linux/drivers/cxl/acpi.c
Alison Schofield 3e23d17ce1 cxl/acpi: Use the ACPI CFMWS to create static decoder objects
The ACPI CXL Early Discovery Table (CEDT) includes a list of CXL memory
resources in CXL Fixed Memory Window Structures (CFMWS). Retrieve each
CFMWS in the CEDT and add a cxl_decoder object to the root port (root0)
for each memory resource.

Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Ben Widawsky <ben.widawsky@intel.com>
Link: https://lore.kernel.org/r/d2b73eecfb7ea22e1103f1894b271a89958b4c41.1623968958.git.alison.schofield@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-17 17:35:43 -07:00

435 lines
10 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/* Copyright(c) 2021 Intel Corporation. All rights reserved. */
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/acpi.h>
#include <linux/pci.h>
#include "cxl.h"
static struct acpi_table_header *acpi_cedt;
/* Encode defined in CXL 2.0 8.2.5.12.7 HDM Decoder Control Register */
#define CFMWS_INTERLEAVE_WAYS(x) (1 << (x)->interleave_ways)
#define CFMWS_INTERLEAVE_GRANULARITY(x) ((x)->granularity + 8)
static unsigned long cfmws_to_decoder_flags(int restrictions)
{
unsigned long flags = 0;
if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_TYPE2)
flags |= CXL_DECODER_F_TYPE2;
if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_TYPE3)
flags |= CXL_DECODER_F_TYPE3;
if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_VOLATILE)
flags |= CXL_DECODER_F_RAM;
if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_PMEM)
flags |= CXL_DECODER_F_PMEM;
if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_FIXED)
flags |= CXL_DECODER_F_LOCK;
return flags;
}
static int cxl_acpi_cfmws_verify(struct device *dev,
struct acpi_cedt_cfmws *cfmws)
{
int expected_len;
if (cfmws->interleave_arithmetic != ACPI_CEDT_CFMWS_ARITHMETIC_MODULO) {
dev_err(dev, "CFMWS Unsupported Interleave Arithmetic\n");
return -EINVAL;
}
if (!IS_ALIGNED(cfmws->base_hpa, SZ_256M)) {
dev_err(dev, "CFMWS Base HPA not 256MB aligned\n");
return -EINVAL;
}
if (!IS_ALIGNED(cfmws->window_size, SZ_256M)) {
dev_err(dev, "CFMWS Window Size not 256MB aligned\n");
return -EINVAL;
}
expected_len = struct_size((cfmws), interleave_targets,
CFMWS_INTERLEAVE_WAYS(cfmws));
if (cfmws->header.length < expected_len) {
dev_err(dev, "CFMWS length %d less than expected %d\n",
cfmws->header.length, expected_len);
return -EINVAL;
}
if (cfmws->header.length > expected_len)
dev_dbg(dev, "CFMWS length %d greater than expected %d\n",
cfmws->header.length, expected_len);
return 0;
}
static void cxl_add_cfmws_decoders(struct device *dev,
struct cxl_port *root_port)
{
struct acpi_cedt_cfmws *cfmws;
struct cxl_decoder *cxld;
acpi_size len, cur = 0;
void *cedt_subtable;
unsigned long flags;
int rc;
len = acpi_cedt->length - sizeof(*acpi_cedt);
cedt_subtable = acpi_cedt + 1;
while (cur < len) {
struct acpi_cedt_header *c = cedt_subtable + cur;
if (c->type != ACPI_CEDT_TYPE_CFMWS) {
cur += c->length;
continue;
}
cfmws = cedt_subtable + cur;
if (cfmws->header.length < sizeof(*cfmws)) {
dev_warn_once(dev,
"CFMWS entry skipped:invalid length:%u\n",
cfmws->header.length);
cur += c->length;
continue;
}
rc = cxl_acpi_cfmws_verify(dev, cfmws);
if (rc) {
dev_err(dev, "CFMWS range %#llx-%#llx not registered\n",
cfmws->base_hpa, cfmws->base_hpa +
cfmws->window_size - 1);
cur += c->length;
continue;
}
flags = cfmws_to_decoder_flags(cfmws->restrictions);
cxld = devm_cxl_add_decoder(dev, root_port,
CFMWS_INTERLEAVE_WAYS(cfmws),
cfmws->base_hpa, cfmws->window_size,
CFMWS_INTERLEAVE_WAYS(cfmws),
CFMWS_INTERLEAVE_GRANULARITY(cfmws),
CXL_DECODER_EXPANDER,
flags);
if (IS_ERR(cxld)) {
dev_err(dev, "Failed to add decoder for %#llx-%#llx\n",
cfmws->base_hpa, cfmws->base_hpa +
cfmws->window_size - 1);
} else {
dev_dbg(dev, "add: %s range %#llx-%#llx\n",
dev_name(&cxld->dev), cfmws->base_hpa,
cfmws->base_hpa + cfmws->window_size - 1);
}
cur += c->length;
}
}
static struct acpi_cedt_chbs *cxl_acpi_match_chbs(struct device *dev, u32 uid)
{
struct acpi_cedt_chbs *chbs, *chbs_match = NULL;
acpi_size len, cur = 0;
void *cedt_subtable;
len = acpi_cedt->length - sizeof(*acpi_cedt);
cedt_subtable = acpi_cedt + 1;
while (cur < len) {
struct acpi_cedt_header *c = cedt_subtable + cur;
if (c->type != ACPI_CEDT_TYPE_CHBS) {
cur += c->length;
continue;
}
chbs = cedt_subtable + cur;
if (chbs->header.length < sizeof(*chbs)) {
dev_warn_once(dev,
"CHBS entry skipped: invalid length:%u\n",
chbs->header.length);
cur += c->length;
continue;
}
if (chbs->uid != uid) {
cur += c->length;
continue;
}
if (chbs_match) {
dev_warn_once(dev,
"CHBS entry skipped: duplicate UID:%u\n",
uid);
cur += c->length;
continue;
}
chbs_match = chbs;
cur += c->length;
}
return chbs_match ? chbs_match : ERR_PTR(-ENODEV);
}
static resource_size_t get_chbcr(struct acpi_cedt_chbs *chbs)
{
return IS_ERR(chbs) ? CXL_RESOURCE_NONE : chbs->base;
}
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;
u32 lnkcap, port_num;
int rc;
if (pdev->bus != root_bus)
return 0;
if (!pci_is_pcie(pdev))
return 0;
if (type != PCI_EXP_TYPE_ROOT_PORT)
return 0;
if (pci_read_config_dword(pdev, pci_pcie_cap(pdev) + PCI_EXP_LNKCAP,
&lnkcap) != PCIBIOS_SUCCESSFUL)
return 0;
/* TODO walk DVSEC to find component register base */
port_num = FIELD_GET(PCI_EXP_LNKCAP_PN, lnkcap);
rc = cxl_add_dport(port, &pdev->dev, port_num, CXL_RESOURCE_NONE);
if (rc) {
ctx->error = rc;
return rc;
}
ctx->count++;
dev_dbg(dev, "add dport%d: %s\n", port_num, dev_name(&pdev->dev));
return 0;
}
static struct cxl_dport *find_dport_by_dev(struct cxl_port *port, struct device *dev)
{
struct cxl_dport *dport;
device_lock(&port->dev);
list_for_each_entry(dport, &port->dports, list)
if (dport->dport == dev) {
device_unlock(&port->dev);
return dport;
}
device_unlock(&port->dev);
return NULL;
}
static struct acpi_device *to_cxl_host_bridge(struct device *dev)
{
struct acpi_device *adev = to_acpi_device(dev);
if (strcmp(acpi_device_hid(adev), "ACPI0016") == 0)
return adev;
return NULL;
}
/*
* A host bridge is a dport to a CFMWS decode and it is a uport to the
* dport (PCIe Root Ports) in the host bridge.
*/
static int add_host_bridge_uport(struct device *match, void *arg)
{
struct acpi_device *bridge = to_cxl_host_bridge(match);
struct cxl_port *root_port = arg;
struct device *host = root_port->dev.parent;
struct acpi_pci_root *pci_root;
struct cxl_walk_context ctx;
struct cxl_decoder *cxld;
struct cxl_dport *dport;
struct cxl_port *port;
if (!bridge)
return 0;
pci_root = acpi_pci_find_root(bridge->handle);
if (!pci_root)
return -ENXIO;
dport = find_dport_by_dev(root_port, match);
if (!dport) {
dev_dbg(host, "host bridge expected and not found\n");
return -ENODEV;
}
port = devm_cxl_add_port(host, match, dport->component_reg_phys,
root_port);
if (IS_ERR(port))
return PTR_ERR(port);
dev_dbg(host, "%s: add: %s\n", dev_name(match), dev_name(&port->dev));
ctx = (struct cxl_walk_context){
.dev = host,
.root = pci_root->bus,
.port = port,
};
pci_walk_bus(pci_root->bus, match_add_root_ports, &ctx);
if (ctx.count == 0)
return -ENODEV;
if (ctx.error)
return ctx.error;
/* TODO: Scan CHBCR for HDM Decoder resources */
/*
* In the single-port host-bridge case there are no HDM decoders
* in the CHBCR and a 1:1 passthrough decode is implied.
*/
if (ctx.count == 1) {
cxld = devm_cxl_add_passthrough_decoder(host, port);
if (IS_ERR(cxld))
return PTR_ERR(cxld);
dev_dbg(host, "add: %s\n", dev_name(&cxld->dev));
}
return 0;
}
static int add_host_bridge_dport(struct device *match, void *arg)
{
int rc;
acpi_status status;
unsigned long long uid;
struct acpi_cedt_chbs *chbs;
struct cxl_port *root_port = arg;
struct device *host = root_port->dev.parent;
struct acpi_device *bridge = to_cxl_host_bridge(match);
if (!bridge)
return 0;
status = acpi_evaluate_integer(bridge->handle, METHOD_NAME__UID, NULL,
&uid);
if (status != AE_OK) {
dev_err(host, "unable to retrieve _UID of %s\n",
dev_name(match));
return -ENODEV;
}
chbs = cxl_acpi_match_chbs(host, uid);
if (IS_ERR(chbs))
dev_dbg(host, "No CHBS found for Host Bridge: %s\n",
dev_name(match));
rc = cxl_add_dport(root_port, match, uid, get_chbcr(chbs));
if (rc) {
dev_err(host, "failed to add downstream port: %s\n",
dev_name(match));
return rc;
}
dev_dbg(host, "add dport%llu: %s\n", uid, dev_name(match));
return 0;
}
static int add_root_nvdimm_bridge(struct device *match, void *data)
{
struct cxl_decoder *cxld;
struct cxl_port *root_port = data;
struct cxl_nvdimm_bridge *cxl_nvb;
struct device *host = root_port->dev.parent;
if (!is_root_decoder(match))
return 0;
cxld = to_cxl_decoder(match);
if (!(cxld->flags & CXL_DECODER_F_PMEM))
return 0;
cxl_nvb = devm_cxl_add_nvdimm_bridge(host, root_port);
if (IS_ERR(cxl_nvb)) {
dev_dbg(host, "failed to register pmem\n");
return PTR_ERR(cxl_nvb);
}
dev_dbg(host, "%s: add: %s\n", dev_name(&root_port->dev),
dev_name(&cxl_nvb->dev));
return 1;
}
static int cxl_acpi_probe(struct platform_device *pdev)
{
int rc;
acpi_status status;
struct cxl_port *root_port;
struct device *host = &pdev->dev;
struct acpi_device *adev = ACPI_COMPANION(host);
root_port = devm_cxl_add_port(host, host, CXL_RESOURCE_NONE, NULL);
if (IS_ERR(root_port))
return PTR_ERR(root_port);
dev_dbg(host, "add: %s\n", dev_name(&root_port->dev));
status = acpi_get_table(ACPI_SIG_CEDT, 0, &acpi_cedt);
if (ACPI_FAILURE(status))
return -ENXIO;
rc = bus_for_each_dev(adev->dev.bus, NULL, root_port,
add_host_bridge_dport);
if (rc)
goto out;
cxl_add_cfmws_decoders(host, root_port);
/*
* Root level scanned with host-bridge as dports, now scan host-bridges
* for their role as CXL uports to their CXL-capable PCIe Root Ports.
*/
rc = bus_for_each_dev(adev->dev.bus, NULL, root_port,
add_host_bridge_uport);
if (rc)
goto out;
if (IS_ENABLED(CONFIG_CXL_PMEM))
rc = device_for_each_child(&root_port->dev, root_port,
add_root_nvdimm_bridge);
out:
acpi_put_table(acpi_cedt);
if (rc < 0)
return rc;
return 0;
}
static const struct acpi_device_id cxl_acpi_ids[] = {
{ "ACPI0017", 0 },
{ "", 0 },
};
MODULE_DEVICE_TABLE(acpi, cxl_acpi_ids);
static struct platform_driver cxl_acpi_driver = {
.probe = cxl_acpi_probe,
.driver = {
.name = KBUILD_MODNAME,
.acpi_match_table = cxl_acpi_ids,
},
};
module_platform_driver(cxl_acpi_driver);
MODULE_LICENSE("GPL v2");
MODULE_IMPORT_NS(CXL);