On 21-06-10 15:26:03, Dan Williams wrote: > Enable devices on the 'cxl' bus to be attached to drivers. The initial > user of this functionality is a driver for an 'nvdimm-bridge' device > that anchors a libnvdimm hierarchy attached to CXL persistent memory > resources. Other device types that will leverage this include: > > cxl_port: map and use component register functionality (HDM Decoders)
Since I'm looking at this now, perhaps I can open the discussion here. Have you thought about how this works yet? Right now I'm thinking there are two "drivers": cxl_port: Switches (and ACPI0016) cxl_mem: The memory device's HDM decoders For port, probe() will figure out that the thing is an upstream port, call cxl_probe_component_regs and then call devm_cxl_add_port(). I think that's straight forward. For the memory device we've already probed the thing via class code so there is no need to use this driver registration, however, I think it would be nice to do so. Is there a clean way to do that? Also, I'd like to make sure we're on the same page about struct cxl_decoder. Right now they are only created for active HDM decoders. Going forward, we can either maintain a count of unused decoders on the given CXL component, or we can instantiate a struct cxl_decoder that isn't active, ie. no interleave ways granularit, base, etc. What's your thinking there? > > cxl_nvdimm: translate CXL memory expander endpoints to libnvdimm > 'nvdimm' objects > > cxl_region: translate CXL interleave sets to libnvdimm 'region' objects > > The pairing of devices to drivers is handled through the cxl_device_id() > matching to cxl_driver.id values. A cxl_device_id() of '0' indicates no > driver support. > > In addition to ->match(), ->probe(), and ->remove() support for the > 'cxl' bus introduce MODULE_ALIAS_CXL() to autoload modules containing > cxl-drivers. Drivers are added in follow-on changes. > > Signed-off-by: Dan Williams <[email protected]> > --- > drivers/cxl/core.c | 73 > ++++++++++++++++++++++++++++++++++++++++++++++++++++ > drivers/cxl/cxl.h | 22 ++++++++++++++++ > 2 files changed, 95 insertions(+) > > diff --git a/drivers/cxl/core.c b/drivers/cxl/core.c > index 1b9ee0b08384..959cecc1f6bf 100644 > --- a/drivers/cxl/core.c > +++ b/drivers/cxl/core.c > @@ -767,8 +767,81 @@ int cxl_map_device_regs(struct pci_dev *pdev, > } > EXPORT_SYMBOL_GPL(cxl_map_device_regs); > > +/** > + * __cxl_driver_register - register a driver for the cxl bus > + * @cxl_drv: cxl driver structure to attach > + * @owner: owning module/driver > + * @modname: KBUILD_MODNAME for parent driver > + */ > +int __cxl_driver_register(struct cxl_driver *cxl_drv, struct module *owner, > + const char *modname) > +{ > + if (!cxl_drv->probe) { > + pr_debug("%s ->probe() must be specified\n", modname); > + return -EINVAL; > + } > + > + if (!cxl_drv->name) { > + pr_debug("%s ->name must be specified\n", modname); > + return -EINVAL; > + } > + > + if (!cxl_drv->id) { > + pr_debug("%s ->id must be specified\n", modname); > + return -EINVAL; > + } > + > + cxl_drv->drv.bus = &cxl_bus_type; > + cxl_drv->drv.owner = owner; > + cxl_drv->drv.mod_name = modname; > + cxl_drv->drv.name = cxl_drv->name; > + > + return driver_register(&cxl_drv->drv); > +} > +EXPORT_SYMBOL_GPL(__cxl_driver_register); > + > +void cxl_driver_unregister(struct cxl_driver *cxl_drv) > +{ > + driver_unregister(&cxl_drv->drv); > +} > +EXPORT_SYMBOL_GPL(cxl_driver_unregister); > + > +static int cxl_device_id(struct device *dev) > +{ > + return 0; > +} > + > +static int cxl_bus_uevent(struct device *dev, struct kobj_uevent_env *env) > +{ > + return add_uevent_var(env, "MODALIAS=" CXL_MODALIAS_FMT, > + cxl_device_id(dev)); > +} > + > +static int cxl_bus_match(struct device *dev, struct device_driver *drv) > +{ > + return cxl_device_id(dev) == to_cxl_drv(drv)->id; > +} > + > +static int cxl_bus_probe(struct device *dev) > +{ > + return to_cxl_drv(dev->driver)->probe(dev); > +} > + > +static int cxl_bus_remove(struct device *dev) > +{ > + struct cxl_driver *cxl_drv = to_cxl_drv(dev->driver); > + > + if (cxl_drv->remove) > + cxl_drv->remove(dev); > + return 0; > +} > + > struct bus_type cxl_bus_type = { > .name = "cxl", > + .uevent = cxl_bus_uevent, > + .match = cxl_bus_match, > + .probe = cxl_bus_probe, > + .remove = cxl_bus_remove, > }; > EXPORT_SYMBOL_GPL(cxl_bus_type); > > diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h > index b988ea288f53..af2237d1c761 100644 > --- a/drivers/cxl/cxl.h > +++ b/drivers/cxl/cxl.h > @@ -261,4 +261,26 @@ devm_cxl_add_passthrough_decoder(struct device *host, > struct cxl_port *port) > } > > extern struct bus_type cxl_bus_type; > + > +struct cxl_driver { > + const char *name; > + int (*probe)(struct device *dev); > + void (*remove)(struct device *dev); > + struct device_driver drv; > + int id; > +}; > + > +static inline struct cxl_driver *to_cxl_drv(struct device_driver *drv) > +{ > + return container_of(drv, struct cxl_driver, drv); > +} > + > +int __cxl_driver_register(struct cxl_driver *cxl_drv, struct module *owner, > + const char *modname); > +#define cxl_driver_register(x) __cxl_driver_register(x, THIS_MODULE, > KBUILD_MODNAME) > +void cxl_driver_unregister(struct cxl_driver *cxl_drv); > + > +#define MODULE_ALIAS_CXL(type) MODULE_ALIAS("cxl:t" __stringify(type) "*") > +#define CXL_MODALIAS_FMT "cxl:t%d" > + > #endif /* __CXL_H__ */ >
