On Tue, Jul 18, 2017 at 3:37 PM, <laurentiu.tudor@xxxxxxx> wrote: > 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); > } Looks good, but just to be sure this is what you intended: On 32-bit systems, this will now write val>>32 to cmd->header+4, followed by writing val&0xffffffff to cmd->header. You said earlier that the command is triggered when the final four bytes are written, but it looks like the order is wrong now. Should you use io-64-nonatomic-lo-hi.h instead of io-64-nonatomic-hi-lo.h then? Arnd _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
