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

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/*
* drivers/i2c/busses/i2c-tegra-bpmp.c
*
* Copyright (c) 2016 NVIDIA Corporation. All rights reserved.
*
* Author: Shardar Shariff Md <smohammed@nvidia.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#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 int tegra_bpmp_xlate_flags(u16 flags, u16 *out)
{
if (flags & I2C_M_TEN) {
*out |= SERIALI2C_TEN;
flags &= ~I2C_M_TEN;
}
if (flags & I2C_M_RD) {
*out |= SERIALI2C_RD;
flags &= ~I2C_M_RD;
}
if (flags & I2C_M_STOP) {
*out |= SERIALI2C_STOP;
flags &= ~I2C_M_STOP;
}
if (flags & I2C_M_NOSTART) {
*out |= SERIALI2C_NOSTART;
flags &= ~I2C_M_NOSTART;
}
if (flags & I2C_M_REV_DIR_ADDR) {
*out |= SERIALI2C_REV_DIR_ADDR;
flags &= ~I2C_M_REV_DIR_ADDR;
}
if (flags & I2C_M_IGNORE_NAK) {
*out |= SERIALI2C_IGNORE_NAK;
flags &= ~I2C_M_IGNORE_NAK;
}
if (flags & I2C_M_NO_RD_ACK) {
*out |= SERIALI2C_NO_RD_ACK;
flags &= ~I2C_M_NO_RD_ACK;
}
if (flags & I2C_M_RECV_LEN) {
*out |= SERIALI2C_RECV_LEN;
flags &= ~I2C_M_RECV_LEN;
}
return (flags != 0) ? -EINVAL : 0;
}
/**
* 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 int 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;
int err;
for (i = 0; i < num; i++) {
struct i2c_msg *msg = &msgs[i];
u16 flags = 0;
err = tegra_bpmp_xlate_flags(msg->flags, &flags);
if (err < 0)
return err;
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;
return 0;
}
/**
* 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);
return err;
}
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));
err = tegra_bpmp_serialize_i2c_msg(i2c, &request, msgs, num);
if (err < 0) {
dev_err(i2c->dev, "failed to serialize message: %d\n", err);
return err;
}
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;
strlcpy(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");
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