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sata_mv: workaround errata SATA#26

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Workaround for errata SATA#26.

Prevents accidently putting a drive to sleep when attempting COMRESET,
by ORing 0xf000 with the values written to SCR_CONTROL.

Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
This commit is contained in:
Mark Lord 2009-04-06 15:24:57 -04:00 committed by Jeff Garzik
parent 65ad7fef10
commit 2009177329
1 changed files with 19 additions and 1 deletions
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20
drivers/ata/sata_mv.c
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@ -1296,7 +1296,25 @@ static int mv_scr_write(struct ata_link *link, unsigned int sc_reg_in, u32 val)
unsigned int ofs = mv_scr_offset(sc_reg_in);
if (ofs != 0xffffffffU) {
writelfl(val, mv_ap_base(link->ap) + ofs);
void __iomem *addr = mv_ap_base(link->ap) + ofs;
if (sc_reg_in == SCR_CONTROL) {
/*
* Workaround for 88SX60x1 FEr SATA#26:
*
* COMRESETs have to take care not to accidently
* put the drive to sleep when writing SCR_CONTROL.
* Setting bits 12..15 prevents this problem.
*
* So if we see an outbound COMMRESET, set those bits.
* Ditto for the followup write that clears the reset.
*
* The proprietary driver does this for
* all chip versions, and so do we.
*/
if ((val & 0xf) == 1 || (readl(addr) & 0xf) == 1)
val |= 0xf000;
}
writelfl(val, addr);
return 0;
} else
return -EINVAL;