drivers/i2c/busses/i2c-tegra-bpmp.c

   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(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         .xfer = tegra_bpmp_i2c_xfer,
 279         .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         strscpy(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 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(&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");