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i.MX31: Busy wait for a couple microseconds at most then sleep until next tick when polling drive status. This prevents pointless jumps to overdrive speed from perceived high load when waiting for lengthy ops to complete such as spinup and sleep.

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@29108 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Michael Sevakis 2011-01-22 09:23:31 +00:00
parent 5729be4017
commit 060609a202
5 changed files with 57 additions and 4 deletions
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39
firmware/target/arm/imx31/ata-imx31.c
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@ -26,6 +26,7 @@
#include "power.h"
#include "panic.h"
#include "ata.h"
#include "ata-defines.h"
#include "ata-target.h"
#include "ccm-imx31.h"
#ifdef HAVE_ATA_DMA
@ -459,6 +460,7 @@ bool ata_dma_setup(void *addr, unsigned long bytes, bool write)
* shouldn't be reached based upon size. Otherwise we simply didn't
* understand the DMA mode setup. Force PIO in both cases. */
ATA_INTF_CONTROL = ATA_FIFO_RST | ATA_ATA_RST;
yield();
return false;
}
@ -645,6 +647,43 @@ bool ata_dma_finish(void)
}
#endif /* HAVE_ATA_DMA */
static int ata_wait_status(unsigned status, unsigned mask, int timeout)
{
long busy_timeout = usec_timer() + 2;
long end_tick = current_tick + timeout;
while (1)
{
if ((ATA_DRIVE_STATUS & mask) == status)
return 1;
if (!TIME_AFTER(usec_timer(), busy_timeout))
continue;
ata_keep_active();
if (TIME_AFTER(current_tick, end_tick))
break;
sleep(0);
busy_timeout = usec_timer() + 2;
}
return 0; /* timed out */
}
int ata_wait_for_bsy(void)
{
/* BSY = 0 */
return ata_wait_status(0, STATUS_BSY, 30*HZ);
}
int ata_wait_for_rdy(void)
{
/* RDY = 1 && BSY = 0 */
return ata_wait_status(STATUS_RDY, STATUS_RDY | STATUS_BSY, 40*HZ);
}
void ata_device_init(void)
{
/* Make sure we're not in reset mode */