From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC][PATCH 2/2] ARM: ioremap: Add IO mapping space reused support.
Date: Tue, 13 May 2014 10:43:06 +0200 [thread overview]
Message-ID: <5026482.P9PDy29y2Y@wuerfel> (raw)
In-Reply-To: <CAHPCO9FRfR5p1N5v7mUk4hUYdPvqfLN6nW1LcnC83sU86ZFbZA@mail.gmail.com>
On Tuesday 13 May 2014 09:45:08 Richard Lee wrote:
> > On Mon, May 12, 2014 at 3:51 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> > On Monday 12 May 2014 10:19:55 Richard Lee wrote:
> >> For the IO mapping, for the same physical address space maybe
> >> mapped more than one time, for example, in some SoCs:
> >> 0x20000000 ~ 0x20001000: are global control IO physical map,
> >> and this range space will be used by many drivers.
> >> And then if each driver will do the same ioremap operation, we
> >> will waste to much malloc virtual spaces.
> >>
> >> This patch add IO mapping space reused support.
> >>
> >> Signed-off-by: Richard Lee <superlibj@gmail.com>
> >
> > What happens if the first driver then unmaps the area?
> >
>
> If the first driver will unmap the area, it shouldn't do any thing
> except decreasing the 'used' counter.
Ah, for some reason I didn't see your first patch that introduces
that counter.
Arnd
WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de>
To: Richard Lee <superlibj8301@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org, linux@arm.linux.org.uk,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Richard Lee <superlibj@gmail.com>
Subject: Re: [RFC][PATCH 2/2] ARM: ioremap: Add IO mapping space reused support.
Date: Tue, 13 May 2014 10:43:06 +0200 [thread overview]
Message-ID: <5026482.P9PDy29y2Y@wuerfel> (raw)
In-Reply-To: <CAHPCO9FRfR5p1N5v7mUk4hUYdPvqfLN6nW1LcnC83sU86ZFbZA@mail.gmail.com>
On Tuesday 13 May 2014 09:45:08 Richard Lee wrote:
> > On Mon, May 12, 2014 at 3:51 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> > On Monday 12 May 2014 10:19:55 Richard Lee wrote:
> >> For the IO mapping, for the same physical address space maybe
> >> mapped more than one time, for example, in some SoCs:
> >> 0x20000000 ~ 0x20001000: are global control IO physical map,
> >> and this range space will be used by many drivers.
> >> And then if each driver will do the same ioremap operation, we
> >> will waste to much malloc virtual spaces.
> >>
> >> This patch add IO mapping space reused support.
> >>
> >> Signed-off-by: Richard Lee <superlibj@gmail.com>
> >
> > What happens if the first driver then unmaps the area?
> >
>
> If the first driver will unmap the area, it shouldn't do any thing
> except decreasing the 'used' counter.
Ah, for some reason I didn't see your first patch that introduces
that counter.
Arnd
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WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de>
To: Richard Lee <superlibj8301@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org, linux@arm.linux.org.uk,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Richard Lee <superlibj@gmail.com>
Subject: Re: [RFC][PATCH 2/2] ARM: ioremap: Add IO mapping space reused support.
Date: Tue, 13 May 2014 10:43:06 +0200 [thread overview]
Message-ID: <5026482.P9PDy29y2Y@wuerfel> (raw)
In-Reply-To: <CAHPCO9FRfR5p1N5v7mUk4hUYdPvqfLN6nW1LcnC83sU86ZFbZA@mail.gmail.com>
On Tuesday 13 May 2014 09:45:08 Richard Lee wrote:
> > On Mon, May 12, 2014 at 3:51 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> > On Monday 12 May 2014 10:19:55 Richard Lee wrote:
> >> For the IO mapping, for the same physical address space maybe
> >> mapped more than one time, for example, in some SoCs:
> >> 0x20000000 ~ 0x20001000: are global control IO physical map,
> >> and this range space will be used by many drivers.
> >> And then if each driver will do the same ioremap operation, we
> >> will waste to much malloc virtual spaces.
> >>
> >> This patch add IO mapping space reused support.
> >>
> >> Signed-off-by: Richard Lee <superlibj@gmail.com>
> >
> > What happens if the first driver then unmaps the area?
> >
>
> If the first driver will unmap the area, it shouldn't do any thing
> except decreasing the 'used' counter.
Ah, for some reason I didn't see your first patch that introduces
that counter.
Arnd
next prev parent reply other threads:[~2014-05-13 8:43 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-12 2:19 [RFC][PATCH 0/2] Add IO mapping space reused support Richard Lee
2014-05-12 2:19 ` Richard Lee
2014-05-12 2:19 ` Richard Lee
2014-05-12 2:19 ` [RFC][PATCH 1/2] mm/vmalloc: Add IO mapping space reused interface Richard Lee
2014-05-12 2:19 ` Richard Lee
2014-05-12 2:19 ` Richard Lee
2014-05-13 3:13 ` Rob Herring
2014-05-13 3:13 ` Rob Herring
2014-05-13 3:13 ` Rob Herring
2014-05-13 6:21 ` Richard Lee
2014-05-13 6:21 ` Richard Lee
2014-05-13 6:21 ` Richard Lee
2014-05-12 2:19 ` [RFC][PATCH 2/2] ARM: ioremap: Add IO mapping space reused support Richard Lee
2014-05-12 2:19 ` Richard Lee
2014-05-12 2:19 ` Richard Lee
2014-05-12 7:51 ` Arnd Bergmann
2014-05-12 7:51 ` Arnd Bergmann
2014-05-12 7:51 ` Arnd Bergmann
2014-05-13 1:45 ` Richard Lee
2014-05-13 1:45 ` Richard Lee
2014-05-13 1:45 ` Richard Lee
2014-05-13 8:43 ` Arnd Bergmann [this message]
2014-05-13 8:43 ` Arnd Bergmann
2014-05-13 8:43 ` Arnd Bergmann
2014-05-14 2:13 ` Richard Lee
2014-05-14 2:13 ` Richard Lee
2014-05-14 2:13 ` Richard Lee
2014-05-15 10:17 ` Catalin Marinas
2014-05-15 10:17 ` Catalin Marinas
2014-05-15 10:17 ` Catalin Marinas
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