cxl/pci: Add debug for DVSEC range init failures

In preparation for not treating DVSEC range initialization failures as
fatal to cxl_pci_probe() add individual dev_dbg() statements for each of
the major failure reasons in cxl_dvsec_ranges().

The rationale for cxl_dvsec_ranges() failure not being fatal is that
there is still value for cxl_pci to enable mailbox operations even if
CXL.mem operation is disabled.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Link: https://lore.kernel.org/r/164730734812.3806189.2726330688692684104.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 39694cc..1cb2557 100644 (file)
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -467,12 +467,15 @@ static int cxl_dvsec_ranges(struct cxl_dev_state *cxlds)
 {
        struct cxl_endpoint_dvsec_info *info = &cxlds->info;
        struct pci_dev *pdev = to_pci_dev(cxlds->dev);
+       struct device *dev = &pdev->dev;
        int d = cxlds->cxl_dvsec;
        int hdm_count, rc, i;
        u16 cap, ctrl;
 
-       if (!d)
+       if (!d) {
+               dev_dbg(dev, "No DVSEC Capability\n");
                return -ENXIO;
+       }
 
        rc = pci_read_config_word(pdev, d + CXL_DVSEC_CAP_OFFSET, &cap);
        if (rc)
@@ -482,8 +485,10 @@ static int cxl_dvsec_ranges(struct cxl_dev_state *cxlds)
        if (rc)
                return rc;
 
-       if (!(cap & CXL_DVSEC_MEM_CAPABLE))
+       if (!(cap & CXL_DVSEC_MEM_CAPABLE)) {
+               dev_dbg(dev, "Not MEM Capable\n");
                return -ENXIO;
+       }
 
        /*
         * It is not allowed by spec for MEM.capable to be set and have 0 legacy
@@ -496,8 +501,10 @@ static int cxl_dvsec_ranges(struct cxl_dev_state *cxlds)
                return -EINVAL;
 
        rc = wait_for_valid(cxlds);
-       if (rc)
+       if (rc) {
+               dev_dbg(dev, "Failure awaiting MEM_INFO_VALID (%d)\n", rc);
                return rc;
+       }
 
        info->mem_enabled = FIELD_GET(CXL_DVSEC_MEM_ENABLE, ctrl);