[PATCH 4/4] libata: skip debounce delay on link resume
From: Florian Fainelli <f.fainelli@gmail.com>
Date: 2016-01-08 00:04:48
Also in:
linux-arm-kernel, lkml
Subsystem:
libata subsystem (serial and parallel ata drivers), the rest · Maintainers:
Damien Le Moal, Niklas Cassel, Linus Torvalds
From: Danesh Petigara <redacted> 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 <redacted> Signed-off-by: Florian Fainelli <f.fainelli@gmail.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