cxl/pci: Split cxl_pci_setup_regs()

In preparation for moving parts of register mapping to cxl_core, split
cxl_pci_setup_regs() into a helper that finds register blocks,
(cxl_find_regblock()), and a generic wrapper that probes the precise
register sets within a block (cxl_setup_regs()).

Move the actual mapping (cxl_map_regs()) of the only register-set that
cxl_pci cares about (memory device registers) up a level from the former
cxl_pci_setup_regs() into cxl_pci_probe().

With this change the unused component registers are no longer mapped,
but the helpers are primed to move into the core.

[djbw: drop cxl_map_regs() for component registers]

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
[djbw: rebase on the cxl_register_map refactor]
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/163434053788.914258.18412599112859205220.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index 7d5e5548b31677fb880610554e9c3e8bfc6cf6aa..691a4e59ad8b797e54035c654d974d5b7bfad691 100644 (file)
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -433,72 +433,69 @@ static void cxl_decode_regblock(u32 reg_lo, u32 reg_hi,
 }
 
 /**
- * cxl_pci_setup_regs() - Setup necessary MMIO.
- * @cxlm: The CXL memory device to communicate with.
+ * 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 all necessary registers mapped.
+ * Return: 0 if register block enumerated, negative error code otherwise
  *
- * A memory device is required by spec to implement a certain set of MMIO
- * regions. The purpose of this function is to enumerate and map those
- * registers.
+ * A CXL DVSEC may point to one or more register blocks, search for them
+ * by @type.
  */
-static int cxl_pci_setup_regs(struct cxl_mem *cxlm)
+static 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, n_maps, ret = 0;
-       struct device *dev = cxlm->dev;
-       struct pci_dev *pdev = to_pci_dev(dev);
-       struct cxl_register_map *map, maps[CXL_REGLOC_RBI_TYPES];
+       int regloc, i;
 
        regloc = cxl_pci_dvsec(pdev, PCI_DVSEC_ID_CXL_REGLOC_DVSEC_ID);
-       if (!regloc) {
-               dev_err(dev, "register location dvsec not found\n");
+       if (!regloc)
                return -ENXIO;
-       }
 
-       /* Get the size of the Register Locator DVSEC */
        pci_read_config_dword(pdev, regloc + PCI_DVSEC_HEADER1, &regloc_size);
        regloc_size = FIELD_GET(PCI_DVSEC_HEADER1_LENGTH_MASK, regloc_size);
 
        regloc += PCI_DVSEC_ID_CXL_REGLOC_BLOCK1_OFFSET;
        regblocks = (regloc_size - PCI_DVSEC_ID_CXL_REGLOC_BLOCK1_OFFSET) / 8;
 
-       for (i = 0, n_maps = 0; i < regblocks; i++, regloc += 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);
 
-               map = &maps[n_maps];
                cxl_decode_regblock(reg_lo, reg_hi, map);
 
-               /* Ignore unknown register block types */
-               if (map->reg_type > CXL_REGLOC_RBI_MEMDEV)
-                       continue;
+               if (map->reg_type == type)
+                       return 0;
+       }
 
-               ret = cxl_map_regblock(pdev, map);
-               if (ret)
-                       return ret;
+       return -ENODEV;
+}
 
-               ret = cxl_probe_regs(pdev, map);
-               cxl_unmap_regblock(pdev, map);
-               if (ret)
-                       return ret;
+static int cxl_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type,
+                         struct cxl_register_map *map)
+{
+       int rc;
 
-               n_maps++;
-       }
+       rc = cxl_find_regblock(pdev, type, map);
+       if (rc)
+               return rc;
 
-       for (i = 0; i < n_maps; i++) {
-               ret = cxl_map_regs(cxlm, &maps[i]);
-               if (ret)
-                       break;
-       }
+       rc = cxl_map_regblock(pdev, map);
+       if (rc)
+               return rc;
+
+       rc = cxl_probe_regs(pdev, map);
+       cxl_unmap_regblock(pdev, map);
 
-       return ret;
+       return rc;
 }
 
 static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
+       struct cxl_register_map map;
        struct cxl_memdev *cxlmd;
        struct cxl_mem *cxlm;
        int rc;
@@ -518,7 +515,11 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
        if (IS_ERR(cxlm))
                return PTR_ERR(cxlm);
 
-       rc = cxl_pci_setup_regs(cxlm);
+       rc = cxl_setup_regs(pdev, CXL_REGLOC_RBI_MEMDEV, &map);
+       if (rc)
+               return rc;
+
+       rc = cxl_map_regs(cxlm, &map);
        if (rc)
                return rc;