sfc: Replace some literal constants with EFX_PAGE_SIZE/EFX_BUF_SIZE
The 'page size' for PCIe DMA, i.e. the alignment of boundaries at
which DMA must be broken, is 4KB. Name this value as EFX_PAGE_SIZE
and use it in efx_max_tx_len(). Redefine EFX_BUF_SIZE as
EFX_PAGE_SIZE since its value is also a result of that requirement,
and use it in efx_init_special_buffer().
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
diff --git a/drivers/net/ethernet/sfc/tx.c b/drivers/net/ethernet/sfc/tx.c
index 5cb81fa..a096e28 100644
--- a/drivers/net/ethernet/sfc/tx.c
+++ b/drivers/net/ethernet/sfc/tx.c
@@ -110,7 +110,7 @@
* little benefit from using descriptors that cross those
* boundaries and we keep things simple by not doing so.
*/
- unsigned len = (~dma_addr & 0xfff) + 1;
+ unsigned len = (~dma_addr & (EFX_PAGE_SIZE - 1)) + 1;
/* Work around hardware bug for unaligned buffers. */
if (EFX_WORKAROUND_5391(efx) && (dma_addr & 0xf))