Re: [PATCH v2] arm64: dts: marvell: armada-37xx: Remap IO space to bus address 0x0

[Pali Rohár]

On Thursday 10 March 2022 11:23:26 Gregory CLEMENT wrote:
> Pali Rohár <pali@xxxxxxxxxx> writes:
> 
> > On Thursday 10 March 2022 11:05:00 Gregory CLEMENT wrote:
> >> Hello Pali,
> >> 
> >> > Legacy and old PCI I/O based cards do not support 32-bit I/O addressing.
> >> >
> >> > Since commit 64f160e19e92 ("PCI: aardvark: Configure PCIe resources from
> >> > 'ranges' DT property") kernel can set different PCIe address on CPU and
> >> > different on the bus for the one A37xx address mapping without any firmware
> >> > support in case the bus address does not conflict with other A37xx mapping.
> >> >
> >> > So remap I/O space to the bus address 0x0 to enable support for old legacy
> >> > I/O port based cards which have hardcoded I/O ports in low address space.
> >> >
> >> > Note that DDR on A37xx is mapped to bus address 0x0. And mapping of I/O
> >> > space can be set to address 0x0 too because MEM space and I/O space are
> >> > separate and so do not conflict.
> >> >
> >> > Remapping IO space on Turris Mox to different address is not possible to
> >> > due bootloader bug.
> >> >
> >> > Signed-off-by: Pali Rohár <pali@xxxxxxxxxx>
> >> > Reported-by: Arnd Bergmann <arnd@xxxxxxxx>
> >> > Fixes: 76f6386b25cc ("arm64: dts: marvell: Add Aardvark PCIe support for Armada 3700")
> >> > Cc: stable@xxxxxxxxxxxxxxx # 64f160e19e92 ("PCI: aardvark: Configure PCIe resources from 'ranges' DT property")
> >> > Cc: stable@xxxxxxxxxxxxxxx # 514ef1e62d65 ("arm64: dts: marvell: armada-37xx: Extend PCIe MEM space")
> >> >
> >> Cc: stable@xxxxxxxxxxxxxxx # ???????????? ("arm64: dts: marvell: armada-37xx: Increase PCIe IO size from 64 KiB to 1 MiB")
> >> 
> >> This patch has been refused by Arnd so I removed it from the mvebu/fixes
> >> branch so you should not apply anything on top of it.
> >
> > Ok, so what is wrong with a change which increase size of IO space to 1 MB?
> 
> https://lore.kernel.org/linux-arm-kernel/CAK8P3a2D8Yv+KpM4NJyP9mosieqbhHh08=mdEy+OA84Vx6FVCQ@xxxxxxxxxxxxxx/

The whole discussion was about remapping IO to 0 and this is addressed
in this patch. Therefore I thought that it is resolved...

Now I see that Arnd wrote also about size increasing, so some
misunderstanding from my side.

> >
> >> Actually I still try to first apply the old patch and then this one but
> >> it still fail. And it is also failed when I applied this one on a
> >> v5.17-rc1, so I wondered on which did create this patch.
> >
> > Ok, at which branch / commit should I rebase it?
> 
> Please create only one single patch on top of v5.17-rc1.

Done in v3. Hopefully now it is correct.

> Thanks!
> 
> Gregory
> 
> >
> >> Grégory
> >> 
> >> > ---
> >> > Changes in v2:
> >> > * Do not remap IO space on Turris Mox
> >> > ---
> >> >  arch/arm64/boot/dts/marvell/armada-3720-turris-mox.dts | 7 ++++++-
> >> >  arch/arm64/boot/dts/marvell/armada-37xx.dtsi           | 2 +-
> >> >  2 files changed, 7 insertions(+), 2 deletions(-)
> >> >
> >> > diff --git a/arch/arm64/boot/dts/marvell/armada-3720-turris-mox.dts b/arch/arm64/boot/dts/marvell/armada-3720-turris-mox.dts
> >> > index 6581092c2c90..2838e3f65ada 100644
> >> > --- a/arch/arm64/boot/dts/marvell/armada-3720-turris-mox.dts
> >> > +++ b/arch/arm64/boot/dts/marvell/armada-3720-turris-mox.dts
> >> > @@ -150,17 +150,22 @@
> >> >  	slot-power-limit = <10000>;
> >> >  	/*
> >> >  	 * U-Boot port for Turris Mox has a bug which always expects that "ranges" DT property
> >> >  	 * contains exactly 2 ranges with 3 (child) address cells, 2 (parent) address cells and
> >> > -	 * 2 size cells and also expects that the second range starts at 16 MB offset. If these
> >> > +	 * 2 size cells and also expects that the second range starts at 16 MB offset. Also it
> >> > +	 * expects that first range uses same address for PCI (child) and CPU (parent) cells (so
> >> > +	 * no remapping) and that this address is the lowest from all specified ranges. If these
> >> >  	 * conditions are not met then U-Boot crashes during loading kernel DTB file. PCIe address
> >> >  	 * space is 128 MB long, so the best split between MEM and IO is to use fixed 16 MB window
> >> >  	 * for IO and the rest 112 MB (64+32+16) for MEM. Controller supports 32-bit IO mapping.
> >> >  	 * This bug is not present in U-Boot ports for other Armada 3700 devices and is fixed in
> >> >  	 * U-Boot version 2021.07. See relevant U-Boot commits (the last one contains fix):
> >> >  	 * https://source.denx.de/u-boot/u-boot/-/commit/cb2ddb291ee6fcbddd6d8f4ff49089dfe580f5d7
> >> >  	 * https://source.denx.de/u-boot/u-boot/-/commit/c64ac3b3185aeb3846297ad7391fc6df8ecd73bf
> >> >  	 * https://source.denx.de/u-boot/u-boot/-/commit/4a82fca8e330157081fc132a591ebd99ba02ee33
> >> > +	 * Bug related to requirement of same child and parent addresses for first range is fixed
> >> > +	 * in U-Boot version 2022.04 by following commit:
> >> > +	 * https://source.denx.de/u-boot/u-boot/-/commit/1fd54253bca7d43d046bba4853fe5fafd034bc17
> >> >  	 */
> >> >  	#address-cells = <3>;
> >> >  	#size-cells = <2>;
> >> >  	ranges = <0x81000000 0 0xe8000000   0 0xe8000000   0 0x01000000   /* Port 0 IO */
> >> > diff --git a/arch/arm64/boot/dts/marvell/armada-37xx.dtsi b/arch/arm64/boot/dts/marvell/armada-37xx.dtsi
> >> > index 549c3f7c5b27..a099b7787429 100644
> >> > --- a/arch/arm64/boot/dts/marvell/armada-37xx.dtsi
> >> > +++ b/arch/arm64/boot/dts/marvell/armada-37xx.dtsi
> >> > @@ -514,9 +514,9 @@
> >> >  			 * IO at the end and the remaining seven windows
> >> >  			 * (totaling 127 MiB) for MEM.
> >> >  			 */
> >> >  			ranges = <0x82000000 0 0xe8000000   0 0xe8000000   0 0x07f00000   /* Port 0 MEM */
> >> > -				  0x81000000 0 0xeff00000   0 0xeff00000   0 0x00100000>; /* Port 0 IO*/
> >> > +				  0x81000000 0 0x00000000   0 0xeff00000   0 0x00100000>; /* Port 0 IO */
> >> >  			interrupt-map-mask = <0 0 0 7>;
> >> >  			interrupt-map = <0 0 0 1 &pcie_intc 0>,
> >> >  					<0 0 0 2 &pcie_intc 1>,
> >> >  					<0 0 0 3 &pcie_intc 2>,
> >> > -- 
> >> > 2.20.1
> >> >
> >> 
> >> -- 
> >> Gregory Clement, Bootlin
> >> Embedded Linux and Kernel engineering
> >> http://bootlin.com
> 
> -- 
> Gregory Clement, Bootlin
> Embedded Linux and Kernel engineering
> http://bootlin.com