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ixgbe: DCB, fix TX hang occurring in stress condition with PFC

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The DCB credits refill quantum _must_ be greater than half the max
packet size. This is needed to guarantee that TX DMA operations
are not attempted during a pause state. Additionally, the min IFG
must be set correctly for DCB mode. If a DMA operation is
requested unexpectedly during the pause state the HW data
store may be corrupted leading to a DMA hang.  The DMA hang
requires a reset to correct. This fixes the HW configuration
to avoid this condition.

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
John Fastabend 2010-10-28 00:59:57 +00:00 committed by David S. Miller
parent affa9dfb04
commit 9806307a1c
5 changed files with 54 additions and 10 deletions
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39
drivers/net/ixgbe/ixgbe_dcb.c
View File

@ -43,9 +43,12 @@
* ixgbe_dcb_check_config().
*/
s32 ixgbe_dcb_calculate_tc_credits(struct ixgbe_dcb_config *dcb_config,
u8 direction)
int max_frame, u8 direction)
{
struct tc_bw_alloc *p;
int min_credit;
int min_multiplier;
int min_percent = 100;
s32 ret_val = 0;
/* Initialization values default for Tx settings */
u32 credit_refill = 0;
@ -59,6 +62,31 @@ s32 ixgbe_dcb_calculate_tc_credits(struct ixgbe_dcb_config *dcb_config,
goto out;
}
min_credit = ((max_frame / 2) + DCB_CREDIT_QUANTUM - 1) /
DCB_CREDIT_QUANTUM;
/* Find smallest link percentage */
for (i = 0; i < MAX_TRAFFIC_CLASS; i++) {
p = &dcb_config->tc_config[i].path[direction];
bw_percent = dcb_config->bw_percentage[direction][p->bwg_id];
link_percentage = p->bwg_percent;
link_percentage = (link_percentage * bw_percent) / 100;
if (link_percentage && link_percentage < min_percent)
min_percent = link_percentage;
}
/*
* The ratio between traffic classes will control the bandwidth
* percentages seen on the wire. To calculate this ratio we use
* a multiplier. It is required that the refill credits must be
* larger than the max frame size so here we find the smallest
* multiplier that will allow all bandwidth percentages to be
* greater than the max frame size.
*/
min_multiplier = (min_credit / min_percent) + 1;
/* Find out the link percentage for each TC first */
for (i = 0; i < MAX_TRAFFIC_CLASS; i++) {
p = &dcb_config->tc_config[i].path[direction];
@ -73,8 +101,9 @@ s32 ixgbe_dcb_calculate_tc_credits(struct ixgbe_dcb_config *dcb_config,
/* Save link_percentage for reference */
p->link_percent = (u8)link_percentage;
/* Calculate credit refill and save it */
credit_refill = link_percentage * MINIMUM_CREDIT_REFILL;
/* Calculate credit refill ratio using multiplier */
credit_refill = min(link_percentage * min_multiplier,
MAX_CREDIT_REFILL);
p->data_credits_refill = (u16)credit_refill;
/* Calculate maximum credit for the TC */
@ -85,8 +114,8 @@ s32 ixgbe_dcb_calculate_tc_credits(struct ixgbe_dcb_config *dcb_config,
* of a TC is too small, the maximum credit may not be
* enough to send out a jumbo frame in data plane arbitration.
*/
if (credit_max && (credit_max < MINIMUM_CREDIT_FOR_JUMBO))
credit_max = MINIMUM_CREDIT_FOR_JUMBO;
if (credit_max && (credit_max < min_credit))
credit_max = min_credit;
if (direction == DCB_TX_CONFIG) {
/*

5
drivers/net/ixgbe/ixgbe_dcb.h
View File

@ -150,15 +150,14 @@ struct ixgbe_dcb_config {
/* DCB driver APIs */
/* DCB credits calculation */
s32 ixgbe_dcb_calculate_tc_credits(struct ixgbe_dcb_config *, u8);
s32 ixgbe_dcb_calculate_tc_credits(struct ixgbe_dcb_config *, int, u8);
/* DCB hw initialization */
s32 ixgbe_dcb_hw_config(struct ixgbe_hw *, struct ixgbe_dcb_config *);
/* DCB definitions for credit calculation */
#define DCB_CREDIT_QUANTUM 64 /* DCB Quantum */
#define MAX_CREDIT_REFILL 511 /* 0x1FF * 64B = 32704B */
#define MINIMUM_CREDIT_REFILL 5 /* 5*64B = 320B */
#define MINIMUM_CREDIT_FOR_JUMBO 145 /* 145= UpperBound((9*1024+54)/64B) for 9KB jumbo frame */
#define DCB_MAX_TSO_SIZE (32*1024) /* MAX TSO packet size supported in DCB mode */
#define MINIMUM_CREDIT_FOR_TSO (DCB_MAX_TSO_SIZE/64 + 1) /* 513 for 32KB TSO packet */
#define MAX_CREDIT 4095 /* Maximum credit supported: 256KB * 1204 / 64B */

5
drivers/net/ixgbe/ixgbe_dcb_82599.c
View File

@ -397,6 +397,11 @@ static s32 ixgbe_dcb_config_82599(struct ixgbe_hw *hw)
reg &= ~IXGBE_RTTDCS_ARBDIS;
IXGBE_WRITE_REG(hw, IXGBE_RTTDCS, reg);
/* Enable Security TX Buffer IFG for DCB */
reg = IXGBE_READ_REG(hw, IXGBE_SECTXMINIFG);
reg |= IXGBE_SECTX_DCB;
IXGBE_WRITE_REG(hw, IXGBE_SECTXMINIFG, reg);
return 0;
}

3
drivers/net/ixgbe/ixgbe_dcb_82599.h
View File

@ -95,6 +95,9 @@
#define IXGBE_TXPBTHRESH_DCB 0xA /* THRESH value for DCB mode */
/* SECTXMINIFG DCB */
#define IXGBE_SECTX_DCB 0x00001F00 /* DCB TX Buffer IFG */
/* DCB hardware-specific driver APIs */

12
drivers/net/ixgbe/ixgbe_main.c
View File

@ -3347,6 +3347,7 @@ static void ixgbe_napi_disable_all(struct ixgbe_adapter *adapter)
static void ixgbe_configure_dcb(struct ixgbe_adapter *adapter)
{
struct ixgbe_hw *hw = &adapter->hw;
int max_frame = adapter->netdev->mtu + ETH_HLEN + ETH_FCS_LEN;
u32 txdctl;
int i, j;
@ -3359,8 +3360,15 @@ static void ixgbe_configure_dcb(struct ixgbe_adapter *adapter)
if (hw->mac.type == ixgbe_mac_82598EB)
netif_set_gso_max_size(adapter->netdev, 32768);
ixgbe_dcb_calculate_tc_credits(&adapter->dcb_cfg, DCB_TX_CONFIG);
ixgbe_dcb_calculate_tc_credits(&adapter->dcb_cfg, DCB_RX_CONFIG);
#ifdef CONFIG_FCOE
if (adapter->netdev->features & NETIF_F_FCOE_MTU)
max_frame = max(max_frame, IXGBE_FCOE_JUMBO_FRAME_SIZE);
#endif
ixgbe_dcb_calculate_tc_credits(&adapter->dcb_cfg, max_frame,
DCB_TX_CONFIG);
ixgbe_dcb_calculate_tc_credits(&adapter->dcb_cfg, max_frame,
DCB_RX_CONFIG);
/* reconfigure the hardware */
ixgbe_dcb_hw_config(&adapter->hw, &adapter->dcb_cfg);