path: root/drivers/cxl/core/cdat.c

// SPDX-License-Identifier: GPL-2.0-only
/* Copyright(c) 2023 Intel Corporation. All rights reserved. */
#include <linux/acpi.h>
#include <linux/xarray.h>
#include <linux/fw_table.h>
#include <linux/node.h>
#include <linux/overflow.h>
#include "cxlpci.h"
#include "cxlmem.h"
#include "core.h"
#include "cxl.h"

struct dsmas_entry {
	struct range dpa_range;
	u8 handle;
	struct access_coordinate coord[ACCESS_COORDINATE_MAX];
	struct access_coordinate cdat_coord[ACCESS_COORDINATE_MAX];
	int entries;
	int qos_class;
};

static u32 cdat_normalize(u16 entry, u64 base, u8 type)
{
	u32 value;

	/*
	 * Check for invalid and overflow values
	 */
	if (entry == 0xffff || !entry)
		return 0;
	else if (base > (UINT_MAX / (entry)))
		return 0;

	/*
	 * CDAT fields follow the format of HMAT fields. See table 5 Device
	 * Scoped Latency and Bandwidth Information Structure in Coherent Device
	 * Attribute Table (CDAT) Specification v1.01.
	 */
	value = entry * base;
	switch (type) {
	case ACPI_HMAT_ACCESS_LATENCY:
	case ACPI_HMAT_READ_LATENCY:
	case ACPI_HMAT_WRITE_LATENCY:
		value = DIV_ROUND_UP(value, 1000);
		break;
	default:
		break;
	}
	return value;
}

static int cdat_dsmas_handler(union acpi_subtable_headers *header, void *arg,
			      const unsigned long end)
{
	struct acpi_cdat_header *hdr = &header->cdat;
	struct acpi_cdat_dsmas *dsmas;
	int size = sizeof(*hdr) + sizeof(*dsmas);
	struct xarray *dsmas_xa = arg;
	struct dsmas_entry *dent;
	u16 len;
	int rc;

	len = le16_to_cpu((__force __le16)hdr->length);
	if (len != size || (unsigned long)hdr + len > end) {
		pr_warn("Malformed DSMAS table length: (%u:%u)\n", size, len);
		return -EINVAL;
	}

	/* Skip common header */
	dsmas = (struct acpi_cdat_dsmas *)(hdr + 1);

	dent = kzalloc(sizeof(*dent), GFP_KERNEL);
	if (!dent)
		return -ENOMEM;

	dent->handle = dsmas->dsmad_handle;
	dent->dpa_range.start = le64_to_cpu((__force __le64)dsmas->dpa_base_address);
	dent->dpa_range.end = le64_to_cpu((__force __le64)dsmas->dpa_base_address) +
			      le64_to_cpu((__force __le64)dsmas->dpa_length) - 1;

	rc = xa_insert(dsmas_xa, dent->handle, dent, GFP_KERNEL);
	if (rc) {
		kfree(dent);
		return rc;
	}

	return 0;
}

static void __cxl_access_coordinate_set(struct access_coordinate *coord,
					int access, unsigned int val)
{
	switch (access) {
	case ACPI_HMAT_ACCESS_LATENCY:
		coord->read_latency = val;
		coord->write_latency = val;
		break;
	case ACPI_HMAT_READ_LATENCY:
		coord->read_latency = val;
		break;
	case ACPI_HMAT_WRITE_LATENCY:
		coord->write_latency = val;
		break;
	case ACPI_HMAT_ACCESS_BANDWIDTH:
		coord->read_bandwidth = val;
		coord->write_bandwidth = val;
		break;
	case ACPI_HMAT_READ_BANDWIDTH:
		coord->read_bandwidth = val;
		break;
	case ACPI_HMAT_WRITE_BANDWIDTH:
		coord->write_bandwidth = val;
		break;
	}
}

static void cxl_access_coordinate_set(struct access_coordinate *coord,
				      int access, unsigned int val)
{
	for (int i = 0; i < ACCESS_COORDINATE_MAX; i++)
		__cxl_access_coordinate_set(&coord[i], access, val);
}

static int cdat_dslbis_handler(union acpi_subtable_headers *header, void *arg,
			       const unsigned long end)
{
	struct acpi_cdat_header *hdr = &header->cdat;
	struct acpi_cdat_dslbis *dslbis;
	int size = sizeof(*hdr) + sizeof(*dslbis);
	struct xarray *dsmas_xa = arg;
	struct dsmas_entry *dent;
	__le64 le_base;
	__le16 le_val;
	u64 val;
	u16 len;

	len = le16_to_cpu((__force __le16)hdr->length);
	if (len != size || (unsigned long)hdr + len > end) {
		pr_warn("Malformed DSLBIS table length: (%u:%u)\n", size, len);
		return -EINVAL;
	}

	/* Skip common header */
	dslbis = (struct acpi_cdat_dslbis *)(hdr + 1);

	/* Skip unrecognized data type */
	if (dslbis->data_type > ACPI_HMAT_WRITE_BANDWIDTH)
		return 0;

	/* Not a memory type, skip */
	if ((dslbis->flags & ACPI_HMAT_MEMORY_HIERARCHY) != ACPI_HMAT_MEMORY)
		return 0;

	dent = xa_load(dsmas_xa, dslbis->handle);
	if (!dent) {
		pr_warn("No matching DSMAS entry for DSLBIS entry.