Re: [PATCH v5 01/13] powerpc: Remove Xilinx PPC405/PPC440 support

From: Michael Ellerman <mpe@ellerman.id.au>
To: Michal Simek <michal.simek@xilinx.com>,
	Nathan Chancellor <natechancellor@gmail.com>,
	Michal Simek <michal.simek@xilinx.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	arnd@arndb.de, linuxppc-dev@lists.ozlabs.org,
	linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com
Subject: Re: [PATCH v5 01/13] powerpc: Remove Xilinx PPC405/PPC440 support
Date: Wed, 17 Jun 2020 20:16:43 +1000	[thread overview]
Message-ID: <87bllidmk4.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <50fb2dd6-4e8f-a550-6eda-073beb86f2ff@xilinx.com>

Michal Simek <michal.simek@xilinx.com> writes:
> On 16. 06. 20 20:16, Nathan Chancellor wrote:
>> On Tue, Jun 16, 2020 at 04:45:20PM +0200, Michal Simek wrote:
>>> On 16. 06. 20 2:27, Nathan Chancellor wrote:
>>>> On Thu, May 21, 2020 at 04:55:52PM +0000, Christophe Leroy wrote:
>>>>> From: Michal Simek <michal.simek@xilinx.com>
>>>>>
>>>>> The latest Xilinx design tools called ISE and EDK has been released in
>>>>> October 2013. New tool doesn't support any PPC405/PPC440 new designs.
>>>>> These platforms are no longer supported and tested.
>>>>>
>>>>> PowerPC 405/440 port is orphan from 2013 by
>>>>> commit cdeb89943bfc ("MAINTAINERS: Fix incorrect status tag") and
>>>>> commit 19624236cce1 ("MAINTAINERS: Update Grant's email address and maintainership")
>>>>> that's why it is time to remove the support fot these platforms.
>>>>>
>>>>> Signed-off-by: Michal Simek <michal.simek@xilinx.com>
>>>>> Acked-by: Arnd Bergmann <arnd@arndb.de>
>>>>> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
>>>>
>>>> This patch causes qemu-system-ppc to fail to load ppc44x_defconfig:
<snip>

> I have took a look at it and was able to run qemu and also saw your
> issue. What happened is that when xilinx platforms were removed zImage
> is generated but it is not u-boot legacy image.
> Don't know details about zImage/uImage in ppc world but if you dump
> zImage you should see this.

<snip>

> It means only Xilinx platforms have been asking for uImage format and
> bamboo doesn't require it. It also looks like that qemu expect uImage
> format.

Yeah, prior to the patch the result of make ppc44x_defconfig contains
CONFIG_DEFAULT_UIMAGE, afterward it doesn't.

That means previously arch/powerpc/boot/zImage was just a hardlink to
the uImage:

  $ ls -li build~/arch/powerpc/boot/{z,u}Image
  7472 -rw-rw-r-- 2 michael michael 3073824 Jun 17 20:02 build~/arch/powerpc/boot/uImage
  7472 -rw-rw-r-- 2 michael michael 3073824 Jun 17 20:02 build~/arch/powerpc/boot/zImage

  $ file build~/arch/powerpc/boot/zImage
  build~/arch/powerpc/boot/zImage: u-boot legacy uImage,
  Linux-5.7.0-rc2-00247-g0bdad33d6\037\213\010, Linux/PowerPC, OS Kernel
  Image (gzip), 3073760 bytes, Wed Jun 17 10:14:32 2020, Load Address:
  0x00000000, Entry Point: 0x00000000, Header CRC: 0xF0283815, Data CRC:
  0x5E5A4D98

> You should know what format qemu expects.
> Anyway if you build it by make uImage and then pass it to qemu you
> should boot just fine.

Yep so you can explicitly build the uImage with:

$ make -skj"$(nproc)" ARCH=powerpc CROSS_COMPILE=powerpc-linux- O=out/ppc distclean ppc44x_defconfig uImage

> Or if bamboo requires uImage to be built by default you can do it via
> Kconfig.
>
> diff --git a/arch/powerpc/platforms/44x/Kconfig
> b/arch/powerpc/platforms/44x/Kconfig
> index 39e93d23fb38..300864d7b8c9 100644
> --- a/arch/powerpc/platforms/44x/Kconfig
> +++ b/arch/powerpc/platforms/44x/Kconfig
> @@ -13,6 +13,7 @@ config BAMBOO
>         select PPC44x_SIMPLE
>         select 440EP
>         select FORCE_PCI
> +       select DEFAULT_UIMAGE
>         help
>           This option enables support for the IBM PPC440EP evaluation board.

Who knows what the actual bamboo board used. But I'd be happy to take a
SOB'ed patch to do the above, because these days the qemu emulation is
much more likely to be used than the actual board.

cheers