diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-tegra-bpmp.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-tegra-bpmp.c | 347 |
1 files changed, 347 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-tegra-bpmp.c b/drivers/i2c/busses/i2c-tegra-bpmp.c new file mode 100644 index 000000000..95139985b --- /dev/null +++ b/drivers/i2c/busses/i2c-tegra-bpmp.c @@ -0,0 +1,347 @@ +// 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 <smohammed@nvidia.com> + */ + +#include <linux/err.h> +#include <linux/i2c.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> + +#include <soc/tegra/bpmp-abi.h> +#include <soc/tegra/bpmp.h> + +/* + * 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 <smohammed@nvidia.com>"); +MODULE_AUTHOR("Juha-Matti Tilli"); +MODULE_LICENSE("GPL v2"); |