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| author | Dan Williams <dan.j.williams@intel.com> | 2022-06-06 23:32:01 +0300 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2022-07-25 22:18:07 +0300 |
| commit | 6aa41144e7f1a624062f1e66a4744c168ade1f31 (patch) | |
| tree | dbc9e873fca39bb4db419da9edc33573b28339a9 /drivers/cxl | |
| parent | b9686e8c8e39d4072081ef078c04915ee51c8af4 (diff) | |
| download | linux-6aa41144e7f1a624062f1e66a4744c168ade1f31.tar.xz | |
cxl/acpi: Add a host-bridge index lookup mechanism
The ACPI CXL Fixed Memory Window Structure (CFMWS) defines multiple
methods to determine which host bridge provides access to a given
endpoint relative to that device's position in the interleave. The
"Interleave Arithmetic" defines either a "standard modulo" /
round-random algorithm, or "xormap" based algorithm which can be defined
as a non-linear transform. Given that there are already more options
beyond "standard modulo" and that "xormap" may turn out to be ACPI CXL
specific, provide a callback for the region provisioning code to map
endpoint positions back to expected host bridge id (cxl_dport target).
For now just support the simple modulo math case and save the xormap for
a follow-on change.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20220624041950.559155-14-dan.j.williams@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/cxl')
| -rw-r--r-- | drivers/cxl/core/port.c | 16 | ||||
| -rw-r--r-- | drivers/cxl/cxl.h | 2 |
2 files changed, 18 insertions, 0 deletions
diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c index ff6ea869fcc9..1bec38385a71 100644 --- a/drivers/cxl/core/port.c +++ b/drivers/cxl/core/port.c @@ -1421,6 +1421,20 @@ static int decoder_populate_targets(struct cxl_switch_decoder *cxlsd, return rc; } +static struct cxl_dport *cxl_hb_modulo(struct cxl_root_decoder *cxlrd, int pos) +{ + struct cxl_switch_decoder *cxlsd = &cxlrd->cxlsd; + struct cxl_decoder *cxld = &cxlsd->cxld; + int iw; + + iw = cxld->interleave_ways; + if (dev_WARN_ONCE(&cxld->dev, iw != cxlsd->nr_targets, + "misconfigured root decoder\n")) + return NULL; + + return cxlrd->cxlsd.target[pos % iw]; +} + static struct lock_class_key cxl_decoder_key; /** @@ -1510,6 +1524,8 @@ struct cxl_root_decoder *cxl_root_decoder_alloc(struct cxl_port *port, return ERR_PTR(rc); } + cxlrd->calc_hb = cxl_hb_modulo; + cxld = &cxlsd->cxld; cxld->dev.type = &cxl_decoder_root_type; /* diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h index 5e84aa2d09e2..8f39cfb0d972 100644 --- a/drivers/cxl/cxl.h +++ b/drivers/cxl/cxl.h @@ -322,11 +322,13 @@ struct cxl_switch_decoder { * struct cxl_root_decoder - Static platform CXL address decoder * @res: host / parent resource for region allocations * @region_id: region id for next region provisioning event + * @calc_hb: which host bridge covers the n'th position by granularity * @cxlsd: base cxl switch decoder */ struct cxl_root_decoder { struct resource *res; atomic_t region_id; + struct cxl_dport *(*calc_hb)(struct cxl_root_decoder *cxlrd, int pos); struct cxl_switch_decoder cxlsd; }; |