[U-Boot] [PATCH v2] net/macb: increase RX buffer size for GEM

Ramon Fried
2019-08-22T11:15:51Z

On August 22, 2019 12:38:08 PM GMT+03:00, Stefan Roese <stefan.roese@gmail.com> wrote:
>Hi Ramon,
>
>On 14.07.19 17:25, Ramon Fried 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@gmail.com>
>
>This patch breaks ethernet on my AT91SAM9G25 based board. With this
>patch now, tftp does not complete the xfer any more:
>
>=> tftp 21000000 big
>ethernet at f802c000: PHY present at 1
>ethernet at f802c000: Starting autonegotiation...
>ethernet at f802c000: Autonegotiation complete
>ethernet at f802c000: link up, 100Mbps full-duplex (lpa: 0xc5e1)
>Using ethernet at f802c000 device
>TFTP from server 192.168.1.5; our IP address is 192.168.1.249
>Filename 'big'.
>Load address: 0x21000000
>Loading: #T T
>
>With this patch reverted (as well as with v2019.07), tftp works
>just fine.
>
>I did not look into the patch yet. Perhaps you have a quick idea
>on why this breaks my platform.
>
>BTW: When I disable the dcache (dcache off), tftp also works fine
>with this patch. So its definitely something cache / dma related.
>
Thanks for letting me know, I'll be next to a PC tomorrow, I'll look into it.
Thanks,
Ramon
>Thanks,
>Stefan
>
>> ---
>> v2: Fix multi-line comment style
>> drivers/net/macb.c | 30 ++++++++++++++++++++++--------
>> 1 file changed, 22 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/net/macb.c b/drivers/net/macb.c
>> index c072f99d8f..3c8b9722b3 100644
>> --- a/drivers/net/macb.c
>> +++ b/drivers/net/macb.c
>> @@ -45,10 +45,17 @@
>>
>> 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
>> + * 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 +102,7 @@ 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 +403,16 @@ 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 +710,7 @@ 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 +755,7 @@ 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 +966,13 @@ 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);
>>

--
Sent from my Android device with K-9 Mail. Please excuse my brevity.