// SPDX-License-Identifier: GPL-2.0-only /* * drivers/i2c/busses/i2c-tegra-bpmp.c * * Copyright (c) 2016 NVIDIA Corporation. All rights reserved. * * Author: Shardar Shariff Md */ #include #include #include #include #include #include #include #include #include #include /* * Serialized I2C message header size is 6 bytes and includes address, flags * and length */ #define SERIALI2C_HDR_SIZE 6 struct tegra_bpmp_i2c { struct i2c_adapter adapter; struct device *dev; struct tegra_bpmp *bpmp; unsigned int bus; }; /* * Linux flags are translated to BPMP defined I2C flags that are used in BPMP * firmware I2C driver to avoid any issues in future if Linux I2C flags are * changed. */ static void tegra_bpmp_xlate_flags(u16 flags, u16 *out) { if (flags & I2C_M_TEN) *out |= SERIALI2C_TEN; if (flags & I2C_M_RD) *out |= SERIALI2C_RD; if (flags & I2C_M_STOP) *out |= SERIALI2C_STOP; if (flags & I2C_M_NOSTART) *out |= SERIALI2C_NOSTART; if (flags & I2C_M_REV_DIR_ADDR) *out |= SERIALI2C_REV_DIR_ADDR; if (flags & I2C_M_IGNORE_NAK) *out |= SERIALI2C_IGNORE_NAK; if (flags & I2C_M_NO_RD_ACK) *out |= SERIALI2C_NO_RD_ACK; if (flags & I2C_M_RECV_LEN) *out |= SERIALI2C_RECV_LEN; } /* * The serialized I2C format is simply the following: * [addr little-endian][flags little-endian][len little-endian][data if write] * [addr little-endian][flags little-endian][len little-endian][data if write] * ... * * The flags are translated from Linux kernel representation to seriali2c * representation. Any undefined flag being set causes an error. * * The data is there only for writes. Reads have the data transferred in the * other direction, and thus data is not present. * * See deserialize_i2c documentation for the data format in the other direction. */ static void tegra_bpmp_serialize_i2c_msg(struct tegra_bpmp_i2c *i2c, struct mrq_i2c_request *request, struct i2c_msg *msgs, unsigned int num) { char *buf = request->xfer.data_buf; unsigned int i, j, pos = 0; for (i = 0; i < num; i++) { struct i2c_msg *msg = &msgs[i]; u16 flags = 0; tegra_bpmp_xlate_flags(msg->flags, &flags); buf[pos++] = msg->addr & 0xff; buf[pos++] = (msg->addr & 0xff00) >> 8; buf[pos++] = flags & 0xff; buf[pos++] = (flags & 0xff00) >> 8; buf[pos++] = msg->len & 0xff; buf[pos++] = (msg->len & 0xff00) >> 8; if ((flags & SERIALI2C_RD) == 0) { for (j = 0; j < msg->len; j++) buf[pos++] = msg->buf[j]; } } request->xfer.data_size = pos; } /* * The data in the BPMP -> CPU direction is composed of sequential blocks for * those messages that have I2C_M_RD. So, for example, if you have: * * - !I2C_M_RD, len == 5, data == a0 01 02 03 04 * - !I2C_M_RD, len == 1, data == a0 * - I2C_M_RD, len == 2, data == [uninitialized buffer 1] * - !I2C_M_RD, len == 1, data == a2 * - I2C_M_RD, len == 2, data == [uninitialized buffer 2] * * ...then the data in the BPMP -> CPU direction would be 4 bytes total, and * would contain 2 bytes that will go to uninitialized buffer 1, and 2 bytes * that will go to uninitialized buffer 2. */ static int tegra_bpmp_i2c_deserialize(struct tegra_bpmp_i2c *i2c, struct mrq_i2c_response *response, struct i2c_msg *msgs, unsigned int num) { size_t size = response->xfer.data_size, len = 0, pos = 0; char *buf = response->xfer.data_buf; unsigned int i; for (i = 0; i < num; i++) if (msgs[i].flags & I2C_M_RD) len += msgs[i].len; if (len != size) return -EINVAL; for (i = 0; i < num; i++) { if (msgs[i].flags & I2C_M_RD) { memcpy(msgs[i].buf, buf + pos, msgs[i].len); pos += msgs[i].len; } } return 0; } static int tegra_bpmp_i2c_msg_len_check(struct i2c_msg *msgs, unsigned int num) { size_t tx_len = 0, rx_len = 0; unsigned int i; for (i = 0; i < num; i++) if (!(msgs[i].flags & I2C_M_RD)) tx_len += SERIALI2C_HDR_SIZE + msgs[i].len; if (tx_len > TEGRA_I2C_IPC_MAX_IN_BUF_SIZE) return -EINVAL; for (i = 0; i < num; i++) if ((msgs[i].flags & I2C_M_RD)) rx_len += msgs[i].len; if (rx_len > TEGRA_I2C_IPC_MAX_OUT_BUF_SIZE) return -EINVAL; return 0; } static int tegra_bpmp_i2c_msg_xfer(struct tegra_bpmp_i2c *i2c, struct mrq_i2c_request *request, struct mrq_i2c_response *response, bool atomic) { struct tegra_bpmp_message msg; int err; request->cmd = CMD_I2C_XFER; request->xfer.bus_id = i2c->bus; memset(&msg, 0, sizeof(msg)); msg.mrq = MRQ_I2C; msg.tx.data = request; msg.tx.size = sizeof(*request); msg.rx.data = response; msg.rx.size = sizeof(*response); if (atomic) err = tegra_bpmp_transfer_atomic(i2c->bpmp, &msg); else err = tegra_bpmp_transfer(i2c->bpmp, &msg); if (err < 0) { dev_err(i2c->dev, "failed to transfer message: %d\n", err); return err; } if (msg.rx.ret != 0) { if (msg.rx.ret == -BPMP_EAGAIN) { dev_dbg(i2c->dev, "arbitration lost\n"); return -EAGAIN; } if (msg.rx.ret == -BPMP_ETIMEDOUT) { dev_dbg(i2c->dev, "timeout\n"); return -ETIMEDOUT; } if (msg.rx.ret == -BPMP_ENXIO) { dev_dbg(i2c->dev, "NAK\n"); return -ENXIO; } dev_err(i2c->dev, "transaction failed: %d\n", msg.rx.ret); return -EIO; } return 0; } static int tegra_bpmp_i2c_xfer_common(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num, bool atomic) { struct tegra_bpmp_i2c *i2c = i2c_get_adapdata(adapter); struct mrq_i2c_response response; struct mrq_i2c_request request; int err; err = tegra_bpmp_i2c_msg_len_check(msgs, num); if (err < 0) { dev_err(i2c->dev, "unsupported message length\n"); return err; } memset(&request, 0, sizeof(request)); memset(&response, 0, sizeof(response)); tegra_bpmp_serialize_i2c_msg(i2c, &request, msgs, num); err = tegra_bpmp_i2c_msg_xfer(i2c, &request, &response, atomic); if (err < 0) { dev_err(i2c->dev, "failed to transfer message: %d\n", err); return err; } err = tegra_bpmp_i2c_deserialize(i2c, &response, msgs, num); if (err < 0) { dev_err(i2c->dev, "failed to deserialize message: %d\n", err); return err; } return num; } static int tegra_bpmp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num) { return tegra_bpmp_i2c_xfer_common(adapter, msgs, num, false); } static int tegra_bpmp_i2c_xfer_atomic(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num) { return tegra_bpmp_i2c_xfer_common(adapter, msgs, num, true); } static u32 tegra_bpmp_i2c_func(struct i2c_adapter *adapter) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING | I2C_FUNC_NOSTART; } static const struct i2c_algorithm tegra_bpmp_i2c_algo = { .master_xfer = tegra_bpmp_i2c_xfer, .master_xfer_atomic = tegra_bpmp_i2c_xfer_atomic, .functionality = tegra_bpmp_i2c_func, }; static int tegra_bpmp_i2c_probe(struct platform_device *pdev) { struct tegra_bpmp_i2c *i2c; u32 value; int err; i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL); if (!i2c) return -ENOMEM; i2c->dev = &pdev->dev; i2c->bpmp = dev_get_drvdata(pdev->dev.parent); if (!i2c->bpmp) return -ENODEV; err = of_property_read_u32(pdev->dev.of_node, "nvidia,bpmp-bus-id", &value); if (err < 0) return err; i2c->bus = value; i2c_set_adapdata(&i2c->adapter, i2c); i2c->adapter.owner = THIS_MODULE; strscpy(i2c->adapter.name, "Tegra BPMP I2C adapter", sizeof(i2c->adapter.name)); i2c->adapter.algo = &tegra_bpmp_i2c_algo; i2c->adapter.dev.parent = &pdev->dev; i2c->adapter.dev.of_node = pdev->dev.of_node; platform_set_drvdata(pdev, i2c); return i2c_add_adapter(&i2c->adapter); } static int tegra_bpmp_i2c_remove(struct platform_device *pdev) { struct tegra_bpmp_i2c *i2c = platform_get_drvdata(pdev); i2c_del_adapter(&i2c->adapter); return 0; } static const struct of_device_id tegra_bpmp_i2c_of_match[] = { { .compatible = "nvidia,tegra186-bpmp-i2c", }, { } }; MODULE_DEVICE_TABLE(of, tegra_bpmp_i2c_of_match); static struct platform_driver tegra_bpmp_i2c_driver = { .driver = { .name = "tegra-bpmp-i2c", .of_match_table = tegra_bpmp_i2c_of_match, }, .probe = tegra_bpmp_i2c_probe, .remove = tegra_bpmp_i2c_remove, }; module_platform_driver(tegra_bpmp_i2c_driver); MODULE_DESCRIPTION("NVIDIA Tegra BPMP I2C bus controller driver"); MODULE_AUTHOR("Shardar Shariff Md "); MODULE_AUTHOR("Juha-Matti Tilli"); MODULE_LICENSE("GPL v2");