libata: add human-readable error value decoding

This adds human-readable decoding of the ATA status and error registers
(similar to what drivers/ide does) as well as the SATA Serror register
to libata error handling output.  This prevents the need to pore
through standards documents to figure out the meaning of the bits
in these registers when looking at error reports.  Some bits that
drivers/ide decoded are not decoded here, since the bits are either
command-dependent or obsolete, and properly parsing them would add
too much complexity.
Signed-off-by: Robert Hancock <hancockr@shaw.ca>

[edited slightly to make output a bit more symmetric]
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/ata/libata-eh.c

@@ -1911,6 +1911,27 @@ static void ata_eh_link_report(struct ata_link *link)
 			ata_link_printk(link, KERN_ERR, "%s\n", desc);
 	}
 
+	if (ehc->i.serror)
+		ata_port_printk(ap, KERN_ERR,
+		  "SError: { %s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s}\n",
+		  ehc->i.serror & SERR_DATA_RECOVERED ? "RecovData " : "",
+		  ehc->i.serror & SERR_COMM_RECOVERED ? "RecovComm " : "",
+		  ehc->i.serror & SERR_DATA ? "UnrecovData " : "",
+		  ehc->i.serror & SERR_PERSISTENT ? "Persist " : "",
+		  ehc->i.serror & SERR_PROTOCOL ? "Proto " : "",
+		  ehc->i.serror & SERR_INTERNAL ? "HostInt " : "",
+		  ehc->i.serror & SERR_PHYRDY_CHG ? "PHYRdyChg " : "",
+		  ehc->i.serror & SERR_PHY_INT_ERR ? "PHYInt " : "",
+		  ehc->i.serror & SERR_COMM_WAKE ? "CommWake " : "",
+		  ehc->i.serror & SERR_10B_8B_ERR ? "10B8B " : "",
+		  ehc->i.serror & SERR_DISPARITY ? "Dispar " : "",
+		  ehc->i.serror & SERR_CRC ? "BadCRC " : "",
+		  ehc->i.serror & SERR_HANDSHAKE ? "Handshk " : "",
+		  ehc->i.serror & SERR_LINK_SEQ_ERR ? "LinkSeq " : "",
+		  ehc->i.serror & SERR_TRANS_ST_ERROR ? "TrStaTrns " : "",
+		  ehc->i.serror & SERR_UNRECOG_FIS ? "UnrecFIS " : "",
+		  ehc->i.serror & SERR_DEV_XCHG ? "DevExch " : "" );
+
 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
 		static const char *dma_str[] = {
 			[DMA_BIDIRECTIONAL]	= "bidi",
@@ -1942,6 +1963,30 @@ static void ata_eh_link_report(struct ata_link *link)
 			res->hob_lbal, res->hob_lbam, res->hob_lbah,
 			res->device, qc->err_mask, ata_err_string(qc->err_mask),
 			qc->err_mask & AC_ERR_NCQ ? " <F>" : "");
+
+		if (res->command & (ATA_BUSY | ATA_DRDY | ATA_DF | ATA_DRQ |
+				    ATA_ERR) ) {
+			if (res->command & ATA_BUSY)
+				ata_dev_printk(qc->dev, KERN_ERR,
+				  "status: { Busy }\n" );
+			else
+				ata_dev_printk(qc->dev, KERN_ERR,
+				  "status: { %s%s%s%s}\n",
+				  res->command & ATA_DRDY ? "DRDY " : "",
+				  res->command & ATA_DF ? "DF " : "",
+				  res->command & ATA_DRQ ? "DRQ " : "",
+				  res->command & ATA_ERR ? "ERR " : "" );
+		}
+
+		if (cmd->command != ATA_CMD_PACKET &&
+		    (res->feature & (ATA_ICRC | ATA_UNC | ATA_IDNF |
+				     ATA_ABORTED)))
+			ata_dev_printk(qc->dev, KERN_ERR,
+			  "error: { %s%s%s%s}\n",
+			  res->feature & ATA_ICRC ? "ICRC " : "",
+			  res->feature & ATA_UNC ? "UNC " : "",
+			  res->feature & ATA_IDNF ? "IDNF " : "",
+			  res->feature & ATA_ABORTED ? "ABRT " : "" );
 	}
 }
 

include/linux/ata.h

@@ -287,6 +287,15 @@ enum {
 	SERR_PROTOCOL		= (1 << 10), /* protocol violation */
 	SERR_INTERNAL		= (1 << 11), /* host internal error */
 	SERR_PHYRDY_CHG		= (1 << 16), /* PHY RDY changed */
+	SERR_PHY_INT_ERR	= (1 << 17), /* PHY internal error */
+	SERR_COMM_WAKE		= (1 << 18), /* Comm wake */
+	SERR_10B_8B_ERR		= (1 << 19), /* 10b to 8b decode error */
+	SERR_DISPARITY		= (1 << 20), /* Disparity */
+	SERR_CRC		= (1 << 21), /* CRC error */
+	SERR_HANDSHAKE		= (1 << 22), /* Handshake error */
+	SERR_LINK_SEQ_ERR	= (1 << 23), /* Link sequence error */
+	SERR_TRANS_ST_ERROR	= (1 << 24), /* Transport state trans. error */
+	SERR_UNRECOG_FIS	= (1 << 25), /* Unrecognized FIS */
 	SERR_DEV_XCHG		= (1 << 26), /* device exchanged */
 
 	/* struct ata_taskfile flags */