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| author | Oliver O'Halloran <oohall@gmail.com> | 2018-09-20 15:03:26 +1000 |
|---|---|---|
| committer | Stewart Smith <stewart@linux.ibm.com> | 2018-09-27 00:41:48 -0500 |
| commit | 30ffd4c6a528c7dc51ae0099db592dd442a314a4 (patch) | |
| tree | dc930338d9278d24b3cc1fc1bd4deb6d022c8bef /hdata | |
| parent | a800fa35b8222996a634baeec27cd2369f7619f5 (diff) | |
| download | blackbird-skiboot-30ffd4c6a528c7dc51ae0099db592dd442a314a4.tar.gz blackbird-skiboot-30ffd4c6a528c7dc51ae0099db592dd442a314a4.zip | |
hdata: Explain what the xscom node bus-frequency is
Vague documentation is about as annoying as no documentation.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Stewart Smith <stewart@linux.ibm.com>
Diffstat (limited to 'hdata')
| -rw-r--r-- | hdata/spira.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/hdata/spira.c b/hdata/spira.c index 2dd0dd36..56218709 100644 --- a/hdata/spira.c +++ b/hdata/spira.c @@ -281,7 +281,10 @@ static struct dt_node *add_xscom_node(uint64_t base, uint32_t hw_id, } dt_add_property_u64s(node, "reg", addr, size); - /* Derive bus frquency */ + /* + * The bus-frequency of the xscom node is actually the PIB/PCB + * frequency. It is derived from the nest-clock via a 4:1 divider + */ freq = dt_prop_get_u64_def(dt_root, "nest-frequency", 0); freq /= 4; if (freq) |
