On Fri, 26 Apr 2019 09:32:22 +0200, Esben Haabendal wrote:
> The use of buffer descriptor APP4 field (32-bit) for storing skb pointer
> obviously does not work on 64-bit platforms.
> As APP3 is also unused, we can use that to store the other half of 64-bit
> pointer values.
>
> Contrary to what is hinted at in commit message of commit 15bfe05c8d63
> ("net: ethernet: xilinx: Mark XILINX_LL_TEMAC broken on 64-bit")
> there are no other pointers stored in cdmac_bd.
>
> Signed-off-by: Esben Haabendal <[email protected]>
This is a bit strange, the driver stores the host's virtual address into
the HW descriptor?
> diff --git a/drivers/net/ethernet/xilinx/Kconfig
> b/drivers/net/ethernet/xilinx/Kconfig
> index da4ec57..6d68c8a 100644
> --- a/drivers/net/ethernet/xilinx/Kconfig
> +++ b/drivers/net/ethernet/xilinx/Kconfig
> @@ -34,7 +34,6 @@ config XILINX_AXI_EMAC
> config XILINX_LL_TEMAC
> tristate "Xilinx LL TEMAC (LocalLink Tri-mode Ethernet MAC) driver"
> depends on (PPC || MICROBLAZE)
> - depends on !64BIT || BROKEN
> select PHYLIB
> ---help---
> This driver supports the Xilinx 10/100/1000 LocalLink TEMAC
> diff --git a/drivers/net/ethernet/xilinx/ll_temac_main.c
> b/drivers/net/ethernet/xilinx/ll_temac_main.c
> index 4594fe3..a365bfd 100644
> --- a/drivers/net/ethernet/xilinx/ll_temac_main.c
> +++ b/drivers/net/ethernet/xilinx/ll_temac_main.c
> @@ -619,11 +619,39 @@ static void temac_adjust_link(struct net_device *ndev)
> mutex_unlock(&lp->indirect_mutex);
> }
>
> +#ifdef CONFIG_64BIT
> +
> +void ptr_to_txbd(void *p, struct cdmac_bd *bd)
> +{
> + bd->app3 = (u32)(((u64)p) >> 32);
> + bd->app4 = (u32)((u64)p & 0xFFFFFFFF);
> +}
> +
> +void *ptr_from_txbd(struct cdmac_bd *bd)
> +{
> + return (void *)(((u64)(bd->app3) << 32) | bd->app4);
> +}
> +
> +#else
> +
> +void ptr_to_txbd(void *p, struct cmdac_bd *bd)
> +{
> + bd->app4 = (u32)p;
> +}
> +
> +void *ptr_from_txbd(struct cdmac_bd *bd)
> +{
> + return (void *)(bd->app4);
> +}
> +
> +#endif
> +
> static void temac_start_xmit_done(struct net_device *ndev)
> {
> struct temac_local *lp = netdev_priv(ndev);
> struct cdmac_bd *cur_p;
> unsigned int stat = 0;
> + struct sk_buff *skb;
>
> cur_p = &lp->tx_bd_v[lp->tx_bd_ci];
> stat = cur_p->app0;
> @@ -631,8 +659,9 @@ static void temac_start_xmit_done(struct net_device *ndev)
> while (stat & STS_CTRL_APP0_CMPLT) {
> dma_unmap_single(ndev->dev.parent, cur_p->phys, cur_p->len,
> DMA_TO_DEVICE);
> - if (cur_p->app4)
> - dev_consume_skb_irq((struct sk_buff *)cur_p->app4);
> + skb = (struct sk_buff *)ptr_from_txbd(cur_p);
> + if (skb)
> + dev_consume_skb_irq(skb);
> cur_p->app0 = 0;
> cur_p->app1 = 0;
> cur_p->app2 = 0;
> @@ -711,7 +740,7 @@ temac_start_xmit(struct sk_buff *skb, struct net_device
> *ndev)
> cur_p->len = skb_headlen(skb);
> cur_p->phys = dma_map_single(ndev->dev.parent, skb->data,
> skb_headlen(skb), DMA_TO_DEVICE);
> - cur_p->app4 = (unsigned long)skb;
> + ptr_to_txbd((void *)skb, cur_p);
>
> for (ii = 0; ii < num_frag; ii++) {
> lp->tx_bd_tail++;
