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![Dan Williams](/assets/img/avatar_default.png)
Pick up the first half of the RCH error handling series. The back half needs some fixups for test regressions. Small conflicts with the PMU work around register enumeration and setup helpers.
207 lines
5.1 KiB
C
207 lines
5.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* Copyright(c) 2022 Intel Corporation. All rights reserved. */
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#include <linux/device.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include "cxlmem.h"
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#include "cxlpci.h"
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/**
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* DOC: cxl port
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*
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* The port driver enumerates dport via PCI and scans for HDM
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* (Host-managed-Device-Memory) decoder resources via the
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* @component_reg_phys value passed in by the agent that registered the
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* port. All descendant ports of a CXL root port (described by platform
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* firmware) are managed in this drivers context. Each driver instance
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* is responsible for tearing down the driver context of immediate
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* descendant ports. The locking for this is validated by
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* CONFIG_PROVE_CXL_LOCKING.
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*
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* The primary service this driver provides is presenting APIs to other
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* drivers to utilize the decoders, and indicating to userspace (via bind
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* status) the connectivity of the CXL.mem protocol throughout the
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* PCIe topology.
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*/
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static void schedule_detach(void *cxlmd)
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{
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schedule_cxl_memdev_detach(cxlmd);
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}
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static int discover_region(struct device *dev, void *root)
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{
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struct cxl_endpoint_decoder *cxled;
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int rc;
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if (!is_endpoint_decoder(dev))
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return 0;
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cxled = to_cxl_endpoint_decoder(dev);
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if ((cxled->cxld.flags & CXL_DECODER_F_ENABLE) == 0)
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return 0;
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if (cxled->state != CXL_DECODER_STATE_AUTO)
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return 0;
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/*
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* Region enumeration is opportunistic, if this add-event fails,
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* continue to the next endpoint decoder.
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*/
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rc = cxl_add_to_region(root, cxled);
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if (rc)
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dev_dbg(dev, "failed to add to region: %#llx-%#llx\n",
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cxled->cxld.hpa_range.start, cxled->cxld.hpa_range.end);
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return 0;
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}
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static int cxl_switch_port_probe(struct cxl_port *port)
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{
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struct cxl_hdm *cxlhdm;
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int rc;
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rc = devm_cxl_port_enumerate_dports(port);
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if (rc < 0)
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return rc;
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cxlhdm = devm_cxl_setup_hdm(port, NULL);
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if (!IS_ERR(cxlhdm))
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return devm_cxl_enumerate_decoders(cxlhdm, NULL);
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if (PTR_ERR(cxlhdm) != -ENODEV) {
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dev_err(&port->dev, "Failed to map HDM decoder capability\n");
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return PTR_ERR(cxlhdm);
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}
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if (rc == 1) {
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dev_dbg(&port->dev, "Fallback to passthrough decoder\n");
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return devm_cxl_add_passthrough_decoder(port);
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}
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dev_err(&port->dev, "HDM decoder capability not found\n");
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return -ENXIO;
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}
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static int cxl_endpoint_port_probe(struct cxl_port *port)
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{
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struct cxl_endpoint_dvsec_info info = { .port = port };
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struct cxl_memdev *cxlmd = to_cxl_memdev(port->uport_dev);
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struct cxl_dev_state *cxlds = cxlmd->cxlds;
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struct cxl_hdm *cxlhdm;
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struct cxl_port *root;
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int rc;
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rc = cxl_dvsec_rr_decode(cxlds->dev, cxlds->cxl_dvsec, &info);
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if (rc < 0)
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return rc;
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cxlhdm = devm_cxl_setup_hdm(port, &info);
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if (IS_ERR(cxlhdm)) {
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if (PTR_ERR(cxlhdm) == -ENODEV)
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dev_err(&port->dev, "HDM decoder registers not found\n");
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return PTR_ERR(cxlhdm);
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}
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/* Cache the data early to ensure is_visible() works */
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read_cdat_data(port);
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get_device(&cxlmd->dev);
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rc = devm_add_action_or_reset(&port->dev, schedule_detach, cxlmd);
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if (rc)
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return rc;
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rc = cxl_hdm_decode_init(cxlds, cxlhdm, &info);
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if (rc)
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return rc;
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rc = devm_cxl_enumerate_decoders(cxlhdm, &info);
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if (rc)
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return rc;
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/*
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* This can't fail in practice as CXL root exit unregisters all
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* descendant ports and that in turn synchronizes with cxl_port_probe()
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*/
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root = find_cxl_root(port);
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/*
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* Now that all endpoint decoders are successfully enumerated, try to
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* assemble regions from committed decoders
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*/
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device_for_each_child(&port->dev, root, discover_region);
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put_device(&root->dev);
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return 0;
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}
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static int cxl_port_probe(struct device *dev)
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{
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struct cxl_port *port = to_cxl_port(dev);
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if (is_cxl_endpoint(port))
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return cxl_endpoint_port_probe(port);
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return cxl_switch_port_probe(port);
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}
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static ssize_t CDAT_read(struct file *filp, struct kobject *kobj,
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struct bin_attribute *bin_attr, char *buf,
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loff_t offset, size_t count)
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{
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struct device *dev = kobj_to_dev(kobj);
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struct cxl_port *port = to_cxl_port(dev);
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if (!port->cdat_available)
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return -ENXIO;
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if (!port->cdat.table)
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return 0;
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return memory_read_from_buffer(buf, count, &offset,
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port->cdat.table,
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port->cdat.length);
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}
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static BIN_ATTR_ADMIN_RO(CDAT, 0);
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static umode_t cxl_port_bin_attr_is_visible(struct kobject *kobj,
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struct bin_attribute *attr, int i)
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{
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struct device *dev = kobj_to_dev(kobj);
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struct cxl_port *port = to_cxl_port(dev);
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if ((attr == &bin_attr_CDAT) && port->cdat_available)
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return attr->attr.mode;
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return 0;
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}
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static struct bin_attribute *cxl_cdat_bin_attributes[] = {
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&bin_attr_CDAT,
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NULL,
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};
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static struct attribute_group cxl_cdat_attribute_group = {
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.bin_attrs = cxl_cdat_bin_attributes,
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.is_bin_visible = cxl_port_bin_attr_is_visible,
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};
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static const struct attribute_group *cxl_port_attribute_groups[] = {
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&cxl_cdat_attribute_group,
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NULL,
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};
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static struct cxl_driver cxl_port_driver = {
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.name = "cxl_port",
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.probe = cxl_port_probe,
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.id = CXL_DEVICE_PORT,
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.drv = {
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.dev_groups = cxl_port_attribute_groups,
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},
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};
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module_cxl_driver(cxl_port_driver);
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MODULE_LICENSE("GPL v2");
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MODULE_IMPORT_NS(CXL);
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MODULE_ALIAS_CXL(CXL_DEVICE_PORT);
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