net: ethernet: ravb: Suspend and resume the transmission flow

The current driver does not follow the latest datasheet and does not
suspend the flow when stopping DMA and resume it when starting. Update
the driver to do so.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
[Niklas: Rebase from BSP and reword commit message]
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Link: https://patch.msgid.link/20260401183608.1852225-1-niklas.soderlund+renesas@ragnatech.se
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 2c725824b34885ae98c9957c811fe79d41d570c1..1dbfadb2a88145b5e006d106b8f6c0edfb469865 100644 (file)
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -694,6 +694,9 @@ static int ravb_dmac_init(struct net_device *ndev)
        const struct ravb_hw_info *info = priv->info;
        int error;
 
+       /* Clear transmission suspension */
+       ravb_modify(ndev, CCC, CCC_DTSR, 0);
+
        /* Set CONFIG mode */
        error = ravb_set_opmode(ndev, CCC_OPC_CONFIG);
        if (error)
@@ -1103,6 +1106,12 @@ static int ravb_stop_dma(struct net_device *ndev)
        if (error)
                return error;
 
+       /* Request for transmission suspension */
+       ravb_modify(ndev, CCC, CCC_DTSR, CCC_DTSR);
+       error = ravb_wait(ndev, CSR, CSR_DTS, CSR_DTS);
+       if (error)
+               netdev_err(ndev, "failed to stop AXI BUS\n");
+
        /* Stop AVB-DMAC process */
        return ravb_set_opmode(ndev, CCC_OPC_CONFIG);
 }