ata: move *sata_set_spd*() to libata-sata.c

* move *sata_set_spd*() to libata-sata.c

* add static inlines for CONFIG_SATA_HOST=n case

Code size savings on m68k arch using (modified) atari_defconfig:

   text    data     bss     dec     hex filename
before:
  32842     572      40   33458    82ae drivers/ata/libata-core.o
after:
  32812     572      40   33428    8290 drivers/ata/libata-core.o

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 81 insertions, 0 deletions

diff --git a/drivers/ata/libata-sata.c b/drivers/ata/libata-sata.c
index 1ef4c19864ac..d66afdc33d54 100644
--- a/drivers/ata/libata-sata.c
+++ b/drivers/ata/libata-sata.c
@@ -271,6 +271,87 @@ int sata_link_scr_lpm(struct ata_link *link, enum ata_lpm_policy policy,
 }
 EXPORT_SYMBOL_GPL(sata_link_scr_lpm);
 
+static int __sata_set_spd_needed(struct ata_link *link, u32 *scontrol)
+{
+	struct ata_link *host_link = &link->ap->link;
+	u32 limit, target, spd;
+
+	limit = link->sata_spd_limit;
+
+	/* Don't configure downstream link faster than upstream link.
+	 * It doesn't speed up anything and some PMPs choke on such
+	 * configuration.
+	 */
+	if (!ata_is_host_link(link) && host_link->sata_spd)
+		limit &= (1 << host_link->sata_spd) - 1;
+
+	if (limit == UINT_MAX)
+		target = 0;
+	else
+		target = fls(limit);
+
+	spd = (*scontrol >> 4) & 0xf;
+	*scontrol = (*scontrol & ~0xf0) | ((target & 0xf) << 4);
+
+	return spd != target;
+}
+
+/**
+ *	sata_set_spd_needed - is SATA spd configuration needed
+ *	@link: Link in question
+ *
+ *	Test whether the spd limit in SControl matches
+ *	@link->sata_spd_limit.  This function is used to determine
+ *	whether hardreset is necessary to apply SATA spd
+ *	configuration.
+ *
+ *	LOCKING:
+ *	Inherited from caller.
+ *
+ *	RETURNS:
+ *	1 if SATA spd configuration is needed, 0 otherwise.
+ */
+int sata_set_spd_needed(struct ata_link *link)
+{
+	u32 scontrol;
+
+	if (sata_scr_read(link, SCR_CONTROL, &scontrol))
+		return 1;
+
+	return __sata_set_spd_needed(link, &scontrol);
+}
+
+/**
+ *	sata_set_spd - set SATA spd according to spd limit
+ *	@link: Link to set SATA spd for
+ *
+ *	Set SATA spd of @link according to sata_spd_limit.
+ *
+ *	LOCKING:
+ *	Inherited from caller.
+ *
+ *	RETURNS:
+ *	0 if spd doesn't need to be changed, 1 if spd has been
+ *	changed.  Negative errno if SCR registers are inaccessible.
+ */
+int sata_set_spd(struct ata_link *link)
+{
+	u32 scontrol;
+	int rc;
+
+	if ((rc = sata_scr_read(link, SCR_CONTROL, &scontrol)))
+		return rc;
+
+	if (!__sata_set_spd_needed(link, &scontrol))
+		return 0;
+
+	if ((rc = sata_scr_write(link, SCR_CONTROL, scontrol)))
+		return rc;
+
+	return 1;
+}
+EXPORT_SYMBOL_GPL(sata_set_spd);
+
 /**
  *	ata_slave_link_init - initialize slave link
  *	@ap: port to initialize slave link for