From: Laurentiu Tudor <laurentiu.tudor@xxxxxxx>
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@xxxxxxx>
---
Notes:
-v2
-new patch replacing https://lkml.org/lkml/2017/7/17/419
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 195d9f3..8a6dc47 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;
}
--
2.9.4
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