diff options
Diffstat (limited to 'drivers/ata/libata-sata.c')
-rw-r--r-- | drivers/ata/libata-sata.c | 81 |
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 |