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From:   Suman Tripathi <stripathi@amperecomputing.com>
To:     hdegoede@redhat.com, axboe@kernel.dk, tj@kernel.org,
        linux-ide@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
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        gregkh@linuxfoundation.org
Cc:     patches@amperecomputing.com,
        Suman Tripathi <stripathi@amperecomputing.com>,
        Rameshwar Prasad Sahu <rameshwar.sahu@amperecomputing.com>
Subject: [PATCH v3] ata: Disable AHCI ALPM feature for Ampere Computing eMAG SATA
Date:   Thu,  6 Sep 2018 11:05:11 -0700
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Due to hardware errata, Ampere Computing eMAG SATA can't support
AHCI ALPM feature. This patch disables the AHCI ALPM feature for
eMAG SATA.

Signed-off-by: Suman Trpathi <stripathi@amperecomputing.com>
Signed-off-by: Rameshwar Prasad Sahu <rameshwar.sahu@amperecomputing.com>

---
Changes for v3:

* Fix the indentation and whitespace warnings.

Changes for v2:

* Introduce the new ata_port_info object which includes ATA_FLAG_NO_LPM.
* Include this object for eMAG SATA inside the acpi match table.
* Retrieve the ata_port_info from the acpi match table.

---
 drivers/ata/ahci_platform.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/ata/ahci_platform.c b/drivers/ata/ahci_platform.c
index 99f9a89..9ba283f 100644
--- a/drivers/ata/ahci_platform.c
+++ b/drivers/ata/ahci_platform.c
@@ -33,6 +33,13 @@ static const struct ata_port_info ahci_port_info = {
 	.port_ops	= &ahci_platform_ops,
 };

+static const struct ata_port_info ahci_port_info_nolpm = {
+	.flags		= AHCI_FLAG_COMMON | ATA_FLAG_NO_LPM,
+	.pio_mask	= ATA_PIO4,
+	.udma_mask	= ATA_UDMA6,
+	.port_ops	= &ahci_platform_ops,
+};
+
 static struct scsi_host_template ahci_platform_sht = {
 	AHCI_SHT(DRV_NAME),
 };
@@ -41,6 +48,7 @@ static int ahci_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct ahci_host_priv *hpriv;
+	const struct ata_port_info *port;
 	int rc;

 	hpriv = ahci_platform_get_resources(pdev);
@@ -57,7 +65,11 @@ static int ahci_probe(struct platform_device *pdev)
 	if (of_device_is_compatible(dev->of_node, "hisilicon,hisi-ahci"))
 		hpriv->flags |= AHCI_HFLAG_NO_FBS | AHCI_HFLAG_NO_NCQ;

-	rc = ahci_platform_init_host(pdev, hpriv, &ahci_port_info,
+	port = acpi_device_get_match_data(dev);
+	if (!port)
+		port = &ahci_port_info;
+
+	rc = ahci_platform_init_host(pdev, hpriv, port,
 				     &ahci_platform_sht);
 	if (rc)
 		goto disable_resources;
@@ -85,6 +97,7 @@ static const struct of_device_id ahci_of_match[] = {
 MODULE_DEVICE_TABLE(of, ahci_of_match);

 static const struct acpi_device_id ahci_acpi_match[] = {
+	{ "APMC0D33", (unsigned long)&ahci_port_info_nolpm },
 	{ ACPI_DEVICE_CLASS(PCI_CLASS_STORAGE_SATA_AHCI, 0xffffff) },
 	{},
 };
--
2.7.4