From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- drivers/cxl/port.c | 207 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 207 insertions(+) create mode 100644 drivers/cxl/port.c (limited to 'drivers/cxl/port.c') diff --git a/drivers/cxl/port.c b/drivers/cxl/port.c new file mode 100644 index 0000000000..6240e05b95 --- /dev/null +++ b/drivers/cxl/port.c @@ -0,0 +1,207 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright(c) 2022 Intel Corporation. All rights reserved. */ +#include +#include +#include + +#include "cxlmem.h" +#include "cxlpci.h" + +/** + * DOC: cxl port + * + * The port driver enumerates dport via PCI and scans for HDM + * (Host-managed-Device-Memory) decoder resources via the + * @component_reg_phys value passed in by the agent that registered the + * port. All descendant ports of a CXL root port (described by platform + * firmware) are managed in this drivers context. Each driver instance + * is responsible for tearing down the driver context of immediate + * descendant ports. The locking for this is validated by + * CONFIG_PROVE_CXL_LOCKING. + * + * The primary service this driver provides is presenting APIs to other + * drivers to utilize the decoders, and indicating to userspace (via bind + * status) the connectivity of the CXL.mem protocol throughout the + * PCIe topology. + */ + +static void schedule_detach(void *cxlmd) +{ + schedule_cxl_memdev_detach(cxlmd); +} + +static int discover_region(struct device *dev, void *root) +{ + struct cxl_endpoint_decoder *cxled; + int rc; + + if (!is_endpoint_decoder(dev)) + return 0; + + cxled = to_cxl_endpoint_decoder(dev); + if ((cxled->cxld.flags & CXL_DECODER_F_ENABLE) == 0) + return 0; + + if (cxled->state != CXL_DECODER_STATE_AUTO) + return 0; + + /* + * Region enumeration is opportunistic, if this add-event fails, + * continue to the next endpoint decoder. + */ + rc = cxl_add_to_region(root, cxled); + if (rc) + dev_dbg(dev, "failed to add to region: %#llx-%#llx\n", + cxled->cxld.hpa_range.start, cxled->cxld.hpa_range.end); + + return 0; +} + +static int cxl_switch_port_probe(struct cxl_port *port) +{ + struct cxl_hdm *cxlhdm; + int rc; + + rc = devm_cxl_port_enumerate_dports(port); + if (rc < 0) + return rc; + + cxlhdm = devm_cxl_setup_hdm(port, NULL); + if (!IS_ERR(cxlhdm)) + return devm_cxl_enumerate_decoders(cxlhdm, NULL); + + if (PTR_ERR(cxlhdm) != -ENODEV) { + dev_err(&port->dev, "Failed to map HDM decoder capability\n"); + return PTR_ERR(cxlhdm); + } + + if (rc == 1) { + dev_dbg(&port->dev, "Fallback to passthrough decoder\n"); + return devm_cxl_add_passthrough_decoder(port); + } + + dev_err(&port->dev, "HDM decoder capability not found\n"); + return -ENXIO; +} + +static int cxl_endpoint_port_probe(struct cxl_port *port) +{ + struct cxl_endpoint_dvsec_info info = { .port = port }; + struct cxl_memdev *cxlmd = to_cxl_memdev(port->uport_dev); + struct cxl_dev_state *cxlds = cxlmd->cxlds; + struct cxl_hdm *cxlhdm; + struct cxl_port *root; + int rc; + + rc = cxl_dvsec_rr_decode(cxlds->dev, cxlds->cxl_dvsec, &info); + if (rc < 0) + return rc; + + cxlhdm = devm_cxl_setup_hdm(port, &info); + if (IS_ERR(cxlhdm)) { + if (PTR_ERR(cxlhdm) == -ENODEV) + dev_err(&port->dev, "HDM decoder registers not found\n"); + return PTR_ERR(cxlhdm); + } + + /* Cache the data early to ensure is_visible() works */ + read_cdat_data(port); + + get_device(&cxlmd->dev); + rc = devm_add_action_or_reset(&port->dev, schedule_detach, cxlmd); + if (rc) + return rc; + + rc = cxl_hdm_decode_init(cxlds, cxlhdm, &info); + if (rc) + return rc; + + rc = devm_cxl_enumerate_decoders(cxlhdm, &info); + if (rc) + return rc; + + /* + * This can't fail in practice as CXL root exit unregisters all + * descendant ports and that in turn synchronizes with cxl_port_probe() + */ + root = find_cxl_root(port); + + /* + * Now that all endpoint decoders are successfully enumerated, try to + * assemble regions from committed decoders + */ + device_for_each_child(&port->dev, root, discover_region); + put_device(&root->dev); + + return 0; +} + +static int cxl_port_probe(struct device *dev) +{ + struct cxl_port *port = to_cxl_port(dev); + + if (is_cxl_endpoint(port)) + return cxl_endpoint_port_probe(port); + return cxl_switch_port_probe(port); +} + +static ssize_t CDAT_read(struct file *filp, struct kobject *kobj, + struct bin_attribute *bin_attr, char *buf, + loff_t offset, size_t count) +{ + struct device *dev = kobj_to_dev(kobj); + struct cxl_port *port = to_cxl_port(dev); + + if (!port->cdat_available) + return -ENXIO; + + if (!port->cdat.table) + return 0; + + return memory_read_from_buffer(buf, count, &offset, + port->cdat.table, + port->cdat.length); +} + +static BIN_ATTR_ADMIN_RO(CDAT, 0); + +static umode_t cxl_port_bin_attr_is_visible(struct kobject *kobj, + struct bin_attribute *attr, int i) +{ + struct device *dev = kobj_to_dev(kobj); + struct cxl_port *port = to_cxl_port(dev); + + if ((attr == &bin_attr_CDAT) && port->cdat_available) + return attr->attr.mode; + + return 0; +} + +static struct bin_attribute *cxl_cdat_bin_attributes[] = { + &bin_attr_CDAT, + NULL, +}; + +static struct attribute_group cxl_cdat_attribute_group = { + .bin_attrs = cxl_cdat_bin_attributes, + .is_bin_visible = cxl_port_bin_attr_is_visible, +}; + +static const struct attribute_group *cxl_port_attribute_groups[] = { + &cxl_cdat_attribute_group, + NULL, +}; + +static struct cxl_driver cxl_port_driver = { + .name = "cxl_port", + .probe = cxl_port_probe, + .id = CXL_DEVICE_PORT, + .drv = { + .dev_groups = cxl_port_attribute_groups, + }, +}; + +module_cxl_driver(cxl_port_driver); +MODULE_LICENSE("GPL v2"); +MODULE_IMPORT_NS(CXL); +MODULE_ALIAS_CXL(CXL_DEVICE_PORT); -- cgit v1.2.3