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AT91 serial driver


Hello all,

This patch seriously improves the at91 serial driver.
We are now able to handle heavy load at up to 230400 baud (and probably
more, but not yet tested).
The major advantage of this patch is to dramatically reduces the IT rate
for incoming data bursts.
The major drawback is its code size (for my target 1500 bytes instead of
900).

I am aware that there is a lot of work to make it fully configurable,
but my concern was mainly the performance (because I use serial line for
networking).

Some issues about performance:
EB55 with at91m55800 running at 32 Mhz, and 1WS external 16-bit sram.
I successfully run io/serial/current/tests/serial3.c :
 - at 230400 baud
 - with the 'large packet' code enabled
During the test the MCU receives 93702 chars and generates 3000
reception interruptions. This demonstrates the lower IT rate, which
saves a lot of CPU for the other threads.

happy hacking.

-- 
GONZALEZ Laurent
Silicomp Research Institute
Tel: 04 76 41 66 98

Attachment: at91_serial.patch
Description: Binary data


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