On Mon, May 27, 2019 at 08:29:45PM +0200, Heiner Kallweit wrote:
> Especially with fibre links there may be very short link drops. And if
> interrupt handling is slow we may miss such a link drop. To deal with
> this we remove the double link status read from the generic link status
> read functions, and call the state machine twice instead.
> The flag for double-reading link status can be set by phy_mac_interrupt
> from hard irq context, therefore we have to use an atomic operation.
I came up with a different solution to this - I haven't extensively
tested it yet though:
drivers/net/phy/phy-c45.c | 12 ------------
drivers/net/phy/phy.c | 29 +++++++++++++++++++----------
drivers/net/phy/phy_device.c | 14 --------------
3 files changed, 19 insertions(+), 36 deletions(-)
diff --git a/drivers/net/phy/phy-c45.c b/drivers/net/phy/phy-c45.c
index 9e24d9569424..756d7711cbc5 100644
--- a/drivers/net/phy/phy-c45.c
+++ b/drivers/net/phy/phy-c45.c
@@ -222,18 +222,6 @@ int genphy_c45_read_link(struct phy_device *phydev)
devad = __ffs(mmd_mask);
mmd_mask &= ~BIT(devad);
- /* The link state is latched low so that momentary link
- * drops can be detected. Do not double-read the status
- * in polling mode to detect such short link drops.
- */
- if (!phy_polling_mode(phydev)) {
- val = phy_read_mmd(phydev, devad, MDIO_STAT1);
- if (val < 0)
- return val;
- else if (val & MDIO_STAT1_LSTATUS)
- continue;
- }
-
val = phy_read_mmd(phydev, devad, MDIO_STAT1);
if (val < 0)
return val;
diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index 7b3c5eec0129..2e7f0428e8fa 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -507,20 +507,29 @@ static int phy_config_aneg(struct phy_device *phydev)
*/
static int phy_check_link_status(struct phy_device *phydev)
{
- int err;
+ int err, i;
WARN_ON(!mutex_is_locked(&phydev->lock));
- err = phy_read_status(phydev);
- if (err)
- return err;
+ /* The link state is latched low so that momentary link drops can
+ * be detected. If the link has failed, re-read the link status
+ * to ensure that we are up to date with the current link state,
+ * while notifying that the link status has changed.
+ */
+ for (i = 0; i < 2; i++) {
+ err = phy_read_status(phydev);
+ if (err)
+ return err;
- if (phydev->link && phydev->state != PHY_RUNNING) {
- phydev->state = PHY_RUNNING;
- phy_link_up(phydev);
- } else if (!phydev->link && phydev->state != PHY_NOLINK) {
- phydev->state = PHY_NOLINK;
- phy_link_down(phydev, true);
+ if (phydev->link && phydev->state != PHY_RUNNING) {
+ phydev->state = PHY_RUNNING;
+ phy_link_up(phydev);
+ } else if (!phydev->link && phydev->state != PHY_NOLINK) {
+ phydev->state = PHY_NOLINK;
+ phy_link_down(phydev, true);
+ }
+ if (phydev->link)
+ break;
}
return 0;
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 77068c545de0..ccc292c0f585 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -1704,20 +1704,6 @@ int genphy_update_link(struct phy_device *phydev)
{
int status;
- /* The link state is latched low so that momentary link
- * drops can be detected. Do not double-read the status
- * in polling mode to detect such short link drops.
- */
- if (!phy_polling_mode(phydev)) {
- status = phy_read(phydev, MII_BMSR);
- if (status < 0) {
- return status;
- } else if (status & BMSR_LSTATUS) {
- phydev->link = 1;
- return 0;
- }
- }
-
/* Read link and autonegotiation status */
status = phy_read(phydev, MII_BMSR);
if (status < 0)
--
2.7.4
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
According to speedtest.net: 11.9Mbps down 500kbps up
