Messages in this thread | | | Date | Mon, 26 Nov 2012 11:44:03 +0100 | From | Nicolas Ferre <> | Subject | Re: [PATCH] net/macb: Use non-coherent memory for rx buffers |
| |
On 11/23/2012 05:12 PM, Joachim Eastwood : > Hi Nicolas, > > On 23 November 2012 14:50, Nicolas Ferre <nicolas.ferre@atmel.com> wrote: >> From: Havard Skinnemoen <havard@skinnemoen.net> >> >> Allocate regular pages to use as backing for the RX ring and use the >> DMA API to sync the caches. This should give a bit better performance >> since it allows the CPU to do burst transfers from memory. It is also >> a necessary step on the way to reduce the amount of copying done by >> the driver. >> >> Signed-off-by: Havard Skinnemoen <havard@skinnemoen.net> >> [nicolas.ferre@atmel.com: adapt to newer kernel] >> Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com> >> --- >> drivers/net/ethernet/cadence/macb.c | 206 +++++++++++++++++++++++------------- >> drivers/net/ethernet/cadence/macb.h | 20 +++- >> 2 files changed, 148 insertions(+), 78 deletions(-) > > <snip> > >> diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h >> index 570908b..74e68a3 100644 >> --- a/drivers/net/ethernet/cadence/macb.h >> +++ b/drivers/net/ethernet/cadence/macb.h >> @@ -453,6 +453,23 @@ struct macb_dma_desc { >> #define MACB_TX_USED_SIZE 1 >> >> /** >> + * struct macb_rx_page - data associated with a page used as RX buffers >> + * @page: Physical page used as storage for the buffers >> + * @phys: DMA address of the page >> + * >> + * Each page is used to provide %MACB_RX_BUFFERS_PER_PAGE RX buffers. >> + * The page gets an initial reference when it is inserted into the >> + * ring, and an additional reference each time it is passed up the >> + * stack as a fragment. When all the buffers have been used, we drop >> + * the initial reference and allocate a new page. Any additional >> + * references are dropped when the higher layers free the skb. >> + */ >> +struct macb_rx_page { >> + struct page *page; >> + dma_addr_t phys; >> +}; >> + >> +/** >> * struct macb_tx_skb - data about an skb which is being transmitted >> * @skb: skb currently being transmitted >> * @mapping: DMA address of the skb's data buffer >> @@ -543,7 +560,7 @@ struct macb { >> >> unsigned int rx_tail; >> struct macb_dma_desc *rx_ring; >> - void *rx_buffers; >> + struct macb_rx_page *rx_page; >> >> unsigned int tx_head, tx_tail; >> struct macb_dma_desc *tx_ring; >> @@ -564,7 +581,6 @@ struct macb { >> >> dma_addr_t rx_ring_dma; >> dma_addr_t tx_ring_dma; >> - dma_addr_t rx_buffers_dma; >> >> struct mii_bus *mii_bus; >> struct phy_device *phy_dev; >> -- > > struct macb is shared between at91_ether and macb. Removing > rx_buffers_dma and rx_buffers will break compilation on at91_ether.
OMG, you are absolutely right.
> So please either leave the two struct members alone, for now, or fix > up at91_ether at the same time.
Well, I do not plan to touch at91_ether driver for the moment, so I certainly will keep the two struct members for now.
I will wait a little more feedback before sending a v2 patch with these changes.
Best regards, -- Nicolas Ferre
| |