From: Nikita Yushchenko <nikita.yo...@cogentembedded.com> Sent: Monday,
November 28, 2016 10:27 PM
>To: David S. Miller <da...@davemloft.net>; Andy Duan
><fugang.d...@nxp.com>; Troy Kisky <troy.ki...@boundarydevices.com>;
>Andrew Lunn <and...@lunn.ch>; Eric Nelson <e...@nelint.com>; Philippe
>Reynes <trem...@gmail.com>; Johannes Berg <johan...@sipsolutions.net>;
>netdev@vger.kernel.org
>Cc: Chris Healy <cphe...@gmail.com>; Fabio Estevam
><fabio.este...@nxp.com>; linux-ker...@vger.kernel.org; Nikita
>Yushchenko <nikita.yo...@cogentembedded.com>
>Subject: [patch net] net: fec: cache statistics while device is down
>
>Execution 'ethtool -S' on fec device that is down causes OOPS on Vybrid
>board:
>
>Unhandled fault: external abort on non-linefetch (0x1008) at 0xe0898200 pgd
>= ddecc000 [e0898200] *pgd=9e406811, *pte=400d1653, *ppte=400d1453
>Internal error: : 1008 [#1] SMP ARM ...
>
>Reason of OOPS is that fec_enet_get_ethtool_stats() accesses fec registers
>while IPG clock is stopped by PM.
>
>Fix that by caching statistics in fec_enet_private. Cache is updated just
>before statistics request if device is up, and also just before turning device
>off on down path.
>
>Additional locking is not needed, since cached statistics is always updated
>under rtnl_lock().
>
>Signed-off-by: Nikita Yushchenko <nikita.yo...@cogentembedded.com>
>---
> drivers/net/ethernet/freescale/fec.h | 2 ++
> drivers/net/ethernet/freescale/fec_main.c | 21 +++++++++++++++++----
> 2 files changed, 19 insertions(+), 4 deletions(-)
>
>diff --git a/drivers/net/ethernet/freescale/fec.h
>b/drivers/net/ethernet/freescale/fec.h
>index c865135f3cb9..5ea740b4cf14 100644
>--- a/drivers/net/ethernet/freescale/fec.h
>+++ b/drivers/net/ethernet/freescale/fec.h
>@@ -574,6 +574,8 @@ struct fec_enet_private {
> unsigned int reload_period;
> int pps_enable;
> unsigned int next_counter;
>+
>+ u64 ethtool_stats[0];
> };
>
> void fec_ptp_init(struct platform_device *pdev); diff --git
>a/drivers/net/ethernet/freescale/fec_main.c
>b/drivers/net/ethernet/freescale/fec_main.c
>index 5aa9d4ded214..7da2d94ec8e5 100644
>--- a/drivers/net/ethernet/freescale/fec_main.c
>+++ b/drivers/net/ethernet/freescale/fec_main.c
>@@ -2313,14 +2313,24 @@ static const struct fec_stat {
> { "IEEE_rx_octets_ok", IEEE_R_OCTETS_OK }, };
>
>-static void fec_enet_get_ethtool_stats(struct net_device *dev,
>- struct ethtool_stats *stats, u64 *data)
>+static void fec_enet_update_ethtool_stats(struct net_device *dev)
> {
> struct fec_enet_private *fep = netdev_priv(dev);
> int i;
>
> for (i = 0; i < ARRAY_SIZE(fec_stats); i++)
>- data[i] = readl(fep->hwp + fec_stats[i].offset);
>+ fep->ethtool_stats[i] = readl(fep->hwp +
>fec_stats[i].offset); }
>+
>+static void fec_enet_get_ethtool_stats(struct net_device *dev,
>+ struct ethtool_stats *stats, u64 *data) {
>+ struct fec_enet_private *fep = netdev_priv(dev);
>+
>+ if (netif_running(dev))
>+ fec_enet_update_ethtool_stats(dev);
>+
>+ memcpy(data, fep->ethtool_stats, ARRAY_SIZE(fec_stats) *
>sizeof(u64));
> }
>
> static void fec_enet_get_strings(struct net_device *netdev, @@ -2874,6
>+2884,8 @@ fec_enet_close(struct net_device *ndev)
> if (fep->quirks & FEC_QUIRK_ERR006687)
> imx6q_cpuidle_fec_irqs_unused();
>
>+ fec_enet_update_ethtool_stats(ndev);
>+
If user never open the interface, ethtool_stats[] always is 0 that are not
expected.
So, it also should be called at . fec_enet_init() ?
> fec_enet_clk_enable(ndev, false);
> pinctrl_pm_select_sleep_state(&fep->pdev->dev);
> pm_runtime_mark_last_busy(&fep->pdev->dev);
>@@ -3278,7 +3290,8 @@ fec_probe(struct platform_device *pdev)
> fec_enet_get_queue_num(pdev, &num_tx_qs, &num_rx_qs);
>
> /* Init network device */
>- ndev = alloc_etherdev_mqs(sizeof(struct fec_enet_private),
>+ ndev = alloc_etherdev_mqs(sizeof(struct fec_enet_private) +
>+ ARRAY_SIZE(fec_stats) * sizeof(u64),
> num_tx_qs, num_rx_qs);
> if (!ndev)
> return -ENOMEM;
>--
>2.1.4
