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| author | Baruch Siach <baruch@tkos.co.il> | 2008-12-19 06:39:14 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2008-12-19 09:27:39 +0300 |
| commit | 5664dd5561850df580414783cf3c8e0aa834c62e (patch) | |
| tree | aac02f7e39a2adbac4920c131c1a49f6ddb571e2 /include | |
| parent | b88a2a22c6670c31586d1a716255eae4c320b363 (diff) | |
| download | linux-5664dd5561850df580414783cf3c8e0aa834c62e.tar.xz | |
enc28j60: reduce the number of spi transfers in enc28j60_set_bank()
A major source of overhead in the enc28j60 driver is the SPI transfers. Each
SPI transfer entails two kernel thread context switches. One major source of
SPI transfers is the enc28j60_set_bank() functions which runs before every
register access. This patch reduces the number of SPI transfers that
enc28j60_set_bank() performs in two ways:
1. removes unnecessary bank switch for the registers that are present in all
banks
2. when switching from banks 0 or 3 to banks 1 or 2 (i.e. only one bit
changes) enc28j60_set_bank() does only one SPI transfer instead of two
According to my tests these changes reduce the number of SPI transfers in
about 25%.
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
0 files changed, 0 insertions, 0 deletions