// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) IBM Corporation 2023 */
#include <linux/device.h>
#include <linux/fsi.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/mutex.h>
#include "fsi-master-i2cr.h"
#define CREATE_TRACE_POINTS
#include <trace/events/fsi_master_i2cr.h>
#define I2CR_ADDRESS_CFAM(a) ((a) >> 2)
#define I2CR_INITIAL_PARITY true
#define I2CR_STATUS_CMD 0x60002
#define I2CR_STATUS_ERR BIT_ULL(61)
#define I2CR_ERROR_CMD 0x60004
#define I2CR_LOG_CMD 0x60008
static const u8 i2cr_cfam[] = {
0xc0, 0x02, 0x0d, 0xa6,
0x80, 0x01, 0x10, 0x02,
0x80, 0x01, 0x10, 0x02,
0x80, 0x01, 0x10, 0x02,
0x80, 0x01, 0x80, 0x52,
0x80, 0x01, 0x10, 0x02,
0x80, 0x01, 0x10, 0x02,
0x80, 0x01, 0x10, 0x02,
0x80, 0x01, 0x10, 0x02,
0x80, 0x01, 0x22, 0x2d,
0x00, 0x00, 0x00, 0x00,
0xde, 0xad, 0xc0, 0xde
};
static bool i2cr_check_parity32(u32 v, bool parity)
{
u32 i;
for (i = 0; i < 32; ++i) {
if (v & (1u << i))
parity = !parity;
}
return parity;
}
static bool i2cr_check_parity64(u64 v)
{
u32 i;
bool parity = I2CR_INITIAL_PARITY;
for (i = 0; i < 64; ++i) {
if (v & (1llu << i))
parity = !parity;
}
return parity;
}
static u32 i2cr_get_command(u32 address, bool parity)
{
address <<= 1;
if (i2cr_check_parity32(address, parity))
address |= 1;
return address;
}
static int i2cr_transfer(struct i2c_client *client, u32 command, u64 *data)
{
struct i2c_msg msgs[2];
int ret;
msgs[0].addr = client->addr;
msgs[0].flags = 0;
msgs[0].len = sizeof(command);
msgs[0].buf = (__u8 *)&command;
msgs[1].addr = client->addr;
msgs[1].flags = I2C_M_RD;
msgs[1].len = sizeof(*data);
msgs[1].buf = (__u8 *)data;
ret = i2c_transfer(client->adapter, msgs, 2);
if (ret == 2)
return 0;
trace_i2cr_i2c_error(client, command, ret);
if (ret < 0)
return ret;
return -EIO;
}
static int i2cr_check_status(struct i2c_client *client)
{
u64 status;
int ret;
ret = i2cr_transfer(client, I2CR_STATUS_CMD, &status);
if (ret)
return ret;
if (status & I2CR_STATUS_ERR) {
u32 buf[3] = { 0, 0, 0 };
u64 error;
u64 log;
i2cr_transfer(client, I2CR_ERROR_CMD, &error);
i2cr_transfer(client, I2CR_LOG_CMD, &log);
trace_i2cr_status_error(client, status, error, log);
buf[0] = I2CR_STATUS_CMD;
i2c_master_send(client, (const char *)buf, sizeof(buf));
buf[0] = I2CR_ERROR_CMD;
i2c_master_send(client, (const char *)buf, sizeof(buf));
buf[0] = I2CR_LOG_CMD;
i2c_master_send(client, (const char *)buf, sizeof(buf));
dev_err(&client->dev, "status:%016llx error:%016llx log:%016llx\n", status, error,
log);
return -EREMOTEIO;
}
trace_i2cr_status(client, status);
return 0;
}
int fsi_master_i2cr_read(struct fsi_master_i2cr *i2cr, u32 addr, u64 *data)
{
u32 command = i2cr_get_command(addr, I2CR_INITIAL_PARITY);
int ret;
mutex_lock(&i2cr->lock);
ret = i2cr_transfer(i2cr->client, command, data);
if (ret)
goto unlock;
ret = i2cr_check_status(i2cr->client);
if (ret)
goto unlock;
trace_i2cr_read(i2cr->client, command, data);
unlock:
mutex_unlock(&i2cr->lock);
return ret;
}
EXPORT_SYMBOL_GPL(fsi_master_i2cr_read);
int fsi_master_i2cr_write(struct fsi_master_i2cr *i2cr, u32 addr, u64 data)
{
u32 buf[3] = { 0 };
int ret;
buf[0] = i2cr_get_command(addr, i2cr_check_parity64(data));
memcpy(&buf[1], &data, sizeof(data));
mutex_lock(&i2cr->lock);
ret = i2c_master_send(i2cr->client, (const char *)buf, sizeof(buf));
if (ret == sizeof(buf)) {
ret = i2cr_check_status(i2cr->client);
if (!ret)
trace_i2cr_write(i2cr->client, buf[0], data);
} else {
trace_i2cr_i2c_error(i2cr->client, buf[0], ret);
if (ret >= 0)
ret = -EIO;
}
mutex_unlock(&i2cr->lock);
return ret;
}
EXPORT_SYMBOL_GPL(fsi_master_i2cr_write);
static int i2cr_read(struct fsi_master *master, int link, uint8_t id, uint32_t addr, void *val,
size_t size)
{
struct fsi_master_i2cr *i2cr = container_of(master, struct fsi_master_i2cr, master);
u64 data;
size_t i;
int ret;
if (link || id || (addr & 0xffff0000) || !(size == 1 || size == 2 || size == 4))
return -EINVAL;
/*
* The I2CR doesn't have CFAM or FSI slave address space - only the
* engines. In order for this to work with the FSI core, we need to
* emulate at minimum the CFAM config table so that the appropriate
* engines are discovered.
*/
if (addr < 0xc00) {
if (addr > sizeof(i2cr_cfam) - 4)
addr = (addr & 0x3) + (sizeof(i2cr_cfam) - 4);
memcpy(val, &i2cr_cfam[addr], size);
return 0;
}
ret = fsi_master_i2cr_read(i2cr, I2CR_ADDRESS_CFAM(addr), &data);
if (ret)
return ret;
/*
* FSI core expects up to 4 bytes BE back, while I2CR replied with LE
* bytes on the wire.
*/
for (i = 0; i < size; ++i)
((u8 *)val)[i] = ((u8 *)&data)[7 - i];
return 0;
}
static int i2cr_write(struct fsi_master *master, int link, uint8_t id, uint32_t addr,
const void *val, size_t size)
{
struct fsi_master_i2cr *i2cr = container_of(master, struct fsi_master_i2cr, master);
u64 data = 0;
size_t i;
if (link || id || (addr & 0xffff0000) || !(size == 1 || size == 2 || size == 4))
return -EINVAL;
/* I2CR writes to CFAM or FSI slave address are a successful no-op. */
if (addr < 0xc00)
return 0;
/*
* FSI core passes up to 4 bytes BE, while the I2CR expects LE bytes on
* the wire.
*/
for (i = 0; i < size; ++i)
((u8 *)&data)[7 - i] = ((u8 *)val)[i];
return fsi_master_i2cr_write(i2cr, I2CR_ADDRESS_CFAM(addr), data);
}
static void i2cr_release(struct device *dev)
{
struct fsi_master_i2cr *i2cr = to_fsi_master_i2cr(to_fsi_master(dev));
of_node_put(dev->of_node);
kfree(i2cr);
}
static int i2cr_probe(struct i2c_client *client)
{
struct fsi_master_i2cr *i2cr;
int ret;
i2cr = kzalloc(sizeof(*i2cr), GFP_KERNEL);
if (!i2cr)
return -ENOMEM;
/* Only one I2CR on any given I2C bus (fixed I2C device address) */
i2cr->master.idx = client->adapter->nr;
dev_set_name(&i2cr->master.dev, "i2cr%d", i2cr->master.idx);
i2cr->master.dev.parent = &client->dev;
i2cr->master.dev.of_node = of_node_get(dev_of_node(&client->dev));
i2cr->master.dev.release = i2cr_release;
i2cr->master.n_links = 1;
i2cr->master.read = i2cr_read;
i2cr->master.write = i2cr_write;
mutex_init(&i2cr->lock);
i2cr->client = client;
ret = fsi_master_register(&i2cr->master);
if (ret)
return ret;
i2c_set_clientdata(client, i2cr);
return 0;
}
static void i2cr_remove(struct i2c_client *client)
{
struct fsi_master_i2cr *i2cr = i2c_get_clientdata(client);
fsi_master_unregister(&i2cr->master);
}
static const struct of_device_id i2cr_ids[] = {
{ .compatible = "ibm,i2cr-fsi-master" },
{ }
};
MODULE_DEVICE_TABLE(of, i2cr_ids);
static struct i2c_driver i2cr_driver = {
.probe_new = i2cr_probe,
.remove = i2cr_remove,
.driver = {
.name = "fsi-master-i2cr",
.of_match_table = i2cr_ids,
},
};
module_i2c_driver(i2cr_driver)
MODULE_AUTHOR("Eddie James <eajames@linux.ibm.com>");
MODULE_DESCRIPTION("IBM I2C Responder virtual FSI master driver");
MODULE_LICENSE("GPL");
