From a8648887880f90137f0893aeb1a0abef30858c01 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Sat, 17 Apr 2021 02:42:25 +0300 Subject: [PATCH] net: enetc: add support for flow control In the ENETC receive path, a frame received by the MAC is first stored in a 256KB 'FIFO' memory, then transferred to DRAM when enqueuing it to the RX ring. The FIFO is a shared resource for all ENETC ports, but every port keeps track of its own memory utilization, on RX and on TX. There is a setting for RX rings through which they can either operate in 'lossy' mode (where the lack of a free buffer causes an immediate discard of the frame) or in 'lossless' mode (where the lack of a free buffer in the ring makes the frame stay longer in the FIFO). In turn, when the memory utilization of the FIFO exceeds a certain margin, the MAC can be configured to emit PAUSE frames. There is enough FIFO memory to buffer up to 3 MTU-sized frames per RX port while not jeopardizing the other use cases (jumbo frames), and also not consume bytes from the port TX allocations. Also, 3 MTU-sized frames worth of memory is enough to ensure zero loss for 64 byte packets at 1G line rate. Signed-off-by: Vladimir Oltean Reviewed-by: Claudiu Manoil Signed-off-by: David S. Miller --- .../net/ethernet/freescale/enetc/enetc_ethtool.c | 18 +++++++ drivers/net/ethernet/freescale/enetc/enetc_hw.h | 9 ++++ drivers/net/ethernet/freescale/enetc/enetc_pf.c | 60 +++++++++++++++++++++- 3 files changed, 85 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/freescale/enetc/enetc_ethtool.c b/drivers/net/ethernet/freescale/enetc/enetc_ethtool.c index 49835e8..ebccaf0 100644 --- a/drivers/net/ethernet/freescale/enetc/enetc_ethtool.c +++ b/drivers/net/ethernet/freescale/enetc/enetc_ethtool.c @@ -708,6 +708,22 @@ static int enetc_set_wol(struct net_device *dev, return ret; } +static void enetc_get_pauseparam(struct net_device *dev, + struct ethtool_pauseparam *pause) +{ + struct enetc_ndev_priv *priv = netdev_priv(dev); + + phylink_ethtool_get_pauseparam(priv->phylink, pause); +} + +static int enetc_set_pauseparam(struct net_device *dev, + struct ethtool_pauseparam *pause) +{ + struct enetc_ndev_priv *priv = netdev_priv(dev); + + return phylink_ethtool_set_pauseparam(priv->phylink, pause); +} + static int enetc_get_link_ksettings(struct net_device *dev, struct ethtool_link_ksettings *cmd) { @@ -754,6 +770,8 @@ static const struct ethtool_ops enetc_pf_ethtool_ops = { .get_ts_info = enetc_get_ts_info, .get_wol = enetc_get_wol, .set_wol = enetc_set_wol, + .get_pauseparam = enetc_get_pauseparam, + .set_pauseparam = enetc_set_pauseparam, }; static const struct ethtool_ops enetc_vf_ethtool_ops = { diff --git a/drivers/net/ethernet/freescale/enetc/enetc_hw.h b/drivers/net/ethernet/freescale/enetc/enetc_hw.h index 04ac7fc..0f5f081 100644 --- a/drivers/net/ethernet/freescale/enetc/enetc_hw.h +++ b/drivers/net/ethernet/freescale/enetc/enetc_hw.h @@ -109,6 +109,7 @@ enum enetc_bdr_type {TX, RX}; /* RX BDR reg offsets */ #define ENETC_RBMR 0 #define ENETC_RBMR_BDS BIT(2) +#define ENETC_RBMR_CM BIT(4) #define ENETC_RBMR_VTE BIT(5) #define ENETC_RBMR_EN BIT(31) #define ENETC_RBSR 0x4 @@ -180,6 +181,8 @@ enum enetc_bdr_type {TX, RX}; #define ENETC_PSIVLANR(n) (0x0240 + (n) * 4) /* n = SI index */ #define ENETC_PSIVLAN_EN BIT(31) #define ENETC_PSIVLAN_SET_QOS(val) ((u32)(val) << 12) +#define ENETC_PPAUONTR 0x0410 +#define ENETC_PPAUOFFTR 0x0414 #define ENETC_PTXMBAR 0x0608 #define ENETC_PCAPR0 0x0900 #define ENETC_PCAPR0_RXBDR(val) ((val) >> 24) @@ -227,6 +230,7 @@ enum enetc_bdr_type {TX, RX}; #define ENETC_PM0_TX_EN BIT(0) #define ENETC_PM0_RX_EN BIT(1) #define ENETC_PM0_PROMISC BIT(4) +#define ENETC_PM0_PAUSE_IGN BIT(8) #define ENETC_PM0_CMD_XGLP BIT(10) #define ENETC_PM0_CMD_TXP BIT(11) #define ENETC_PM0_CMD_PHY_TX_EN BIT(15) @@ -239,6 +243,11 @@ enum enetc_bdr_type {TX, RX}; #define ENETC_PM_IMDIO_BASE 0x8030 +#define ENETC_PM0_PAUSE_QUANTA 0x8054 +#define ENETC_PM0_PAUSE_THRESH 0x8064 +#define ENETC_PM1_PAUSE_QUANTA 0x9054 +#define ENETC_PM1_PAUSE_THRESH 0x9064 + #define ENETC_PM0_SINGLE_STEP 0x80c0 #define ENETC_PM1_SINGLE_STEP 0x90c0 #define ENETC_PM0_SINGLE_STEP_CH BIT(7) diff --git a/drivers/net/ethernet/freescale/enetc/enetc_pf.c b/drivers/net/ethernet/freescale/enetc/enetc_pf.c index 7ca17bb..3127432 100644 --- a/drivers/net/ethernet/freescale/enetc/enetc_pf.c +++ b/drivers/net/ethernet/freescale/enetc/enetc_pf.c @@ -1014,7 +1014,12 @@ static void enetc_pl_mac_link_up(struct phylink_config *config, int duplex, bool tx_pause, bool rx_pause) { struct enetc_pf *pf = phylink_to_enetc_pf(config); + u32 pause_off_thresh = 0, pause_on_thresh = 0; + u32 init_quanta = 0, refresh_quanta = 0; + struct enetc_hw *hw = &pf->si->hw; struct enetc_ndev_priv *priv; + u32 rbmr, cmd_cfg; + int idx; priv = netdev_priv(pf->si->ndev); if (priv->active_offloads & ENETC_F_QBV) @@ -1022,9 +1027,60 @@ static void enetc_pl_mac_link_up(struct phylink_config *config, if (!phylink_autoneg_inband(mode) && phy_interface_mode_is_rgmii(interface)) - enetc_force_rgmii_mac(&pf->si->hw, speed, duplex); + enetc_force_rgmii_mac(hw, speed, duplex); + + /* Flow control */ + for (idx = 0; idx < priv->num_rx_rings; idx++) { + rbmr = enetc_rxbdr_rd(hw, idx, ENETC_RBMR); + + if (tx_pause) + rbmr |= ENETC_RBMR_CM; + else + rbmr &= ~ENETC_RBMR_CM; + + enetc_rxbdr_wr(hw, idx, ENETC_RBMR, rbmr); + } + + if (tx_pause) { + /* When the port first enters congestion, send a PAUSE request + * with the maximum number of quanta. When the port exits + * congestion, it will automatically send a PAUSE frame with + * zero quanta. + */ + init_quanta = 0xffff; + + /* Also, set up the refresh timer to send follow-up PAUSE + * frames at half the quanta value, in case the congestion + * condition persists. + */ + refresh_quanta = 0xffff / 2; + + /* Start emitting PAUSE frames when 3 large frames (or more + * smaller frames) have accumulated in the FIFO waiting to be + * DMAed to the RX ring. + */ + pause_on_thresh = 3 * ENETC_MAC_MAXFRM_SIZE; + pause_off_thresh = 1 * ENETC_MAC_MAXFRM_SIZE; + } + + enetc_port_wr(hw, ENETC_PM0_PAUSE_QUANTA, init_quanta); + enetc_port_wr(hw, ENETC_PM1_PAUSE_QUANTA, init_quanta); + enetc_port_wr(hw, ENETC_PM0_PAUSE_THRESH, refresh_quanta); + enetc_port_wr(hw, ENETC_PM1_PAUSE_THRESH, refresh_quanta); + enetc_port_wr(hw, ENETC_PPAUONTR, pause_on_thresh); + enetc_port_wr(hw, ENETC_PPAUOFFTR, pause_off_thresh); + + cmd_cfg = enetc_port_rd(hw, ENETC_PM0_CMD_CFG); + + if (rx_pause) + cmd_cfg &= ~ENETC_PM0_PAUSE_IGN; + else + cmd_cfg |= ENETC_PM0_PAUSE_IGN; + + enetc_port_wr(hw, ENETC_PM0_CMD_CFG, cmd_cfg); + enetc_port_wr(hw, ENETC_PM1_CMD_CFG, cmd_cfg); - enetc_mac_enable(&pf->si->hw, true); + enetc_mac_enable(hw, true); } static void enetc_pl_mac_link_down(struct phylink_config *config, -- 2.7.4