Hi,
On Fri, 13 Jan 2012, Dmitry Antipov wrote:
Use the usleep_range() to simplify mmc_delay() and give some more
accuracy to it - but with an exception of mmc_card_sleepawake():
since sleep/awake timeout varies in a wide range, different
delay methods should be used.
Signed-off-by: Dmitry Antipov <dmitry.antipov@xxxxxxxxxx>
[...]
+ if (!(host->caps & MMC_CAP_WAIT_WHILE_BUSY)) {
+ /* JEDEC MMCA 4.41 specifies the timeout value is in 200ns..838.86ms
+ range. Round it up to 1us and use an appropriate delay method. */
+ unsigned long us = DIV_ROUND_UP(card->ext_csd.sa_timeout, 10);
+ if (us < 10)
+ udelay(us);
+ else
+ usleep_range(us, us + 100);
+ }
I think this part of the patch is over-engineered. What difference
does it make in practice if you round it up to a bigger value so that
usleep_range() makes always sense? The S/A timeout defines the max time
the transition can take, it's not wrong to wait a bit longer. Also note
that udelay() is not accurate so you need to add some margin anyway.
A.
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