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SubjectRe: [PATCH] smsc: RFC: Workaround for problems with lan8710 phy auto MDI-X
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On Nov 30, 2012, at 4:23 PM, Jiri Kosina <jkosina@suse.cz> wrote:

> I am not sure whether compile-time option for something like this is
> appropriate. Kernel module parameter, perhaps?
>
> Of course it'd be far better if faulty hardware can be autodetected in
> runtime.
Thanks for the input. Currently only the symbol error counter seems to give
a good indication that there might be a problem. So I suggest monitoring
the symbol error counter. When a certain amount of symbol errors per
poll interval is exceeded the auto MDI-X will be disabled.

Signed-off-by: Peter Turczak <pt@netconsequence.de>
---
drivers/net/phy/smsc.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++-
include/linux/smscphy.h | 7 +++++
2 files changed, 64 insertions(+), 1 deletions(-)

diff --git a/drivers/net/phy/smsc.c b/drivers/net/phy/smsc.c
index 88e3991..0748266 100644
--- a/drivers/net/phy/smsc.c
+++ b/drivers/net/phy/smsc.c
@@ -24,6 +24,16 @@
#include <linux/netdevice.h>
#include <linux/smscphy.h>

+/* Maximum number of symbol errors between two lan8720_read_status calls. */
+#define LAN8720_MAX_SYM_ERR_CNT 100
+
+static struct phy_driver lan8710_driver;
+
+struct smsc_phy_private {
+ /* Keeps track of the number of the broken received packets */
+ int sym_err_count;
+};
+
static int smsc_phy_config_intr(struct phy_device *phydev)
{
int rc = phy_write (phydev, MII_LAN83C185_IM,
@@ -58,6 +68,7 @@ static int smsc_phy_config_init(struct phy_device *phydev)

static int lan87xx_config_init(struct phy_device *phydev)
{
+ struct smsc_phy_private *privdata;
/*
* Make sure the EDPWRDOWN bit is NOT set. Setting this bit on
* LAN8710/LAN8720 PHY causes the PHY to misbehave, likely due
@@ -79,6 +90,12 @@ static int lan87xx_config_init(struct phy_device *phydev)
if (rc < 0)
return rc;

+ privdata = kzalloc(sizeof(*privdata), GFP_KERNEL);
+ if (!privdata)
+ return -ENOMEM;
+
+ phydev->priv = privdata;
+
return smsc_phy_ack_interrupt(phydev);
}

@@ -87,6 +104,44 @@ static int lan911x_config_init(struct phy_device *phydev)
return smsc_phy_ack_interrupt(phydev);
}

+int lan8720_read_status(struct phy_device *phydev)
+{
+ int err_count, err_since_last, rc;
+ struct smsc_phy_private *priv = phydev->priv;
+
+ if (priv != NULL) {
+
+ err_count = phy_read(phydev, MII_LAN8710_SYM_ERR_CNT);
+ err_since_last = err_count - priv->sym_err_count;
+
+ if (err_since_last < 0)
+ err_since_last += 65535;
+
+ priv->sym_err_count = err_count;
+ if (err_since_last > LAN8720_MAX_SYM_ERR_CNT) {
+ rc = phy_read(phydev, MII_LAN8710_SCSI);
+
+ if (rc < 0)
+ return rc;
+
+ if (!(rc & MII_LAN8710_SCSI_AMDIXCTRL)) {
+
+ pr_warn("%s: Too may RX errors.",
+ phydev->bus->name);
+ pr_warn("Disabling MDI-X\n");
+
+ rc = phy_write(phydev, MII_LAN8710_SCSI,
+ rc | MII_LAN8710_SCSI_AMDIXCTRL);
+ }
+
+ if (rc < 0)
+ return rc;
+ }
+ }
+
+ return genphy_read_status(phydev);
+}
+
static struct phy_driver smsc_phy_driver[] = {
{
.phy_id = 0x0007c0a0, /* OUI=0x00800f, Model#=0x0a */
@@ -187,7 +242,7 @@ static struct phy_driver smsc_phy_driver[] = {

/* basic functions */
.config_aneg = genphy_config_aneg,
- .read_status = genphy_read_status,
+ .read_status = lan8720_read_status,
.config_init = lan87xx_config_init,

/* IRQ related */
diff --git a/include/linux/smscphy.h b/include/linux/smscphy.h
index ce718cb..a0d3893 100644
--- a/include/linux/smscphy.h
+++ b/include/linux/smscphy.h
@@ -22,4 +22,11 @@
#define MII_LAN83C185_EDPWRDOWN (1 << 13) /* EDPWRDOWN */
#define MII_LAN83C185_ENERGYON (1 << 1) /* ENERGYON */

+#define MII_LAN8710_SCSI 27 /* Special Control/Status register */
+
+#define MII_LAN8710_SCSI_AMDIXCTRL (1<<15) /* Flag to disable Auto-MDIX */
+
+#define MII_LAN8710_SYM_ERR_CNT 26 /* Amount of invalid code symbols received */
+
+
#endif /* __LINUX_SMSCPHY_H__ */
--
1.7.0.4



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