diff options
Diffstat (limited to 'drivers/cxl/core/regs.c')
| -rw-r--r-- | drivers/cxl/core/regs.c | 304 |
1 files changed, 304 insertions, 0 deletions
diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c new file mode 100644 index 000000000..39a129c57 --- /dev/null +++ b/drivers/cxl/core/regs.c @@ -0,0 +1,304 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright(c) 2020 Intel Corporation. */ +#include <linux/io-64-nonatomic-lo-hi.h> +#include <linux/device.h> +#include <linux/slab.h> +#include <linux/pci.h> +#include <cxlmem.h> +#include <cxlpci.h> + +/** + * DOC: cxl registers + * + * CXL device capabilities are enumerated by PCI DVSEC (Designated + * Vendor-specific) and / or descriptors provided by platform firmware. + * They can be defined as a set like the device and component registers + * mandated by CXL Section 8.1.12.2 Memory Device PCIe Capabilities and + * Extended Capabilities, or they can be individual capabilities + * appended to bridged and endpoint devices. + * + * Provide common infrastructure for enumerating and mapping these + * discrete capabilities. + */ + +/** + * cxl_probe_component_regs() - Detect CXL Component register blocks + * @dev: Host device of the @base mapping + * @base: Mapping containing the HDM Decoder Capability Header + * @map: Map object describing the register block information found + * + * See CXL 2.0 8.2.4 Component Register Layout and Definition + * See CXL 2.0 8.2.5.5 CXL Device Register Interface + * + * Probe for component register information and return it in map object. + */ +void cxl_probe_component_regs(struct device *dev, void __iomem *base, + struct cxl_component_reg_map *map) +{ + int cap, cap_count; + u32 cap_array; + + *map = (struct cxl_component_reg_map) { 0 }; + + /* + * CXL.cache and CXL.mem registers are at offset 0x1000 as defined in + * CXL 2.0 8.2.4 Table 141. + */ + base += CXL_CM_OFFSET; + + cap_array = readl(base + CXL_CM_CAP_HDR_OFFSET); + + if (FIELD_GET(CXL_CM_CAP_HDR_ID_MASK, cap_array) != CM_CAP_HDR_CAP_ID) { + dev_err(dev, + "Couldn't locate the CXL.cache and CXL.mem capability array header.\n"); + return; + } + + /* It's assumed that future versions will be backward compatible */ + cap_count = FIELD_GET(CXL_CM_CAP_HDR_ARRAY_SIZE_MASK, cap_array); + + for (cap = 1; cap <= cap_count; cap++) { + void __iomem *register_block; + u32 hdr; + int decoder_cnt; + u16 cap_id, offset; + u32 length; + + hdr = readl(base + cap * 0x4); + + cap_id = FIELD_GET(CXL_CM_CAP_HDR_ID_MASK, hdr); + offset = FIELD_GET(CXL_CM_CAP_PTR_MASK, hdr); + register_block = base + offset; + + switch (cap_id) { + case CXL_CM_CAP_CAP_ID_HDM: + dev_dbg(dev, "found HDM decoder capability (0x%x)\n", + offset); + + hdr = readl(register_block); + + decoder_cnt = cxl_hdm_decoder_count(hdr); + length = 0x20 * decoder_cnt + 0x10; + + map->hdm_decoder.valid = true; + map->hdm_decoder.offset = CXL_CM_OFFSET + offset; + map->hdm_decoder.size = length; + break; + default: + dev_dbg(dev, "Unknown CM cap ID: %d (0x%x)\n", cap_id, + offset); + break; + } + } +} +EXPORT_SYMBOL_NS_GPL(cxl_probe_component_regs, CXL); + +/** + * cxl_probe_device_regs() - Detect CXL Device register blocks + * @dev: Host device of the @base mapping + * @base: Mapping of CXL 2.0 8.2.8 CXL Device Register Interface + * @map: Map object describing the register block information found + * + * Probe for device register information and return it in map object. + */ +void cxl_probe_device_regs(struct device *dev, void __iomem *base, + struct cxl_device_reg_map *map) +{ + int cap, cap_count; + u64 cap_array; + + *map = (struct cxl_device_reg_map){ 0 }; + + cap_array = readq(base + CXLDEV_CAP_ARRAY_OFFSET); + if (FIELD_GET(CXLDEV_CAP_ARRAY_ID_MASK, cap_array) != + CXLDEV_CAP_ARRAY_CAP_ID) + return; + + cap_count = FIELD_GET(CXLDEV_CAP_ARRAY_COUNT_MASK, cap_array); + + for (cap = 1; cap <= cap_count; cap++) { + u32 offset, length; + u16 cap_id; + + cap_id = FIELD_GET(CXLDEV_CAP_HDR_CAP_ID_MASK, + readl(base + cap * 0x10)); + offset = readl(base + cap * 0x10 + 0x4); + length = readl(base + cap * 0x10 + 0x8); + + switch (cap_id) { + case CXLDEV_CAP_CAP_ID_DEVICE_STATUS: + dev_dbg(dev, "found Status capability (0x%x)\n", offset); + + map->status.valid = true; + map->status.offset = offset; + map->status.size = length; + break; + case CXLDEV_CAP_CAP_ID_PRIMARY_MAILBOX: + dev_dbg(dev, "found Mailbox capability (0x%x)\n", offset); + map->mbox.valid = true; + map->mbox.offset = offset; + map->mbox.size = length; + break; + case CXLDEV_CAP_CAP_ID_SECONDARY_MAILBOX: + dev_dbg(dev, "found Secondary Mailbox capability (0x%x)\n", offset); + break; + case CXLDEV_CAP_CAP_ID_MEMDEV: + dev_dbg(dev, "found Memory Device capability (0x%x)\n", offset); + map->memdev.valid = true; + map->memdev.offset = offset; + map->memdev.size = length; + break; + default: + if (cap_id >= 0x8000) + dev_dbg(dev, "Vendor cap ID: %#x offset: %#x\n", cap_id, offset); + else + dev_dbg(dev, "Unknown cap ID: %#x offset: %#x\n", cap_id, offset); + break; + } + } +} +EXPORT_SYMBOL_NS_GPL(cxl_probe_device_regs, CXL); + +void __iomem *devm_cxl_iomap_block(struct device *dev, resource_size_t addr, + resource_size_t length) +{ + void __iomem *ret_val; + struct resource *res; + + res = devm_request_mem_region(dev, addr, length, dev_name(dev)); + if (!res) { + resource_size_t end = addr + length - 1; + + dev_err(dev, "Failed to request region %pa-%pa\n", &addr, &end); + return NULL; + } + + ret_val = devm_ioremap(dev, addr, length); + if (!ret_val) + dev_err(dev, "Failed to map region %pr\n", res); + + return ret_val; +} + +int cxl_map_component_regs(struct pci_dev *pdev, + struct cxl_component_regs *regs, + struct cxl_register_map *map) +{ + struct device *dev = &pdev->dev; + resource_size_t phys_addr; + resource_size_t length; + + phys_addr = pci_resource_start(pdev, map->barno); + phys_addr += map->block_offset; + + phys_addr += map->component_map.hdm_decoder.offset; + length = map->component_map.hdm_decoder.size; + regs->hdm_decoder = devm_cxl_iomap_block(dev, phys_addr, length); + if (!regs->hdm_decoder) + return -ENOMEM; + + return 0; +} +EXPORT_SYMBOL_NS_GPL(cxl_map_component_regs, CXL); + +int cxl_map_device_regs(struct pci_dev *pdev, + struct cxl_device_regs *regs, + struct cxl_register_map *map) +{ + struct device *dev = &pdev->dev; + resource_size_t phys_addr; + + phys_addr = pci_resource_start(pdev, map->barno); + phys_addr += map->block_offset; + + if (map->device_map.status.valid) { + resource_size_t addr; + resource_size_t length; + + addr = phys_addr + map->device_map.status.offset; + length = map->device_map.status.size; + regs->status = devm_cxl_iomap_block(dev, addr, length); + if (!regs->status) + return -ENOMEM; + } + + if (map->device_map.mbox.valid) { + resource_size_t addr; + resource_size_t length; + + addr = phys_addr + map->device_map.mbox.offset; + length = map->device_map.mbox.size; + regs->mbox = devm_cxl_iomap_block(dev, addr, length); + if (!regs->mbox) + return -ENOMEM; + } + + if (map->device_map.memdev.valid) { + resource_size_t addr; + resource_size_t length; + + addr = phys_addr + map->device_map.memdev.offset; + length = map->device_map.memdev.size; + regs->memdev = devm_cxl_iomap_block(dev, addr, length); + if (!regs->memdev) + return -ENOMEM; + } + + return 0; +} +EXPORT_SYMBOL_NS_GPL(cxl_map_device_regs, CXL); + +static void cxl_decode_regblock(u32 reg_lo, u32 reg_hi, + struct cxl_register_map *map) +{ + map->block_offset = ((u64)reg_hi << 32) | + (reg_lo & CXL_DVSEC_REG_LOCATOR_BLOCK_OFF_LOW_MASK); + map->barno = FIELD_GET(CXL_DVSEC_REG_LOCATOR_BIR_MASK, reg_lo); + map->reg_type = FIELD_GET(CXL_DVSEC_REG_LOCATOR_BLOCK_ID_MASK, reg_lo); +} + +/** + * cxl_find_regblock() - Locate register blocks by type + * @pdev: The CXL PCI device to enumerate. + * @type: Register Block Indicator id + * @map: Enumeration output, clobbered on error + * + * Return: 0 if register block enumerated, negative error code otherwise + * + * A CXL DVSEC may point to one or more register blocks, search for them + * by @type. + */ +int cxl_find_regblock(struct pci_dev *pdev, enum cxl_regloc_type type, + struct cxl_register_map *map) +{ + u32 regloc_size, regblocks; + int regloc, i; + + map->block_offset = U64_MAX; + regloc = pci_find_dvsec_capability(pdev, PCI_DVSEC_VENDOR_ID_CXL, + CXL_DVSEC_REG_LOCATOR); + if (!regloc) + return -ENXIO; + + pci_read_config_dword(pdev, regloc + PCI_DVSEC_HEADER1, ®loc_size); + regloc_size = FIELD_GET(PCI_DVSEC_HEADER1_LENGTH_MASK, regloc_size); + + regloc += CXL_DVSEC_REG_LOCATOR_BLOCK1_OFFSET; + regblocks = (regloc_size - CXL_DVSEC_REG_LOCATOR_BLOCK1_OFFSET) / 8; + + for (i = 0; i < regblocks; i++, regloc += 8) { + u32 reg_lo, reg_hi; + + pci_read_config_dword(pdev, regloc, ®_lo); + pci_read_config_dword(pdev, regloc + 4, ®_hi); + + cxl_decode_regblock(reg_lo, reg_hi, map); + + if (map->reg_type == type) + return 0; + } + + map->block_offset = U64_MAX; + return -ENODEV; +} +EXPORT_SYMBOL_NS_GPL(cxl_find_regblock, CXL); |