Hi!
> I used to delve into zaurus code for awhile ago. There are some local changes
> left from that time.
> One thing is the change to pxa pcmcia timings.
> Here's the original code from 2.6.16:
>
> static inline u_int pxa2xx_mcxx_hold(u_int pcmcia_cycle_ns,
> u_int mem_clk_10khz)
> {
> u_int code = pcmcia_cycle_ns * mem_clk_10khz;
> return (code / 300000) + ((code % 300000) ? 1 : 0) - 1;
> }
>
> static inline u_int pxa2xx_mcxx_asst(u_int pcmcia_cycle_ns,
> u_int mem_clk_10khz)
> {
> u_int code = pcmcia_cycle_ns * mem_clk_10khz;
> return (code / 300000) + ((code % 300000) ? 1 : 0) - 1;
> }
>
> static inline u_int pxa2xx_mcxx_setup(u_int pcmcia_cycle_ns,
> u_int mem_clk_10khz)
> {
> u_int code = pcmcia_cycle_ns * mem_clk_10khz;
> return (code / 100000) + ((code % 100000) ? 1 : 0) - 1;
> }
>
> I don't know the original reasons why the timings are calculated in this way.
> My guess that it's sa1100 adapted to pxa. But the pxa has more control of the
> bus cycle. After looking at pxa docs and CF/PCMCIA standard I've changed
> the formula to the following:
>
> static inline u_int pxa2xx_mcxx_hold(u_int hold,
> u_int mem_clk_10khz)
> {
> u_int code = hold * mem_clk_10khz;
> return (code / 100000) + ((code % 100000) ? 1 : 0);
> }
>
> static inline u_int pxa2xx_mcxx_asst(u_int cas,
> u_int mem_clk_10khz)
> {
> u_int code = cas * mem_clk_10khz;
> if(code % 300000 > 200000) return code/300000;
> else return code/300000-1;
> }
>
> static inline u_int pxa2xx_mcxx_setup(u_int set,
> u_int mem_clk_10khz)
> {
> u_int code = set * mem_clk_10khz;
> return (code / 100000) + ((code % 100000) ? 1 : 0) - 2;
> }
>
> The functions above take specific time as a parameter, not the whole cycle
> length.
> For example, pxa2xx_pcmcia_set_mcio looked like this:
> static int pxa2xx_pcmcia_set_mcio( int sock, int speed, int clock )
> {
> u_int set, cas, hold;
>
> if(speed == 255) {
> set = 70;
> hold = 20;
> cas = 165;
>
>
> Although I can't guarantee that my calculations are correct, it worked with
> all of my CF cards on c3000.
> If anyone is interested, I can prepare the patch.
Yes, patch would be nice. I am currently debugging some PCMCIA
problems... Question: is/was there situation where your version worked
but old one did not? Does it provide faster data rates?
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures)
http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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