/*
* Copyright (C) 2018 Sylvie Barlow <sylvie.c.barlow@gmail.com>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <stdint.h>
#include <unistd.h>
#include <ipxe/bitbash.h>
#include <ipxe/mii_bit.h>
/**
* Transfer bits over MII bit-bashing interface
*
* @v basher Bit basher
* @v mask Mask
* @v write Data to write
* @ret read Data read
*/
static uint32_t mii_bit_xfer ( struct bit_basher *basher,
uint32_t mask, uint32_t write ) {
uint32_t read = 0;
int bit;
for ( ; mask ; mask >>= 1 ) {
/* Delay */
udelay ( 1 );
/* Write bit to basher */
write_bit ( basher, MII_BIT_MDIO, ( write & mask ) );
/* Read bit from basher */
bit = read_bit ( basher, MII_BIT_MDIO );
read <<= 1;
read |= ( bit & 1 );
/* Set clock high */
write_bit ( basher, MII_BIT_MDC, 1 );
/* Delay */
udelay ( 1 );
/* Set clock low */
write_bit ( basher, MII_BIT_MDC, 0 );
}
return read;
}
/**
* Read or write via MII bit-bashing interface
*
* @v basher Bit basher
* @v phy PHY address
* @v reg Register address
* @v data Data to write
* @v cmd Command
* @ret data Data read
*/
static unsigned int mii_bit_rw ( struct bit_basher *basher,
unsigned int phy, unsigned int reg,
unsigned int data, unsigned int cmd ) {
/* Initiate drive for write */
write_bit ( basher, MII_BIT_DRIVE, 1 );
/* Write start */
mii_bit_xfer ( basher, MII_BIT_START_MASK, MII_BIT_START );
/* Write command */
mii_bit_xfer ( basher, MII_BIT_CMD_MASK, cmd );
/* Write PHY address */
mii_bit_xfer ( basher, MII_BIT_PHY_MASK, phy );
/* Write register address */
mii_bit_xfer ( basher, MII_BIT_REG_MASK, reg );
/* Switch drive to read if applicable */
write_bit ( basher, MII_BIT_DRIVE, ( cmd & MII_BIT_CMD_RW ) );
/* Allow space for turnaround */
mii_bit_xfer ( basher, MII_BIT_SWITCH_MASK, MII_BIT_SWITCH );
/* Read or write data */
data = mii_bit_xfer (basher, MII_BIT_DATA_MASK, data );
/* Initiate drive for read */
write_bit ( basher, MII_BIT_DRIVE, 0 );
return data;
}
/**
* Read from MII register
*
* @v mdio MII interface
* @v phy PHY address
* @v reg Register address
* @ret data Data read, or negative error
*/
static int mii_bit_read ( struct mii_interface *mdio, unsigned int phy,
unsigned int reg ) {
struct mii_bit_basher *miibit =
container_of ( mdio, struct mii_bit_basher, mdio );
struct bit_basher *basher = &miibit->basher;
return mii_bit_rw ( basher, phy, reg, 0, MII_BIT_CMD_READ );
}
/**
* Write to MII register
*
* @v mdio MII interface
* @v phy PHY address
* @v reg Register address
* @v data Data to write
* @ret rc Return status code
*/
static int mii_bit_write ( struct mii_interface *mdio, unsigned int phy,
unsigned int reg, unsigned int data ) {
struct mii_bit_basher *miibit =
container_of ( mdio, struct mii_bit_basher, mdio );
struct bit_basher *basher = &miibit->basher;
mii_bit_rw ( basher, phy, reg, data, MII_BIT_CMD_WRITE );
return 0;
}
/** MII bit basher operations */
static struct mii_operations mii_bit_op = {
.read = mii_bit_read,
.write = mii_bit_write,
};
/**
* Initialise bit-bashing interface
*
* @v miibit MII bit basher
*/
void init_mii_bit_basher ( struct mii_bit_basher *miibit ) {
mdio_init ( &miibit->mdio, &mii_bit_op );
};
