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Message-Id: <1452211413-1350-5-git-send-email-f.fainelli@gmail.com>
Date: Thu, 7 Jan 2016 16:03:33 -0800
From: Florian Fainelli <f.fainelli@...il.com>
To: linux-ide@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
bcm-kernel-feedback-list@...adcom.com, computersforpeace@...il.com,
gregory.0xf0@...il.com, Danesh Petigara <dpetigara@...adcom.com>,
Florian Fainelli <f.fainelli@...il.com>
Subject: [PATCH 4/4] libata: skip debounce delay on link resume
From: Danesh Petigara <dpetigara@...adcom.com>
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@...adcom.com>
Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
---
drivers/ata/ahci_brcmstb.c | 1 +
drivers/ata/libata-core.c | 3 ++-
include/linux/libata.h | 1 +
3 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/ata/ahci_brcmstb.c b/drivers/ata/ahci_brcmstb.c
index e518a992e774..9d57a27944bc 100644
--- a/drivers/ata/ahci_brcmstb.c
+++ b/drivers/ata/ahci_brcmstb.c
@@ -86,6 +86,7 @@ struct brcm_ahci_priv {
static const struct ata_port_info ahci_brcm_port_info = {
.flags = AHCI_FLAG_COMMON | ATA_FLAG_NO_DIPM,
.flags2 = ATA_FLAG2_WAKE_BEFORE_STOP,
+ .link_flags = ATA_LFLAG_NO_DB_DELAY,
.pio_mask = ATA_PIO4,
.udma_mask = ATA_UDMA6,
.port_ops = &ahci_platform_ops,
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index c6117e1ad373..b7b578522a13 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -3597,7 +3597,8 @@ 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)))
diff --git a/include/linux/libata.h b/include/linux/libata.h
index f278ca897274..e8b1759ff855 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -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 */
--
2.1.0
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