[PATCH net-next v3 4/4] net: lan966x: Update FDMA to change MTU.

From: Horatiu Vultur
Date: Mon Apr 04 2022 - 09:04:14 EST


When changing the MTU, it is required to change also the size of the
DBs. In case those frames will arrive to CPU.

Signed-off-by: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx>
---
.../ethernet/microchip/lan966x/lan966x_fdma.c | 95 +++++++++++++++++++
.../ethernet/microchip/lan966x/lan966x_main.c | 2 +-
.../ethernet/microchip/lan966x/lan966x_main.h | 1 +
3 files changed, 97 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
index 9cccb5f5f8e5..68bc53344326 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
@@ -633,6 +633,101 @@ int lan966x_fdma_xmit(struct sk_buff *skb, __be32 *ifh, struct net_device *dev)
return err;
}

+static int lan966x_fdma_get_max_mtu(struct lan966x *lan966x)
+{
+ int max_mtu = 0;
+ int i;
+
+ for (i = 0; i < lan966x->num_phys_ports; ++i) {
+ int mtu;
+
+ if (!lan966x->ports[i])
+ continue;
+
+ mtu = lan966x->ports[i]->dev->mtu;
+ if (mtu > max_mtu)
+ max_mtu = mtu;
+ }
+
+ return max_mtu;
+}
+
+static int lan966x_qsys_sw_status(struct lan966x *lan966x)
+{
+ return lan_rd(lan966x, QSYS_SW_STATUS(CPU_PORT));
+}
+
+static void lan966x_fdma_reload(struct lan966x *lan966x, int new_mtu)
+{
+ void *rx_dcb, *tx_dcb, *tx_dcb_buf;
+ dma_addr_t rx_dma, tx_dma;
+ unsigned long flags;
+ u32 size;
+
+ /* Store these for later to free them */
+ rx_dma = lan966x->rx.dma;
+ tx_dma = lan966x->tx.dma;
+ rx_dcb = lan966x->rx.dcbs;
+ tx_dcb = lan966x->tx.dcbs;
+ tx_dcb_buf = lan966x->tx.dcbs_buf;
+
+ lan966x_fdma_rx_disable(&lan966x->rx);
+ lan966x_fdma_rx_free_skbs(&lan966x->rx);
+ lan966x->rx.page_order = round_up(new_mtu, PAGE_SIZE) / PAGE_SIZE - 1;
+ lan966x_fdma_rx_alloc(&lan966x->rx);
+ lan966x_fdma_rx_start(&lan966x->rx);
+
+ spin_lock_irqsave(&lan966x->tx_lock, flags);
+ lan966x_fdma_tx_disable(&lan966x->tx);
+ lan966x_fdma_tx_alloc(&lan966x->tx);
+ spin_unlock_irqrestore(&lan966x->tx_lock, flags);
+
+ /* Now it is possible to clean */
+ size = sizeof(struct lan966x_tx_dcb) * FDMA_DCB_MAX;
+ size = ALIGN(size, PAGE_SIZE);
+ dma_free_coherent(lan966x->dev, size, tx_dcb, tx_dma);
+
+ kfree(tx_dcb_buf);
+
+ size = sizeof(struct lan966x_rx_dcb) * FDMA_DCB_MAX;
+ size = ALIGN(size, PAGE_SIZE);
+ dma_free_coherent(lan966x->dev, size, rx_dcb, rx_dma);
+}
+
+int lan966x_fdma_change_mtu(struct lan966x *lan966x)
+{
+ int max_mtu;
+ u32 val;
+
+ max_mtu = lan966x_fdma_get_max_mtu(lan966x);
+ if (round_up(max_mtu, PAGE_SIZE) / PAGE_SIZE - 1 ==
+ lan966x->rx.page_order)
+ return 0;
+
+ /* 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(1000, 2000);
+
+ lan966x_fdma_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 0;
+}
+
void lan966x_fdma_netdev_init(struct lan966x *lan966x, struct net_device *dev)
{
if (lan966x->fdma_ndev)
diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_main.c b/drivers/net/ethernet/microchip/lan966x/lan966x_main.c
index 245cf4168de0..ca1cef79b83f 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_main.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_main.c
@@ -359,7 +359,7 @@ static int lan966x_port_change_mtu(struct net_device *dev, int new_mtu)
lan966x, DEV_MAC_MAXLEN_CFG(port->chip_port));
dev->mtu = new_mtu;

- return 0;
+ return !lan966x->fdma ? 0 : lan966x_fdma_change_mtu(lan966x);
}

static int lan966x_mc_unsync(struct net_device *dev, const unsigned char *addr)
diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_main.h b/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
index 47f42087b78d..e6642083ab9e 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
@@ -398,6 +398,7 @@ void lan966x_ptp_txtstamp_release(struct lan966x_port *port,
irqreturn_t lan966x_ptp_irq_handler(int irq, void *args);

int lan966x_fdma_xmit(struct sk_buff *skb, __be32 *ifh, struct net_device *dev);
+int lan966x_fdma_change_mtu(struct lan966x *lan966x);
void lan966x_fdma_netdev_init(struct lan966x *lan966x, struct net_device *dev);
void lan966x_fdma_netdev_deinit(struct lan966x *lan966x, struct net_device *dev);
int lan966x_fdma_init(struct lan966x *lan966x);
--
2.33.0