| Message ID | 162295952254.1109360.12071591891784594995.stgit@dwillia2-desk3.amr.corp.intel.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
| Series | CXL port and decoder enumeration | expand |
On Sat, 5 Jun 2021 23:05:22 -0700 Dan Williams <dan.j.williams@intel.com> wrote: > While the resources enumerated by the CEDT.CFMWS identify a cxl_port > with host bridges as downstream ports, host bridges themselves are > upstream ports that decode to downstream ports represented by PCIe Root > Ports. Walk the PCIe Root Ports connected to a CXL Host Bridge, > identified by the ACPI0016 _HID, and add each one as a cxl_dport of the > host bridge cxl_port. > > For now, component registers are not enumerated, only the first order > uport / dport relationships. > > Signed-off-by: Dan Williams <dan.j.williams@intel.com> LGTM Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> > --- > drivers/cxl/acpi.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 95 insertions(+), 2 deletions(-) > > diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c > index 0ae7464b603d..ec324bf063b8 100644 > --- a/drivers/cxl/acpi.c > +++ b/drivers/cxl/acpi.c > @@ -8,6 +8,48 @@ > #include <linux/pci.h> > #include "cxl.h" > > +struct cxl_walk_context { > + struct device *dev; > + struct pci_bus *root; > + struct cxl_port *port; > + int error; > + int count; > +}; > + > +static int match_add_root_ports(struct pci_dev *pdev, void *data) > +{ > + struct cxl_walk_context *ctx = data; > + struct pci_bus *root_bus = ctx->root; > + struct cxl_port *port = ctx->port; > + int type = pci_pcie_type(pdev); > + struct device *dev = ctx->dev; > + u32 lnkcap, port_num; > + int rc; > + > + if (pdev->bus != root_bus) > + return 0; > + if (!pci_is_pcie(pdev)) > + return 0; > + if (type != PCI_EXP_TYPE_ROOT_PORT) > + return 0; > + if (pci_read_config_dword(pdev, pci_pcie_cap(pdev) + PCI_EXP_LNKCAP, > + &lnkcap) != PCIBIOS_SUCCESSFUL) > + return 0; > + > + /* TODO walk DVSEC to find component register base */ > + port_num = FIELD_GET(PCI_EXP_LNKCAP_PN, lnkcap); > + rc = cxl_add_dport(port, &pdev->dev, port_num, CXL_RESOURCE_NONE); > + if (rc) { > + ctx->error = rc; > + return rc; > + } > + ctx->count++; > + > + dev_dbg(dev, "add dport%d: %s\n", port_num, dev_name(&pdev->dev)); > + > + return 0; > +} > + > static struct acpi_device *to_cxl_host_bridge(struct device *dev) > { > struct acpi_device *adev = to_acpi_device(dev); > @@ -17,6 +59,44 @@ static struct acpi_device *to_cxl_host_bridge(struct device *dev) > return NULL; > } > > +/* > + * A host bridge is a dport to a CFMWS decode and it is a uport to the > + * dport (PCIe Root Ports) in the host bridge. > + */ > +static int add_host_bridge_uport(struct device *match, void *arg) > +{ > + struct acpi_device *bridge = to_cxl_host_bridge(match); > + struct cxl_port *root_port = arg; > + struct device *host = root_port->dev.parent; > + struct acpi_pci_root *pci_root; > + struct cxl_walk_context ctx; > + struct cxl_port *port; > + > + if (!bridge) > + return 0; > + > + pci_root = acpi_pci_find_root(bridge->handle); > + if (!pci_root) > + return -ENXIO; > + > + /* TODO: fold in CEDT.CHBS retrieval */ > + port = devm_cxl_add_port(host, match, CXL_RESOURCE_NONE, root_port); > + if (IS_ERR(port)) > + return PTR_ERR(port); > + dev_dbg(host, "%s: add: %s\n", dev_name(match), dev_name(&port->dev)); > + > + ctx = (struct cxl_walk_context){ > + .dev = host, > + .root = pci_root->bus, > + .port = port, > + }; > + pci_walk_bus(pci_root->bus, match_add_root_ports, &ctx); > + > + if (ctx.count == 0) > + return -ENODEV; > + return ctx.error; > +} > + > static int add_host_bridge_dport(struct device *match, void *arg) > { > int rc; > @@ -49,6 +129,7 @@ static int add_host_bridge_dport(struct device *match, void *arg) > > static int cxl_acpi_probe(struct platform_device *pdev) > { > + int rc; > struct cxl_port *root_port; > struct device *host = &pdev->dev; > struct acpi_device *adev = ACPI_COMPANION(host); > @@ -58,8 +139,20 @@ static int cxl_acpi_probe(struct platform_device *pdev) > return PTR_ERR(root_port); > dev_dbg(host, "add: %s\n", dev_name(&root_port->dev)); > > - return bus_for_each_dev(adev->dev.bus, NULL, root_port, > - add_host_bridge_dport); > + rc = bus_for_each_dev(adev->dev.bus, NULL, root_port, > + add_host_bridge_dport); > + if (rc) > + return rc; > + > + /* > + * Root level scanned with host-bridge as dports, now scan host-bridges > + * for their role as CXL uports to their CXL-capable PCIe Root Ports. > + */ > + rc = bus_for_each_dev(adev->dev.bus, NULL, root_port, > + add_host_bridge_uport); > + if (rc) > + dev_err(host, "failed to scan host bridges\n"); > + return 0; > } > > static const struct acpi_device_id cxl_acpi_ids[] = { >
diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c index 0ae7464b603d..ec324bf063b8 100644 --- a/drivers/cxl/acpi.c +++ b/drivers/cxl/acpi.c @@ -8,6 +8,48 @@ #include <linux/pci.h> #include "cxl.h" +struct cxl_walk_context { + struct device *dev; + struct pci_bus *root; + struct cxl_port *port; + int error; + int count; +}; + +static int match_add_root_ports(struct pci_dev *pdev, void *data) +{ + struct cxl_walk_context *ctx = data; + struct pci_bus *root_bus = ctx->root; + struct cxl_port *port = ctx->port; + int type = pci_pcie_type(pdev); + struct device *dev = ctx->dev; + u32 lnkcap, port_num; + int rc; + + if (pdev->bus != root_bus) + return 0; + if (!pci_is_pcie(pdev)) + return 0; + if (type != PCI_EXP_TYPE_ROOT_PORT) + return 0; + if (pci_read_config_dword(pdev, pci_pcie_cap(pdev) + PCI_EXP_LNKCAP, + &lnkcap) != PCIBIOS_SUCCESSFUL) + return 0; + + /* TODO walk DVSEC to find component register base */ + port_num = FIELD_GET(PCI_EXP_LNKCAP_PN, lnkcap); + rc = cxl_add_dport(port, &pdev->dev, port_num, CXL_RESOURCE_NONE); + if (rc) { + ctx->error = rc; + return rc; + } + ctx->count++; + + dev_dbg(dev, "add dport%d: %s\n", port_num, dev_name(&pdev->dev)); + + return 0; +} + static struct acpi_device *to_cxl_host_bridge(struct device *dev) { struct acpi_device *adev = to_acpi_device(dev); @@ -17,6 +59,44 @@ static struct acpi_device *to_cxl_host_bridge(struct device *dev) return NULL; } +/* + * A host bridge is a dport to a CFMWS decode and it is a uport to the + * dport (PCIe Root Ports) in the host bridge. + */ +static int add_host_bridge_uport(struct device *match, void *arg) +{ + struct acpi_device *bridge = to_cxl_host_bridge(match); + struct cxl_port *root_port = arg; + struct device *host = root_port->dev.parent; + struct acpi_pci_root *pci_root; + struct cxl_walk_context ctx; + struct cxl_port *port; + + if (!bridge) + return 0; + + pci_root = acpi_pci_find_root(bridge->handle); + if (!pci_root) + return -ENXIO; + + /* TODO: fold in CEDT.CHBS retrieval */ + port = devm_cxl_add_port(host, match, CXL_RESOURCE_NONE, root_port); + if (IS_ERR(port)) + return PTR_ERR(port); + dev_dbg(host, "%s: add: %s\n", dev_name(match), dev_name(&port->dev)); + + ctx = (struct cxl_walk_context){ + .dev = host, + .root = pci_root->bus, + .port = port, + }; + pci_walk_bus(pci_root->bus, match_add_root_ports, &ctx); + + if (ctx.count == 0) + return -ENODEV; + return ctx.error; +} + static int add_host_bridge_dport(struct device *match, void *arg) { int rc; @@ -49,6 +129,7 @@ static int add_host_bridge_dport(struct device *match, void *arg) static int cxl_acpi_probe(struct platform_device *pdev) { + int rc; struct cxl_port *root_port; struct device *host = &pdev->dev; struct acpi_device *adev = ACPI_COMPANION(host); @@ -58,8 +139,20 @@ static int cxl_acpi_probe(struct platform_device *pdev) return PTR_ERR(root_port); dev_dbg(host, "add: %s\n", dev_name(&root_port->dev)); - return bus_for_each_dev(adev->dev.bus, NULL, root_port, - add_host_bridge_dport); + rc = bus_for_each_dev(adev->dev.bus, NULL, root_port, + add_host_bridge_dport); + if (rc) + return rc; + + /* + * Root level scanned with host-bridge as dports, now scan host-bridges + * for their role as CXL uports to their CXL-capable PCIe Root Ports. + */ + rc = bus_for_each_dev(adev->dev.bus, NULL, root_port, + add_host_bridge_uport); + if (rc) + dev_err(host, "failed to scan host bridges\n"); + return 0; } static const struct acpi_device_id cxl_acpi_ids[] = {
While the resources enumerated by the CEDT.CFMWS identify a cxl_port with host bridges as downstream ports, host bridges themselves are upstream ports that decode to downstream ports represented by PCIe Root Ports. Walk the PCIe Root Ports connected to a CXL Host Bridge, identified by the ACPI0016 _HID, and add each one as a cxl_dport of the host bridge cxl_port. For now, component registers are not enumerated, only the first order uport / dport relationships. Signed-off-by: Dan Williams <dan.j.williams@intel.com> --- drivers/cxl/acpi.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 95 insertions(+), 2 deletions(-)