ata: ahci: Disable SXS for Hisilicon Kunpeng920

On Hisilicon Kunpeng920, ESP is set to 1 by default for all ports of
SATA controller. In some scenarios, some ports are not external SATA ports,
and it cause disks connected to these ports to be identified as removable
disks. So disable the SXS capability on the software side to prevent users
from mistakenly considering non-removable disks as removable disks and
performing related operations.
Signed-off-by: Xingui Yang <yangxingui@huawei.com>
Signed-off-by: Luo Jiaxing <luojiaxing@huawei.com>
Reviewed-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/1615544676-61926-1-git-send-email-luojiaxing@huawei.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/ata/ahci.c

@@ -1772,6 +1772,11 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 		hpriv->flags |= AHCI_HFLAG_NO_DEVSLP;
 
 #ifdef CONFIG_ARM64
+	if (pdev->vendor == PCI_VENDOR_ID_HUAWEI &&
+	    pdev->device == 0xa235 &&
+	    pdev->revision < 0x30)
+		hpriv->flags |= AHCI_HFLAG_NO_SXS;
+
 	if (pdev->vendor == 0x177d && pdev->device == 0xa01c)
 		hpriv->irq_handler = ahci_thunderx_irq_handler;
 #endif

drivers/ata/ahci.h

@@ -242,6 +242,7 @@ enum {
 							suspend/resume */
 	AHCI_HFLAG_IGN_NOTSUPP_POWER_ON	= (1 << 27), /* ignore -EOPNOTSUPP
 							from phy_power_on() */
+	AHCI_HFLAG_NO_SXS		= (1 << 28), /* SXS not supported */
 
 	/* ap->flags bits */
 

drivers/ata/libahci.c

@@ -493,6 +493,11 @@ void ahci_save_initial_config(struct device *dev, struct ahci_host_priv *hpriv)
 		cap |= HOST_CAP_ALPM;
 	}
 
+	if ((cap & HOST_CAP_SXS) && (hpriv->flags & AHCI_HFLAG_NO_SXS)) {
+		dev_info(dev, "controller does not support SXS, disabling CAP_SXS\n");
+		cap &= ~HOST_CAP_SXS;
+	}
+
 	if (hpriv->force_port_map && port_map != hpriv->force_port_map) {
 		dev_info(dev, "forcing port_map 0x%x -> 0x%x\n",
 			 port_map, hpriv->force_port_map);