/*
* FSI core driver
*
* Copyright (C) IBM Corporation 2016
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that 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.
*/
#include <linux/crc4.h>
#include <linux/device.h>
#include <linux/fsi.h>
#include <linux/idr.h>
#include <linux/module.h>
#include <linux/slab.h>
#include "fsi-master.h"
#define FSI_SLAVE_SIZE_23b 0x800000
static DEFINE_IDA(master_ida);
struct fsi_slave {
struct device dev;
struct fsi_master *master;
int id;
int link;
uint32_t size; /* size of slave address space */
};
#define to_fsi_slave(d) container_of(d, struct fsi_slave, dev)
static int fsi_master_read(struct fsi_master *master, int link,
uint8_t slave_id, uint32_t addr, void *val, size_t size);
static int fsi_master_write(struct fsi_master *master, int link,
uint8_t slave_id, uint32_t addr, const void *val, size_t size);
/* FSI slave support */
static int fsi_slave_calc_addr(struct fsi_slave *slave, uint32_t *addrp,
uint8_t *idp)
{
uint32_t addr = *addrp;
uint8_t id = *idp;
if (addr > slave->size)
return -EINVAL;
/* For 23 bit addressing, we encode the extra two bits in the slave
* id (and the slave's actual ID needs to be 0).
*/
if (addr > 0x1fffff) {
if (slave->id != 0)
return -EINVAL;
id = (addr >> 21) & 0x3;
addr &= 0x1fffff;
}
*addrp = addr;
*idp = id;
return 0;
}
static int fsi_slave_read(struct fsi_slave *slave, uint32_t addr,
void *val, size_t size)
{
uint8_t id = slave->id;
int rc;
rc = fsi_slave_calc_addr(slave, &addr, &id);
if (rc)
return rc;
return fsi_master_read(slave->master, slave->link, id,
addr, val, size);
}
static int fsi_slave_write(struct fsi_slave *slave, uint32_t addr,
const void *val, size_t size)
{
uint8_t id = slave->id;
int rc;
rc = fsi_slave_calc_addr(slave, &addr, &id);
if (rc)
return rc;
return fsi_master_write(slave->master, slave->link, id,
addr, val, size);
}
static void fsi_slave_release(struct device *dev)
{
struct fsi_slave *slave = to_fsi_slave(dev);
kfree(slave);
}
static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
{
struct fsi_slave *slave;
uint32_t chip_id;
uint8_t crc;
int rc;
/* Currently, we only support single slaves on a link, and use the
* full 23-bit address range
*/
if (id != 0)
return -EINVAL;
rc = fsi_master_read(master, link, id, 0, &chip_id, sizeof(chip_id));
if (rc) {
dev_dbg(&master->dev, "can't read slave %02x:%02x %d\n",
link, id, rc);
return -ENODEV;
}
chip_id = be32_to_cpu(chip_id);
crc = crc4(0, chip_id, 32);
if (crc) {
dev_warn(&master->dev, "slave %02x:%02x invalid chip id CRC!\n",
link, id);
return -EIO;
}
dev_info(&master->dev, "fsi: found chip %08x at %02x:%02x:%02x\n",
chip_id, master->idx, link, id);
/* We can communicate with a slave; create the slave device and
* register.
*/
slave = kzalloc(sizeof(*slave), GFP_KERNEL);
if (!slave)
return -ENOMEM;
slave->master = master;
slave->dev.parent = &master->dev;
slave->dev.release = fsi_slave_release;
slave->link = link;
slave->id = id;
slave->size = FSI_SLAVE_SIZE_23b;
dev_set_name(&slave->dev, "slave@%02x:%02x", link, id);
rc = device_register(&slave->dev);
if (rc < 0) {
dev_warn(&master->dev, "failed to create slave device: %d\n",
rc);
put_device(&slave->dev);
return rc;
}
/* todo: perform engine scan */
return rc;
}
/* FSI master support */
static int fsi_check_access(uint32_t addr, size_t size)
{
if (size != 1 && size != 2 && size != 4)
return -EINVAL;
if ((addr & 0x3) != (size & 0x3))
return -EINVAL;
return 0;
}
static int fsi_master_read(struct fsi_master *master, int link,
uint8_t slave_id, uint32_t addr, void *val, size_t size)
{
int rc;
rc = fsi_check_access(addr, size);
if (rc)
return rc;
return master->read(master, link, slave_id, addr, val, size);
}
static int fsi_master_write(struct fsi_master *master, int link,
uint8_t slave_id, uint32_t addr, const void *val, size_t size)
{
int rc;
rc = fsi_check_access(addr, size);
if (rc)
return rc;
return master->write(master, link, slave_id, addr, val, size);
}
static int fsi_master_link_enable(struct fsi_master *master, int link)
{
if (master->link_enable)
return master->link_enable(master, link);
return 0;
}
/*
* Issue a break command on this link
*/
static int fsi_master_break(struct fsi_master *master, int link)
{
if (master->send_break)
return master->send_break(master, link);
return 0;
}
static int fsi_master_scan(struct fsi_master *master)
{
int link, rc;
for (link = 0; link < master->n_links; link++) {
rc = fsi_master_link_enable(master, link);
if (rc) {
dev_dbg(&master->dev,
"enable link %d failed: %d\n", link, rc);
continue;
}
rc = fsi_master_break(master, link);
if (rc) {
dev_dbg(&master->dev,
"break to link %d failed: %d\n", link, rc);
continue;
}
fsi_slave_init(master, link, 0);
}
return 0;
}
int fsi_master_register(struct fsi_master *master)
{
int rc;
if (!master)
return -EINVAL;
master->idx = ida_simple_get(&master_ida, 0, INT_MAX, GFP_KERNEL);
dev_set_name(&master->dev, "fsi%d", master->idx);
rc = device_register(&master->dev);
if (rc) {
ida_simple_remove(&master_ida, master->idx);
return rc;
}
fsi_master_scan(master);
return 0;
}
EXPORT_SYMBOL_GPL(fsi_master_register);
void fsi_master_unregister(struct fsi_master *master)
{
if (master->idx >= 0) {
ida_simple_remove(&master_ida, master->idx);
master->idx = -1;
}
device_unregister(&master->dev);
}
EXPORT_SYMBOL_GPL(fsi_master_unregister);
/* FSI core & Linux bus type definitions */
static int fsi_bus_match(struct device *dev, struct device_driver *drv)
{
struct fsi_device *fsi_dev = to_fsi_dev(dev);
struct fsi_driver *fsi_drv = to_fsi_drv(drv);
const struct fsi_device_id *id;
if (!fsi_drv->id_table)
return 0;
for (id = fsi_drv->id_table; id->engine_type; id++) {
if (id->engine_type != fsi_dev->engine_type)
continue;
if (id->version == FSI_VERSION_ANY ||
id->version == fsi_dev->version)
return 1;
}
return 0;
}
struct bus_type fsi_bus_type = {
.name = "fsi",
.match = fsi_bus_match,
};
EXPORT_SYMBOL_GPL(fsi_bus_type);
static int fsi_init(void)
{
return bus_register(&fsi_bus_type);
}
static void fsi_exit(void)
{
bus_unregister(&fsi_bus_type);
}
module_init(fsi_init);
module_exit(fsi_exit);
