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@xxxxxxxxx>
--- old/drivers/ata/sata_mv.c 2009-04-06 13:29:05.000000000 -0400
+++ new/drivers/ata/sata_mv.c 2009-04-06 14:20:53.000000000 -0400
@@ -1296,7 +1296,25 @@
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;
--
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