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SubjectRe: [40/85] net/tg3: Avoid delay during MMIO access
Date
Ben Hutchings <ben@decadent.org.uk> writes:

> 3.2.49-rc1 review patch. If anyone has any objections, please let me know.
>
> ------------------
>
> From: Gavin Shan <shangw@linux.vnet.ibm.com>
>
> commit 6d446ec32f169c6a5d9bc90684a8082a6cbe90f6 upstream.
>
> When the EEH error is the result of a fenced host bridge, MMIO accesses
> can be very slow (milliseconds) to timeout and return all 1's,
> thus causing the driver various timeout loops to take way too long and
> trigger soft-lockup warnings (in addition to taking minutes to recover).
>
> It might be worthwhile to check if for any of these cases, ffffffff is
> a valid possible value, and if not, bail early since that means the HW
> is either gone or isolated. In the meantime, checking that the PCI channel
> is offline would be workaround of the problem.
>
> Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
> [bwh: Backported to 3.2: adjust context, indentation]
> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
> ---
> drivers/net/ethernet/broadcom/tg3.c | 36 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 36 insertions(+)
>
> --- a/drivers/net/ethernet/broadcom/tg3.c
> +++ b/drivers/net/ethernet/broadcom/tg3.c
> @@ -688,6 +688,9 @@ static int tg3_ape_lock(struct tg3 *tp,
> status = tg3_ape_read32(tp, gnt + off);
> if (status == bit)
> break;
> + if (pci_channel_offline(tp->pdev))
> + break;
> +
> udelay(10);
> }
>
> @@ -1465,6 +1468,9 @@ static void tg3_wait_for_event_ack(struc
> for (i = 0; i < delay_cnt; i++) {
> if (!(tr32(GRC_RX_CPU_EVENT) & GRC_RX_CPU_DRIVER_EVENT))
> break;
> + if (pci_channel_offline(tp->pdev))
> + break;
> +
> udelay(8);
> }
> }
> @@ -1628,6 +1634,9 @@ static int tg3_poll_fw(struct tg3 *tp)
> for (i = 0; i < 200; i++) {
> if (tr32(VCPU_STATUS) & VCPU_STATUS_INIT_DONE)
> return 0;
> + if (pci_channel_offline(tp->pdev))
> + return -ENODEV;
> +
> udelay(100);
> }
> return -ENODEV;
> @@ -1638,6 +1647,15 @@ static int tg3_poll_fw(struct tg3 *tp)
> tg3_read_mem(tp, NIC_SRAM_FIRMWARE_MBOX, &val);
> if (val == ~NIC_SRAM_FIRMWARE_MBOX_MAGIC1)
> break;
> + if (pci_channel_offline(tp->pdev)) {
> + if (!tg3_flag(tp, NO_FWARE_REPORTED)) {
> + tg3_flag_set(tp, NO_FWARE_REPORTED);
> + netdev_info(tp->dev, "No firmware running\n");
> + }
> +
> + break;
> + }
> +
> udelay(10);
> }
>
> @@ -3067,6 +3085,10 @@ static int tg3_halt_cpu(struct tg3 *tp,
> tw32(offset + CPU_MODE, CPU_MODE_HALT);
> if (tr32(offset + CPU_MODE) & CPU_MODE_HALT)
> break;
> + if (pci_channel_offline(tp->pdev))
> + return -EBUSY;
> + if (pci_channel_offline(tp->pdev))
> + return -EBUSY;
> }

I believe you didn't want to have these two invocations to the
pci_channel_offline() function. i guess you wanted to have one of
these moved to the other branch of the 'if' statement.

[ btw, I've just replied to an email by David S. Miller about his
backport to 3.4 (and 3.2) of this commit. ]

Cheers,
--
Luis


>
> tw32(offset + CPU_STATE, 0xffffffff); @@ -7569,6
> +7591,14 @@ static int tg3_stop_block(struct tg3 *tp tw32_f(ofs,
> val);
>
> for (i = 0; i < MAX_WAIT_CNT; i++) {
> + if (pci_channel_offline(tp->pdev)) {
> + dev_err(&tp->pdev->dev,
> + "tg3_stop_block device offline, "
> + "ofs=%lx enable_bit=%x\n",
> + ofs, enable_bit);
> + return -ENODEV;
> + }
> +
> udelay(100);
> val = tr32(ofs);
> if ((val & enable_bit) == 0)
> @@ -7592,6 +7622,13 @@ static int tg3_abort_hw(struct tg3 *tp,
>
> tg3_disable_ints(tp);
>
> + if (pci_channel_offline(tp->pdev)) {
> + tp->rx_mode &= ~(RX_MODE_ENABLE | TX_MODE_ENABLE);
> + tp->mac_mode &= ~MAC_MODE_TDE_ENABLE;
> + err = -ENODEV;
> + goto err_no_dev;
> + }
> +
> tp->rx_mode &= ~RX_MODE_ENABLE;
> tw32_f(MAC_RX_MODE, tp->rx_mode);
> udelay(10);
> @@ -7640,6 +7677,7 @@ static int tg3_abort_hw(struct tg3 *tp,
> err |= tg3_stop_block(tp, BUFMGR_MODE, BUFMGR_MODE_ENABLE, silent);
> err |= tg3_stop_block(tp, MEMARB_MODE, MEMARB_MODE_ENABLE, silent);
>
> +err_no_dev:
> for (i = 0; i < tp->irq_cnt; i++) {
> struct tg3_napi *tnapi = &tp->napi[i];
> if (tnapi->hw_status)
>
> --
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