lkml.org 
[lkml]   [2018]   [May]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCHv4 1/2] ARM: imx53: add secure-reg-access support for PMU
Hi Shawn,

On Tue, Feb 27, 2018 at 11:17:12AM +0100, Sebastian Reichel wrote:
> Hi,
>
> On Tue, Feb 27, 2018 at 09:10:34AM +0800, Shawn Guo wrote:
> > On Mon, Feb 26, 2018 at 02:47:41PM +0100, Sebastian Reichel wrote:
> > > On Sat, Feb 24, 2018 at 03:45:44PM +0800, Shawn Guo wrote:
> > > > On Mon, Feb 12, 2018 at 01:39:44PM +0100, Sebastian Reichel wrote:
> > > > > On i.MX53 it is necessary to set the DBG_EN bit in the
> > > > > platform GPC register to enable access to PMU counters
> > > > > other than the cycle counter.
> > > > >
> > > > > Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
> > > > > ---
> > > > > arch/arm/mach-imx/mach-imx53.c | 39 ++++++++++++++++++++++++++++++++++++++-
> > > > > 1 file changed, 38 insertions(+), 1 deletion(-)
> > > > >
> > > > > diff --git a/arch/arm/mach-imx/mach-imx53.c b/arch/arm/mach-imx/mach-imx53.c
> > > > > index 07c2e8dca494..658e28604dca 100644
> > > > > --- a/arch/arm/mach-imx/mach-imx53.c
> > > > > +++ b/arch/arm/mach-imx/mach-imx53.c
> > > > > @@ -28,10 +28,47 @@ static void __init imx53_init_early(void)
> > > > > mxc_set_cpu_type(MXC_CPU_MX53);
> > > > > }
> > > > >
> > > > > +#define MXC_CORTEXA8_PLAT_GPC 0x63fa0004
> > > >
> > > > The base address should be retrieved from device tree.
> > >
> > > DT has no entry for 0x63fa0000-0x63fa3fff. iMX53 TRM lists it as "ARM Platform"
> > > with 8 platform specific 32 bit registers. Do you think it's worth the trouble
> > > adding a new binding? Do you have a suggestion for a compatible value?
> >
> > Looking at it more closely, I feel that patching every single platform
> > which needs to set up additional register for secure-reg-access support
> > doesn't really scale. Can we have pmu driver do it with a phandle in
> > DT pointing to the register and bit that need to be configured?
>
> The PMU driver used to have a feature for initialising platform
> specific bits, but it is currently being removed to make the PMU
> code more maintainable. My understanding is, that it's very uncommon
> to require platform specific setup to get secure-reg-access working.
> E.g. it is not needed for newer iMX platforms.

You never replied to this one. Are you fine with adding the
function? This is kind of a deadlock situation with neither
you wanting to enable the platform bit, nor the generic PMU
driver.

-- Sebastian
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2018-05-25 17:46    [W:0.095 / U:0.828 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site