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Subject[PATCH v6 07/10] cxl/pci: Split cxl_pci_setup_regs()
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From: Ben Widawsky <ben.widawsky@intel.com>

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>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
Changes since v3:
- fixup grammar in kernel-doc for cxl_find_regblock() (Jonathan)

drivers/cxl/pci.c | 73 +++++++++++++++++++++++++++--------------------------
1 file changed, 37 insertions(+), 36 deletions(-)

diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index 7d5e5548b316..691a4e59ad8b 100644
--- 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;

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