staging: fsl-mc: don't use raw device io functions

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>

diff --git a/drivers/staging/fsl-mc/bus/mc-sys.c b/drivers/staging/fsl-mc/bus/mc-sys.c
index 195d9f3..8a6dc47 100644 (file)
--- 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;
 }