From: Robin Murphy <robin.murphy@arm.com>
To: Ilkka Koskinen <ilkka@os.amperecomputing.com>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, patches@amperecomputing.com
Subject: Re: [PATCH 1/1] perf/arm-cmn: Add more bits to child node address offset field
Date: Wed, 21 Sep 2022 17:17:04 +0100 [thread overview]
Message-ID: <b341c342-954d-a261-7ebf-df20573fa2fb@arm.com> (raw)
In-Reply-To: <20220808195455.79277-1-ilkka@os.amperecomputing.com>
On 08/08/2022 8:54 pm, Ilkka Koskinen wrote:
> CMN-600 uses bits [27:0] for child node address offset while bits [30:28]
> are required to be zero.
>
> For CMN-650, the child node address offset field has been increased
> to include bits [29:0] while leaving only bit 30 set to zero.
>
> Let's include the missing two bits and assume older implementations
> comply with the spec and set bits [29:28] to 0.
Just to add that other users have run into this as well, so getting it
applied as a fix would be just lovely. Technically I think it's:
Fixes: 60d1504070c2 ("perf/arm-cmn: Support new IP features")
Cheers,
Robin.
> Signed-off-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
> ---
>
> I have tested this patch on CMN-600 and CMN-650.
>
> drivers/perf/arm-cmn.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c
> index 80d8309652a4..b80a9b74662b 100644
> --- a/drivers/perf/arm-cmn.c
> +++ b/drivers/perf/arm-cmn.c
> @@ -36,7 +36,7 @@
> #define CMN_CI_CHILD_COUNT GENMASK_ULL(15, 0)
> #define CMN_CI_CHILD_PTR_OFFSET GENMASK_ULL(31, 16)
>
> -#define CMN_CHILD_NODE_ADDR GENMASK(27, 0)
> +#define CMN_CHILD_NODE_ADDR GENMASK(29, 0)
> #define CMN_CHILD_NODE_EXTERNAL BIT(31)
>
> #define CMN_MAX_DIMENSION 12
next prev parent reply other threads:[~2022-09-21 16:35 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-08 19:54 [PATCH 1/1] perf/arm-cmn: Add more bits to child node address offset field Ilkka Koskinen
2022-08-09 10:05 ` Robin Murphy
2022-08-31 4:46 ` Ilkka Koskinen
2022-09-21 16:17 ` Robin Murphy [this message]
2022-09-21 19:56 ` Ilkka Koskinen
2022-09-22 20:33 ` Will Deacon
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