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Increase the wait time for acquiring the bus from 10 to 250ms.

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Normally it never needs to wait here at all; waiting is done at the end
of the prior command.  When doing a crash dump, the normal interrupt
mechanism isn't used; instead the interrupt handler is called repeatedly
in a polling-like manner.  This can subvert hardware-specific drivers
and lead to trying to start a new command while the previous command is
still busy on the bus.  Since the SD spec says the longest a card can
take to execute any command is 250ms, use that as a timeout.
This commit is contained in:
Ian Lepore 2014-02-15 17:59:32 +00:00
parent f1887a86aa
commit 8775ab4589
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=261940
1 changed files with 11 additions and 2 deletions
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13
sys/dev/sdhci/sdhci.c
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@ -767,8 +767,17 @@ sdhci_start_command(struct sdhci_slot *slot, struct mmc_command *cmd)
/* We shouldn't wait for DAT for stop commands. */
if (cmd == slot->req->stop)
mask &= ~SDHCI_DAT_INHIBIT;
/* Wait for bus no more then 10 ms. */
timeout = 10;
/*
* Wait for bus no more then 250 ms. Typically there will be no wait
* here at all, but when writing a crash dump we may be bypassing the
* host platform's interrupt handler, and in some cases that handler
* may be working around hardware quirks such as not respecting r1b
* busy indications. In those cases, this wait-loop serves the purpose
* of waiting for the prior command and data transfers to be done, and
* SD cards are allowed to take up to 250ms for write and erase ops.
* (It's usually more like 20-30ms in the real world.)
*/
timeout = 250;
while (state & mask) {
if (timeout == 0) {
slot_printf(slot, "Controller never released "