diff options
Diffstat (limited to 'drivers/cxl/core/atl.c')
| -rw-r--r-- | drivers/cxl/core/atl.c | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/drivers/cxl/core/atl.c b/drivers/cxl/core/atl.c new file mode 100644 index 000000000000..310668786189 --- /dev/null +++ b/drivers/cxl/core/atl.c @@ -0,0 +1,211 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2025 Advanced Micro Devices, Inc. + */ + +#include <linux/prmt.h> +#include <linux/pci.h> +#include <linux/acpi.h> + +#include <cxlmem.h> +#include "core.h" + +/* + * PRM Address Translation - CXL DPA to System Physical Address + * + * Reference: + * + * AMD Family 1Ah Models 00h–0Fh and Models 10h–1Fh + * ACPI v6.5 Porting Guide, Publication # 58088 + */ + +static const guid_t prm_cxl_dpa_spa_guid = + GUID_INIT(0xee41b397, 0x25d4, 0x452c, 0xad, 0x54, 0x48, 0xc6, 0xe3, + 0x48, 0x0b, 0x94); + +struct prm_cxl_dpa_spa_data { + u64 dpa; + u8 reserved; + u8 devfn; + u8 bus; + u8 segment; + u64 *spa; +} __packed; + +static u64 prm_cxl_dpa_spa(struct pci_dev *pci_dev, u64 dpa) +{ + struct prm_cxl_dpa_spa_data data; + u64 spa; + int rc; + + data = (struct prm_cxl_dpa_spa_data) { + .dpa = dpa, + .devfn = pci_dev->devfn, + .bus = pci_dev->bus->number, + .segment = pci_domain_nr(pci_dev->bus), + .spa = &spa, + }; + + rc = acpi_call_prm_handler(prm_cxl_dpa_spa_guid, &data); + if (rc) { + pci_dbg(pci_dev, "failed to get SPA for %#llx: %d\n", dpa, rc); + return ULLONG_MAX; + } + + pci_dbg(pci_dev, "PRM address translation: DPA -> SPA: %#llx -> %#llx\n", dpa, spa); + + return spa; +} + +static int cxl_prm_setup_root(struct cxl_root *cxl_root, void *data) +{ + struct cxl_region_context *ctx = data; + struct cxl_endpoint_decoder *cxled = ctx->cxled; + struct cxl_decoder *cxld = &cxled->cxld; + struct cxl_memdev *cxlmd = cxled_to_memdev(cxled); + struct range hpa_range = ctx->hpa_range; + struct pci_dev *pci_dev; + u64 spa_len, len; + u64 addr, base_spa, base; + int ways, gran; + + /* + * When Normalized Addressing is enabled, the endpoint maintains a 1:1 + * mapping between HPA and DPA. If disabled, skip address translation + * and perform only a range check. + */ + if (hpa_range.start != cxled->dpa_res->start) + return 0; + + /* + * Endpoints are programmed passthrough in Normalized Addressing mode. + */ + if (ctx->interleave_ways != 1) { + dev_dbg(&cxld->dev, "unexpected interleaving config: ways: %d granularity: %d\n", + ctx->interleave_ways, ctx->interleave_granularity); + return -ENXIO; + } + + if (!cxlmd || !dev_is_pci(cxlmd->dev.parent)) { + dev_dbg(&cxld->dev, "No endpoint found: %s, range %#llx-%#llx\n", + dev_name(cxld->dev.parent), hpa_range.start, + hpa_range.end); + return -ENXIO; + } + + pci_dev = to_pci_dev(cxlmd->dev.parent); + + /* Translate HPA range to SPA. */ + base = hpa_range.start; + hpa_range.start = prm_cxl_dpa_spa(pci_dev, hpa_range.start); + hpa_range.end = prm_cxl_dpa_spa(pci_dev, hpa_range.end); + base_spa = hpa_range.start; + + if (hpa_range.start == ULLONG_MAX || hpa_range.end == ULLONG_MAX) { + dev_dbg(cxld->dev.parent, + "CXL address translation: Failed to translate HPA range: %#llx-%#llx:%#llx-%#llx(%s)\n", + hpa_range.start, hpa_range.end, ctx->hpa_range.start, + ctx->hpa_range.end, dev_name(&cxld->dev)); + return -ENXIO; + } + + /* + * Since translated addresses include the interleaving offsets, align + * the range to 256 MB. + */ + hpa_range.start = ALIGN_DOWN(hpa_range.start, SZ_256M); + hpa_range.end = ALIGN(hpa_range.end, SZ_256M) - 1; + + len = range_len(&ctx->hpa_range); + spa_len = range_len(&hpa_range); + if (!len || !spa_len || spa_len % len) { + dev_dbg(cxld->dev.parent, + "CXL address translation: HPA range not contiguous: %#llx-%#llx:%#llx-%#llx(%s)\n", + hpa_range.start, hpa_range.end, ctx->hpa_range.start, + ctx->hpa_range.end, dev_name(&cxld->dev)); + return -ENXIO; + } + + ways = spa_len / len; + gran = SZ_256; + + /* + * Determine interleave granularity + * + * Note: The position of the chunk from one interleaving block to the + * next may vary and thus cannot be considered constant. Address offsets + * larger than the interleaving block size cannot be used to calculate + * the granularity. + */ + if (ways > 1) { + while (gran <= SZ_16M) { + addr = prm_cxl_dpa_spa(pci_dev, base + gran); + if (addr != base_spa + gran) + break; + gran <<= 1; + } + } + + if (gran > SZ_16M) { + dev_dbg(cxld->dev.parent, + "CXL address translation: Cannot determine granularity: %#llx-%#llx:%#llx-%#llx(%s)\n", + hpa_range.start, hpa_range.end, ctx->hpa_range.start, + ctx->hpa_range.end, dev_name(&cxld->dev)); + return -ENXIO; + } + + /* + * The current kernel implementation does not support endpoint + * setup with Normalized Addressing. It only translates an + * endpoint's DPA to the SPA range of the host bridge. + * Therefore, the endpoint address range cannot be determined, + * making a non-auto setup impossible. If a decoder requires + * address translation, reprogramming should be disabled and + * the decoder locked. + * + * The BIOS, however, provides all the necessary address + * translation data, which the kernel can use to reconfigure + * endpoint decoders with normalized addresses. Locking the + * decoders in the BIOS would prevent a capable kernel (or + * other operating systems) from shutting down auto-generated + * regions and managing resources dynamically. + * + * Indicate that Normalized Addressing is enabled. + */ + cxld->flags |= CXL_DECODER_F_LOCK; + cxld->flags |= CXL_DECODER_F_NORMALIZED_ADDRESSING; + + ctx->hpa_range = hpa_range; + ctx->interleave_ways = ways; + ctx->interleave_granularity = gran; + + dev_dbg(&cxld->dev, + "address mapping found for %s (hpa -> spa): %#llx+%#llx -> %#llx+%#llx ways:%d granularity:%d\n", + dev_name(cxlmd->dev.parent), base, len, hpa_range.start, + spa_len, ways, gran); + + return 0; +} + +void cxl_setup_prm_address_translation(struct cxl_root *cxl_root) +{ + struct device *host = cxl_root->port.uport_dev; + u64 spa; + struct prm_cxl_dpa_spa_data data = { .spa = &spa }; + int rc; + + /* + * Applies only to PCIe Host Bridges which are children of the CXL Root + * Device (HID=“ACPI0017”). Check this and drop cxl_test instances. + */ + if (!acpi_match_device(host->driver->acpi_match_table, host)) + return; + + /* Check kernel (-EOPNOTSUPP) and firmware support (-ENODEV) */ + rc = acpi_call_prm_handler(prm_cxl_dpa_spa_guid, &data); + if (rc == -EOPNOTSUPP || rc == -ENODEV) + return; + + cxl_root->ops.translation_setup_root = cxl_prm_setup_root; +} +EXPORT_SYMBOL_NS_GPL(cxl_setup_prm_address_translation, "CXL"); |