On 2/28/24 1:33 AM, Niklas Söderlund wrote: > The RAVB device requires the SKB data to be aligned to 128 bytes. The I prefer calling it Ether[net]AVB (like the manuals do), that "ravb" is the driver's name... :-) > alignment is done by allocating a skb 128 bytes larger than the maximum s/a/an/. > frame size supported by the device and adjusting the headroom to fit the > requirement. > > This code has been refactored a few times and small issues have been > added along the way. The issues are not harmful but prevents merging Prevent. > parts of the Rx code which have been split in two implementations with > the addition of RZ/G2L support, a device that supports larger frame > sizes. > > This change removes the need for duplicated and somewhat inaccurate > hardware alignment constrains stored in the hardware information struct > by creating a helper to handle the allocation of a skb and alignment of s/a/an/. > a skb data. s/a/an/. > For the R-Car class of devices the maximum frame size is 4K and each > descriptor is limited to 2K of data. The current implementation does not > support split descriptors, this limits the frame size to 2K. The > current hardware information however records the descriptor size just > under 2K due to bad understanding of the device when larger MTUs where > added. > > For the RZ/G2L device the maximum frame size is 8K and each descriptor > is limited to 4K of data. The current hardware information records this > correctly, but it gets the alignment constrains wrong as just aligns it > by 128, it does not extend it by 128 bytes to allow the full frame to be > stored. This works because the RZ/G2L device supports split descriptors > and allocates each skb to 8K and aligns each 4K descriptor in this > space. > > Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx> Reviewed-by: Sergey Shtylyov <s.shtylyov@xxxxxx> [...] > diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c > index 5c72b780d623..e6b025058847 100644 > --- a/drivers/net/ethernet/renesas/ravb_main.c > +++ b/drivers/net/ethernet/renesas/ravb_main.c [...] > @@ -372,7 +383,7 @@ static void ravb_rx_ring_format_rcar(struct net_device *ndev, int q) > rx_desc = &priv->rx_ring[q].ex_desc[i]; > rx_desc->ds_cc = cpu_to_le16(RX_BUF_SZ); Don't we need to also update this? > dma_addr = dma_map_single(ndev->dev.parent, priv->rx_skb[q][i]->data, > - RX_BUF_SZ, > + priv->info->rx_max_frame_size, > DMA_FROM_DEVICE); > /* We just set the data size to 0 for a failed mapping which > * should prevent DMA from happening... [...] MBR, Sergey
