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References: <20231219-sam-sparc32-sunset-v3-v1-0-64bb44b598c5@ravnborg.org>
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From: Kjetil Oftedal <oftedal@gmail.com>
Date: Wed, 20 Dec 2023 15:42:59 +0100
Message-ID: <CALMQjD-BG6FtQw5LFkDf2LOZgFnfhEUe+nN+5XSaUEUL_QZxqQ@mail.gmail.com>
Subject: Re: [PATCH 00/27] sparc32: sunset sun4m and sun4d
To: sam@ravnborg.org
Cc: "David S. Miller" <davem@davemloft.net>, Arnd Bergmann <arnd@kernel.org>, 
	Andreas Larsson <andreas@gaisler.com>, Helge Deller <deller@gmx.de>, 
	Alexander Viro <viro@zeniv.linux.org.uk>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, 
	Alan Stern <stern@rowland.harvard.edu>, Jaroslav Kysela <perex@perex.cz>, 
	Takashi Iwai <tiwai@suse.com>, sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org, 
	linux-usb@vger.kernel.org, linux-fbdev@vger.kernel.org, 
	dri-devel@lists.freedesktop.org, linux-sound@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"

On Tue, 19 Dec 2023 at 23:03, Sam Ravnborg via B4 Relay
<devnull+sam.ravnborg.org@kernel.org> wrote:
>
> This is the second attempt to sunset sun4m and sun4d.
> See [1] for the inital attempt.
>
> The sun4m and sun4d parts of the kernel have seen no real interest
> for several years now. Last time a few people surfaced, but it was
> either due to a personal project or for nostalgic reasons.
> It is time to let go and drop the parts of sparc32 that in reality
> are not in use.
>
> LEON from Frontgrade Gaisler is the only real user of sparc32,
> and this patchset reduces sparc32 to what is required by LEON.
>
> The defconfig is first adapted to the one used by Gaisler.
> Then the patches removes sun4m and sun4d specific
> implementations such as small drivers, SMP support, IRQ suppor etc.
>
> Removing sun4m and sun4d support allowed removal of the run time
> patching of the code as well as a lot of assembler code.
> The result is a much cleaner assembler code that is easier to
> understand and thus maintain and extend.
>
> So far the code builds but it has seen no run-time testing.
>
> If anyone can tell me how to boot a linux kernel with the leon_genric
> machine with QEMU that would be super as this would be a minimal
> testing that others can reproduce as well.
> I assume QEMU needs a few patches to make it work, but maybe I
> just failed to use the right bootloader.
>
> TODO before this can be applied:
> - Ack from davem - as he is the principal sparc maintainer
> - Tested-by: preferably on a target or QEMU (see above)
>   I expect bugs as there are some involved changes!
>
> Ideas for the future
> - Apply the most relevant downstream Gaisler patches
>   - The ones introducing CAS should have preference as we then
>     can drop the cmpxchg emulation
> - Adjust defconfig to include all Gaisler drivers to make sure they
>   see build time coverage
> - Move the leon bits from leon files to the general files
>   - Add leon smp support to smp_32.c
>   - Add leon irq support to irq_32.c
> - Integrate leom_mm support with srmmu and drop some of the
>   function operations that are no longer needed
> - The current sparc32 code assume the bootloader uses the prom
>   provided by sun. Maybe migrate over to a more modern device tree
>   way of working.
> - Drop some of the homegrown memory allocators and use memblocks
>
> [1]: https://lore.kernel.org/all/20201218184347.2180772-1-sam@ravnborg.org/
>
>         Sam
>
> ---
> Sam Ravnborg (27):
>       sparc32: Update defconfig to LEON SMP
>       sparc32: Drop sun4m/sun4d support from head_32.S
>       sparc32: Drop floppy support
>       sparc32: Drop sun4m specific led driver
>       sparc32: Drop sun specific power management drivers
>       sparc32: Drop auxio support
>       sparc32: Drop run-time patching of ipi trap
>       sparc32: Drop patching of interrupt vector
>       sparc32: Drop sun4m/sun4d specific irq handling
>       sparc32: Drop sun4d/sun4m smp support
>       sparc32: Drop pcic support
>       sparc32: Drop mbus support
>       sparc32: Drop unused function __get_{phys,iospace}
>       sparc32: Drop unused mmu models
>       sparc32: Drop check for sparc_model
>       sparc32: Drop use of sparc_config
>       sparc32: Drop run-time patching of ASI instructions
>       sparc32: Drop support for 7 register windows
>       sparc32: Drop additional sun4d bits
>       sparc32: Drop unused prom ranges support
>       sparc32: Drop unused iommu support
>       sparc32: Drop sun4m irq support
>       sparc32: Drop unused trampoline code
>       sparc32: Drop config SPARC_LEON
>       sparc32: Drop sbus support
>       sbus: char: Drop now unused uctrl driver
>       fbdev/p9100: Drop now unused driver p9100
>
>  arch/sparc/Kconfig                    |  54 +--
>  arch/sparc/configs/sparc32_defconfig  | 170 +++----
>  arch/sparc/include/asm/asmmacro.h     |  22 -
>  arch/sparc/include/asm/auxio_32.h     |  73 +--
>  arch/sparc/include/asm/cpu_type.h     |  18 -
>  arch/sparc/include/asm/elf_32.h       |   2 -
>  arch/sparc/include/asm/fb.h           |   8 +-
>  arch/sparc/include/asm/floppy.h       |   2 -
>  arch/sparc/include/asm/floppy_32.h    | 393 ----------------
>  arch/sparc/include/asm/io-unit.h      |  59 ---
>  arch/sparc/include/asm/io_32.h        |  83 ----
>  arch/sparc/include/asm/iommu.h        |   2 -
>  arch/sparc/include/asm/iommu_32.h     | 122 -----
>  arch/sparc/include/asm/irq_32.h       |   2 -
>  arch/sparc/include/asm/mbus.h         |  97 ----
>  arch/sparc/include/asm/mxcc.h         | 138 ------
>  arch/sparc/include/asm/obio.h         | 226 ---------
>  arch/sparc/include/asm/oplib_32.h     |  11 -
>  arch/sparc/include/asm/pcic.h         | 130 ------
>  arch/sparc/include/asm/pgtable_32.h   |  24 -
>  arch/sparc/include/asm/pgtsrmmu.h     |  33 +-
>  arch/sparc/include/asm/ross.h         | 192 --------
>  arch/sparc/include/asm/sbi.h          | 116 -----
>  arch/sparc/include/asm/sections.h     |   3 -
>  arch/sparc/include/asm/swift.h        | 107 -----
>  arch/sparc/include/asm/switch_to_32.h |   1 -
>  arch/sparc/include/asm/timer_32.h     |   1 +
>  arch/sparc/include/asm/tsunami.h      |  65 ---
>  arch/sparc/include/asm/turbosparc.h   | 126 -----
>  arch/sparc/include/asm/viking.h       | 255 -----------
>  arch/sparc/include/asm/winmacro.h     |  11 +-
>  arch/sparc/kernel/Makefile            |   8 +-
>  arch/sparc/kernel/apc.c               | 196 --------
>  arch/sparc/kernel/auxio_32.c          | 139 ------
>  arch/sparc/kernel/cpu.c               |   1 -
>  arch/sparc/kernel/devices.c           |  10 +-
>  arch/sparc/kernel/entry.S             | 413 +----------------
>  arch/sparc/kernel/etrap_32.S          |  50 +-
>  arch/sparc/kernel/head_32.S           | 255 +----------
>  arch/sparc/kernel/ioport.c            |  55 +--
>  arch/sparc/kernel/irq.h               |  85 +---
>  arch/sparc/kernel/irq_32.c            | 133 +-----
>  arch/sparc/kernel/kernel.h            |  53 +--
>  arch/sparc/kernel/led.c               | 146 ------
>  arch/sparc/kernel/leon_kernel.c       |  53 +--
>  arch/sparc/kernel/leon_pmc.c          |  16 +-
>  arch/sparc/kernel/leon_smp.c          |   3 -
>  arch/sparc/kernel/of_device_32.c      |  18 +-
>  arch/sparc/kernel/pcic.c              | 840 ----------------------------------
>  arch/sparc/kernel/pmc.c               | 100 ----
>  arch/sparc/kernel/process_32.c        |  10 -
>  arch/sparc/kernel/rtrap_32.S          |  73 ++-
>  arch/sparc/kernel/setup_32.c          | 115 -----
>  arch/sparc/kernel/smp_32.c            | 102 +----
>  arch/sparc/kernel/sun4d_irq.c         | 519 ---------------------
>  arch/sparc/kernel/sun4d_smp.c         | 415 -----------------
>  arch/sparc/kernel/sun4m_irq.c         | 478 -------------------
>  arch/sparc/kernel/sun4m_smp.c         | 275 -----------
>  arch/sparc/kernel/time_32.c           |  68 +--
>  arch/sparc/kernel/trampoline_32.S     | 127 +----
>  arch/sparc/kernel/ttable_32.S         |   9 +-
>  arch/sparc/kernel/vmlinux.lds.S       |   5 -
>  arch/sparc/kernel/wof.S               |  61 +--
>  arch/sparc/kernel/wuf.S               |  41 +-
>  arch/sparc/mm/Makefile                |   4 +-
>  arch/sparc/mm/hypersparc.S            | 414 -----------------
>  arch/sparc/mm/io-unit.c               | 286 ------------
>  arch/sparc/mm/iommu.c                 | 455 ------------------
>  arch/sparc/mm/mm_32.h                 |   4 -
>  arch/sparc/mm/srmmu.c                 | 836 +--------------------------------
>  arch/sparc/mm/srmmu_access.S          |  83 ----
>  arch/sparc/mm/swift.S                 | 256 -----------
>  arch/sparc/mm/tsunami.S               | 132 ------
>  arch/sparc/mm/viking.S                | 284 ------------
>  arch/sparc/prom/Makefile              |   1 -
>  arch/sparc/prom/init_32.c             |   2 -
>  arch/sparc/prom/misc_32.c             |   2 -
>  arch/sparc/prom/ranges.c              | 114 -----
>  drivers/sbus/char/Kconfig             |   8 -
>  drivers/sbus/char/Makefile            |   1 -
>  drivers/sbus/char/uctrl.c             | 435 ------------------
>  drivers/usb/host/Kconfig              |   2 +-
>  drivers/usb/host/ehci-hcd.c           |   4 +-
>  drivers/usb/host/uhci-hcd.c           |   2 +-
>  drivers/video/fbdev/Kconfig           |  10 +-
>  drivers/video/fbdev/Makefile          |   1 -
>  drivers/video/fbdev/p9100.c           | 372 ---------------
>  sound/sparc/Kconfig                   |   1 +
>  88 files changed, 318 insertions(+), 10809 deletions(-)
> ---
> base-commit: bee0e7762ad2c6025b9f5245c040fcc36ef2bde8
> change-id: 20231219-sam-sparc32-sunset-v3-4751ea89da2d
>
> Best regards,
> --
> Sam Ravnborg <sam@ravnborg.org>
>
>


Hi everyone,

These changes will now effectively make the sparc32 port into a port
that is only really supported by
a rather specific sparc32 implementation delivered by Gaisler. I will
therefore suggest to remove any remaining
references to sparc32 and replaced them with leon, to symbolize the
end of common sparc32 support.


Best regards,
Kjetil Oftedal