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

[Ramon Fried]

On August 22, 2019 12:38:08 PM GMT+03:00, Stefan Roese <stefan.roese at 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 at 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);
>> 

-- 
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