[U-Boot] [PATCH] net/macb: increase RX buffer size for GEM

[Joe Hershberger]

On Mon, Jun 24, 2019 at 2:02 PM Ramon Fried <rfried.dev at gmail.com> wrote:
>
> Macb Ethernet controller requires a RX buffer of 128 bytes. It is
> highly sub-optimal for Gigabit-capable GEM that is able to use
> a bigger DMA buffer. Change this constant and associated macros
> with data stored in the private structure.
> RX DMA buffer size has to be multiple of 64 bytes as indicated in
> DMA Configuration Register specification.
>
> Signed-off-by: Ramon Fried <rfried.dev at gmail.com>

Mostly good, but please address the nit below.

Acked-by: Joe Hershberger <joe.hershberger at ni.com>

> ---
>  drivers/net/macb.c | 29 +++++++++++++++++++++--------
>  1 file changed, 21 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/net/macb.c b/drivers/net/macb.c
> index c072f99d8f..8eb6977fa9 100644
> --- a/drivers/net/macb.c
> +++ b/drivers/net/macb.c
> @@ -45,10 +45,16 @@
>
>  DECLARE_GLOBAL_DATA_PTR;
>
> -#define MACB_RX_BUFFER_SIZE            4096
> -#define MACB_RX_RING_SIZE              (MACB_RX_BUFFER_SIZE / 128)
> +/* These buffer sizes must be power of 2 and divisible

Please correct the multi-line comment format.

> + * by RX_BUFFER_MULTIPLE
> + */
> +#define MACB_RX_BUFFER_SIZE            128
> +#define GEM_RX_BUFFER_SIZE             2048
>  #define RX_BUFFER_MULTIPLE             64
> +
> +#define MACB_RX_RING_SIZE              32
>  #define MACB_TX_RING_SIZE              16
> +
>  #define MACB_TX_TIMEOUT                1000
>  #define MACB_AUTONEG_TIMEOUT   5000000
>
> @@ -95,6 +101,7 @@ struct macb_device {
>         void                    *tx_buffer;
>         struct macb_dma_desc    *rx_ring;
>         struct macb_dma_desc    *tx_ring;
> +       size_t                  rx_buffer_size;
>
>         unsigned long           rx_buffer_dma;
>         unsigned long           rx_ring_dma;
> @@ -395,15 +402,16 @@ static int _macb_recv(struct macb_device *macb, uchar **packetp)
>                 }
>
>                 if (status & MACB_BIT(RX_EOF)) {
> -                       buffer = macb->rx_buffer + 128 * macb->rx_tail;
> +                       buffer = macb->rx_buffer +
> +                               macb->rx_buffer_size * macb->rx_tail;
>                         length = status & RXBUF_FRMLEN_MASK;
>
>                         macb_invalidate_rx_buffer(macb);
>                         if (macb->wrapped) {
>                                 unsigned int headlen, taillen;
>
> -                               headlen = 128 * (MACB_RX_RING_SIZE
> -                                                - macb->rx_tail);
> +                               headlen = macb->rx_buffer_size *
> +                                       (MACB_RX_RING_SIZE - macb->rx_tail);
>                                 taillen = length - headlen;
>                                 memcpy((void *)net_rx_packets[0],
>                                        buffer, headlen);
> @@ -701,7 +709,7 @@ static void gmac_configure_dma(struct macb_device *macb)
>         u32 buffer_size;
>         u32 dmacfg;
>
> -       buffer_size = 128 / RX_BUFFER_MULTIPLE;
> +       buffer_size = macb->rx_buffer_size / RX_BUFFER_MULTIPLE;
>         dmacfg = gem_readl(macb, DMACFG) & ~GEM_BF(RXBS, -1L);
>         dmacfg |= GEM_BF(RXBS, buffer_size);
>
> @@ -746,7 +754,7 @@ static int _macb_init(struct macb_device *macb, const char *name)
>                         paddr |= MACB_BIT(RX_WRAP);
>                 macb->rx_ring[i].addr = paddr;
>                 macb->rx_ring[i].ctrl = 0;
> -               paddr += 128;
> +               paddr += macb->rx_buffer_size;
>         }
>         macb_flush_ring_desc(macb, RX);
>         macb_flush_rx_buffer(macb);
> @@ -957,8 +965,13 @@ static void _macb_eth_initialize(struct macb_device *macb)
>         int id = 0;     /* This is not used by functions we call */
>         u32 ncfgr;
>
> +       if (macb_is_gem(macb))
> +               macb->rx_buffer_size = GEM_RX_BUFFER_SIZE;
> +       else
> +               macb->rx_buffer_size = MACB_RX_BUFFER_SIZE;
> +
>         /* TODO: we need check the rx/tx_ring_dma is dcache line aligned */
> -       macb->rx_buffer = dma_alloc_coherent(MACB_RX_BUFFER_SIZE,
> +       macb->rx_buffer = dma_alloc_coherent(macb->rx_buffer_size * MACB_RX_RING_SIZE,
>                                              &macb->rx_buffer_dma);
>         macb->rx_ring = dma_alloc_coherent(MACB_RX_DMA_DESC_SIZE,
>                                            &macb->rx_ring_dma);
> --
> 2.22.0
>
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