linux-kernel - Re: [PATCH 11/15] ARM: etm: Check arch version and disable data tracing for ptm

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Message-ID: <CAMP5XgceDFLrk3a1yfPHiap56Nvc2XOyvmS9yOrJ9ULVYLbGeQ@mail.gmail.com>
Date:	Thu, 28 Jun 2012 14:31:47 -0700
From:	Arve Hjønnevåg <arve@...roid.com>
To:	Linus Walleij <linus.walleij@...aro.org>
Cc:	John Stultz <john.stultz@...aro.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Russell King <linux@....linux.org.uk>,
	Paul Gortmaker <paul.gortmaker@...driver.com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Subject: Re: [PATCH 11/15] ARM: etm: Check arch version and disable data
 tracing for ptm

On Thu, Jun 28, 2012 at 9:07 AM, Linus Walleij <linus.walleij@...aro.org> wrote:
> On Thu, Jun 21, 2012 at 12:47 AM, John Stultz <john.stultz@...aro.org> wrote:
>
>> +#define ETMR_ID                        0x1e4
>> +#define ETMIDR_VERSION(x)      (((x) >> 4) & 0xff)
>> +#define ETMIDR_VERSION_PFT_1_0 0x30
>
> NAK don't reinvent this stuff.
>
> From <linux/amba/bus.h>
>
> Use these macros on the periphid:
> #define amba_config(d)  AMBA_CONFIG_BITS((d)->periphid)
> #define amba_rev(d)     AMBA_REV_BITS((d)->periphid)
> #define amba_manf(d)    AMBA_MANF_BITS((d)->periphid)
> #define amba_part(d)    AMBA_PART_BITS((d)->periphid)
>

Those values do not come from the same register. The revision is
duplicated there, but I did not find the major and minor etm version
which is what I'm looking at. Also, if these values are set in the
amba_device before calling amba_device_register the hardware registers
are not read at all and the information could be from an older
hardware rev than what you are currently running on.

> I thin amba_rev() is the one you're looking for (not sure).
>
> So here:
>
>> @@ -724,6 +724,9 @@ static int __devinit etm_probe(struct amba_device *dev, const struct amba_id *id
>
>> +       if (etmccr & ETMCCR_ETMIDR_PRESENT) {
>> +               etmidr = etm_readl(t, t->etm_regs_count, ETMR_ID);
>> +               etm_version = ETMIDR_VERSION(etmidr);
>
> etm_version = amba_rev(dev);
>
> etc.
>
> Yours,
> Linus Walleij



-- 
Arve Hjønnevåg
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