| Message ID | 20220624041950.559155-14-dan.j.williams@intel.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | CXL PMEM Region Provisioning | expand |
On Thu, 23 Jun 2022 21:19:43 -0700 Dan Williams <dan.j.williams@intel.com> wrote: > 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. > > Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> > --- > drivers/cxl/core/port.c | 15 +++++++++++++++ > drivers/cxl/cxl.h | 2 ++ > 2 files changed, 17 insertions(+) > > diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c > index 562a6453249b..7756409d0a58 100644 > --- a/drivers/cxl/core/port.c > +++ b/drivers/cxl/core/port.c > @@ -1422,6 +1422,20 @@ 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; > > /** > @@ -1466,6 +1480,7 @@ static struct cxl_decoder *cxl_decoder_alloc(struct cxl_port *port, > if (rc < 0) > goto err; > atomic_set(&cxlrd->region_id, rc); > + cxlrd->calc_hb = cxl_hb_modulo; > } else > cxlsd = NULL; > } else { > diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h > index 9340deccad4f..30227348f768 100644 > --- a/drivers/cxl/cxl.h > +++ b/drivers/cxl/cxl.h > @@ -315,11 +315,13 @@ 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; > }; >
diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c index 562a6453249b..7756409d0a58 100644 --- a/drivers/cxl/core/port.c +++ b/drivers/cxl/core/port.c @@ -1422,6 +1422,20 @@ 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; /** @@ -1466,6 +1480,7 @@ static struct cxl_decoder *cxl_decoder_alloc(struct cxl_port *port, if (rc < 0) goto err; atomic_set(&cxlrd->region_id, rc); + cxlrd->calc_hb = cxl_hb_modulo; } else cxlsd = NULL; } else { diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h index 9340deccad4f..30227348f768 100644 --- a/drivers/cxl/cxl.h +++ b/drivers/cxl/cxl.h @@ -315,11 +315,13 @@ 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; };
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. Signed-off-by: Dan Williams <dan.j.williams@intel.com> --- drivers/cxl/core/port.c | 15 +++++++++++++++ drivers/cxl/cxl.h | 2 ++ 2 files changed, 17 insertions(+)