linux-kernel - [PATCH 5.18 550/879] cxl/pci: Add debug for DVSEC range init failures

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Date:   Tue,  7 Jun 2022 19:01:08 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        Ben Widawsky <ben.widawsky@...el.com>,
        Davidlohr Bueso <dave@...olabs.net>,
        Dan Williams <dan.j.williams@...el.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.18 550/879] cxl/pci: Add debug for DVSEC range init failures

From: Dan Williams <dan.j.williams@...el.com>

[ Upstream commit e39f9be08d9dfe685c8a325ac1755c04f383effc ]

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@...wei.com>
Reviewed-by: Ben Widawsky <ben.widawsky@...el.com>
Reviewed-by: Davidlohr Bueso <dave@...olabs.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@...el.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/cxl/pci.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index 3f2182d66829..c4941a3ca6a8 100644
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -466,12 +466,15 @@ 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)
@@ -481,8 +484,10 @@ 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
@@ -495,8 +500,10 @@ 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);
 
-- 
2.35.1