Commit a5ec5a7b authored by Srinivas Pandruvada's avatar Srinivas Pandruvada Committed by Tejun Heo
Browse files

ata: ahci: Support state with min power but Partial low power state 



Currently when min_power policy is selected, the partial low power state
is not entered and link will try aggressively enter to only slumber state.
Add a new policy which still enable DEVSLP but also try to enter partial
low power state. This policy is presented as "min_power_with_partial".

For information the difference between partial and slumber
Partial – PHY logic is powered up, and in a reduced power state. The link
PM exit latency to active state maximum is 10 ns.
Slumber – PHY logic is powered up, and in a reduced power state. The link
PM exit latency to active state maximum is 10 ms.
Devslp – PHY logic is powered down. The link PM exit latency from this
state to active state maximum is 20 ms, unless otherwise specified by
DETO.

Suggested-and-reviewed-by: default avatarHans de Goede <hdegoede@redhat.com>
Signed-off-by: default avatarSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 04ba9488

drivers/ata/libahci.c

+4 −1
Original line number Diff line number Diff line
@@ -800,6 +800,8 @@ static int ahci_set_lpm(struct ata_link *link, enum ata_lpm_policy policy, 
			cmd |= PORT_CMD_ALPE;

			if (policy == ATA_LPM_MIN_POWER)

				cmd |= PORT_CMD_ASP;

			else if (policy == ATA_LPM_MIN_POWER_WITH_PARTIAL)

				cmd &= ~PORT_CMD_ASP;



			/* write out new cmd value */

			writel(cmd, port_mmio + PORT_CMD);
@@ -810,7 +812,8 @@ static int ahci_set_lpm(struct ata_link *link, enum ata_lpm_policy policy, 
	if ((hpriv->cap2 & HOST_CAP2_SDS) &&

	    (hpriv->cap2 & HOST_CAP2_SADM) &&

	    (link->device->flags & ATA_DFLAG_DEVSLP)) {

		if (policy == ATA_LPM_MIN_POWER)

		if (policy == ATA_LPM_MIN_POWER ||

		    policy == ATA_LPM_MIN_POWER_WITH_PARTIAL)

			ahci_set_aggressive_devslp(ap, true);

		else

			ahci_set_aggressive_devslp(ap, false);

drivers/ata/libata-core.c

+1 −0
Original line number Diff line number Diff line
@@ -3967,6 +3967,7 @@ int sata_link_scr_lpm(struct ata_link *link, enum ata_lpm_policy policy, 
		scontrol |= (0x6 << 8);

		break;

	case ATA_LPM_MED_POWER_WITH_DIPM:

	case ATA_LPM_MIN_POWER_WITH_PARTIAL:

	case ATA_LPM_MIN_POWER:

		if (ata_link_nr_enabled(link) > 0)

			/* no restrictions on LPM transitions */

drivers/ata/libata-scsi.c

+1 −0
Original line number Diff line number Diff line
@@ -110,6 +110,7 @@ static const char *ata_lpm_policy_names[] = { 
	[ATA_LPM_MAX_POWER]		= "max_performance",

	[ATA_LPM_MED_POWER]		= "medium_power",

	[ATA_LPM_MED_POWER_WITH_DIPM]	= "med_power_with_dipm",

	[ATA_LPM_MIN_POWER_WITH_PARTIAL] = "min_power_with_partial",

	[ATA_LPM_MIN_POWER]		= "min_power",

};

include/linux/libata.h

+2 −1
Original line number Diff line number Diff line
@@ -522,7 +522,8 @@ enum ata_lpm_policy { 
	ATA_LPM_MAX_POWER,

	ATA_LPM_MED_POWER,

	ATA_LPM_MED_POWER_WITH_DIPM, /* Med power + DIPM as win IRST does */

	ATA_LPM_MIN_POWER,

	ATA_LPM_MIN_POWER_WITH_PARTIAL, /* Min Power + partial and slumber */

	ATA_LPM_MIN_POWER, /* Min power + no partial (slumber only) */

};



enum ata_lpm_hints {

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