[PATCH 3/4] cxl/mbox: Improve handling of mbox_cmd hw return codes

[Davidlohr Bueso <dave@stgolabs.net>]

Upon a completed command the caller is still expected to check
the actual return_code register to ensure it succeed. This
adds, per the spec, the potential command return codes. It maps
the hardware return code with the kernel's errno style, and by
default continues to use -ENXIO (Command completed, but device
reported an error).

Reviewed by: Adam Manzanares <a.manzanares@samsung.com>
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
---
 drivers/cxl/core/mbox.c |  2 +-
 drivers/cxl/cxlmem.h    | 53 ++++++++++++++++++++++++++++++++++++++++-
 drivers/cxl/pci.c       |  2 +-
 3 files changed, 54 insertions(+), 3 deletions(-)

diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
index a586c0fa9555..353b3f97c7e6 100644
--- a/drivers/cxl/core/mbox.c
+++ b/drivers/cxl/core/mbox.c
@@ -170,7 +170,7 @@ int cxl_mbox_send_cmd(struct cxl_dev_state *cxlds, u16 opcode, void *in,
 		return rc;
 
 	/* TODO: Map return code to proper kernel style errno */
-	if (mbox_cmd.return_code != CXL_MBOX_SUCCESS)
+	if (mbox_cmd.return_code != CXL_MBOX_CMD_RC_SUCCESS)
 		return -ENXIO;
 
 	/*
diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index 5d33ce24fe09..264a3cbfcad6 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -85,9 +85,60 @@ struct cxl_mbox_cmd {
 	size_t size_in;
 	size_t size_out;
 	u16 return_code;
-#define CXL_MBOX_SUCCESS 0
 };
 
+/*
+ * Per CXL 2.0 Section 8.2.8.4.5.1
+ */
+#define CMD_CMD_RC_TABLE							\
+	C(SUCCESS, 0, NULL),							\
+	C(BACKGROUND, -ENXIO, "background cmd started successfully"),           \
+	C(INPUT, -ENXIO, "cmd input was invalid"),				\
+	C(UNSUPPORTED, -ENXIO, "cmd is not supported"),				\
+	C(INTERNAL, -ENXIO, "internal device error"),				\
+	C(RETRY, -ENXIO, "temporary error, retry once"),			\
+	C(BUSY, -ENXIO, "ongoing background operation"),			\
+	C(MEDIADISABLED, -ENXIO, "media access is disabled"),			\
+	C(FWINPROGRESS, -ENXIO,	"one FW package can be transferred at a time"), \
+	C(FWOOO, -ENXIO, "FW package content was transferred out of order"),    \
+	C(FWAUTH, -ENXIO, "FW package authentication failed"),			\
+	C(FWSLOT, -ENXIO, "FW slot is not supported for requested operation"),  \
+	C(FWROLLBACK, -ENXIO, "rolled back to the previous active FW"),         \
+	C(FWRESET, -ENXIO, "FW failed to activate, needs cold reset"),		\
+	C(HANDLE, -ENXIO, "one or more Event Record Handles were invalid"),     \
+	C(PADDR, -ENXIO, "physical address specified is invalid"),		\
+	C(POISONLMT, -ENXIO, "poison injection limit has been reached"),        \
+	C(MEDIAFAILURE, -ENXIO, "permanent issue with the media"),		\
+	C(ABORT, -ENXIO, "background cmd was aborted by device"),               \
+	C(SECURITY, -ENXIO, "not valid in the current security state"),         \
+	C(PASSPHRASE, -ENXIO, "phrase doesn't match current set passphrase"),   \
+	C(MBUNSUPPORTED, -ENXIO, "unsupported on the mailbox it was issued on"),\
+	C(PAYLOADLEN, -ENXIO, "invalid payload length")
+
+#undef C
+#define C(a, b, c) CXL_MBOX_CMD_RC_##a
+enum  { CMD_CMD_RC_TABLE };
+#undef C
+#define C(a, b, c) { b, c }
+struct cxl_mbox_cmd_rc {
+	int err;
+	const char *desc;
+};
+
+static const
+struct cxl_mbox_cmd_rc cxl_mbox_cmd_rctable[] ={ CMD_CMD_RC_TABLE };
+#undef C
+
+static inline const char *cxl_mbox_cmd_rc2str(struct cxl_mbox_cmd *mbox_cmd)
+{
+	return cxl_mbox_cmd_rctable[mbox_cmd->return_code].desc;
+}
+
+static inline int cxl_mbox_cmd_rc2errno(struct cxl_mbox_cmd *mbox_cmd)
+{
+	return cxl_mbox_cmd_rctable[mbox_cmd->return_code].err;
+}
+
 /*
  * CXL 2.0 - Memory capacity multiplier
  * See Section 8.2.9.5
diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index 8b131692ed61..4fbef05e9082 100644
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -177,7 +177,7 @@ static int __cxl_pci_mbox_send_cmd(struct cxl_dev_state *cxlds,
 	mbox_cmd->return_code =
 		FIELD_GET(CXLDEV_MBOX_STATUS_RET_CODE_MASK, status_reg);
 
-	if (mbox_cmd->return_code != CXL_MBOX_SUCCESS) {
+	if (mbox_cmd->return_code != CXL_MBOX_CMD_RC_SUCCESS) {
 		dev_dbg(dev, "Mailbox operation had an error\n");
 		return 0; /* completed but caller must check return_code */
 	}
-- 
2.26.2