rjw | 1f88458 | 2022-01-06 17:20:42 +0800 | [diff] [blame^] | 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"); |