cxl/pci: Cache device DVSEC offset

The PCIe device DVSEC, defined in the CXL 2.0 spec, 8.1.3 is required to
be implemented by CXL 2.0 endpoint devices. In preparation for consuming
this information in a new cxl_mem driver, retrieve the CXL DVSEC
position and warn about the implications of not finding it. Allow for
mailbox operation even if the CXL DVSEC is missing.

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/164375309615.513620.7874131241128599893.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index 90d67fff5bed96c61ca2930162f9ff2013be2e78..5cf5329e13a99dcf36185f42b403482e6c21b542 100644 (file)
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -98,6 +98,7 @@ struct cxl_mbox_cmd {
  *
  * @dev: The device associated with this CXL state
  * @regs: Parsed register blocks
+ * @cxl_dvsec: Offset to the PCIe device DVSEC
  * @payload_size: Size of space for payload
  *                (CXL 2.0 8.2.8.4.3 Mailbox Capabilities Register)
  * @lsa_size: Size of Label Storage Area
@@ -126,6 +127,7 @@ struct cxl_dev_state {
        struct device *dev;
 
        struct cxl_regs regs;
+       int cxl_dvsec;
 
        size_t payload_size;
        size_t lsa_size;

diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index bf14c365ea335ada7c5b725d39abc1a5dfdba68c..c940021660843d8a1d5d22c77587b6c56590203e 100644 (file)
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -408,6 +408,12 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
        if (IS_ERR(cxlds))
                return PTR_ERR(cxlds);
 
+       cxlds->cxl_dvsec = pci_find_dvsec_capability(
+               pdev, PCI_DVSEC_VENDOR_ID_CXL, CXL_DVSEC_PCIE_DEVICE);
+       if (!cxlds->cxl_dvsec)
+               dev_warn(&pdev->dev,
+                        "Device DVSEC not present, skip CXL.mem init\n");
+
        rc = cxl_setup_regs(pdev, CXL_REGLOC_RBI_MEMDEV, &map);
        if (rc)
                return rc;