From: Tom Rini <trini@konsulko.com>
To: Michal Simek <michal.simek@xilinx.com>
Cc: "Andre Przywara" <andre.przywara@arm.com>,
u-boot@lists.denx.de, git@xilinx.com,
"Bin Meng" <bmeng.cn@gmail.com>,
"Chee Hong Ang" <chee.hong.ang@intel.com>,
"Marek Behún" <marek.behun@nic.cz>,
"Pali Rohár" <pali@kernel.org>, "Simon Glass" <sjg@chromium.org>
Subject: Re: [PATCH 07/10] Makefile: Align fit-dtb.blob and u-boot.itb by 64bits for 64bit systems
Date: Thu, 19 Aug 2021 12:44:16 -0400 [thread overview]
Message-ID: <20210819164416.GA858@bill-the-cat> (raw)
In-Reply-To: <e9e13250-64ee-3472-2672-003ca87acdf1@xilinx.com>
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On Thu, Aug 19, 2021 at 06:31:25PM +0200, Michal Simek wrote:
>
>
> On 8/19/21 6:18 PM, Tom Rini wrote:
> > On Thu, Aug 19, 2021 at 06:01:39PM +0200, Michal Simek wrote:
> >> Hi Andre,
> >>
> >> On 8/19/21 5:56 PM, Andre Przywara wrote:
> >>> On 8/19/21 12:19 PM, Michal Simek wrote:
> >>>
> >>> Hi,
> >>>
> >>>> Enabling MULTI_DTB_FIT and DTB_RESELECT can end up with multi DTBs in FIT
> >>>> image placed and aligned only by 32bits (4bytes). For 64bit systems there
> >>>> is 64bit (8bytes) alignment required. That's why make sure that
> >>>> fit-dtb.blob and u-boot.itb as our primary target images for Xilinx
> >>>> ZynqMP
> >>>> are all 64bit aligned. The patch is using CONFIG_PHYS_64BIT macro to
> >>>> identify 64bit systems (including 32bit systems with PAE).
> >>>>
> >>>> Signed-off-by: Michal Simek <michal.simek@xilinx.com>
> >>>> ---
> >>>>
> >>>> Makefile | 7 +++++++
> >>>> 1 file changed, 7 insertions(+)
> >>>>
> >>>> diff --git a/Makefile b/Makefile
> >>>> index 269e353a28ad..1bbe95595efe 100644
> >>>> --- a/Makefile
> >>>> +++ b/Makefile
> >>>> @@ -1169,6 +1169,10 @@ MKIMAGEFLAGS_fit-dtb.blob = -f auto -A $(ARCH)
> >>>> -T firmware -C none -O u-boot \
> >>>> -a 0 -e 0 -E \
> >>>> $(patsubst %,-b arch/$(ARCH)/dts/%.dtb,$(subst
> >>>> ",,$(CONFIG_OF_LIST))) -d /dev/null
> >>>> +ifeq ($(CONFIG_PHYS_64BIT),y)
> >>>
> >>> Why is this restricted to 64-bit "systems"? The DT spec[1] clearly
> >>> states that some DT parts (/memreserved/ block, for instance), must be
> >>> 64-bit aligned, which means the whole blobs needs to be 64-bit aligned.
> >>> Granted this probably does not cause real issues on 32-bit systems, but
> >>> is violating the spec anyway.
> >>> So I'd say we add the alignment requirement unconditionally.
> >>
> >> That's even better for me and we need to make sure that dtbs itself are
> >> aligned and also dtbs inside FIT image are aligned too.
> >
> > Right, all dtbs need to be 8 byte aligned to start with. Enforcing this
> > is what will unblock moving to a newer libfdt where that's checked for
> > up-front now.
>
> As is in the second thread. Does it make sense to also align the end?
> I did that in 8/10 patch.
> The problem with these alignments is that you also need to align the
> start of FIT image. Maybe would the best to copy fdt to different
> aligned location.
Right, so a good question. I have suggested before that we stop
assuming that we (U-Boot SPL, etc) can use the device tree in-place and
instead move it somewhere aligned. I'm not sure off-hand what ends up
being best, someone would need to investigate a bit.
--
Tom
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next prev parent reply other threads:[~2021-08-19 16:44 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-19 11:19 [PATCH 00/10] xilinx: Add support for DTB reselection Michal Simek
2021-08-19 11:19 ` [PATCH 01/10] xilinx: fru: Replace spaces with \0 in detected name Michal Simek
2021-08-19 11:19 ` [PATCH 02/10] xilinx: Use variable for passing board_name Michal Simek
2021-08-19 11:19 ` [PATCH 03/10] xilinx: common: Change board_info[] handling Michal Simek
2021-08-19 11:19 ` [PATCH 04/10] xilinx: common: Free allocated structure Michal Simek
2021-08-19 11:19 ` [PATCH 05/10] xilinx: Add support for generic board detection Michal Simek
2021-08-19 11:19 ` [PATCH 06/10] xilinx: zynqmp: Check that DT is 64bit aligned Michal Simek
2021-08-19 11:19 ` [PATCH 07/10] Makefile: Align fit-dtb.blob and u-boot.itb by 64bits for 64bit systems Michal Simek
2021-08-19 15:56 ` Andre Przywara
2021-08-19 16:01 ` Michal Simek
2021-08-19 16:18 ` Tom Rini
2021-08-19 16:31 ` Michal Simek
2021-08-19 16:44 ` Tom Rini [this message]
2021-08-19 11:19 ` [PATCH 08/10] arm64: dts: Make sure that all DTBs are 64bit aligned " Michal Simek
2021-08-19 16:10 ` Andre Przywara
2021-08-19 16:34 ` Michal Simek
2021-08-19 11:19 ` [PATCH 09/10] xilinx: zynqmp: Generate different u-boot.itb for MULTI_DTB_FIT Michal Simek
2021-08-19 11:19 ` [PATCH 10/10] xilinx: common: Enabling generic function for DT reselection Michal Simek
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