[PATCH 1/7] gpu: host1x: Resize channel register region on Tegra186 and later

[Thierry Reding]

On Mon, Nov 26, 2018 at 10:11:39AM -0500, Ilia Mirkin wrote:
> On Fri, Nov 23, 2018 at 7:31 AM Thierry Reding <thierry.reding at gmail.com> wrote:
> >
> > From: Thierry Reding <treding at nvidia.com>
> >
> > The register region allocated per channel was decreased from 16384 bytes
> > to 256 bytes on Tegra186 and later. Resize the region to make sure every
> > channel (instead of only the first) is properly programmed.
> >
> > Suggested-by: Mikko Perttunen <mperttunen at nvidia.com>
> > Signed-off-by: Thierry Reding <treding at nvidia.com>
> > ---
> >  drivers/gpu/host1x/hw/channel_hw.c | 7 +++++--
> >  1 file changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/host1x/hw/channel_hw.c b/drivers/gpu/host1x/hw/channel_hw.c
> > index d188f9068b91..95ea81172a83 100644
> > --- a/drivers/gpu/host1x/hw/channel_hw.c
> > +++ b/drivers/gpu/host1x/hw/channel_hw.c
> > @@ -26,7 +26,6 @@
> >  #include "../intr.h"
> >  #include "../job.h"
> >
> > -#define HOST1X_CHANNEL_SIZE 16384
> >  #define TRACE_MAX_LENGTH 128U
> >
> >  static void trace_write_gather(struct host1x_cdma *cdma, struct host1x_bo *bo,
> > @@ -203,7 +202,11 @@ static void enable_gather_filter(struct host1x *host,
> >  static int host1x_channel_init(struct host1x_channel *ch, struct host1x *dev,
> >                                unsigned int index)
> >  {
> > -       ch->regs = dev->regs + index * HOST1X_CHANNEL_SIZE;
> > +#if HOST1X_HW < 6
> > +       ch->regs = dev->regs + index * 0x4000;
> > +#else
> > +       ch->regs = dev->regs + index * 0x100;
> > +#endif
> 
> Just an observation ... this makes it impossible to build this module
> for multiple host1x hw revisions in the same kernel. I believe that
> supporting multiple platforms is frequently desirable, but perhaps
> there's more going on here (like arm64 vs arm32, etc).

It actually does work. If you look close enough this file is included
multiple times by generation specific source files. It's sort of like
a template if you want.

It's not a design that's entirely to my liking, but it's not been a
strong enough itch to scratch for me to have gotten around to changing
how it works.

Thierry
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