diff options
Diffstat (limited to 'arch/powerpc/platforms/powernv/opal-xscom.c')
| -rw-r--r-- | arch/powerpc/platforms/powernv/opal-xscom.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/powernv/opal-xscom.c b/arch/powerpc/platforms/powernv/opal-xscom.c index 09a90d8..4d99a8f 100644 --- a/arch/powerpc/platforms/powernv/opal-xscom.c +++ b/arch/powerpc/platforms/powernv/opal-xscom.c @@ -71,11 +71,33 @@ static int opal_xscom_err_xlate(int64_t rc) } } +static u64 opal_scom_unmangle(u64 reg) +{ + /* + * XSCOM indirect addresses have the top bit set. Additionally + * the reset of the top 3 nibbles is always 0. + * + * Because the debugfs interface uses signed offsets and shifts + * the address left by 3, we basically cannot use the top 4 bits + * of the 64-bit address, and thus cannot use the indirect bit. + * + * To deal with that, we support the indirect bit being in bit + * 4 (IBM notation) instead of bit 0 in this API, we do the + * conversion here. To leave room for further xscom address + * expansion, we only clear out the top byte + * + */ + if (reg & (1ull << 59)) + reg = (reg & ~(0xffull << 56)) | (1ull << 63); + return reg; +} + static int opal_scom_read(scom_map_t map, u64 reg, u64 *value) { struct opal_scom_map *m = map; int64_t rc; + reg = opal_scom_unmangle(reg); rc = opal_xscom_read(m->chip, m->addr + reg, (uint64_t *)__pa(value)); return opal_xscom_err_xlate(rc); } @@ -85,6 +107,7 @@ static int opal_scom_write(scom_map_t map, u64 reg, u64 value) struct opal_scom_map *m = map; int64_t rc; + reg = opal_scom_unmangle(reg); rc = opal_xscom_write(m->chip, m->addr + reg, value); return opal_xscom_err_xlate(rc); } |