Add MTU change support for the PCIe FDMA path. When the MTU changes, the contiguous ATU-mapped RX and TX buffers are reallocated with the new size. On allocation failure, the existing buffers are reused after being reset. Cap the PCIe DCB ring at 256 (FDMA_PCI_DCB_MAX) to keep the entire contiguous allocation under MAX_PAGE_ORDER at jumbo MTU, which 512 DCBs would overflow. Tested-by: Herve Codina Signed-off-by: Daniel Machon --- .../ethernet/microchip/lan966x/lan966x_fdma_pci.c | 157 ++++++++++++++++++++- 1 file changed, 154 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma_pci.c b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma_pci.c index c27d9e76e735..3ea6d22ee573 100644 --- a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma_pci.c +++ b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma_pci.c @@ -3,6 +3,11 @@ #include "fdma_api.h" #include "lan966x_main.h" +/* Ring must fit in one MAX_PAGE_ORDER DMA block; 512 DCBs overflows + * at jumbo MTU. + */ +#define FDMA_PCI_DCB_MAX 256 + static int lan966x_fdma_pci_dataptr_cb(struct fdma *fdma, int dcb, int db, u64 *dataptr) { @@ -332,7 +337,7 @@ static int lan966x_fdma_pci_init(struct lan966x *lan966x) lan966x->rx.lan966x = lan966x; lan966x->rx.max_mtu = lan966x_fdma_get_max_frame(lan966x); rx_fdma->channel_id = FDMA_XTR_CHANNEL; - rx_fdma->n_dcbs = FDMA_DCB_MAX; + rx_fdma->n_dcbs = FDMA_PCI_DCB_MAX; rx_fdma->n_dbs = FDMA_RX_DCB_MAX_DBS; rx_fdma->priv = lan966x; rx_fdma->db_size = FDMA_PCI_DB_SIZE(lan966x->rx.max_mtu); @@ -342,7 +347,7 @@ static int lan966x_fdma_pci_init(struct lan966x *lan966x) lan966x->tx.lan966x = lan966x; tx_fdma->channel_id = FDMA_INJ_CHANNEL; - tx_fdma->n_dcbs = FDMA_DCB_MAX; + tx_fdma->n_dcbs = FDMA_PCI_DCB_MAX; tx_fdma->n_dbs = FDMA_TX_DCB_MAX_DBS; tx_fdma->priv = lan966x; tx_fdma->db_size = FDMA_PCI_DB_SIZE(lan966x->rx.max_mtu); @@ -365,9 +370,155 @@ static int lan966x_fdma_pci_init(struct lan966x *lan966x) return 0; } +/* Reset existing rx and tx buffers. */ +static void lan966x_fdma_pci_reset_mem(struct lan966x *lan966x) +{ + struct lan966x_rx *rx = &lan966x->rx; + struct lan966x_tx *tx = &lan966x->tx; + + memset(rx->fdma.dcbs, 0, rx->fdma.size); + memset(tx->fdma.dcbs, 0, tx->fdma.size); + + fdma_dcbs_init(&rx->fdma, + FDMA_DCB_INFO_DATAL(rx->fdma.db_size), + FDMA_DCB_STATUS_INTR); + + fdma_dcbs_init(&tx->fdma, + FDMA_DCB_INFO_DATAL(tx->fdma.db_size), + FDMA_DCB_STATUS_DONE); + + lan966x_fdma_llp_configure(lan966x, + tx->fdma.atu_region->base_addr, + tx->fdma.channel_id); + lan966x_fdma_llp_configure(lan966x, + rx->fdma.atu_region->base_addr, + rx->fdma.channel_id); +} + +/* Drain in-flight xmit callers and stop all TX queues on every port. */ +static void lan966x_fdma_pci_stop_netdev(struct lan966x *lan966x) +{ + for (int i = 0; i < lan966x->num_phys_ports; ++i) { + struct lan966x_port *port = lan966x->ports[i]; + + if (port) + netif_tx_disable(port->dev); + } +} + +/* Wake all TX queues on every port (undoes lan966x_fdma_pci_stop_netdev). */ +static void lan966x_fdma_pci_wakeup_netdev(struct lan966x *lan966x) +{ + for (int i = 0; i < lan966x->num_phys_ports; ++i) { + struct lan966x_port *port = lan966x->ports[i]; + + if (port) + netif_tx_wake_all_queues(port->dev); + } +} + +static int lan966x_fdma_pci_reload(struct lan966x *lan966x, int new_mtu) +{ + struct fdma tx_fdma_old = lan966x->tx.fdma; + struct fdma rx_fdma_old = lan966x->rx.fdma; + u32 old_mtu = lan966x->rx.max_mtu; + int err; + + napi_synchronize(&lan966x->napi); + napi_disable(&lan966x->napi); + lan966x_fdma_pci_stop_netdev(lan966x); + lan966x_fdma_rx_disable(&lan966x->rx); + lan966x_fdma_tx_disable(&lan966x->tx); + + lan966x->rx.max_mtu = new_mtu; + + lan966x->tx.fdma.db_size = FDMA_PCI_DB_SIZE(lan966x->rx.max_mtu); + lan966x->tx.fdma.size = fdma_get_size_contiguous(&lan966x->tx.fdma); + lan966x->rx.fdma.db_size = FDMA_PCI_DB_SIZE(lan966x->rx.max_mtu); + lan966x->rx.fdma.size = fdma_get_size_contiguous(&lan966x->rx.fdma); + + err = lan966x_fdma_pci_rx_alloc(&lan966x->rx); + if (err) + goto restore; + + err = lan966x_fdma_pci_tx_alloc(&lan966x->tx); + if (err) { + fdma_free_coherent_and_unmap(lan966x->dev, &lan966x->rx.fdma); + goto restore; + } + + /* Free and unmap old memory. */ + fdma_free_coherent_and_unmap(lan966x->dev, &rx_fdma_old); + fdma_free_coherent_and_unmap(lan966x->dev, &tx_fdma_old); + + /* Keep this order: rx_start, wakeup_netdev, napi_enable. */ + lan966x_fdma_rx_start(&lan966x->rx); + lan966x_fdma_pci_wakeup_netdev(lan966x); + napi_enable(&lan966x->napi); + + return err; +restore: + + /* No new buffers are allocated at this point. Use the old buffers, + * but reset them before starting the FDMA again. + */ + + memcpy(&lan966x->tx.fdma, &tx_fdma_old, sizeof(struct fdma)); + memcpy(&lan966x->rx.fdma, &rx_fdma_old, sizeof(struct fdma)); + + lan966x->rx.max_mtu = old_mtu; + + lan966x_fdma_pci_reset_mem(lan966x); + + /* Keep this order: rx_start, wakeup_netdev, napi_enable. */ + lan966x_fdma_rx_start(&lan966x->rx); + lan966x_fdma_pci_wakeup_netdev(lan966x); + napi_enable(&lan966x->napi); + + return err; +} + +static int __lan966x_fdma_pci_reload(struct lan966x *lan966x, int max_mtu) +{ + int err; + u32 val; + + /* Disable the CPU port. */ + lan_rmw(QSYS_SW_PORT_MODE_PORT_ENA_SET(0), + QSYS_SW_PORT_MODE_PORT_ENA, + lan966x, QSYS_SW_PORT_MODE(CPU_PORT)); + + /* Flush the CPU queues. */ + readx_poll_timeout(lan966x_qsys_sw_status, + lan966x, + val, + !(QSYS_SW_STATUS_EQ_AVAIL_GET(val)), + READL_SLEEP_US, READL_TIMEOUT_US); + + /* Add a sleep in case there are frames between the queues and the CPU + * port + */ + usleep_range(USEC_PER_MSEC, 2 * USEC_PER_MSEC); + + err = lan966x_fdma_pci_reload(lan966x, max_mtu); + + /* Enable back the CPU port. */ + lan_rmw(QSYS_SW_PORT_MODE_PORT_ENA_SET(1), + QSYS_SW_PORT_MODE_PORT_ENA, + lan966x, QSYS_SW_PORT_MODE(CPU_PORT)); + + return err; +} + static int lan966x_fdma_pci_resize(struct lan966x *lan966x) { - return -EOPNOTSUPP; + int max_mtu; + + max_mtu = lan966x_fdma_get_max_frame(lan966x); + if (max_mtu == lan966x->rx.max_mtu) + return 0; + + return __lan966x_fdma_pci_reload(lan966x, max_mtu); } static void lan966x_fdma_pci_deinit(struct lan966x *lan966x) -- 2.34.1