| Message ID | 1410890290-11248-5-git-send-email-Frank.Li@freescale.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Sep 16, 2014 at 2:58 PM, <Frank.Li@freescale.com> wrote: > From: Fugang Duan <B38611@freescale.com> > > When enable three queues on imx6sx enet, and then do tx performance > test with iperf tool, after some time running, tx hang. > > Found that: > If uDMA is running, software set TDAR may cause tx hang. > If uDMA is in idle, software set TDAR don't cause tx hang. > > There is a TDAR race condition for mutliQ when the software sets TDAR > and the UDMA clears TDAR simultaneously or in a small window (2-4 cycles). > This will cause the udma_tx and udma_tx_arbiter state machines to hang. > The issue exist at i.MX6SX enet IP. > > So, the Workaround is checking TDAR status four time, if TDAR cleared by > hardware and then write TDAR, otherwise don't set TDAR. > > The patch is only one Workaround for the issue TKT210582. As Shawn pointed out, it is better to use the ERR007885 instead of an internal bug numbering.
On Tue, Sep 16, 2014 at 3:52 PM, Fabio Estevam <festevam@gmail.com> wrote: > On Tue, Sep 16, 2014 at 2:58 PM, <Frank.Li@freescale.com> wrote: >> From: Fugang Duan <B38611@freescale.com> >> >> When enable three queues on imx6sx enet, and then do tx performance >> test with iperf tool, after some time running, tx hang. >> >> Found that: >> If uDMA is running, software set TDAR may cause tx hang. >> If uDMA is in idle, software set TDAR don't cause tx hang. >> >> There is a TDAR race condition for mutliQ when the software sets TDAR >> and the UDMA clears TDAR simultaneously or in a small window (2-4 cycles). >> This will cause the udma_tx and udma_tx_arbiter state machines to hang. >> The issue exist at i.MX6SX enet IP. >> >> So, the Workaround is checking TDAR status four time, if TDAR cleared by >> hardware and then write TDAR, otherwise don't set TDAR. >> >> The patch is only one Workaround for the issue TKT210582. > > As Shawn pointed out, it is better to use the ERR007885 instead of an > internal bug numbering. Sorry, I forget change commit message. best regards Frank Li
diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c index 3a735ef..cc8c934 100644 --- a/drivers/net/ethernet/freescale/fec_main.c +++ b/drivers/net/ethernet/freescale/fec_main.c @@ -111,6 +111,12 @@ static void fec_enet_itr_coal_init(struct net_device *ndev); * independent rings */ #define FEC_QUIRK_HAS_AVB (1 << 8) +/* There is a TDAR race condition for mutliQ when the software sets TDAR + * and the UDMA clears TDAR simultaneously or in a small window (2-4 cycles). + * This will cause the udma_tx and udma_tx_arbiter state machines to hang. + * The issue exist at i.MX6SX enet IP. + */ +#define FEC_QUIRK_ERR007885 (1 << 9) static struct platform_device_id fec_devtype[] = { { @@ -139,7 +145,7 @@ static struct platform_device_id fec_devtype[] = { .driver_data = FEC_QUIRK_ENET_MAC | FEC_QUIRK_HAS_GBIT | FEC_QUIRK_HAS_BUFDESC_EX | FEC_QUIRK_HAS_CSUM | FEC_QUIRK_HAS_VLAN | FEC_QUIRK_ERR006358 | - FEC_QUIRK_HAS_AVB, + FEC_QUIRK_HAS_AVB | FEC_QUIRK_ERR007885, }, { /* sentinel */ } @@ -709,6 +715,8 @@ static int fec_enet_txq_submit_tso(struct fec_enet_priv_tx_q *txq, struct tso_t tso; unsigned int index = 0; int ret; + const struct platform_device_id *id_entry = + platform_get_device_id(fep->pdev); if (tso_count_descs(skb) >= fec_enet_get_free_txdesc_num(fep, txq)) { dev_kfree_skb_any(skb); @@ -770,7 +778,12 @@ static int fec_enet_txq_submit_tso(struct fec_enet_priv_tx_q *txq, txq->cur_tx = bdp; /* Trigger transmission start */ - writel(0, fep->hwp + FEC_X_DES_ACTIVE(queue)); + if (!(id_entry->driver_data & FEC_QUIRK_ERR007885) || + !readl(fep->hwp + FEC_X_DES_ACTIVE(queue)) || + !readl(fep->hwp + FEC_X_DES_ACTIVE(queue)) || + !readl(fep->hwp + FEC_X_DES_ACTIVE(queue)) || + !readl(fep->hwp + FEC_X_DES_ACTIVE(queue))) + writel(0, fep->hwp + FEC_X_DES_ACTIVE(queue)); return 0;