[Intel-wired-lan] [PATCH net 1/1] e1000e: Stop tx/rx setup spinning for upwards of 300us.
Jeff Kirsher
jeffrey.t.kirsher at intel.com
Wed Mar 4 18:03:59 UTC 2020
On Tue, 2020-03-03 at 17:06 +0000, David Laight wrote:
> Instead of spinning waiting for the ME to be idle defer the ring
> tail updates until one of the following:
> - The next update for that ring.
> - The receive frame processing.
> - The next timer tick.
>
> Reduce the delay between checks for the ME being idle from 50us
> to uus.
>
> Part fix for bdc125f7.
>
> Signed-off-by: David Laight <david.laight at aculab.com>
Added intel-wired-lan at lists.osuosl.org mailing list, so the right
people can review your patch.
> ---
> This change probably applies as back as far as 3.16.
>
> drivers/net/ethernet/intel/e1000e/e1000.h | 3 +
> drivers/net/ethernet/intel/e1000e/ich8lan.h | 2 +-
> drivers/net/ethernet/intel/e1000e/netdev.c | 131
> ++++++++++++++++++++--------
> 3 files changed, 99 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/e1000e/e1000.h
> b/drivers/net/ethernet/intel/e1000e/e1000.h
> index 6c51b1b..c7819e0 100644
> --- a/drivers/net/ethernet/intel/e1000e/e1000.h
> +++ b/drivers/net/ethernet/intel/e1000e/e1000.h
> @@ -155,6 +155,8 @@ struct e1000_ring {
>
> u16 next_to_use;
> u16 next_to_clean;
> +#define E1000_RING_NOT_DEFERRED 0xffff
> + u16 next_to_use_deferred;
>
> void __iomem *head;
> void __iomem *tail;
> @@ -190,6 +192,7 @@ struct e1000_adapter {
>
> struct work_struct reset_task;
> struct delayed_work watchdog_task;
> + struct delayed_work delay_ring_write_task;
>
> struct workqueue_struct *e1000_workqueue;
>
> diff --git a/drivers/net/ethernet/intel/e1000e/ich8lan.h
> b/drivers/net/ethernet/intel/e1000e/ich8lan.h
> index 1502895..75e5a53 100644
> --- a/drivers/net/ethernet/intel/e1000e/ich8lan.h
> +++ b/drivers/net/ethernet/intel/e1000e/ich8lan.h
> @@ -34,7 +34,7 @@
> /* FW established a valid mode */
> #define E1000_ICH_FWSM_FW_VALID 0x00008000
> #define E1000_ICH_FWSM_PCIM2PCI 0x01000000 /* ME PCIm-
> to-PCI active */
> -#define E1000_ICH_FWSM_PCIM2PCI_COUNT 2000
> +#define E1000_ICH_FWSM_PCIM2PCI_COUNT 20000
>
> #define E1000_ICH_MNG_IAMT_MODE 0x2
>
> diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c
> b/drivers/net/ethernet/intel/e1000e/netdev.c
> index d7d56e4..299e5af 100644
> --- a/drivers/net/ethernet/intel/e1000e/netdev.c
> +++ b/drivers/net/ethernet/intel/e1000e/netdev.c
> @@ -118,13 +118,20 @@ struct e1000_reg_info {
> * an incorrect value. Workaround this by checking the FWSM
> register which
> * has bit 24 set while ME is accessing MAC CSR registers, wait if
> it is set
> * and try again a number of times.
> + * NB: This bit can stay set for 300us even if polled every 5us.
> **/
> +
> +static bool __ew32_prepare_busy(struct e1000_hw *hw)
> +{
> + return (er32(FWSM) & E1000_ICH_FWSM_PCIM2PCI);
> +}
> +
> s32 __ew32_prepare(struct e1000_hw *hw)
> {
> s32 i = E1000_ICH_FWSM_PCIM2PCI_COUNT;
>
> - while ((er32(FWSM) & E1000_ICH_FWSM_PCIM2PCI) && --i)
> - udelay(50);
> + while (__ew32_prepare_busy(hw) && --i)
> + udelay(5);
>
> return i;
> }
> @@ -603,38 +610,75 @@ static void e1000_rx_checksum(struct
> e1000_adapter *adapter, u32 status_err,
> adapter->hw_csum_good++;
> }
>
> -static void e1000e_update_rdt_wa(struct e1000_ring *rx_ring,
> unsigned int i)
> +static bool deferred_update_dt_wa(struct e1000_ring *ring)
> {
> - struct e1000_adapter *adapter = rx_ring->adapter;
> - struct e1000_hw *hw = &adapter->hw;
> - s32 ret_val = __ew32_prepare(hw);
> -
> - writel(i, rx_ring->tail);
> + struct e1000_adapter *adapter;
> + struct e1000_hw *hw;
> + unsigned long flags;
> + u32 deferred;
>
> - if (unlikely(!ret_val && (i != readl(rx_ring->tail)))) {
> - u32 rctl = er32(RCTL);
> + adapter = ring->adapter;
> + hw = &adapter->hw;
> + spin_lock_irqsave(&adapter->systim_lock, flags);
> + deferred = ring->next_to_use_deferred;
> + if (deferred != E1000_RING_NOT_DEFERRED) {
> + if (__ew32_prepare_busy(hw)) {
> + spin_unlock_irqrestore(&adapter->systim_lock,
> flags);
> + /* Caller needs to ensure timer running */
> + return true;
> + }
>
> - ew32(RCTL, rctl & ~E1000_RCTL_EN);
> - e_err("ME firmware caused invalid RDT - resetting\n");
> - schedule_work(&adapter->reset_task);
> + writel(deferred, ring->tail);
> + ring->next_to_use_deferred = E1000_RING_NOT_DEFERRED;
> }
> + spin_unlock_irqrestore(&adapter->systim_lock, flags);
> + return false;
> }
>
> -static void e1000e_update_tdt_wa(struct e1000_ring *tx_ring,
> unsigned int i)
> +/* Inline the cheap unlocked test */
> +#define e1000e_deferred_update_dt_wa(ring) \
> + (likely(READ_ONCE(ring->next_to_use_deferred) == \
> + E1000_RING_NOT_DEFERRED) ? false : \
> + deferred_update_dt_wa(ring))
> +
> +static void e1000e_delay_ring_write_task(struct work_struct *work)
> {
> - struct e1000_adapter *adapter = tx_ring->adapter;
> - struct e1000_hw *hw = &adapter->hw;
> - s32 ret_val = __ew32_prepare(hw);
> + struct e1000_adapter *adapter;
>
> - writel(i, tx_ring->tail);
> + adapter = container_of(work, struct e1000_adapter,
> + delay_ring_write_task.work);
>
> - if (unlikely(!ret_val && (i != readl(tx_ring->tail)))) {
> - u32 tctl = er32(TCTL);
> + if (e1000e_deferred_update_dt_wa(adapter->tx_ring) |
> + e1000e_deferred_update_dt_wa(adapter->rx_ring))
> + mod_delayed_work(adapter->e1000_workqueue,
> + &adapter->delay_ring_write_task, 1);
> +}
>
> - ew32(TCTL, tctl & ~E1000_TCTL_EN);
> - e_err("ME firmware caused invalid TDT - resetting\n");
> - schedule_work(&adapter->reset_task);
> +static void e1000e_update_dt_wa(struct e1000_ring *ring, unsigned
> int i)
> +{
> + struct e1000_adapter *adapter = ring->adapter;
> + struct e1000_hw *hw = &adapter->hw;
> + unsigned long flags;
> + u32 deferred;
> +
> + deferred = READ_ONCE(ring->next_to_use_deferred);
> + if (unlikely(deferred != E1000_RING_NOT_DEFERRED)) {
> + /* previous write was deferred - forget about it */
> + spin_lock_irqsave(&adapter->systim_lock, flags);
> + ring->next_to_use_deferred = E1000_RING_NOT_DEFERRED;
> + spin_unlock_irqrestore(&adapter->systim_lock, flags);
> + }
> +
> + if (!__ew32_prepare_busy(hw)) {
> + writel(i, ring->tail);
> + return;
> }
> +
> + /* We can't write now, defer to rx clean or timeout */
> + WRITE_ONCE(ring->next_to_use_deferred, i);
> +
> + mod_delayed_work(adapter->e1000_workqueue,
> + &adapter->delay_ring_write_task, 1);
> }
>
> /**
> @@ -692,7 +736,7 @@ static void e1000_alloc_rx_buffers(struct
> e1000_ring *rx_ring,
> */
> wmb();
> if (adapter->flags2 &
> FLAG2_PCIM2PCI_ARBITER_WA)
> - e1000e_update_rdt_wa(rx_ring, i);
> + e1000e_update_dt_wa(rx_ring, i);
> else
> writel(i, rx_ring->tail);
> }
> @@ -792,7 +836,7 @@ static void e1000_alloc_rx_buffers_ps(struct
> e1000_ring *rx_ring,
> */
> wmb();
> if (adapter->flags2 &
> FLAG2_PCIM2PCI_ARBITER_WA)
> - e1000e_update_rdt_wa(rx_ring, i << 1);
> + e1000e_update_dt_wa(rx_ring, i << 1);
> else
> writel(i << 1, rx_ring->tail);
> }
> @@ -884,7 +928,7 @@ static void e1000_alloc_jumbo_rx_buffers(struct
> e1000_ring *rx_ring,
> */
> wmb();
> if (adapter->flags2 & FLAG2_PCIM2PCI_ARBITER_WA)
> - e1000e_update_rdt_wa(rx_ring, i);
> + e1000e_update_dt_wa(rx_ring, i);
> else
> writel(i, rx_ring->tail);
> }
> @@ -1256,6 +1300,8 @@ static bool e1000_clean_tx_irq(struct
> e1000_ring *tx_ring)
>
> tx_ring->next_to_clean = i;
>
> + e1000e_deferred_update_dt_wa(tx_ring);
> +
> netdev_completed_queue(netdev, pkts_compl, bytes_compl);
>
> #define TX_WAKE_THRESHOLD 32
> @@ -1729,6 +1775,7 @@ static void e1000_clean_rx_ring(struct
> e1000_ring *rx_ring)
>
> rx_ring->next_to_clean = 0;
> rx_ring->next_to_use = 0;
> + rx_ring->next_to_use_deferred = E1000_RING_NOT_DEFERRED;
> adapter->flags2 &= ~FLAG2_IS_DISCARDING;
> }
>
> @@ -2342,6 +2389,7 @@ int e1000e_setup_tx_resources(struct e1000_ring
> *tx_ring)
>
> tx_ring->next_to_use = 0;
> tx_ring->next_to_clean = 0;
> + tx_ring->next_to_use_deferred = E1000_RING_NOT_DEFERRED;
>
> return 0;
> err:
> @@ -2388,6 +2436,7 @@ int e1000e_setup_rx_resources(struct e1000_ring
> *rx_ring)
>
> rx_ring->next_to_clean = 0;
> rx_ring->next_to_use = 0;
> + rx_ring->next_to_use_deferred = E1000_RING_NOT_DEFERRED;
> rx_ring->rx_skb_top = NULL;
>
> return 0;
> @@ -2427,6 +2476,7 @@ static void e1000_clean_tx_ring(struct
> e1000_ring *tx_ring)
>
> tx_ring->next_to_use = 0;
> tx_ring->next_to_clean = 0;
> + tx_ring->next_to_use_deferred = E1000_RING_NOT_DEFERRED;
> }
>
> /**
> @@ -2666,6 +2716,9 @@ static int e1000e_poll(struct napi_struct
> *napi, int budget)
>
> adapter = netdev_priv(poll_dev);
>
> + e1000e_deferred_update_dt_wa(adapter->tx_ring);
> + e1000e_deferred_update_dt_wa(adapter->rx_ring);
> +
> if (!adapter->msix_entries ||
> (adapter->rx_ring->ims_val & adapter->tx_ring->ims_val))
> tx_cleaned = e1000_clean_tx_irq(adapter->tx_ring);
> @@ -2930,10 +2983,11 @@ static void e1000_configure_tx(struct
> e1000_adapter *adapter)
> tx_ring->tail = adapter->hw.hw_addr + E1000_TDT(0);
>
> writel(0, tx_ring->head);
> - if (adapter->flags2 & FLAG2_PCIM2PCI_ARBITER_WA)
> - e1000e_update_tdt_wa(tx_ring, 0);
> - else
> - writel(0, tx_ring->tail);
> + if (adapter->flags2 & FLAG2_PCIM2PCI_ARBITER_WA) {
> + while (__ew32_prepare_busy(hw))
> + usleep_range(50, 100);
> + }
> + writel(0, tx_ring->tail);
>
> /* Set the Tx Interrupt Delay register */
> ew32(TIDV, adapter->tx_int_delay);
> @@ -3254,10 +3308,11 @@ static void e1000_configure_rx(struct
> e1000_adapter *adapter)
> rx_ring->tail = adapter->hw.hw_addr + E1000_RDT(0);
>
> writel(0, rx_ring->head);
> - if (adapter->flags2 & FLAG2_PCIM2PCI_ARBITER_WA)
> - e1000e_update_rdt_wa(rx_ring, 0);
> - else
> - writel(0, rx_ring->tail);
> + if (adapter->flags2 & FLAG2_PCIM2PCI_ARBITER_WA) {
> + while (__ew32_prepare_busy(hw))
> + usleep_range(50, 100);
> + }
> + writel(0, rx_ring->tail);
>
> /* Enable Receive Checksum Offload for TCP and UDP */
> rxcsum = er32(RXCSUM);
> @@ -5908,8 +5963,8 @@ static netdev_tx_t e1000_xmit_frame(struct
> sk_buff *skb,
> if (!netdev_xmit_more() ||
> netif_xmit_stopped(netdev_get_tx_queue(netdev, 0)))
> {
> if (adapter->flags2 &
> FLAG2_PCIM2PCI_ARBITER_WA)
> - e1000e_update_tdt_wa(tx_ring,
> - tx_ring-
> >next_to_use);
> + e1000e_update_dt_wa(tx_ring,
> + tx_ring-
> >next_to_use);
> else
> writel(tx_ring->next_to_use, tx_ring-
> >tail);
> }
> @@ -7271,6 +7326,9 @@ static int e1000_probe(struct pci_dev *pdev,
> const struct pci_device_id *ent)
> queue_delayed_work(adapter->e1000_workqueue, &adapter-
> >watchdog_task,
> 0);
>
> + INIT_DELAYED_WORK(&adapter->delay_ring_write_task,
> + e1000e_delay_ring_write_task);
> +
> timer_setup(&adapter->phy_info_timer, e1000_update_phy_info,
> 0);
>
> INIT_WORK(&adapter->reset_task, e1000_reset_task);
> @@ -7424,6 +7482,7 @@ static void e1000_remove(struct pci_dev *pdev)
> cancel_work_sync(&adapter->print_hang_task);
>
> cancel_delayed_work(&adapter->watchdog_task);
> + cancel_delayed_work(&adapter->delay_ring_write_task);
> flush_workqueue(adapter->e1000_workqueue);
> destroy_workqueue(adapter->e1000_workqueue);
>
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