ata: libata-core: Improve link flags forced settings

Similarly to the horkage flags, introduce the force_lflag_onoff() macro
to define struct ata_force_param entries of the force_tbl array that
allow turning on or off a link flag using the libata.force boot
parameter. To be consistent with naming, the macro force_lflag() is
renamed to force_lflag_on().

Using force_lflag_onoff(), define a new force_tbl entry for the
ATA_LFLAG_NO_DEBOUNCE_DELAY link flag, thus allowing testing if an
adapter requires a link debounce delay or not.
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Reviewed-by: Hannes Reinecke <hare@suse.de>

drivers/ata/libata-core.c

@@ -96,7 +96,8 @@ struct ata_force_param {
 	unsigned long	xfer_mask;
 	unsigned int	horkage_on;
 	unsigned int	horkage_off;
-	u16		lflags;
+	u16		lflags_on;
+	u16		lflags_off;
 };
 
 struct ata_force_ent {
@@ -386,11 +387,17 @@ static void ata_force_link_limits(struct ata_link *link)
 		}
 
 		/* let lflags stack */
-		if (fe->param.lflags) {
-			link->flags |= fe->param.lflags;
+		if (fe->param.lflags_on) {
+			link->flags |= fe->param.lflags_on;
 			ata_link_notice(link,
 					"FORCE: link flag 0x%x forced -> 0x%x\n",
-					fe->param.lflags, link->flags);
+					fe->param.lflags_on, link->flags);
+		}
+		if (fe->param.lflags_off) {
+			link->flags &= ~fe->param.lflags_off;
+			ata_link_notice(link,
+				"FORCE: link flag 0x%x cleared -> 0x%x\n",
+				fe->param.lflags_off, link->flags);
 		}
 	}
 }
@@ -6110,8 +6117,12 @@ EXPORT_SYMBOL_GPL(ata_platform_remove_one);
 #define force_xfer(mode, shift)				\
 	{ #mode,	.xfer_mask	= (1UL << (shift)) }
 
-#define force_lflag(name, flags)			\
-	{ #name,	.lflags		= (flags) }
+#define force_lflag_on(name, flags)			\
+	{ #name,	.lflags_on	= (flags) }
+
+#define force_lflag_onoff(name, flags)			\
+	{ "no" #name,	.lflags_on	= (flags) },	\
+	{ #name,	.lflags_off	= (flags) }
 
 #define force_horkage_on(name, flag)			\
 	{ #name,	.horkage_on	= (flag) }
@@ -6166,10 +6177,11 @@ static const struct ata_force_param force_tbl[] __initconst = {
 	force_xfer(udma/133,		ATA_SHIFT_UDMA + 6),
 	force_xfer(udma7,		ATA_SHIFT_UDMA + 7),
 
-	force_lflag(nohrst,		ATA_LFLAG_NO_HRST),
-	force_lflag(nosrst,		ATA_LFLAG_NO_SRST),
-	force_lflag(norst,		ATA_LFLAG_NO_HRST | ATA_LFLAG_NO_SRST),
-	force_lflag(rstonce,		ATA_LFLAG_RST_ONCE),
+	force_lflag_on(nohrst,		ATA_LFLAG_NO_HRST),
+	force_lflag_on(nosrst,		ATA_LFLAG_NO_SRST),
+	force_lflag_on(norst,		ATA_LFLAG_NO_HRST | ATA_LFLAG_NO_SRST),
+	force_lflag_on(rstonce,		ATA_LFLAG_RST_ONCE),
+	force_lflag_onoff(dbdelay,	ATA_LFLAG_NO_DEBOUNCE_DELAY),
 
 	force_horkage_onoff(ncq,	ATA_HORKAGE_NONCQ),
 	force_horkage_onoff(ncqtrim,	ATA_HORKAGE_NO_NCQ_TRIM),