From: Shawn Guo <shawnguo@kernel.org>
To: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Cc: Sascha Hauer <kernel@pengutronix.de>,
Fabio Estevam <fabio.estevam@nxp.com>,
Will Deacon <will.deacon@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Russell King <linux@armlinux.org.uk>, Ian Ray <ian.ray@ge.com>,
Nandor Han <nandor.han@ge.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, kernel@collabora.com
Subject: Re: [PATCHv4 1/2] ARM: imx53: add secure-reg-access support for PMU
Date: Mon, 28 May 2018 10:26:54 +0800 [thread overview]
Message-ID: <20180528022652.GA3143@dragon> (raw)
In-Reply-To: <20180227101712.3zwobvs4ox4jchcj@earth.universe>
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.
> I.e. it is not needed for newer iMX platforms.
Are you saying this is a very specific setup required by i.MX53 only?
In that case, I can live with it.
Shawn
next prev parent reply other threads:[~2018-05-28 2:27 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-12 12:39 [PATCHv4 0/2] Improved perf support for imx53/ppd Sebastian Reichel
2018-02-12 12:39 ` [PATCHv4 1/2] ARM: imx53: add secure-reg-access support for PMU Sebastian Reichel
2018-02-12 12:48 ` Fabio Estevam
2018-02-24 7:45 ` Shawn Guo
2018-02-26 13:47 ` Sebastian Reichel
2018-02-27 1:10 ` Shawn Guo
2018-02-27 10:17 ` Sebastian Reichel
2018-05-25 15:45 ` Sebastian Reichel
2018-05-28 2:26 ` Shawn Guo [this message]
2018-05-28 6:41 ` Sebastian Reichel
2018-05-28 7:20 ` Shawn Guo
2018-05-28 15:50 ` Sebastian Reichel
2018-06-18 4:00 ` Fabio Estevam
2018-02-12 12:39 ` [PATCHv4 2/2] ARM: dts: imx53: PPD: Enable secure-reg-access Sebastian Reichel
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180528022652.GA3143@dragon \
--to=shawnguo@kernel.org \
--cc=fabio.estevam@nxp.com \
--cc=ian.ray@ge.com \
--cc=kernel@collabora.com \
--cc=kernel@pengutronix.de \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@armlinux.org.uk \
--cc=mark.rutland@arm.com \
--cc=nandor.han@ge.com \
--cc=sebastian.reichel@collabora.co.uk \
--cc=will.deacon@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).