[PATCH] libata: add human-readable error value decoding (v2)

[Robert Hancock <hancockr@shaw.ca>]

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.

This version reduces the length of the SError parsed output strings relative to the
previous version of this patch.

Signed-off-by: Robert Hancock <hancockr@shaw.ca>

--- linux-2.6.21.1/drivers/ata/libata-eh.c	2007-04-27 15:49:26.000000000 -0600
+++ linux-2.6.21.1edit/drivers/ata/libata-eh.c	2007-05-14 17:38:35.000000000 -0600
@@ -1523,6 +1523,27 @@ static void ata_eh_report(struct ata_por
 			ata_port_printk(ap, 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",
@@ -1552,6 +1573,29 @@ static void ata_eh_report(struct ata_por
 			res->hob_feature, res->hob_nsect,
 			res->hob_lbal, res->hob_lbam, res->hob_lbah,
 			res->device, qc->err_mask, ata_err_string(qc->err_mask));
+		
+		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 " : "" );
 	}
 }
 
--- linux-2.6.21.1/include/linux/ata.h	2007-04-27 15:49:26.000000000 -0600
+++ linux-2.6.21.1edit/include/linux/ata.h	2007-05-09 19:25:54.000000000 -0600
@@ -223,6 +223,15 @@ 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 transition error */
+	SERR_UNRECOG_FIS	= (1 << 25), /* Unrecognized FIS */
 	SERR_DEV_XCHG		= (1 << 26), /* device exchanged */
 
 	/* struct ata_taskfile flags */