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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * drivers/i2c/busses/i2c-tegra-bpmp.c4 *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, flags24 * and length25 */26#define SERIALI2C_HDR_SIZE 627 28struct 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 BPMP38 * firmware I2C driver to avoid any issues in future if Linux I2C flags are39 * changed.40 */41static 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 seriali2c75 * representation. Any undefined flag being set causes an error.76 *77 * The data is there only for writes. Reads have the data transferred in the78 * other direction, and thus data is not present.79 *80 * See deserialize_i2c documentation for the data format in the other direction.81 */82static 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 for114 * 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 04117 * - !I2C_M_RD, len == 1, data == a0118 * - I2C_M_RD, len == 2, data == [uninitialized buffer 1]119 * - !I2C_M_RD, len == 1, data == a2120 * - I2C_M_RD, len == 2, data == [uninitialized buffer 2]121 *122 * ...then the data in the BPMP -> CPU direction would be 4 bytes total, and123 * would contain 2 bytes that will go to uninitialized buffer 1, and 2 bytes124 * that will go to uninitialized buffer 2.125 */126static 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 152static 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 174static 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 else195 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 225static 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 259static 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 265static 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 271static 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 277static 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 283static 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 319static 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 326static const struct of_device_id tegra_bpmp_i2c_of_match[] = {327 { .compatible = "nvidia,tegra186-bpmp-i2c", },328 { }329};330MODULE_DEVICE_TABLE(of, tegra_bpmp_i2c_of_match);331 332static 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};340module_platform_driver(tegra_bpmp_i2c_driver);341 342MODULE_DESCRIPTION("NVIDIA Tegra BPMP I2C bus controller driver");343MODULE_AUTHOR("Shardar Shariff Md <smohammed@nvidia.com>");344MODULE_AUTHOR("Juha-Matti Tilli");345MODULE_LICENSE("GPL v2");346