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| author | Ben Hutchings <bhutchings@solarflare.com> | 2009-10-23 08:31:20 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-10-24 04:27:07 -0700 |
| commit | 63f1988419ccaa544d1d31aadc1dd309f6471ffe (patch) | |
| tree | d973e7c103b9453063d02c8895f629c4ca692a33 /drivers/net/sfc/tx.c | |
| parent | 6d51d307509f98f070688b4bff1d0f7462c4d3ec (diff) | |
| download | lwn-63f1988419ccaa544d1d31aadc1dd309f6471ffe.tar.gz lwn-63f1988419ccaa544d1d31aadc1dd309f6471ffe.zip | |
sfc: Move all TX DMA length limiting into tx.c
Replace the duplicated logic in efx_enqueue_skb() and
efx_tx_queue_insert() with an inline function, efx_max_tx_len().
Remove the failed attempt at abstracting hardware-specifics and put
all the magic numbers in efx_max_tx_len().
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/sfc/tx.c')
| -rw-r--r-- | drivers/net/sfc/tx.c | 37 |
1 files changed, 23 insertions, 14 deletions
diff --git a/drivers/net/sfc/tx.c b/drivers/net/sfc/tx.c index ae554eec0563..303919a34df6 100644 --- a/drivers/net/sfc/tx.c +++ b/drivers/net/sfc/tx.c @@ -124,6 +124,24 @@ static void efx_tsoh_free(struct efx_tx_queue *tx_queue, } +static inline unsigned +efx_max_tx_len(struct efx_nic *efx, dma_addr_t dma_addr) +{ + /* Depending on the NIC revision, we can use descriptor + * lengths up to 8K or 8K-1. However, since PCI Express + * devices must split read requests at 4K boundaries, there is + * little benefit from using descriptors that cross those + * boundaries and we keep things simple by not doing so. + */ + unsigned len = (~dma_addr & 0xfff) + 1; + + /* Work around hardware bug for unaligned buffers. */ + if (EFX_WORKAROUND_5391(efx) && (dma_addr & 0xf)) + len = min_t(unsigned, len, 512 - (dma_addr & 0xf)); + + return len; +} + /* * Add a socket buffer to a TX queue * @@ -146,7 +164,7 @@ static netdev_tx_t efx_enqueue_skb(struct efx_tx_queue *tx_queue, skb_frag_t *fragment; struct page *page; int page_offset; - unsigned int len, unmap_len = 0, fill_level, insert_ptr, misalign; + unsigned int len, unmap_len = 0, fill_level, insert_ptr; dma_addr_t dma_addr, unmap_addr = 0; unsigned int dma_len; bool unmap_single; @@ -223,14 +241,10 @@ static netdev_tx_t efx_enqueue_skb(struct efx_tx_queue *tx_queue, EFX_BUG_ON_PARANOID(!buffer->continuation); EFX_BUG_ON_PARANOID(buffer->unmap_len); - dma_len = (((~dma_addr) & efx->type->tx_dma_mask) + 1); - if (likely(dma_len > len)) + dma_len = efx_max_tx_len(efx, dma_addr); + if (likely(dma_len >= len)) dma_len = len; - misalign = (unsigned)dma_addr & efx->type->bug5391_mask; - if (misalign && dma_len + misalign > 512) - dma_len = 512 - misalign; - /* Fill out per descriptor fields */ buffer->len = dma_len; buffer->dma_addr = dma_addr; @@ -703,7 +717,7 @@ static int efx_tx_queue_insert(struct efx_tx_queue *tx_queue, { struct efx_tx_buffer *buffer; struct efx_nic *efx = tx_queue->efx; - unsigned dma_len, fill_level, insert_ptr, misalign; + unsigned dma_len, fill_level, insert_ptr; int q_space; EFX_BUG_ON_PARANOID(len <= 0); @@ -752,12 +766,7 @@ static int efx_tx_queue_insert(struct efx_tx_queue *tx_queue, buffer->dma_addr = dma_addr; - /* Ensure we do not cross a boundary unsupported by H/W */ - dma_len = (~dma_addr & efx->type->tx_dma_mask) + 1; - - misalign = (unsigned)dma_addr & efx->type->bug5391_mask; - if (misalign && dma_len + misalign > 512) - dma_len = 512 - misalign; + dma_len = efx_max_tx_len(efx, dma_addr); /* If there is enough space to send then do so */ if (dma_len >= len) |