From a46cfc0f011ce77d120e1cdbf973f733d18f0105 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Mon, 31 Jan 2022 16:34:40 -0800 Subject: cxl/pmem: Introduce a find_cxl_root() helper In preparation for switch port enumeration while also preserving the potential for multi-domain / multi-root CXL topologies. Introduce a 'struct device' generic mechanism for retrieving a root CXL port, if one is registered. Note that the only known multi-domain CXL configurations are running the cxl_test unit test on a system that also publishes an ACPI0017 device. With this in hand the nvdimm-bridge lookup can be with device_find_child() instead of bus_find_device() + custom mocked lookup infrastructure in cxl_test. The mechanism looks for a 2nd level port since the root level topology is platform-firmware specific and the 2nd level down follows standard PCIe topology expectations. The cxl_acpi 2nd level is associated with a PCIe Root Port. Reported-by: Ben Widawsky Reviewed-by: Jonathan Cameron Link: https://lore.kernel.org/r/164367562182.225521.9488555616768096049.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams --- drivers/cxl/core/pmem.c | 14 ++++++++++---- drivers/cxl/core/port.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++ drivers/cxl/cxl.h | 1 + 3 files changed, 60 insertions(+), 4 deletions(-) (limited to 'drivers/cxl') diff --git a/drivers/cxl/core/pmem.c b/drivers/cxl/core/pmem.c index 40b3f5030496..8de240c4d96b 100644 --- a/drivers/cxl/core/pmem.c +++ b/drivers/cxl/core/pmem.c @@ -57,24 +57,30 @@ bool is_cxl_nvdimm_bridge(struct device *dev) } EXPORT_SYMBOL_NS_GPL(is_cxl_nvdimm_bridge, CXL); -__mock int match_nvdimm_bridge(struct device *dev, const void *data) +static int match_nvdimm_bridge(struct device *dev, void *data) { return is_cxl_nvdimm_bridge(dev); } struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(struct cxl_nvdimm *cxl_nvd) { + struct cxl_port *port = find_cxl_root(&cxl_nvd->dev); struct device *dev; - dev = bus_find_device(&cxl_bus_type, NULL, cxl_nvd, match_nvdimm_bridge); + if (!port) + return NULL; + + dev = device_find_child(&port->dev, NULL, match_nvdimm_bridge); + put_device(&port->dev); + if (!dev) return NULL; + return to_cxl_nvdimm_bridge(dev); } EXPORT_SYMBOL_NS_GPL(cxl_find_nvdimm_bridge, CXL); -static struct cxl_nvdimm_bridge * -cxl_nvdimm_bridge_alloc(struct cxl_port *port) +static struct cxl_nvdimm_bridge *cxl_nvdimm_bridge_alloc(struct cxl_port *port) { struct cxl_nvdimm_bridge *cxl_nvb; struct device *dev; diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c index 2a4230d685d5..af7a515e4572 100644 --- a/drivers/cxl/core/port.c +++ b/drivers/cxl/core/port.c @@ -455,6 +455,55 @@ int devm_cxl_register_pci_bus(struct device *host, struct device *uport, } EXPORT_SYMBOL_NS_GPL(devm_cxl_register_pci_bus, CXL); +/* Find a 2nd level CXL port that has a dport that is an ancestor of @match */ +static int match_root_child(struct device *dev, const void *match) +{ + const struct device *iter = NULL; + struct cxl_port *port, *parent; + struct cxl_dport *dport; + + if (!is_cxl_port(dev)) + return 0; + + port = to_cxl_port(dev); + if (is_cxl_root(port)) + return 0; + + parent = to_cxl_port(port->dev.parent); + if (!is_cxl_root(parent)) + return 0; + + cxl_device_lock(&port->dev); + list_for_each_entry(dport, &port->dports, list) { + iter = match; + while (iter) { + if (iter == dport->dport) + goto out; + iter = iter->parent; + } + } +out: + cxl_device_unlock(&port->dev); + + return !!iter; +} + +struct cxl_port *find_cxl_root(struct device *dev) +{ + struct device *port_dev; + struct cxl_port *root; + + port_dev = bus_find_device(&cxl_bus_type, NULL, dev, match_root_child); + if (!port_dev) + return NULL; + + root = to_cxl_port(port_dev->parent); + get_device(&root->dev); + put_device(port_dev); + return root; +} +EXPORT_SYMBOL_NS_GPL(find_cxl_root, CXL); + static struct cxl_dport *find_dport(struct cxl_port *port, int id) { struct cxl_dport *dport; diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h index 4d4cc8292137..61b0db526fa2 100644 --- a/drivers/cxl/cxl.h +++ b/drivers/cxl/cxl.h @@ -304,6 +304,7 @@ struct cxl_port *devm_cxl_add_port(struct device *host, struct device *uport, int cxl_add_dport(struct cxl_port *port, struct device *dport, int port_id, resource_size_t component_reg_phys); +struct cxl_port *find_cxl_root(struct device *dev); struct cxl_decoder *to_cxl_decoder(struct device *dev); bool is_root_decoder(struct device *dev); -- cgit v1.2.3-58-ga151