEN) { 55 *out |= SERIALI2C_TEN; 56 flags &= ~I2C_M_TEN; 57 } 58 59 if (flags & I2C_M_RD) { 60 *out |= SERIALI2C_RD; 61 flags &= ~I2C_M_RD; 62 } 63 64 if (flags & I2C_M_STOP) { 65 *out |= SERIALI2C_STOP; 66 flags &= ~I2C_M_STOP; 67 } 68 69 if (flags & I2C_M_NOSTART) { 70 *out |= SERIALI2C_NOSTART; 71 flags &= ~I2C_M_NOSTART; 72 } 73 74 if (flags & I2C_M_REV_DIR_ADDR) { 75 *out |= SERIALI2C_REV_DIR_ADDR; 76 flags &= ~I2C_M_REV_DIR_ADDR; 77 } 78 79 if (flags & I2C_M_IGNORE_NAK) { 80 *out |= SERIALI2C_IGNORE_NAK; 81 flags &= ~I2C_M_IGNORE_NAK; 82 } 83 84 if (flags & I2C_M_NO_RD_ACK) { 85 *out |= SERIALI2C_NO_RD_ACK; 86 flags &= ~I2C_M_NO_RD_ACK; 87 } 88 89 if (flags & I2C_M_RECV_LEN) { 90 *out |= SERIALI2C_RECV_LEN; 91 flags &= ~I2C_M_RECV_LEN; 92 } 93 94 return (flags != 0) ? -EINVAL : 0; 95 } 96 97 /** 98 * The serialized I2C format is simply the following: 99 * [addr little-endian][flags little-endian][len little-endian][data if write] 100 * [addr little-endian][flags little-endian][len little-endian][data if write] 101 * ... 102 * 103 * The flags are translated from Linux kernel representation to seriali2c 104 * representation. Any undefined flag being set causes an error. 105 * 106 * The data is there only for writes. Reads have the data transferred in the 107 * other direction, and thus data is not present. 108 * 109 * See deserialize_i2c documentation for the data format in the other direction. 110 */ 111 static int tegra_bpmp_serialize_i2c_msg(struct tegra_bpmp_i2c *i2c, 112 struct mrq_i2c_request *request, 113 struct i2c_msg *msgs, 114 unsigned int num) 115 { 116 char *buf = request->xfer.data_buf; 117 unsigned int i, j, pos = 0; 118 int err; 119 120 for (i = 0; i < num; i++) { 121 struct i2c_msg *msg = &msgs[i]; 122 u16 flags = 0; 123 124 err = tegra_bpmp_xlate_flags(msg->flags, &flags); 125 if (err < 0) 126 return err; 127 128 buf[pos++] = msg->addr & 0xff; 129 buf[pos++] = (msg->addr & 0xff00) >> 8; 130 buf[pos++] = flags & 0xff; 131 buf[pos++] = (flags & 0xff00) >> 8; 132 buf[pos++] = msg->len & 0xff; 133 buf[pos++] = (msg->len & 0xff00) >> 8; 134 135 if ((flags & SERIALI2C_RD) == 0) { 136 for (j = 0; j < msg->len; j++) 137 buf[pos++] = msg->buf[j]; 138 } 139 } 140 141 request->xfer.data_size = pos; 142 143 return 0; 144 } 145 146 /** 147 * The data in the BPMP -> CPU direction is composed of sequential blocks for 148 * those messages that have I2C_M_RD. So, for example, if you have: 149 * 150 * - !I2C_M_RD, len == 5, data == a0 01 02 03 04 151 * - !I2C_M_RD, len == 1, data == a0 152 * - I2C_M_RD, len == 2, data == [uninitialized buffer 1] 153 * - !I2C_M_RD, len == 1, data == a2 154 * - I2C_M_RD, len == 2, data == [uninitialized buffer 2] 155 * 156 * ...then the data in the BPMP -> CPU direction would be 4 bytes total, and 157 * would contain 2 bytes that will go to uninitialized buffer 1, and 2 bytes 158 * that will go to uninitialized buffer 2. 159 */ 160 static int tegra_bpmp_i2c_deserialize(struct tegra_bpmp_i2c *i2c, 161 struct mrq_i2c_response *response, 162 struct i2c_msg *msgs, 163 unsigned int num) 164 { 165 size_t size = response->xfer.data_size, len = 0, pos = 0; 166 char *buf = response->xfer.data_buf; 167 unsigned int i; 168 169 for (i = 0; i < num; i++) 170 if (msgs[i].flags & I2C_M_RD) 171 len += msgs[i].len; 172 173 if (len != size) 174 return -EINVAL; 175 176 for (i = 0; i < num; i++) { 177 if (msgs[i].flags & I2C_M_RD) { 178 memcpy(msgs[i].buf, buf + pos, msgs[i].len); 179 pos += msgs[i].len; 180 } 181 } 182 183 return 0; 184 } 185 186 static int tegra_bpmp_i2c_msg_len_check(struct i2c_msg *msgs, unsigned int num) 187 { 188 size_t tx_len = 0, rx_len = 0; 189 unsigned int i; 190 191 for (i = 0; i < num; i++) 192 if (!(msgs[i].flags & I2C_M_RD)) 193 tx_len += SERIALI2C_HDR_SIZE + msgs[i].len; 194 195 if (tx_len > TEGRA_I2C_IPC_MAX_IN_BUF_SIZE) 196 return -EINVAL; 197 198 for (i = 0; i < num; i++) 199 if ((msgs[i].flags & I2C_M_RD)) 200 rx_len += msgs[i].len; 201 202 if (rx_len > TEGRA_I2C_IPC_MAX_OUT_BUF_SIZE) 203 return -EINVAL; 204 205 return 0; 206 } 207 208 static int tegra_bpmp_i2c_msg_xfer(struct tegra_bpmp_i2c *i2c, 209 struct mrq_i2c_request *request, 210 struct mrq_i2c_response *response) 211 { 212 struct tegra_bpmp_message msg; 213 int err; 214 215 request->cmd = CMD_I2C_XFER; 216 request->xfer.bus_id = i2c->bus; 217 218 memset(&msg, 0, sizeof(msg)); 219 msg.mrq = MRQ_I2C; 220 msg.tx.data = request; 221 msg.tx.size = sizeof(*request); 222 msg.rx.data = response; 223 msg.rx.size = sizeof(*response); 224 225 if (irqs_disabled()) 226 err = tegra_bpmp_transfer_atomic(i2c->bpmp, &msg); 227 else 228 err = tegra_bpmp_transfer(i2c->bpmp, &msg); 229 230 return err; 231 } 232 233 static int tegra_bpmp_i2c_xfer(struct i2c_adapter *adapter, 234 struct i2c_msg *msgs, int num) 235 { 236 struct tegra_bpmp_i2c *i2c = i2c_get_adapdata(adapter); 237 struct mrq_i2c_response response; 238 struct mrq_i2c_request request; 239 int err; 240 241 err = tegra_bpmp_i2c_msg_len_check(msgs, num); 242 if (err < 0) { 243 dev_err(i2c->dev, "unsupported message length\n"); 244 return err; 245 } 246 247 memset(&request, 0, sizeof(request)); 248 memset(&response, 0, sizeof(response)); 249 250 err = tegra_bpmp_serialize_i2c_msg(i2c, &request, msgs, num); 251 if (err < 0) { 252 dev_err(i2c->dev, "failed to serialize message: %d\n", err); 253 return err; 254 } 255 256 err = tegra_bpmp_i2c_msg_xfer(i2c, &request, &response); 257 if (err < 0) { 258 dev_err(i2c->dev, "failed to transfer message: %d\n", err); 259 return err; 260 } 261 262 err = tegra_bpmp_i2c_deserialize(i2c, &response, msgs, num); 263 if (err < 0) { 264 dev_err(i2c->dev, "failed to deserialize message: %d\n", err); 265 return err; 266 } 267 268 return num; 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 .functionality = tegra_bpmp_i2c_func, 280 }; 281 282 static int tegra_bpmp_i2c_probe(struct platform_device *pdev) 283 { 284 struct tegra_bpmp_i2c *i2c; 285 u32 value; 286 int err; 287 288 i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL); 289 if (!i2c) 290 return -ENOMEM; 291 292 i2c->dev = &pdev->dev; 293 294 i2c->bpmp = dev_get_drvdata(pdev->dev.parent); 295 if (!i2c->bpmp) 296 return -ENODEV; 297 298 err = of_property_read_u32(pdev->dev.of_node, "nvidia,bpmp-bus-id", 299 &value); 300 if (err < 0) 301 return err; 302 303 i2c->bus = value; 304 305 i2c_set_adapdata(&i2c->adapter, i2c); 306 i2c->adapter.owner = THIS_MODULE; 307 strlcpy(i2c->adapter.name, "Tegra BPMP I2C adapter", 308 sizeof(i2c->adapter.name)); 309 i2c->adapter.algo = &tegra_bpmp_i2c_algo; 310 i2c->adapter.dev.parent = &pdev->dev; 311 i2c->adapter.dev.of_node = pdev->dev.of_node; 312 313 platform_set_drvdata(pdev, i2c); 314 315 return i2c_add_adapter(&i2c->adapter); 316 } 317 318 static int tegra_bpmp_i2c_remove(struct platform_device *pdev) 319 { 320 struct tegra_bpmp_i2c *i2c = platform_get_drvdata(pdev); 321 322 i2c_del_adapter(&i2c->adapter); 323 324 return 0; 325 } 326 327 static const struct of_device_id tegra_bpmp_i2c_of_match[] = { 328 { .compatible = "nvidia,tegra186-bpmp-i2c", }, 329 { } 330 }; 331 MODULE_DEVICE_TABLE(of, tegra_bpmp_i2c_of_match); 332 333 static struct platform_driver tegra_bpmp_i2c_driver = { 334 .driver = { 335 .name = "tegra-bpmp-i2c", 336 .of_match_table = tegra_bpmp_i2c_of_match, 337 }, 338 .probe = tegra_bpmp_i2c_probe, 339 .remove = tegra_bpmp_i2c_remove, 340 }; 341 module_platform_driver(tegra_bpmp_i2c_driver); 342 343 MODULE_DESCRIPTION("NVIDIA Tegra BPMP I2C bus controller driver"); 344 MODULE_AUTHOR("Shardar Shariff Md <smohammed@nvidia.com>"); 345 MODULE_AUTHOR("Juha-Matti Tilli"); 346 MODULE_LICENSE("GPL v2"); 347