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