From: "Kweh, Hock Leong" <hock.leong.k...@intel.com>
If kernel module stmmac driver being loaded after OS booted, there is a
race condition between stmmac_open() and stmmac_mdio_register(), which is
invoked inside stmmac_dvr_probe(), and the error is showed in dmesg log as
PHY not found and stmmac_open() failed:
[ 473.919358] stmmaceth 0000:01:00.0 (unnamed net_device) (uninitialized):
stmmac_dvr_probe: warning: cannot get CSR clock
[ 473.919382] stmmaceth 0000:01:00.0: no reset control found
[ 473.919412] stmmac - user ID: 0x10, Synopsys ID: 0x42
[ 473.919429] stmmaceth 0000:01:00.0: DMA HW capability register supported
[ 473.919436] stmmaceth 0000:01:00.0: RX Checksum Offload Engine supported
[ 473.919443] stmmaceth 0000:01:00.0: TX Checksum insertion supported
[ 473.919451] stmmaceth 0000:01:00.0 (unnamed net_device) (uninitialized):
Enable RX Mitigation via HW Watchdog Timer
[ 473.921395] libphy: PHY stmmac-1:00 not found
[ 473.921417] stmmaceth 0000:01:00.0 eth0: Could not attach to PHY
[ 473.921427] stmmaceth 0000:01:00.0 eth0: stmmac_open: Cannot attach to
PHY (error: -19)
[ 473.959710] libphy: stmmac: probed
[ 473.959724] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 0 IRQ POLL
(stmmac-1:00) active
[ 473.959728] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 1 IRQ POLL
(stmmac-1:01)
[ 473.959731] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 2 IRQ POLL
(stmmac-1:02)
[ 473.959734] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 3 IRQ POLL
(stmmac-1:03)
The resolution used wait_for_completion_interruptible() to synchronize
stmmac_open() and stmmac_dvr_probe() to prevent the race condition
happening.
Signed-off-by: Kweh, Hock Leong <hock.leong.k...@intel.com>
---
drivers/net/ethernet/stmicro/stmmac/stmmac.h | 1 +
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 10 ++++++++++
2 files changed, 11 insertions(+)
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index eab04ae..5daf8a5 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -131,6 +131,7 @@ struct stmmac_priv {
u32 rx_tail_addr;
u32 tx_tail_addr;
u32 mss;
+ struct completion probe_done;
#ifdef CONFIG_DEBUG_FS
struct dentry *dbgfs_dir;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index bb40382..28e85f6 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1770,6 +1770,14 @@ static int stmmac_open(struct net_device *dev)
struct stmmac_priv *priv = netdev_priv(dev);
int ret;
+ ret = wait_for_completion_interruptible(&priv->probe_done);
+ if (ret) {
+ netdev_err(priv->dev,
+ "%s: Interrupted while waiting probe completion\n",
+ __func__);
+ return ret;
+ }
+
stmmac_check_ether_addr(priv);
if (priv->hw->pcs != STMMAC_PCS_RGMII &&
@@ -3226,6 +3234,7 @@ int stmmac_dvr_probe(struct device *device,
priv = netdev_priv(ndev);
priv->device = device;
priv->dev = ndev;
+ init_completion(&priv->probe_done);
stmmac_set_ethtool_ops(ndev);
priv->pause = pause;
@@ -3372,6 +3381,7 @@ int stmmac_dvr_probe(struct device *device,
}
}
+ complete_all(&priv->probe_done);
return 0;
error_mdio_register:
--
1.7.9.5
