[RFC V2 PATCH 01/11] cxl/mbox: Add debug of hardware error code

From: ira.weiny@intel.com
To: Dan Williams <dan.j.williams@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>,
	Alison Schofield <alison.schofield@intel.com>,
	Vishal Verma <vishal.l.verma@intel.com>,
	Ben Widawsky <bwidawsk@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>,
	Davidlohr Bueso <dave@stgolabs.net>,
	linux-kernel@vger.kernel.org, linux-cxl@vger.kernel.org
Subject: [RFC V2 PATCH 01/11] cxl/mbox: Add debug of hardware error code
Date: Mon, 10 Oct 2022 15:41:21 -0700	[thread overview]
Message-ID: <20221010224131.1866246-2-ira.weiny@intel.com> (raw)
In-Reply-To: <20221010224131.1866246-1-ira.weiny@intel.com>

From: Ira Weiny <ira.weiny@intel.com>

If a mailbox command fails the driver always reports ENXIO.  But this
may not be enough information to understand why the hardware, or in my
case Qemu, was failing.

Add a debug print of the error code returned from the hardware.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
---
 drivers/cxl/core/mbox.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
index 16176b9278b4..6c4d024ad0e8 100644
--- a/drivers/cxl/core/mbox.c
+++ b/drivers/cxl/core/mbox.c
@@ -181,8 +181,11 @@ int cxl_mbox_send_cmd(struct cxl_dev_state *cxlds, u16 opcode, void *in,
 	if (rc)
 		return rc;
 
-	if (mbox_cmd.return_code != CXL_MBOX_CMD_RC_SUCCESS)
+	if (mbox_cmd.return_code != CXL_MBOX_CMD_RC_SUCCESS) {
+		dev_dbg(cxlds->dev, "MB error : %s\n",
+			cxl_mbox_cmd_rc2str(&mbox_cmd));
 		return cxl_mbox_cmd_rc2errno(&mbox_cmd);
+	}
 
 	/*
 	 * Variable sized commands can't be validated and so it's up to the
-- 
2.37.2

