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linux/drivers/net/ibm_emac/ibm_emac_phy.c
Eugene Surovegin 5bb96e9f24 ibm_emac: improved PHY support 
Original patch is from Jeff Haran  <jharan@brocade.com> with my minor style
fixes. His comments follow:

The first problem was in the function that configures the PHY for
autonegotiation, genmii_setup_aneg(). The original code does a
read/modify/write of the autonegotiation advertizement register (reg 4),
followed by a read/modify/write of the control register (reg 0). While
the original code follows the proper procedure as per reading the IEEE
specs, what I found is that on at least one PHY model (National DP83843)
the read of the control register comes back with the soft reset bit set
(bit 15). Because of the read/modify/write operation, this causes the
write to write a 1 back to the reset bit, which initiates a software
reset of the PHY. This software reset causes the PHY to return to its
power up state which advertizes all modes of operation, thus negating
the write to the autoneg advertizement register. The modification is to
spin reading the control register until the soft reset bit is clear
before doing the modify/write.
The second problem was in the function that configures the PHY for
forced operation, genmii_setup_forced(). The original code initiates a
software reset operation via a write of a 1 to bit 15 of the control
register (reg 0), but then proceeds to do a second write to that same
register without waiting until that reset bit is cleared by the PHY
itself (which according to the IEEE specs indicates that the PHY reset
is complete). This is a violation of how one is supposed to use this
software reset feature of these PHYs and I believe was the cause of
mysterious, difficult to reproduce link failures that we've observed on
some of our systems that use this driver. The fix is to modify the
function so that it spins waiting for the reset bit to clear after doing
the soft reset and before doing the subsequent write.

Signed-off-by: Jeff Haran <jharan@brocade.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Eugene Surovegin <ebs@ebshome.net>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-05-17 20:43:14 -04:00

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/*
* drivers/net/ibm_emac/ibm_emac_phy.c
*
* Driver for PowerPC 4xx on-chip ethernet controller, PHY support.
* Borrowed from sungem_phy.c, though I only kept the generic MII
* driver for now.
*
* This file should be shared with other drivers or eventually
* merged as the "low level" part of miilib
*
* (c) 2003, Benjamin Herrenscmidt (benh@kernel.crashing.org)
* (c) 2004-2005, Eugene Surovegin <ebs@ebshome.net>
*
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/netdevice.h>
#include <linux/mii.h>
#include <linux/ethtool.h>
#include <linux/delay.h>
#include <asm/ocp.h>
#include "ibm_emac_core.h"
#include "ibm_emac_phy.h"
static inline int phy_read(struct mii_phy *phy, int reg)
{
return phy->mdio_read(phy->dev, phy->address, reg);
}
static inline void phy_write(struct mii_phy *phy, int reg, int val)
{
phy->mdio_write(phy->dev, phy->address, reg, val);
}
/*
* polls MII_BMCR until BMCR_RESET bit clears or operation times out.
*
* returns:
* >= 0 => success, value in BMCR returned to caller
* -EBUSY => failure, RESET bit never cleared
* otherwise => failure, lower level PHY read failed
*/
static int mii_spin_reset_complete(struct mii_phy *phy)
{
int val;
int limit = 10000;
while (limit--) {
val = phy_read(phy, MII_BMCR);
if (val >= 0 && !(val & BMCR_RESET))
return val; /* success */
udelay(10);
}
if (val & BMCR_RESET)
val = -EBUSY;
if (net_ratelimit())
printk(KERN_ERR "emac%d: PHY reset timeout (%d)\n",
((struct ocp_enet_private *)phy->dev->priv)->def->index,
val);
return val;
}
int mii_reset_phy(struct mii_phy *phy)
{
int val;
val = phy_read(phy, MII_BMCR);
val &= ~BMCR_ISOLATE;
val |= BMCR_RESET;
phy_write(phy, MII_BMCR, val);
udelay(300);
val = mii_spin_reset_complete(phy);
if (val >= 0 && (val & BMCR_ISOLATE))
phy_write(phy, MII_BMCR, val & ~BMCR_ISOLATE);
return val < 0;
}
static int genmii_setup_aneg(struct mii_phy *phy, u32 advertise)
{
int ctl, adv;
phy->autoneg = AUTONEG_ENABLE;
phy->speed = SPEED_10;
phy->duplex = DUPLEX_HALF;
phy->pause = phy->asym_pause = 0;
phy->advertising = advertise;
/* Setup standard advertise */
adv = phy_read(phy, MII_ADVERTISE);
if (adv < 0)
return adv;
adv &= ~(ADVERTISE_ALL | ADVERTISE_100BASE4 | ADVERTISE_PAUSE_CAP |
ADVERTISE_PAUSE_ASYM);
if (advertise & ADVERTISED_10baseT_Half)
adv |= ADVERTISE_10HALF;
if (advertise & ADVERTISED_10baseT_Full)
adv |= ADVERTISE_10FULL;
if (advertise & ADVERTISED_100baseT_Half)
adv |= ADVERTISE_100HALF;
if (advertise & ADVERTISED_100baseT_Full)
adv |= ADVERTISE_100FULL;
if (advertise & ADVERTISED_Pause)
adv |= ADVERTISE_PAUSE_CAP;
if (advertise & ADVERTISED_Asym_Pause)
adv |= ADVERTISE_PAUSE_ASYM;
phy_write(phy, MII_ADVERTISE, adv);
if (phy->features &
(SUPPORTED_1000baseT_Full | SUPPORTED_1000baseT_Half)) {
adv = phy_read(phy, MII_CTRL1000);
if (adv < 0)
return adv;
adv &= ~(ADVERTISE_1000FULL | ADVERTISE_1000HALF);
if (advertise & ADVERTISED_1000baseT_Full)
adv |= ADVERTISE_1000FULL;
if (advertise & ADVERTISED_1000baseT_Half)
adv |= ADVERTISE_1000HALF;
phy_write(phy, MII_CTRL1000, adv);
}
/* Start/Restart aneg */
/* on some PHYs (e.g. National DP83843) a write to MII_ADVERTISE
* causes BMCR_RESET to be set on the next read of MII_BMCR, which
* if not checked for causes the PHY to be reset below */
ctl = mii_spin_reset_complete(phy);
if (ctl < 0)
return ctl;
ctl |= BMCR_ANENABLE | BMCR_ANRESTART;
phy_write(phy, MII_BMCR, ctl);
return 0;
}
static int genmii_setup_forced(struct mii_phy *phy, int speed, int fd)
{
int ctl;
phy->autoneg = AUTONEG_DISABLE;
phy->speed = speed;
phy->duplex = fd;
phy->pause = phy->asym_pause = 0;
/* First reset the PHY */
mii_reset_phy(phy);
ctl = phy_read(phy, MII_BMCR);
if (ctl < 0)
return ctl;
ctl &= ~(BMCR_FULLDPLX | BMCR_SPEED100 | BMCR_ANENABLE | BMCR_SPEED1000);
/* Select speed & duplex */
switch (speed) {
case SPEED_10:
break;
case SPEED_100:
ctl |= BMCR_SPEED100;
break;
case SPEED_1000:
ctl |= BMCR_SPEED1000;
break;
default:
return -EINVAL;
}
if (fd == DUPLEX_FULL)
ctl |= BMCR_FULLDPLX;
phy_write(phy, MII_BMCR, ctl);
return 0;
}
static int genmii_poll_link(struct mii_phy *phy)
{
int status;
/* Clear latched value with dummy read */
phy_read(phy, MII_BMSR);
status = phy_read(phy, MII_BMSR);
if (status < 0 || (status & BMSR_LSTATUS) == 0)
return 0;
if (phy->autoneg == AUTONEG_ENABLE && !(status & BMSR_ANEGCOMPLETE))
return 0;
return 1;
}
static int genmii_read_link(struct mii_phy *phy)
{
if (phy->autoneg == AUTONEG_ENABLE) {
int glpa = 0;
int lpa = phy_read(phy, MII_LPA) & phy_read(phy, MII_ADVERTISE);
if (lpa < 0)
return lpa;
if (phy->features &
(SUPPORTED_1000baseT_Full | SUPPORTED_1000baseT_Half)) {
int adv = phy_read(phy, MII_CTRL1000);
glpa = phy_read(phy, MII_STAT1000);
if (glpa < 0 || adv < 0)
return adv;
glpa &= adv << 2;
}
phy->speed = SPEED_10;
phy->duplex = DUPLEX_HALF;
phy->pause = phy->asym_pause = 0;
if (glpa & (LPA_1000FULL | LPA_1000HALF)) {
phy->speed = SPEED_1000;
if (glpa & LPA_1000FULL)
phy->duplex = DUPLEX_FULL;
} else if (lpa & (LPA_100FULL | LPA_100HALF)) {
phy->speed = SPEED_100;
if (lpa & LPA_100FULL)
phy->duplex = DUPLEX_FULL;
} else if (lpa & LPA_10FULL)
phy->duplex = DUPLEX_FULL;
if (phy->duplex == DUPLEX_FULL) {
phy->pause = lpa & LPA_PAUSE_CAP ? 1 : 0;
phy->asym_pause = lpa & LPA_PAUSE_ASYM ? 1 : 0;
}
} else {
int bmcr = phy_read(phy, MII_BMCR);
if (bmcr < 0)
return bmcr;
if (bmcr & BMCR_FULLDPLX)
phy->duplex = DUPLEX_FULL;
else
phy->duplex = DUPLEX_HALF;
if (bmcr & BMCR_SPEED1000)
phy->speed = SPEED_1000;
else if (bmcr & BMCR_SPEED100)
phy->speed = SPEED_100;
else
phy->speed = SPEED_10;
phy->pause = phy->asym_pause = 0;
}
return 0;
}
/* Generic implementation for most 10/100/1000 PHYs */
static struct mii_phy_ops generic_phy_ops = {
.setup_aneg = genmii_setup_aneg,
.setup_forced = genmii_setup_forced,
.poll_link = genmii_poll_link,
.read_link = genmii_read_link
};
static struct mii_phy_def genmii_phy_def = {
.phy_id = 0x00000000,
.phy_id_mask = 0x00000000,
.name = "Generic MII",
.ops = &generic_phy_ops
};
/* CIS8201 */
#define MII_CIS8201_10BTCSR 0x16
#define TENBTCSR_ECHO_DISABLE 0x2000
#define MII_CIS8201_EPCR 0x17
#define EPCR_MODE_MASK 0x3000
#define EPCR_GMII_MODE 0x0000
#define EPCR_RGMII_MODE 0x1000
#define EPCR_TBI_MODE 0x2000
#define EPCR_RTBI_MODE 0x3000
#define MII_CIS8201_ACSR 0x1c
#define ACSR_PIN_PRIO_SELECT 0x0004
static int cis8201_init(struct mii_phy *phy)
{
int epcr;
epcr = phy_read(phy, MII_CIS8201_EPCR);
if (epcr < 0)
return epcr;
epcr &= ~EPCR_MODE_MASK;
switch (phy->mode) {
case PHY_MODE_TBI:
epcr |= EPCR_TBI_MODE;
break;
case PHY_MODE_RTBI:
epcr |= EPCR_RTBI_MODE;
break;
case PHY_MODE_GMII:
epcr |= EPCR_GMII_MODE;
break;
case PHY_MODE_RGMII:
default:
epcr |= EPCR_RGMII_MODE;
}
phy_write(phy, MII_CIS8201_EPCR, epcr);
/* MII regs override strap pins */
phy_write(phy, MII_CIS8201_ACSR,
phy_read(phy, MII_CIS8201_ACSR) | ACSR_PIN_PRIO_SELECT);
/* Disable TX_EN -> CRS echo mode, otherwise 10/HDX doesn't work */
phy_write(phy, MII_CIS8201_10BTCSR,
phy_read(phy, MII_CIS8201_10BTCSR) | TENBTCSR_ECHO_DISABLE);
return 0;
}
static struct mii_phy_ops cis8201_phy_ops = {
.init = cis8201_init,
.setup_aneg = genmii_setup_aneg,
.setup_forced = genmii_setup_forced,
.poll_link = genmii_poll_link,
.read_link = genmii_read_link
};
static struct mii_phy_def cis8201_phy_def = {
.phy_id = 0x000fc410,
.phy_id_mask = 0x000ffff0,
.name = "CIS8201 Gigabit Ethernet",
.ops = &cis8201_phy_ops
};
static struct mii_phy_def *mii_phy_table[] = {
&cis8201_phy_def,
&genmii_phy_def,
NULL
};
int mii_phy_probe(struct mii_phy *phy, int address)
{
struct mii_phy_def *def;
int i;
int id;
phy->autoneg = AUTONEG_DISABLE;
phy->advertising = 0;
phy->address = address;
phy->speed = SPEED_10;
phy->duplex = DUPLEX_HALF;
phy->pause = phy->asym_pause = 0;
/* Take PHY out of isolate mode and reset it. */
if (mii_reset_phy(phy))
return -ENODEV;
/* Read ID and find matching entry */
id = (phy_read(phy, MII_PHYSID1) << 16) | phy_read(phy, MII_PHYSID2);
if (id < 0)
return -ENODEV;
for (i = 0; (def = mii_phy_table[i]) != NULL; i++)
if ((id & def->phy_id_mask) == def->phy_id)
break;
/* Should never be NULL (we have a generic entry), but... */
if (!def)
return -ENODEV;
phy->def = def;
/* Determine PHY features if needed */
phy->features = def->features;
if (!phy->features) {
u16 bmsr = phy_read(phy, MII_BMSR);
if (bmsr & BMSR_ANEGCAPABLE)
phy->features |= SUPPORTED_Autoneg;
if (bmsr & BMSR_10HALF)
phy->features |= SUPPORTED_10baseT_Half;
if (bmsr & BMSR_10FULL)
phy->features |= SUPPORTED_10baseT_Full;
if (bmsr & BMSR_100HALF)
phy->features |= SUPPORTED_100baseT_Half;
if (bmsr & BMSR_100FULL)
phy->features |= SUPPORTED_100baseT_Full;
if (bmsr & BMSR_ESTATEN) {
u16 esr = phy_read(phy, MII_ESTATUS);
if (esr & ESTATUS_1000_TFULL)
phy->features |= SUPPORTED_1000baseT_Full;
if (esr & ESTATUS_1000_THALF)
phy->features |= SUPPORTED_1000baseT_Half;
}
phy->features |= SUPPORTED_MII;
}
/* Setup default advertising */
phy->advertising = phy->features;
return 0;
}
MODULE_LICENSE("GPL");
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