@@ -89,6 +89,17 @@ Description:
"1" if the capability is supported, and is not present,
or shows "0" is the capability is not supported.
+What: /sys/bus/cxl/devices/portX/host
+Date: May, 2021
+KernelVersion: v5.14
+Contact: linux-cxl@vger.kernel.org
+Description:
+ CXL port objects are enumerated from either a platform
+ firmware device (representing a host bridge), or a PCIe
+ device (representing a root port, or a switch port). The
+ 'host' symlink connects the CXL portX object to the
+ device that published the CXL port capability.
+
What: /sys/bus/cxl/devices/portX/target_id
Date: May, 2021
KernelVersion: v5.14
@@ -5,18 +5,117 @@
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/acpi.h>
+#include <linux/pci.h>
#include "cxl.h"
+static int match_ACPI0016(struct device *dev, const void *host)
+{
+ struct acpi_device *adev = to_acpi_device(dev);
+ const char *hid = acpi_device_hid(adev);
+
+ return strcmp(hid, "ACPI0016") == 0;
+}
+
+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;
+ resource_size_t cxl_regs_phys;
+ int target_id = ctx->count;
+
+ if (pdev->bus != root_bus)
+ return 0;
+ if (!pci_is_pcie(pdev))
+ return 0;
+ if (type != PCI_EXP_TYPE_ROOT_PORT)
+ return 0;
+
+ ctx->count++;
+
+ /* TODO walk DVSEC to find component register base */
+ cxl_regs_phys = -1;
+
+ port = devm_cxl_add_port(dev, port, &pdev->dev, target_id,
+ cxl_regs_phys);
+ if (IS_ERR(port)) {
+ ctx->error = PTR_ERR(port);
+ return ctx->error;
+ }
+
+ dev_dbg(dev, "%s: register: %s\n", dev_name(&pdev->dev),
+ dev_name(&port->dev));
+
+ return 0;
+}
+
+/*
+ * A host bridge may contain one or more root ports. Register each port
+ * as a child of the cxl_root.
+ */
+static int cxl_acpi_register_ports(struct device *dev, struct acpi_device *root,
+ struct cxl_port *port, int idx)
+{
+ struct acpi_pci_root *pci_root = acpi_pci_find_root(root->handle);
+ struct cxl_walk_context ctx;
+
+ if (!pci_root)
+ return -ENXIO;
+
+ /* TODO: fold in CEDT.CHBS retrieval */
+ port = devm_cxl_add_port(dev, port, &root->dev, idx, ~0);
+ if (IS_ERR(port))
+ return PTR_ERR(port);
+ dev_dbg(dev, "%s: register: %s\n", dev_name(&root->dev),
+ dev_name(&port->dev));
+
+ ctx = (struct cxl_walk_context) {
+ .dev = dev,
+ .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 cxl_acpi_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
+ struct acpi_device *adev = ACPI_COMPANION(dev);
+ struct device *bridge = NULL;
struct cxl_root *cxl_root;
+ int rc, i = 0;
cxl_root = devm_cxl_add_root(dev, NULL, 0);
if (IS_ERR(cxl_root))
return PTR_ERR(cxl_root);
dev_dbg(dev, "register: %s\n", dev_name(&cxl_root->port.dev));
+ while (true) {
+ bridge = bus_find_device(adev->dev.bus, bridge, dev,
+ match_ACPI0016);
+ if (!bridge)
+ break;
+
+ rc = cxl_acpi_register_ports(dev, to_acpi_device(bridge),
+ &cxl_root->port, i++);
+ if (rc)
+ return rc;
+ }
+
return 0;
}
@@ -153,6 +153,15 @@ static void cxl_root_release(struct device *dev)
kfree(cxl_root);
}
+static void cxl_port_release(struct device *dev)
+{
+ struct cxl_port *port = to_cxl_port(dev);
+
+ ida_free(&cxl_port_ida, port->id);
+ put_device(port->port_host);
+ kfree(port);
+}
+
static ssize_t target_id_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
@@ -183,6 +192,12 @@ static const struct device_type cxl_root_type = {
.groups = cxl_port_attribute_groups,
};
+static const struct device_type cxl_port_type = {
+ .name = "cxl_port",
+ .release = cxl_port_release,
+ .groups = cxl_port_attribute_groups,
+};
+
struct cxl_root *to_cxl_root(struct device *dev)
{
if (dev_WARN_ONCE(dev, dev->type != &cxl_root_type,
@@ -193,7 +208,9 @@ struct cxl_root *to_cxl_root(struct device *dev)
struct cxl_port *to_cxl_port(struct device *dev)
{
- if (dev_WARN_ONCE(dev, dev->type != &cxl_root_type,
+ if (dev_WARN_ONCE(dev,
+ dev->type != &cxl_root_type &&
+ dev->type != &cxl_port_type,
"not a cxl_port device\n"))
return NULL;
return container_of(dev, struct cxl_port, dev);
@@ -372,6 +389,108 @@ struct cxl_root *devm_cxl_add_root(struct device *host,
}
EXPORT_SYMBOL_GPL(devm_cxl_add_root);
+static void cxl_unlink_port(void *_port)
+{
+ struct cxl_port *port = _port;
+
+ sysfs_remove_link(&port->dev.kobj, "host");
+}
+
+static int devm_cxl_link_port(struct device *dev, struct cxl_port *port)
+{
+ int rc;
+
+ rc = sysfs_create_link(&port->dev.kobj, &port->port_host->kobj, "host");
+ if (rc)
+ return rc;
+ return devm_add_action_or_reset(dev, cxl_unlink_port, port);
+}
+
+static struct cxl_port *cxl_port_alloc(struct cxl_port *parent_port,
+ struct device *port_dev, int target_id,
+ resource_size_t component_regs_phys)
+{
+ struct cxl_port *port;
+ struct device *dev;
+ int rc;
+
+ if (!port_dev)
+ return ERR_PTR(-EINVAL);
+
+ port = kzalloc(sizeof(*port), GFP_KERNEL);
+ if (!port)
+ return ERR_PTR(-ENOMEM);
+
+ rc = ida_alloc(&cxl_port_ida, GFP_KERNEL);
+ if (rc < 0)
+ goto err;
+
+ port->id = rc;
+ port->target_id = target_id;
+ port->port_host = get_device(port_dev);
+ port->component_regs_phys = component_regs_phys;
+
+ dev = &port->dev;
+ device_initialize(dev);
+ device_set_pm_not_required(dev);
+ dev->parent = &parent_port->dev;
+ dev->bus = &cxl_bus_type;
+ dev->type = &cxl_port_type;
+
+ return port;
+
+err:
+ kfree(port);
+ return ERR_PTR(rc);
+}
+
+/**
+ * devm_cxl_add_port() - add a cxl_port to the topology
+ * @host: devm context / discovery agent
+ * @parent_port: immediate ancestor towards cxl_root
+ * @port_host: PCI or platform-firmware device hosting this port
+ * @target_id: ordinal id relative to other siblings under @parent_port
+ * @component_regs_phys: CXL component register base address
+ */
+struct cxl_port *devm_cxl_add_port(struct device *host,
+ struct cxl_port *parent_port,
+ struct device *port_host, int target_id,
+ resource_size_t component_regs_phys)
+{
+ struct cxl_port *port;
+ struct device *dev;
+ int rc;
+
+ port = cxl_port_alloc(parent_port, port_host, target_id,
+ component_regs_phys);
+ if (IS_ERR(port))
+ return port;
+
+ dev = &port->dev;
+ rc = dev_set_name(dev, "port%d", port->id);
+ if (rc)
+ goto err;
+
+ rc = device_add(dev);
+ if (rc)
+ goto err;
+
+ rc = devm_add_action_or_reset(host, unregister_dev, dev);
+ if (rc)
+ return ERR_PTR(rc);
+
+ rc = devm_cxl_link_port(host, port);
+ if (rc)
+ return ERR_PTR(rc);
+
+ return port;
+
+err:
+ put_device(dev);
+ return ERR_PTR(rc);
+}
+EXPORT_SYMBOL_GPL(devm_cxl_add_port);
+
/**
* cxl_setup_device_regs() - Detect CXL Device register blocks
* @dev: Host device of the @base mapping
@@ -134,5 +134,10 @@ struct cxl_address_space_dev *to_cxl_address_space(struct device *dev);
struct cxl_root *devm_cxl_add_root(struct device *parent,
struct cxl_address_space *cxl_space,
int nr_spaces);
+struct cxl_port *devm_cxl_add_port(struct device *host,
+ struct cxl_port *parent_port,
+ struct device *port_host, int target_id,
+ resource_size_t component_regs_phys);
+
extern struct bus_type cxl_bus_type;
#endif /* __CXL_H__ */