ahci: Marvell 88SE9215 controllers prefer DMA for ATAPI

We use CD/DVD drives under Marvell 88SE9215 SATA controller on many
Loongson-based machines. We found its PIO doesn't work well, and on the
opposite its DMA seems work very well.

We don't know the detail of the 88SE9215 SATA controller, but we have
tested different CD/DVD drives and they all have problems under 88SE9215
(but they all work well under an Intel SATA controller). So, we consider
this problem is bound to 88SE9215 SATA controller rather than bound to
CD/DVD drives.

As a solution, we define a new dedicated AHCI board id which is named
board_ahci_yes_fbs_atapi_dma for 88SE9215, and for this id we set the
AHCI_HFLAG_ATAPI_DMA_QUIRK and ATA_QUIRK_ATAPI_MOD16_DMA flags on the
SATA controller in order to prefer ATAPI DMA.

Reported-by: Yuli Wang <wangyuli@uniontech.com>
Tested-by: Jie Fan <fanjie@uniontech.com>
Tested-by: Erpeng Xu <xuerpeng@uniontech.com>
Tested-by: Yuli Wang <wangyuli@uniontech.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Link: https://lore.kernel.org/r/20250318104314.2160526-1-chenhuacai@loongson.cn
Signed-off-by: Niklas Cassel <cassel@kernel.org>

drivers/ata/ahci.c

@@ -63,6 +63,7 @@ enum board_ids {
 	board_ahci_pcs_quirk_no_devslp,
 	board_ahci_pcs_quirk_no_sntf,
 	board_ahci_yes_fbs,
+	board_ahci_yes_fbs_atapi_dma,
 
 	/* board IDs for specific chipsets in alphabetical order */
 	board_ahci_al,
@@ -188,6 +189,14 @@ static const struct ata_port_info ahci_port_info[] = {
 		.udma_mask	= ATA_UDMA6,
 		.port_ops	= &ahci_ops,
 	},
+	[board_ahci_yes_fbs_atapi_dma] = {
+		AHCI_HFLAGS	(AHCI_HFLAG_YES_FBS |
+				 AHCI_HFLAG_ATAPI_DMA_QUIRK),
+		.flags		= AHCI_FLAG_COMMON,
+		.pio_mask	= ATA_PIO4,
+		.udma_mask	= ATA_UDMA6,
+		.port_ops	= &ahci_ops,
+	},
 	/* by chipsets */
 	[board_ahci_al] = {
 		AHCI_HFLAGS	(AHCI_HFLAG_NO_PMP | AHCI_HFLAG_NO_MSI),
@@ -590,7 +599,7 @@ static const struct pci_device_id ahci_pci_tbl[] = {
 	{ PCI_DEVICE(PCI_VENDOR_ID_MARVELL_EXT, 0x91a3),
 	  .driver_data = board_ahci_yes_fbs },
 	{ PCI_DEVICE(PCI_VENDOR_ID_MARVELL_EXT, 0x9215),
-	  .driver_data = board_ahci_yes_fbs },
+	  .driver_data = board_ahci_yes_fbs_atapi_dma },
 	{ PCI_DEVICE(PCI_VENDOR_ID_MARVELL_EXT, 0x9230),
 	  .driver_data = board_ahci_yes_fbs },
 	{ PCI_DEVICE(PCI_VENDOR_ID_MARVELL_EXT, 0x9235),

drivers/ata/ahci.h

@@ -246,6 +246,7 @@ enum {
 	AHCI_HFLAG_NO_SXS		= BIT(26), /* SXS not supported */
 	AHCI_HFLAG_43BIT_ONLY		= BIT(27), /* 43bit DMA addr limit */
 	AHCI_HFLAG_INTEL_PCS_QUIRK	= BIT(28), /* apply Intel PCS quirk */
+	AHCI_HFLAG_ATAPI_DMA_QUIRK	= BIT(29), /* force ATAPI to use DMA */
 
 	/* ap->flags bits */
 

drivers/ata/libahci.c

@@ -1321,6 +1321,10 @@ static void ahci_dev_config(struct ata_device *dev)
 {
 	struct ahci_host_priv *hpriv = dev->link->ap->host->private_data;
 
+	if ((dev->class == ATA_DEV_ATAPI) &&
+	    (hpriv->flags & AHCI_HFLAG_ATAPI_DMA_QUIRK))
+		dev->quirks |= ATA_QUIRK_ATAPI_MOD16_DMA;
+
 	if (hpriv->flags & AHCI_HFLAG_SECT255) {
 		dev->max_sectors = 255;
 		ata_dev_info(dev,