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libata: skip debounce delay on link resume 

The link resume logic uses a 200msec delay while debouncing
the SControl register. The rationale behind that delay is
to accommodate some PHYs that behave badly if their SStatus/
SControl registers are pounded immediately on resume.
The Broadcom STB SATA PHY does not seem to have this issue.
This patch introduces a new link flag that allows platforms
to skip the debounce delay if it isn't needed.

Signed-off-by: Danesh Petigara <dpetigara@broadcom.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Danesh Petigara 2016-01-07 16:03:33 -08:00 committed by Tejun Heo
parent 6ca92dd7af
commit e39b2bb3b7
3 changed files with 4 additions and 1 deletions
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1
drivers/ata/ahci_brcmstb.c
View File

@ -85,6 +85,7 @@ struct brcm_ahci_priv {
static const struct ata_port_info ahci_brcm_port_info = {
.flags = AHCI_FLAG_COMMON | ATA_FLAG_NO_DIPM,
.link_flags = ATA_LFLAG_NO_DB_DELAY,
.pio_mask = ATA_PIO4,
.udma_mask = ATA_UDMA6,
.port_ops = &ahci_platform_ops,

3
drivers/ata/libata-core.c
View File

@ -3598,7 +3598,8 @@ int sata_link_resume(struct ata_link *link, const unsigned long *params,
* immediately after resuming. Delay 200ms before
* debouncing.
*/
ata_msleep(link->ap, 200);
if (!(link->flags & ATA_LFLAG_NO_DB_DELAY))
ata_msleep(link->ap, 200);
/* is SControl restored correctly? */
if ((rc = sata_scr_read(link, SCR_CONTROL, &scontrol)))

1
include/linux/libata.h
View File

@ -205,6 +205,7 @@ enum {
ATA_LFLAG_NO_LPM = (1 << 8), /* disable LPM on this link */
ATA_LFLAG_RST_ONCE = (1 << 9), /* limit recovery to one reset */
ATA_LFLAG_CHANGED = (1 << 10), /* LPM state changed on this link */
ATA_LFLAG_NO_DB_DELAY = (1 << 11), /* no debounce delay on link resume */
/* struct ata_port flags */
ATA_FLAG_SLAVE_POSS = (1 << 0), /* host supports slave dev */