[PATCH 03/23] cxl/pci: Extract device status check

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The Memory Device Status register is inspected in the same way for at
least two flows in the CXL Type 3 Memory Device Software Guide
(Revision: 1.0): 2.13.9 Device discovery and mailbox ready sequence,
and 2.13.10 Media ready sequence. Extract this common functionality for
use by both.

Signed-off-by: Ben Widawsky <ben.widawsky@xxxxxxxxx>
---
This patch did not exist in RFCv2
---
 drivers/cxl/pci.c | 33 +++++++++++++++++++++++++--------
 1 file changed, 25 insertions(+), 8 deletions(-)

diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index a6ea9811a05b..6c8d09fb3a17 100644
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -182,6 +182,27 @@ static int __cxl_pci_mbox_send_cmd(struct cxl_dev_state *cxlds,
 	return 0;
 }
 
+/*
+ * Implements roughly the bottom half of Figure 42 of the CXL Type 3 Memory
+ * Device Software Guide
+ */
+static int check_device_status(struct cxl_dev_state *cxlds)
+{
+	const u64 md_status = readq(cxlds->regs.memdev + CXLMDEV_STATUS_OFFSET);
+
+	if (md_status & CXLMDEV_DEV_FATAL) {
+		dev_err(cxlds->dev, "Fatal: replace device\n");
+		return -EIO;
+	}
+
+	if (md_status & CXLMDEV_FW_HALT) {
+		dev_err(cxlds->dev, "FWHalt: reset or replace device\n");
+		return -EBUSY;
+	}
+
+	return 0;
+}
+
 /**
  * cxl_pci_mbox_get() - Acquire exclusive access to the mailbox.
  * @cxlds: The device state to gain access to.
@@ -231,17 +252,13 @@ static int cxl_pci_mbox_get(struct cxl_dev_state *cxlds)
 	 * Hardware shouldn't allow a ready status but also have failure bits
 	 * set. Spit out an error, this should be a bug report
 	 */
-	rc = -EFAULT;
-	if (md_status & CXLMDEV_DEV_FATAL) {
-		dev_err(dev, "mbox: reported ready, but fatal\n");
+	rc = check_device_status(cxlds);
+	if (rc)
 		goto out;
-	}
-	if (md_status & CXLMDEV_FW_HALT) {
-		dev_err(dev, "mbox: reported ready, but halted\n");
-		goto out;
-	}
+
 	if (CXLMDEV_RESET_NEEDED(md_status)) {
 		dev_err(dev, "mbox: reported ready, but reset needed\n");
+		rc = -EFAULT;
 		goto out;
 	}
 
-- 
2.34.0




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