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linux-stable/drivers/cxl/core/pci.c

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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright(c) 2021 Intel Corporation. All rights reserved. */
#include <linux/io-64-nonatomic-lo-hi.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/pci.h>
#include <linux/pci-doe.h>
#include <cxlpci.h>
#include <cxlmem.h>
#include <cxl.h>
#include "core.h"
#include "trace.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.
*/
static unsigned short media_ready_timeout = 60;
module_param(media_ready_timeout, ushort, 0644);
MODULE_PARM_DESC(media_ready_timeout, "seconds to wait for media ready");
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, map.resource);
if (IS_ERR(dport)) {
ctx->error = PTR_ERR(dport);
return PTR_ERR(dport);
}
ctx->count++;
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);
/*
* Wait up to @media_ready_timeout for the device to report memory
* active.
*/
int cxl_await_media_ready(struct cxl_dev_state *cxlds)
{
struct pci_dev *pdev = to_pci_dev(cxlds->dev);
int d = cxlds->cxl_dvsec;
bool active = false;
u64 md_status;
int rc, i;
for (i = media_ready_timeout; i; i--) {
u32 temp;
rc = pci_read_config_dword(
pdev, d + CXL_DVSEC_RANGE_SIZE_LOW(0), &temp);
if (rc)
return rc;
active = FIELD_GET(CXL_DVSEC_MEM_ACTIVE, temp);
if (active)
break;
msleep(1000);
}
if (!active) {
dev_err(&pdev->dev,
"timeout awaiting memory active after %d seconds\n",
media_ready_timeout);
return -ETIMEDOUT;
}
md_status = readq(cxlds->regs.memdev + CXLMDEV_STATUS_OFFSET);
if (!CXLMDEV_READY(md_status))
return -EIO;
return 0;
}
EXPORT_SYMBOL_NS_GPL(cxl_await_media_ready, CXL);
static int wait_for_valid(struct pci_dev *pdev, int d)
{
u32 val;
int rc;
/*
* Memory_Info_Valid: When set, indicates that the CXL Range 1 Size high
* and Size Low registers are valid. Must be set within 1 second of
* deassertion of reset to CXL device. Likely it is already set by the
* time this runs, but otherwise give a 1.5 second timeout in case of
* clock skew.
*/
rc = pci_read_config_dword(pdev, d + CXL_DVSEC_RANGE_SIZE_LOW(0), &val);
if (rc)
return rc;
if (val & CXL_DVSEC_MEM_INFO_VALID)
return 0;
msleep(1500);
rc = pci_read_config_dword(pdev, d + CXL_DVSEC_RANGE_SIZE_LOW(0), &val);
if (rc)
return rc;
if (val & CXL_DVSEC_MEM_INFO_VALID)
return 0;
return -ETIMEDOUT;
}
static int cxl_set_mem_enable(struct cxl_dev_state *cxlds, u16 val)
{
struct pci_dev *pdev = to_pci_dev(cxlds->dev);
int d = cxlds->cxl_dvsec;
u16 ctrl;
int rc;
rc = pci_read_config_word(pdev, d + CXL_DVSEC_CTRL_OFFSET, &ctrl);
if (rc < 0)
return rc;
if ((ctrl & CXL_DVSEC_MEM_ENABLE) == val)
return 1;
ctrl &= ~CXL_DVSEC_MEM_ENABLE;
ctrl |= val;
rc = pci_write_config_word(pdev, d + CXL_DVSEC_CTRL_OFFSET, ctrl);
if (rc < 0)
return rc;
return 0;
}
static void clear_mem_enable(void *cxlds)
{
cxl_set_mem_enable(cxlds, 0);
}
static int devm_cxl_enable_mem(struct device *host, struct cxl_dev_state *cxlds)
{
int rc;
rc = cxl_set_mem_enable(cxlds, CXL_DVSEC_MEM_ENABLE);
if (rc < 0)
return rc;
if (rc > 0)
return 0;
return devm_add_action_or_reset(host, clear_mem_enable, cxlds);
}
/* require dvsec ranges to be covered by a locked platform window */
static int dvsec_range_allowed(struct device *dev, void *arg)
{
struct range *dev_range = arg;
struct cxl_decoder *cxld;
if (!is_root_decoder(dev))
return 0;
cxld = to_cxl_decoder(dev);
if (!(cxld->flags & CXL_DECODER_F_RAM))
return 0;
return range_contains(&cxld->hpa_range, dev_range);
}
static void disable_hdm(void *_cxlhdm)
{
u32 global_ctrl;
struct cxl_hdm *cxlhdm = _cxlhdm;
void __iomem *hdm = cxlhdm->regs.hdm_decoder;
global_ctrl = readl(hdm + CXL_HDM_DECODER_CTRL_OFFSET);
writel(global_ctrl & ~CXL_HDM_DECODER_ENABLE,
hdm + CXL_HDM_DECODER_CTRL_OFFSET);
}
static int devm_cxl_enable_hdm(struct device *host, struct cxl_hdm *cxlhdm)
{
void __iomem *hdm = cxlhdm->regs.hdm_decoder;
u32 global_ctrl;
global_ctrl = readl(hdm + CXL_HDM_DECODER_CTRL_OFFSET);
writel(global_ctrl | CXL_HDM_DECODER_ENABLE,
hdm + CXL_HDM_DECODER_CTRL_OFFSET);
return devm_add_action_or_reset(host, disable_hdm, cxlhdm);
}
int cxl_dvsec_rr_decode(struct device *dev, int d,
struct cxl_endpoint_dvsec_info *info)
{
struct pci_dev *pdev = to_pci_dev(dev);
int hdm_count, rc, i, ranges = 0;
u16 cap, ctrl;
if (!d) {
dev_dbg(dev, "No DVSEC Capability\n");
return -ENXIO;
}
rc = pci_read_config_word(pdev, d + CXL_DVSEC_CAP_OFFSET, &cap);
if (rc)
return rc;
rc = pci_read_config_word(pdev, d + CXL_DVSEC_CTRL_OFFSET, &ctrl);
if (rc)
return rc;
if (!(cap & CXL_DVSEC_MEM_CAPABLE)) {
dev_dbg(dev, "Not MEM Capable\n");
return -ENXIO;
}
/*
* It is not allowed by spec for MEM.capable to be set and have 0 legacy
* HDM decoders (values > 2 are also undefined as of CXL 2.0). As this
* driver is for a spec defined class code which must be CXL.mem
* capable, there is no point in continuing to enable CXL.mem.
*/
hdm_count = FIELD_GET(CXL_DVSEC_HDM_COUNT_MASK, cap);
if (!hdm_count || hdm_count > 2)
return -EINVAL;
rc = wait_for_valid(pdev, d);
if (rc) {
dev_dbg(dev, "Failure awaiting MEM_INFO_VALID (%d)\n", rc);
return rc;
}
/*
* The current DVSEC values are moot if the memory capability is
* disabled, and they will remain moot after the HDM Decoder
* capability is enabled.
*/
info->mem_enabled = FIELD_GET(CXL_DVSEC_MEM_ENABLE, ctrl);
if (!info->mem_enabled)
return 0;
for (i = 0; i < hdm_count; i++) {
u64 base, size;
u32 temp;
rc = pci_read_config_dword(
pdev, d + CXL_DVSEC_RANGE_SIZE_HIGH(i), &temp);
if (rc)
return rc;
size = (u64)temp << 32;
rc = pci_read_config_dword(
pdev, d + CXL_DVSEC_RANGE_SIZE_LOW(i), &temp);
if (rc)
return rc;
size |= temp & CXL_DVSEC_MEM_SIZE_LOW_MASK;
if (!size) {
info->dvsec_range[i] = (struct range) {
.start = 0,
.end = CXL_RESOURCE_NONE,
};
continue;
}
rc = pci_read_config_dword(
pdev, d + CXL_DVSEC_RANGE_BASE_HIGH(i), &temp);
if (rc)
return rc;
base = (u64)temp << 32;
rc = pci_read_config_dword(
pdev, d + CXL_DVSEC_RANGE_BASE_LOW(i), &temp);
if (rc)
return rc;
base |= temp & CXL_DVSEC_MEM_BASE_LOW_MASK;
info->dvsec_range[i] = (struct range) {
.start = base,
.end = base + size - 1
};
ranges++;
}
info->ranges = ranges;
return 0;
}
EXPORT_SYMBOL_NS_GPL(cxl_dvsec_rr_decode, CXL);
/**
* cxl_hdm_decode_init() - Setup HDM decoding for the endpoint
* @cxlds: Device state
* @cxlhdm: Mapped HDM decoder Capability
* @info: Cached DVSEC range registers info
*
* Try to enable the endpoint's HDM Decoder Capability
*/
int cxl_hdm_decode_init(struct cxl_dev_state *cxlds, struct cxl_hdm *cxlhdm,
struct cxl_endpoint_dvsec_info *info)
{
void __iomem *hdm = cxlhdm->regs.hdm_decoder;
struct cxl_port *port = cxlhdm->port;
struct device *dev = cxlds->dev;
struct cxl_port *root;
int i, rc, allowed;
u32 global_ctrl = 0;
if (hdm)
global_ctrl = readl(hdm + CXL_HDM_DECODER_CTRL_OFFSET);
/*
* If the HDM Decoder Capability is already enabled then assume
* that some other agent like platform firmware set it up.
*/
if (global_ctrl & CXL_HDM_DECODER_ENABLE || (!hdm && info->mem_enabled))
return devm_cxl_enable_mem(&port->dev, cxlds);
else if (!hdm)
return -ENODEV;
root = to_cxl_port(port->dev.parent);
while (!is_cxl_root(root) && is_cxl_port(root->dev.parent))
root = to_cxl_port(root->dev.parent);
if (!is_cxl_root(root)) {
dev_err(dev, "Failed to acquire root port for HDM enable\n");
return -ENODEV;
}
for (i = 0, allowed = 0; info->mem_enabled && i < info->ranges; i++) {
struct device *cxld_dev;
cxld_dev = device_find_child(&root->dev, &info->dvsec_range[i],
dvsec_range_allowed);
if (!cxld_dev) {
dev_dbg(dev, "DVSEC Range%d denied by platform\n", i);
continue;
}
dev_dbg(dev, "DVSEC Range%d allowed by platform\n", i);
put_device(cxld_dev);
allowed++;
}
if (!allowed) {
cxl_set_mem_enable(cxlds, 0);
info->mem_enabled = 0;
}
/*
* Per CXL 2.0 Section 8.1.3.8.3 and 8.1.3.8.4 DVSEC CXL Range 1 Base
* [High,Low] when HDM operation is enabled the range register values
* are ignored by the device, but the spec also recommends matching the
* DVSEC Range 1,2 to HDM Decoder Range 0,1. So, non-zero info->ranges
* are expected even though Linux does not require or maintain that
* match. If at least one DVSEC range is enabled and allowed, skip HDM
* Decoder Capability Enable.
*/
if (info->mem_enabled)
return 0;
rc = devm_cxl_enable_hdm(&port->dev, cxlhdm);
if (rc)
return rc;
return devm_cxl_enable_mem(&port->dev, cxlds);
}
EXPORT_SYMBOL_NS_GPL(cxl_hdm_decode_init, CXL);
#define CXL_DOE_TABLE_ACCESS_REQ_CODE 0x000000ff
#define CXL_DOE_TABLE_ACCESS_REQ_CODE_READ 0
#define CXL_DOE_TABLE_ACCESS_TABLE_TYPE 0x0000ff00
#define CXL_DOE_TABLE_ACCESS_TABLE_TYPE_CDATA 0
#define CXL_DOE_TABLE_ACCESS_ENTRY_HANDLE 0xffff0000
#define CXL_DOE_TABLE_ACCESS_LAST_ENTRY 0xffff
#define CXL_DOE_PROTOCOL_TABLE_ACCESS 2
#define CDAT_DOE_REQ(entry_handle) cpu_to_le32 \
(FIELD_PREP(CXL_DOE_TABLE_ACCESS_REQ_CODE, \
CXL_DOE_TABLE_ACCESS_REQ_CODE_READ) | \
FIELD_PREP(CXL_DOE_TABLE_ACCESS_TABLE_TYPE, \
CXL_DOE_TABLE_ACCESS_TABLE_TYPE_CDATA) | \
FIELD_PREP(CXL_DOE_TABLE_ACCESS_ENTRY_HANDLE, (entry_handle)))
static int cxl_cdat_get_length(struct device *dev,
struct pci_doe_mb *cdat_doe,
size_t *length)
{
__le32 request = CDAT_DOE_REQ(0);
__le32 response[2];
int rc;
rc = pci_doe(cdat_doe, PCI_DVSEC_VENDOR_ID_CXL,
CXL_DOE_PROTOCOL_TABLE_ACCESS,
&request, sizeof(request),
&response, sizeof(response));
if (rc < 0) {
dev_err(dev, "DOE failed: %d", rc);
return rc;
}
if (rc < sizeof(response))
return -EIO;
*length = le32_to_cpu(response[1]);
dev_dbg(dev, "CDAT length %zu\n", *length);
return 0;
}
static int cxl_cdat_read_table(struct device *dev,
struct pci_doe_mb *cdat_doe,
void *cdat_table, size_t *cdat_length)
{
size_t length = *cdat_length + sizeof(__le32);
__le32 *data = cdat_table;
int entry_handle = 0;
__le32 saved_dw = 0;
do {
__le32 request = CDAT_DOE_REQ(entry_handle);
struct cdat_entry_header *entry;
size_t entry_dw;
int rc;
rc = pci_doe(cdat_doe, PCI_DVSEC_VENDOR_ID_CXL,
CXL_DOE_PROTOCOL_TABLE_ACCESS,
&request, sizeof(request),
data, length);
if (rc < 0) {
dev_err(dev, "DOE failed: %d", rc);
return rc;
}
/* 1 DW Table Access Response Header + CDAT entry */
entry = (struct cdat_entry_header *)(data + 1);
if ((entry_handle == 0 &&
rc != sizeof(__le32) + sizeof(struct cdat_header)) ||
(entry_handle > 0 &&
(rc < sizeof(__le32) + sizeof(*entry) ||
rc != sizeof(__le32) + le16_to_cpu(entry->length))))
return -EIO;
/* Get the CXL table access header entry handle */
entry_handle = FIELD_GET(CXL_DOE_TABLE_ACCESS_ENTRY_HANDLE,
le32_to_cpu(data[0]));
entry_dw = rc / sizeof(__le32);
/* Skip Header */
entry_dw -= 1;
/*
* Table Access Response Header overwrote the last DW of
* previous entry, so restore that DW
*/
*data = saved_dw;
length -= entry_dw * sizeof(__le32);
data += entry_dw;
saved_dw = *data;
} while (entry_handle != CXL_DOE_TABLE_ACCESS_LAST_ENTRY);
/* Length in CDAT header may exceed concatenation of CDAT entries */
*cdat_length -= length - sizeof(__le32);
return 0;
}
/**
* read_cdat_data - Read the CDAT data on this port
* @port: Port to read data from
*
* This call will sleep waiting for responses from the DOE mailbox.
*/
void read_cdat_data(struct cxl_port *port)
{
struct cxl_memdev *cxlmd = to_cxl_memdev(port->uport);
struct device *host = cxlmd->dev.parent;
struct device *dev = &port->dev;
struct pci_doe_mb *cdat_doe;
size_t cdat_length;
void *cdat_table;
int rc;
if (!dev_is_pci(host))
return;
cdat_doe = pci_find_doe_mailbox(to_pci_dev(host),
PCI_DVSEC_VENDOR_ID_CXL,
CXL_DOE_PROTOCOL_TABLE_ACCESS);
if (!cdat_doe) {
dev_dbg(dev, "No CDAT mailbox\n");
return;
}
port->cdat_available = true;
if (cxl_cdat_get_length(dev, cdat_doe, &cdat_length)) {
dev_dbg(dev, "No CDAT length\n");
return;
}
cdat_table = devm_kzalloc(dev, cdat_length + sizeof(__le32),
GFP_KERNEL);
if (!cdat_table)
return;
rc = cxl_cdat_read_table(dev, cdat_doe, cdat_table, &cdat_length);
if (rc) {
/* Don't leave table data allocated on error */
devm_kfree(dev, cdat_table);
dev_err(dev, "CDAT data read error\n");
}
port->cdat.table = cdat_table + sizeof(__le32);
port->cdat.length = cdat_length;
}
EXPORT_SYMBOL_NS_GPL(read_cdat_data, CXL);
void cxl_cor_error_detected(struct pci_dev *pdev)
{
struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);
void __iomem *addr;
u32 status;
if (!cxlds->regs.ras)
return;
addr = cxlds->regs.ras + CXL_RAS_CORRECTABLE_STATUS_OFFSET;
status = readl(addr);
if (status & CXL_RAS_CORRECTABLE_STATUS_MASK) {
writel(status & CXL_RAS_CORRECTABLE_STATUS_MASK, addr);
trace_cxl_aer_correctable_error(cxlds->cxlmd, status);
}
}
EXPORT_SYMBOL_NS_GPL(cxl_cor_error_detected, CXL);
/* CXL spec rev3.0 8.2.4.16.1 */
static void header_log_copy(struct cxl_dev_state *cxlds, u32 *log)
{
void __iomem *addr;
u32 *log_addr;
int i, log_u32_size = CXL_HEADERLOG_SIZE / sizeof(u32);
addr = cxlds->regs.ras + CXL_RAS_HEADER_LOG_OFFSET;
log_addr = log;
for (i = 0; i < log_u32_size; i++) {
*log_addr = readl(addr);
log_addr++;
addr += sizeof(u32);
}
}
/*
* Log the state of the RAS status registers and prepare them to log the
* next error status. Return 1 if reset needed.
*/
static bool cxl_report_and_clear(struct cxl_dev_state *cxlds)
{
u32 hl[CXL_HEADERLOG_SIZE_U32];
void __iomem *addr;
u32 status;
u32 fe;
if (!cxlds->regs.ras)
return false;
addr = cxlds->regs.ras + CXL_RAS_UNCORRECTABLE_STATUS_OFFSET;
status = readl(addr);
if (!(status & CXL_RAS_UNCORRECTABLE_STATUS_MASK))
return false;
/* If multiple errors, log header points to first error from ctrl reg */
if (hweight32(status) > 1) {
void __iomem *rcc_addr =
cxlds->regs.ras + CXL_RAS_CAP_CONTROL_OFFSET;
fe = BIT(FIELD_GET(CXL_RAS_CAP_CONTROL_FE_MASK,
readl(rcc_addr)));
} else {
fe = status;
}
header_log_copy(cxlds, hl);
trace_cxl_aer_uncorrectable_error(cxlds->cxlmd, status, fe, hl);
writel(status & CXL_RAS_UNCORRECTABLE_STATUS_MASK, addr);
return true;
}
pci_ers_result_t cxl_error_detected(struct pci_dev *pdev,
pci_channel_state_t state)
{
struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);
struct cxl_memdev *cxlmd = cxlds->cxlmd;
struct device *dev = &cxlmd->dev;
bool ue;
/*
* A frozen channel indicates an impending reset which is fatal to
* CXL.mem operation, and will likely crash the system. On the off
* chance the situation is recoverable dump the status of the RAS
* capability registers and bounce the active state of the memdev.
*/
ue = cxl_report_and_clear(cxlds);
switch (state) {
case pci_channel_io_normal:
if (ue) {
device_release_driver(dev);
return PCI_ERS_RESULT_NEED_RESET;
}
return PCI_ERS_RESULT_CAN_RECOVER;
case pci_channel_io_frozen:
dev_warn(&pdev->dev,
"%s: frozen state error detected, disable CXL.mem\n",
dev_name(dev));
device_release_driver(dev);
return PCI_ERS_RESULT_NEED_RESET;
case pci_channel_io_perm_failure:
dev_warn(&pdev->dev,
"failure state error detected, request disconnect\n");
return PCI_ERS_RESULT_DISCONNECT;
}
return PCI_ERS_RESULT_NEED_RESET;
}
EXPORT_SYMBOL_NS_GPL(cxl_error_detected, CXL);
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