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-rw-r--r--drivers/cxl/core/regs.c304
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, &regloc_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, &reg_lo);
+ pci_read_config_dword(pdev, regloc + 4, &reg_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);