From mboxrd@z Thu Jan 1 00:00:00 1970 From: m.szyprowski@samsung.com (Marek Szyprowski) Date: Thu, 06 Feb 2014 14:26:13 +0100 Subject: [PATCH v2 4/5] ARM: init: add support for reserved memory defined by device tree In-Reply-To: <20140205101510.59A95C40A89@trevor.secretlab.ca> References: <1391515773-6112-1-git-send-email-m.szyprowski@samsung.com> <1391515773-6112-5-git-send-email-m.szyprowski@samsung.com> <20140205101510.59A95C40A89@trevor.secretlab.ca> Message-ID: <52F38D75.4030704@samsung.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hello, On 2014-02-05 11:15, Grant Likely wrote: > On Tue, 04 Feb 2014 13:09:32 +0100, Marek Szyprowski wrote: > > Enable reserved memory initialization from device tree. > > > > Cc: Benjamin Herrenschmidt > > Cc: Laura Abbott > > Signed-off-by: Marek Szyprowski > > --- > > arch/arm/mm/init.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c > > index 804d61566a53..ebafdb479410 100644 > > --- a/arch/arm/mm/init.c > > +++ b/arch/arm/mm/init.c > > @@ -17,6 +17,7 @@ > > #include > > #include > > #include > > +#include > > #include > > #include > > #include > > @@ -323,6 +324,8 @@ void __init arm_memblock_init(struct meminfo *mi, > > if (mdesc->reserve) > > mdesc->reserve(); > > > > + early_init_dt_scan_reserved_mem(); > > + > > The new binding is being made fundamental. If the reserved-memory node > is present, then it needs to be honored, even if the kernel doesn't know > how to use the regions. Therefore, This needs to be unconditional for > all architectures. The hook should be called in early_init_dt_scan() > (drivers/of/fdt.c) immediately after the early_init_dt_scan_memory() > hook. In theory this will be the best solution, but it practice there is a problem. early_init_dt_scan() is called as the first function from kernel booting code. That time there is no memory yet added to the system, so it would be really hard to reserve anything. Memory nodes are being added later either with memblock_add() or by some other arch specific way. Finally, once all memory has been added to the system we can parse and reserve all regions defined in the device tree. This really requires creating another function which will be called by arch specific code. Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Szyprowski Subject: Re: [PATCH v2 4/5] ARM: init: add support for reserved memory defined by device tree Date: Thu, 06 Feb 2014 14:26:13 +0100 Message-ID: <52F38D75.4030704@samsung.com> References: <1391515773-6112-1-git-send-email-m.szyprowski@samsung.com> <1391515773-6112-5-git-send-email-m.szyprowski@samsung.com> <20140205101510.59A95C40A89@trevor.secretlab.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-reply-to: <20140205101510.59A95C40A89@trevor.secretlab.ca> Sender: linux-doc-owner@vger.kernel.org To: Grant Likely , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linaro-mm-sig@lists.linaro.org, devicetree@vger.kernel.org, linux-doc@vger.kernel.org Cc: Kyungmin Park , Benjamin Herrenschmidt , Arnd Bergmann , Michal Nazarewicz , Tomasz Figa , Sascha Hauer , Laura Abbott , Rob Herring , Olof Johansson , Pawel Moll , Mark Rutland , Stephen Warren , Ian Campbell , Tomasz Figa , Kumar Gala , Nishanth Peethambaran , Marc , Josh Cartwright List-Id: devicetree@vger.kernel.org Hello, On 2014-02-05 11:15, Grant Likely wrote: > On Tue, 04 Feb 2014 13:09:32 +0100, Marek Szyprowski wrote: > > Enable reserved memory initialization from device tree. > > > > Cc: Benjamin Herrenschmidt > > Cc: Laura Abbott > > Signed-off-by: Marek Szyprowski > > --- > > arch/arm/mm/init.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c > > index 804d61566a53..ebafdb479410 100644 > > --- a/arch/arm/mm/init.c > > +++ b/arch/arm/mm/init.c > > @@ -17,6 +17,7 @@ > > #include > > #include > > #include > > +#include > > #include > > #include > > #include > > @@ -323,6 +324,8 @@ void __init arm_memblock_init(struct meminfo *mi, > > if (mdesc->reserve) > > mdesc->reserve(); > > > > + early_init_dt_scan_reserved_mem(); > > + > > The new binding is being made fundamental. If the reserved-memory node > is present, then it needs to be honored, even if the kernel doesn't know > how to use the regions. Therefore, This needs to be unconditional for > all architectures. The hook should be called in early_init_dt_scan() > (drivers/of/fdt.c) immediately after the early_init_dt_scan_memory() > hook. In theory this will be the best solution, but it practice there is a problem. early_init_dt_scan() is called as the first function from kernel booting code. That time there is no memory yet added to the system, so it would be really hard to reserve anything. Memory nodes are being added later either with memblock_add() or by some other arch specific way. Finally, once all memory has been added to the system we can parse and reserve all regions defined in the device tree. This really requires creating another function which will be called by arch specific code. Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland