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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright(c) 2021 Intel Corporation. All rights reserved. */
#include <linux/device.h>
#include <linux/pci.h>
#include <cxlpci.h>
#include <cxl.h>
#include "core.h"
/**
* DOC: cxl core pci
*
* Compute Express Link protocols are layered on top of PCIe. CXL core provides
* a set of helpers for CXL interactions which occur via PCIe.
*/
struct cxl_walk_context {
struct pci_bus *bus;
struct cxl_port *port;
int type;
int error;
int count;
};
static int match_add_dports(struct pci_dev *pdev, void *data)
{
struct cxl_walk_context *ctx = data;
struct cxl_port *port = ctx->port;
int type = pci_pcie_type(pdev);
struct cxl_register_map map;
struct cxl_dport *dport;
u32 lnkcap, port_num;
int rc;
if (pdev->bus != ctx->bus)
return 0;
if (!pci_is_pcie(pdev))
return 0;
if (type != ctx->type)
return 0;
if (pci_read_config_dword(pdev, pci_pcie_cap(pdev) + PCI_EXP_LNKCAP,
&lnkcap))
return 0;
rc = cxl_find_regblock(pdev, CXL_REGLOC_RBI_COMPONENT, &map);
if (rc)
dev_dbg(&port->dev, "failed to find component registers\n");
port_num = FIELD_GET(PCI_EXP_LNKCAP_PN, lnkcap);
dport = devm_cxl_add_dport(port, &pdev->dev, port_num,
cxl_regmap_to_base(pdev, &map));
if (IS_ERR(dport)) {
ctx->error = PTR_ERR(dport);
return PTR_ERR(dport);
}
ctx->count++;
dev_dbg(&port->dev, "add dport%d: %s\n", port_num, dev_name(&pdev->dev));
return 0;
}
/**
* devm_cxl_port_enumerate_dports - enumerate downstream ports of the upstream port
* @port: cxl_port whose ->uport is the upstream of dports to be enumerated
*
* Returns a positive number of dports enumerated or a negative error
* code.
*/
int devm_cxl_port_enumerate_dports(struct cxl_port *port)
{
struct pci_bus *bus = cxl_port_to_pci_bus(port);
struct cxl_walk_context ctx;
int type;
if (!bus)
return -ENXIO;
if (pci_is_root_bus(bus))
type = PCI_EXP_TYPE_ROOT_PORT;
else
type = PCI_EXP_TYPE_DOWNSTREAM;
ctx = (struct cxl_walk_context) {
.port = port,
.bus = bus,
.type = type,
};
pci_walk_bus(bus, match_add_dports, &ctx);
if (ctx.count == 0)
return -ENODEV;
if (ctx.error)
return ctx.error;
return ctx.count;
}
EXPORT_SYMBOL_NS_GPL(devm_cxl_port_enumerate_dports, CXL);
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