Commit df3e6548 authored by Michael Chan's avatar Michael Chan Committed by David S. Miller
Browse files

[TG3]: Add recovery logic when MMIOs are re-ordered 



Add recovery logic when we suspect that the system is re-ordering
MMIOs. Re-ordered MMIOs to the send mailbox can cause bogus tx
completions and hit BUG_ON() in the tx completion path.

tg3 already has logic to handle re-ordered MMIOs by flushing the MMIOs
that must be strictly ordered (such as the send mailbox).  Determining
when to enable the flush is currently a manual process of adding known
chipsets to a list.

The new code replaces the BUG_ON() in the tx completion path with the
call to tg3_tx_recover(). It will set the TG3_FLAG_MBOX_WRITE_REORDER
flag and reset the chip later in the workqueue to recover and start
flushing MMIOs to the mailbox.

A message to report the problem will be printed. We will then decide
whether or not to add the host bridge to the list of chipsets that do
re-ordering.

We may add some additional code later to print the host bridge's ID so
that the user can report it more easily.

The assumption that re-ordering can only happen on x86 systems is also
removed.

Signed-off-by: default avatarMichael Chan <mchan@broadcom.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 30b6c28d

drivers/net/tg3.c

+48 −5
Original line number Diff line number Diff line
@@ -2967,6 +2967,29 @@ static int tg3_setup_phy(struct tg3 *tp, int force_reset) 
	return err;

}



/* This is called whenever we suspect that the system chipset is re-

 * ordering the sequence of MMIO to the tx send mailbox. The symptom

 * is bogus tx completions. We try to recover by setting the

 * TG3_FLAG_MBOX_WRITE_REORDER flag and resetting the chip later

 * in the workqueue.

 */

static void tg3_tx_recover(struct tg3 *tp)

{

	BUG_ON((tp->tg3_flags & TG3_FLAG_MBOX_WRITE_REORDER) ||

	       tp->write32_tx_mbox == tg3_write_indirect_mbox);



	printk(KERN_WARNING PFX "%s: The system may be re-ordering memory-"

	       "mapped I/O cycles to the network device, attempting to "

	       "recover. Please report the problem to the driver maintainer "

	       "and include system chipset information.\n", tp->dev->name);



	spin_lock(&tp->lock);

	spin_lock(&tp->tx_lock);

	tp->tg3_flags |= TG3_FLAG_TX_RECOVERY_PENDING;

	spin_unlock(&tp->tx_lock);

	spin_unlock(&tp->lock);

}



/* Tigon3 never reports partial packet sends.  So we do not

 * need special logic to handle SKBs that have not had all

 * of their frags sent yet, like SunGEM does.
@@ -2979,9 +3002,13 @@ static void tg3_tx(struct tg3 *tp) 
	while (sw_idx != hw_idx) {

		struct tx_ring_info *ri = &tp->tx_buffers[sw_idx];

		struct sk_buff *skb = ri->skb;

		int i;

		int i, tx_bug = 0;



		if (unlikely(skb == NULL)) {

			tg3_tx_recover(tp);

			return;

		}



		BUG_ON(skb == NULL);

		pci_unmap_single(tp->pdev,

				 pci_unmap_addr(ri, mapping),

				 skb_headlen(skb),
@@ -2992,10 +3019,9 @@ static void tg3_tx(struct tg3 *tp) 
		sw_idx = NEXT_TX(sw_idx);



		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {

			BUG_ON(sw_idx == hw_idx);



			ri = &tp->tx_buffers[sw_idx];

			BUG_ON(ri->skb != NULL);

			if (unlikely(ri->skb != NULL || sw_idx == hw_idx))

				tx_bug = 1;



			pci_unmap_page(tp->pdev,

				       pci_unmap_addr(ri, mapping),
@@ -3006,6 +3032,11 @@ static void tg3_tx(struct tg3 *tp) 
		}



		dev_kfree_skb(skb);



		if (unlikely(tx_bug)) {

			tg3_tx_recover(tp);

			return;

		}

	}



	tp->tx_cons = sw_idx;
@@ -3333,6 +3364,11 @@ static int tg3_poll(struct net_device *netdev, int *budget) 
	/* run TX completion thread */

	if (sblk->idx[0].tx_consumer != tp->tx_cons) {

		tg3_tx(tp);

		if (unlikely(tp->tg3_flags & TG3_FLAG_TX_RECOVERY_PENDING)) {

			netif_rx_complete(netdev);

			schedule_work(&tp->reset_task);

			return 0;

		}

	}



	/* run RX thread, within the bounds set by NAPI.
@@ -3581,6 +3617,13 @@ static void tg3_reset_task(void *_data) 
	restart_timer = tp->tg3_flags2 & TG3_FLG2_RESTART_TIMER;

	tp->tg3_flags2 &= ~TG3_FLG2_RESTART_TIMER;



	if (tp->tg3_flags & TG3_FLAG_TX_RECOVERY_PENDING) {

		tp->write32_tx_mbox = tg3_write32_tx_mbox;

		tp->write32_rx_mbox = tg3_write_flush_reg32;

		tp->tg3_flags |= TG3_FLAG_MBOX_WRITE_REORDER;

		tp->tg3_flags &= ~TG3_FLAG_TX_RECOVERY_PENDING;

	}



	tg3_halt(tp, RESET_KIND_SHUTDOWN, 0);

	tg3_init_hw(tp, 1);

drivers/net/tg3.h

+1 −4
Original line number Diff line number Diff line
@@ -2155,11 +2155,7 @@ struct tg3 { 
#define TG3_FLAG_ENABLE_ASF		0x00000020

#define TG3_FLAG_5701_REG_WRITE_BUG	0x00000040

#define TG3_FLAG_POLL_SERDES		0x00000080

#if defined(CONFIG_X86)

#define TG3_FLAG_MBOX_WRITE_REORDER	0x00000100

#else

#define TG3_FLAG_MBOX_WRITE_REORDER	0	/* disables code too */

#endif

#define TG3_FLAG_PCIX_TARGET_HWBUG	0x00000200

#define TG3_FLAG_WOL_SPEED_100MB	0x00000400

#define TG3_FLAG_WOL_ENABLE		0x00000800
@@ -2172,6 +2168,7 @@ struct tg3 { 
#define TG3_FLAG_PCI_HIGH_SPEED		0x00040000

#define TG3_FLAG_PCI_32BIT		0x00080000

#define TG3_FLAG_SRAM_USE_CONFIG	0x00100000

#define TG3_FLAG_TX_RECOVERY_PENDING	0x00200000

#define TG3_FLAG_SERDES_WOL_CAP		0x00400000

#define TG3_FLAG_JUMBO_RING_ENABLE	0x00800000

#define TG3_FLAG_10_100_ONLY		0x01000000

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