From: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Date: Wed, 19 Jul 2017 14:42:30 +0300
Subject: staging: fsl-mc: don't use raw device io functions

Git-commit: b064d0e6e42ed4774c42bfbec0db60f8249a9de2
Patch-mainline: v4.14-rc1
References: fate#326530,fate#326531,fate#326535,fate#326538,fate#326539

As raw device io functions are not portable and don't handle byte-order
(triggering suspicion that endianness isn't handled well) switch to
using the standard api.
Since MC expects LE byte-order and the upper layers already take care
of that, we need to trick the device io api by doing a LE -> CPU
conversion just before calling it. This way, the CPU -> LE conversion
done in the api puts the data back in the right byte-order. Obviously,
for reads the extra step is mirrored: there's a CPU -> LE conversion
following the API call.

Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
---
 drivers/staging/fsl-mc/bus/mc-sys.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/staging/fsl-mc/bus/mc-sys.c b/drivers/staging/fsl-mc/bus/mc-sys.c
index 195d9f347788..8a6dc477920f 100644
--- a/drivers/staging/fsl-mc/bus/mc-sys.c
+++ b/drivers/staging/fsl-mc/bus/mc-sys.c
@@ -126,12 +126,15 @@ static inline void mc_write_command(struct mc_command __iomem *portal,
 
 	/* copy command parameters into the portal */
 	for (i = 0; i < MC_CMD_NUM_OF_PARAMS; i++)
-		__raw_writeq(cmd->params[i], &portal->params[i]);
-	/* ensure command params are committed before submitting it */
-	wmb();
+		/*
+		 * Data is already in the expected LE byte-order. Do an
+		 * extra LE -> CPU conversion so that the CPU -> LE done in
+		 * the device io write api puts it back in the right order.
+		 */
+		writeq_relaxed(le64_to_cpu(cmd->params[i]), &portal->params[i]);
 
 	/* submit the command by writing the header */
-	__raw_writeq(cmd->header, &portal->header);
+	writeq(le64_to_cpu(cmd->header), &portal->header);
 }
 
 /**
@@ -151,14 +154,20 @@ static inline enum mc_cmd_status mc_read_response(struct mc_command __iomem *
 	enum mc_cmd_status status;
 
 	/* Copy command response header from MC portal: */
-	resp->header = __raw_readq(&portal->header);
+	resp->header = cpu_to_le64(readq_relaxed(&portal->header));
 	status = mc_cmd_hdr_read_status(resp);
 	if (status != MC_CMD_STATUS_OK)
 		return status;
 
 	/* Copy command response data from MC portal: */
 	for (i = 0; i < MC_CMD_NUM_OF_PARAMS; i++)
-		resp->params[i] = __raw_readq(&portal->params[i]);
+		/*
+		 * Data is expected to be in LE byte-order. Do an
+		 * extra CPU -> LE to revert the LE -> CPU done in
+		 * the device io read api.
+		 */
+		resp->params[i] =
+			cpu_to_le64(readq_relaxed(&portal->params[i]));
 
 	return status;
 }
-- 
2.11.0