linux/drivers/cxl/port.c
Ben Widawsky 9b71e1c9c3 cxl/core/port: Add endpoint decoders
Recall that a CXL Port is any object that publishes a CXL HDM Decoder
Capability structure. That is Host Bridge and Switches that have been
enabled so far. Now, add decoder support to the 'endpoint' CXL Ports
registered by the cxl_mem driver. They mostly share the same enumeration
as Bridges and Switches, but witout a target list. The target of
endpoint decode is device-internal DPA space, not another downstream
port.

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
[djbw: clarify changelog, hookup enumeration in the port driver]
Link: https://lore.kernel.org/r/164386092069.765089.14895687988217608642.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-02-08 22:57:32 -08:00

77 lines
2.0 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/* Copyright(c) 2022 Intel Corporation. All rights reserved. */
#include <linux/device.h>
#include <linux/module.h>
#include <linux/slab.h>
#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 cxl_port_probe(struct device *dev)
{
struct cxl_port *port = to_cxl_port(dev);
struct cxl_hdm *cxlhdm;
int rc;
if (is_cxl_endpoint(port)) {
struct cxl_memdev *cxlmd = to_cxl_memdev(port->uport);
get_device(&cxlmd->dev);
rc = devm_add_action_or_reset(dev, schedule_detach, cxlmd);
if (rc)
return rc;
} else {
rc = devm_cxl_port_enumerate_dports(port);
if (rc < 0)
return rc;
if (rc == 1)
return devm_cxl_add_passthrough_decoder(port);
}
cxlhdm = devm_cxl_setup_hdm(port);
if (IS_ERR(cxlhdm))
return PTR_ERR(cxlhdm);
rc = devm_cxl_enumerate_decoders(cxlhdm);
if (rc) {
dev_err(dev, "Couldn't enumerate decoders (%d)\n", rc);
return rc;
}
return 0;
}
static struct cxl_driver cxl_port_driver = {
.name = "cxl_port",
.probe = cxl_port_probe,
.id = CXL_DEVICE_PORT,
};
module_cxl_driver(cxl_port_driver);
MODULE_LICENSE("GPL v2");
MODULE_IMPORT_NS(CXL);
MODULE_ALIAS_CXL(CXL_DEVICE_PORT);