diff options
| -rw-r--r-- | arch/powerpc/platforms/powernv/opal-xscom.c | 27 |
1 files changed, 17 insertions, 10 deletions
diff --git a/arch/powerpc/platforms/powernv/opal-xscom.c b/arch/powerpc/platforms/powernv/opal-xscom.c index d0ac535cf5d7..28651fb25417 100644 --- a/arch/powerpc/platforms/powernv/opal-xscom.c +++ b/arch/powerpc/platforms/powernv/opal-xscom.c @@ -73,25 +73,32 @@ static int opal_xscom_err_xlate(int64_t rc) static u64 opal_scom_unmangle(u64 addr) { + u64 tmp; + /* - * XSCOM indirect addresses have the top bit set. Additionally - * the rest of the top 3 nibbles is always 0. + * XSCOM addresses use the top nibble to set indirect mode and + * its form. Bits 4-11 are 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 + * To deal with that, we support the indirect bits being in + * bits 4-7 (IBM notation) instead of bit 0-3 in this API, we + * do the conversion here. * - * For in-kernel use, we also support the real indirect bit, so - * we test for any of the top 5 bits + * For in-kernel use, we don't need to do this mangling. In + * kernel won't have bits 4-7 set. * + * So: + * debugfs will always set 0-3 = 0 and clear 4-7 + * kernel will always clear 0-3 = 0 and set 4-7 */ - if (addr & (0x1full << 59)) - addr = (addr & ~(0xffull << 56)) | (1ull << 63); + tmp = addr; + tmp &= 0x0f00000000000000; + addr &= 0xf0ffffffffffffff; + addr |= tmp << 4; + return addr; } |