Hi Joel,
> -----Original Message-----
> From: Joel Stanley [mailto:j...@jms.id.au]
> Sent: Wednesday, October 14, 2020 2:41 PM
> To: Dylan Hung <dylan_h...@aspeedtech.com>
> Cc: David S . Miller <da...@davemloft.net>; Jakub Kicinski
> <k...@kernel.org>; netdev@vger.kernel.org; Linux Kernel Mailing List
> <linux-ker...@vger.kernel.org>; Po-Yu Chuang <ratb...@faraday-tech.com>;
> linux-aspeed <linux-asp...@lists.ozlabs.org>; OpenBMC Maillist
> <open...@lists.ozlabs.org>; BMC-SW <bmc...@aspeedtech.com>
> Subject: Re: [PATCH 1/1] net: ftgmac100: Fix Aspeed ast2600 TX hang issue
>
> On Wed, 14 Oct 2020 at 06:07, Dylan Hung <dylan_h...@aspeedtech.com>
> wrote:
> >
> > The new HW arbitration feature on Aspeed ast2600 will cause MAC TX to
> > hang when handling scatter-gather DMA. Disable the problematic
> > feature by setting MAC register 0x58 bit28 and bit27.
>
> Hi Dylan,
>
> What are the symptoms of this issue? We are seeing this on our systems:
>
> [29376.090637] WARNING: CPU: 0 PID: 9 at net/sched/sch_generic.c:442
> dev_watchdog+0x2f0/0x2f4
> [29376.099898] NETDEV WATCHDOG: eth0 (ftgmac100): transmit queue 0
> timed out
>
May I know your soc version? This issue happens on ast2600 version A1. The
registers to fix this issue are meaningless/reserved on A0 chip, so it is okay
to set them on either A0 or A1.
I was encountering this issue when I was running the iperf TX test. The
symptom is the TX descriptors are consumed, but no complete packet is sent out.
> > Signed-off-by: Dylan Hung <dylan_h...@aspeedtech.com>
>
> This fixes support for the ast2600, so we can put:
>
> Fixes: 39bfab8844a0 ("net: ftgmac100: Add support for DT phy-handle
> property")
>
> Reviewed-by: Joel Stanley <j...@jms.id.au>
>
> > ---
> > drivers/net/ethernet/faraday/ftgmac100.c | 5 +++++
> > drivers/net/ethernet/faraday/ftgmac100.h | 8 ++++++++
> > 2 files changed, 13 insertions(+)
> >
> > diff --git a/drivers/net/ethernet/faraday/ftgmac100.c
> > b/drivers/net/ethernet/faraday/ftgmac100.c
> > index 87236206366f..00024dd41147 100644
> > --- a/drivers/net/ethernet/faraday/ftgmac100.c
> > +++ b/drivers/net/ethernet/faraday/ftgmac100.c
> > @@ -1817,6 +1817,11 @@ static int ftgmac100_probe(struct
> platform_device *pdev)
> > priv->rxdes0_edorr_mask = BIT(30);
> > priv->txdes0_edotr_mask = BIT(30);
> > priv->is_aspeed = true;
> > + /* Disable ast2600 problematic HW arbitration */
> > + if (of_device_is_compatible(np, "aspeed,ast2600-mac"))
> {
> > + iowrite32(FTGMAC100_TM_DEFAULT,
> > + priv->base +
> FTGMAC100_OFFSET_TM);
> > + }
> > } else {
> > priv->rxdes0_edorr_mask = BIT(15);
> > priv->txdes0_edotr_mask = BIT(15); diff --git
> > a/drivers/net/ethernet/faraday/ftgmac100.h
> > b/drivers/net/ethernet/faraday/ftgmac100.h
> > index e5876a3fda91..63b3e02fab16 100644
> > --- a/drivers/net/ethernet/faraday/ftgmac100.h
> > +++ b/drivers/net/ethernet/faraday/ftgmac100.h
> > @@ -169,6 +169,14 @@
> > #define FTGMAC100_MACCR_FAST_MODE (1 << 19)
> > #define FTGMAC100_MACCR_SW_RST (1 << 31)
> >
> > +/*
> > + * test mode control register
> > + */
> > +#define FTGMAC100_TM_RQ_TX_VALID_DIS (1 << 28) #define
> > +FTGMAC100_TM_RQ_RR_IDLE_PREV (1 << 27)
> > +#define FTGMAC100_TM_DEFAULT
> \
> > + (FTGMAC100_TM_RQ_TX_VALID_DIS |
> FTGMAC100_TM_RQ_RR_IDLE_PREV)
>
> Will aspeed issue an updated datasheet with this register documented?
>
>
> > +
> > /*
> > * PHY control register
> > */
> > --
> > 2.17.1
> >
