[PATCH v4 11/14] ata: ahci: add helper for ATA commands without data

[Luca Lauro via B4 Relay <devnull+famlauro93l.gmail.com@kernel.org>]

From: Luca Lauro <famlauro93l@gmail.com>

Introduce ahci_ata_nodata(), a small wrapper that prepares a FIS and
submits an AHCI command without PRDT entries or DMA setup. This avoids
duplicating zero-length handling logic across callers and simplifies
ATA command submission paths.

Signed-off-by: Luca Lauro <famlauro93l@gmail.com>
---
 drivers/ata/ahci.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index ea2df31515..1175d76881 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -233,6 +233,21 @@ static int ahci_io(struct ahci_port *ahci_port, u8 *fis, int fis_len, void *rbuf
 	return ret;
 }
 
+static int ahci_ata_nodata(struct ahci_port *ahci, u8 command, u8 feature)
+{
+	u8 fis[20] = {
+		0x27,        /* Host to device FIS */
+		1 << 7,      /* Command FIS */
+		command,     /* Command */
+		feature,     /* Features */
+	};
+
+	if (!ahci_link_ok(ahci, 0))
+		return -ENODEV;
+
+	return ahci_io(ahci, fis, sizeof(fis), NULL, NULL, 0);
+}
+
 /*
  * SCSI INQUIRY command operation.
  */

-- 
2.47.3