From 91c0d987a9788dcc5fe26baafd73bf9242b68900 Mon Sep 17 00:00:00 2001 From: Nimrod Andy Date: Thu, 21 Aug 2014 17:09:38 +0800 Subject: net: fec: ptp: avoid register access when ipg clock is disabled The current kernel hang on i.MX6SX with rootfs mount from MMC. The root cause is that ptp uses a periodic timer to access enet register even if ipg clock is disabled. FEC ptp driver start one period timer to read 1588 counter register in the ptp init function that is called after FEC driver is probed. To save power, after FEC probe finish, FEC driver disable all clocks including ipg clock that is needed for register access. i.MX5x, i.MX6q/dl/sl FEC register access don't cause system hang when ipg clock is disabled, just return zero value. But for i.MX6sx SOC, it cause system hang. To avoid the issue, we need to check ptp clock status before ptp timer count access. Signed-off-by: Fugang Duan Signed-off-by: David S. Miller --- drivers/net/ethernet/freescale/fec_main.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) (limited to 'drivers/net/ethernet/freescale/fec_main.c') diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c index 4f87dffcb9b..89355a71962 100644 --- a/drivers/net/ethernet/freescale/fec_main.c +++ b/drivers/net/ethernet/freescale/fec_main.c @@ -1611,17 +1611,27 @@ static int fec_enet_clk_enable(struct net_device *ndev, bool enable) goto failed_clk_enet_out; } if (fep->clk_ptp) { + mutex_lock(&fep->ptp_clk_mutex); ret = clk_prepare_enable(fep->clk_ptp); - if (ret) + if (ret) { + mutex_unlock(&fep->ptp_clk_mutex); goto failed_clk_ptp; + } else { + fep->ptp_clk_on = true; + } + mutex_unlock(&fep->ptp_clk_mutex); } } else { clk_disable_unprepare(fep->clk_ahb); clk_disable_unprepare(fep->clk_ipg); if (fep->clk_enet_out) clk_disable_unprepare(fep->clk_enet_out); - if (fep->clk_ptp) + if (fep->clk_ptp) { + mutex_lock(&fep->ptp_clk_mutex); clk_disable_unprepare(fep->clk_ptp); + fep->ptp_clk_on = false; + mutex_unlock(&fep->ptp_clk_mutex); + } } return 0; @@ -2625,6 +2635,8 @@ fec_probe(struct platform_device *pdev) if (IS_ERR(fep->clk_enet_out)) fep->clk_enet_out = NULL; + fep->ptp_clk_on = false; + mutex_init(&fep->ptp_clk_mutex); fep->clk_ptp = devm_clk_get(&pdev->dev, "ptp"); fep->bufdesc_ex = pdev->id_entry->driver_data & FEC_QUIRK_HAS_BUFDESC_EX; @@ -2715,10 +2727,10 @@ fec_drv_remove(struct platform_device *pdev) struct net_device *ndev = platform_get_drvdata(pdev); struct fec_enet_private *fep = netdev_priv(ndev); + cancel_delayed_work_sync(&fep->time_keep); cancel_work_sync(&fep->tx_timeout_work); unregister_netdev(ndev); fec_enet_mii_remove(fep); - del_timer_sync(&fep->time_keep); if (fep->reg_phy) regulator_disable(fep->reg_phy); if (fep->ptp_clock) -- cgit v1.2.3-70-g09d2