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

[Gregory CLEMENT]

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/

>
>> 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.

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