| Message ID | 20200218171321.30990-1-robh@kernel.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | Removing Calxeda platform support | expand |
On Tue, 18 Feb 2020 11:13:10 -0600 Rob Herring <robh@kernel.org> wrote: Hi, > Calxeda has been defunct for 6 years now. Use of Calxeda servers carried > on for some time afterwards primarily as distro builders for 32-bit ARM. > AFAIK, those systems have been retired in favor of 32-bit VMs on 64-bit > hosts. > > The other use of Calxeda Midway I'm aware of was testing 32-bit ARM KVM > support as there are few or no other systems with enough RAM and LPAE. Now > 32-bit KVM host support is getting removed[1]. > > While it's not much maintenance to support, I don't care to convert the > Calxeda DT bindings to schema nor fix any resulting errors in the dts files > (which already don't exactly match what's shipping in firmware). While every kernel maintainer seems always happy to take patches with a negative diffstat, I wonder if this is really justification enough to remove a perfectly working platform. I don't really know about any active users, but experience tells that some platforms really are used for quite a long time, even if they are somewhat obscure. N900 or Netwinder, anyone? So to not give the impression that actually *everyone* (from that small subset of people actively reading the kernel list) is happy with that, I think that having support for at least Midway would be useful. On the one hand it's a decent LPAE platform (with memory actually exceeding 4GB), and on the other hand it's something with capable I/O (SATA) and networking, so one can actually stress test the system. Which is the reason I was using that for KVM testing, but even with that probably going away now there remain still some use cases, and be it for general ARM(32) testing. I don't particularly care about the more optional parts like EDAC, cpuidle, or cpufreq, but I wonder if keeping in at least the rather small SATA and XGMAC drivers and basic platform support is feasible. If YAML DT bindings are used as an excuse, I am more than happy to convert those over. And if anyone has any particular gripes with some code, maybe there is a way to fix that instead of removing it? I was always wondering if we could get rid of the mach-highbank directory, for instance. I think most of it is Highbank (Cortex-A9) related. Cheers, Andre > > Rob > > [1] https://lore.kernel.org/linux-arm-kernel/20200210141324.21090-1-maz@kernel.org/ > > Rob Herring (11): > vfio: Remove Calxeda XGMAC reset driver > ata: Remove Calxeda AHCI driver > cpuidle: Remove Calxeda driver > cpufreq: Remove Calxeda driver > EDAC: Remove Calxeda drivers > iommu: arm-smmu: Remove Calxeda secure mode quirk > net: Remove Calxeda XGMAC driver > clk: Remove Calxeda driver > ARM: Remove Calxeda platform support > ARM: dts: Remove Calxeda platforms > dt-bindings: Remove Calxeda platforms bindings > > .../devicetree/bindings/arm/calxeda.yaml | 22 - > .../devicetree/bindings/arm/calxeda/l2ecc.txt | 15 - > .../devicetree/bindings/ata/sata_highbank.txt | 44 - > .../devicetree/bindings/clock/calxeda.txt | 17 - > .../memory-controllers/calxeda-ddr-ctrlr.txt | 16 - > .../devicetree/bindings/net/calxeda-xgmac.txt | 18 - > .../bindings/phy/calxeda-combophy.txt | 17 - > MAINTAINERS | 14 - > arch/arm/Kconfig | 2 - > arch/arm/Kconfig.debug | 12 +- > arch/arm/Makefile | 1 - > arch/arm/boot/dts/Makefile | 3 - > arch/arm/boot/dts/ecx-2000.dts | 103 - > arch/arm/boot/dts/ecx-common.dtsi | 230 -- > arch/arm/boot/dts/highbank.dts | 161 -- > arch/arm/configs/multi_v7_defconfig | 5 - > arch/arm/mach-highbank/Kconfig | 19 - > arch/arm/mach-highbank/Makefile | 4 - > arch/arm/mach-highbank/core.h | 18 - > arch/arm/mach-highbank/highbank.c | 175 -- > arch/arm/mach-highbank/pm.c | 49 - > arch/arm/mach-highbank/smc.S | 25 - > arch/arm/mach-highbank/sysregs.h | 75 - > arch/arm/mach-highbank/system.c | 22 - > drivers/ata/Kconfig | 9 - > drivers/ata/Makefile | 1 - > drivers/ata/sata_highbank.c | 635 ------ > drivers/clk/Makefile | 1 - > drivers/clk/clk-highbank.c | 329 --- > drivers/cpufreq/Kconfig.arm | 10 - > drivers/cpufreq/Makefile | 3 +- > drivers/cpufreq/cpufreq-dt-platdev.c | 3 - > drivers/cpufreq/highbank-cpufreq.c | 106 - > drivers/cpuidle/Kconfig.arm | 7 - > drivers/cpuidle/Makefile | 1 - > drivers/cpuidle/cpuidle-calxeda.c | 72 - > drivers/edac/Kconfig | 14 - > drivers/edac/Makefile | 3 - > drivers/edac/highbank_l2_edac.c | 142 -- > drivers/edac/highbank_mc_edac.c | 272 --- > drivers/iommu/arm-smmu-impl.c | 43 - > drivers/net/ethernet/Kconfig | 1 - > drivers/net/ethernet/Makefile | 1 - > drivers/net/ethernet/calxeda/Kconfig | 9 - > drivers/net/ethernet/calxeda/Makefile | 2 - > drivers/net/ethernet/calxeda/xgmac.c | 1927 ----------------- > drivers/vfio/platform/reset/Kconfig | 8 - > drivers/vfio/platform/reset/Makefile | 2 - > .../reset/vfio_platform_calxedaxgmac.c | 74 - > 49 files changed, 2 insertions(+), 4740 deletions(-) > delete mode 100644 Documentation/devicetree/bindings/arm/calxeda.yaml > delete mode 100644 Documentation/devicetree/bindings/arm/calxeda/l2ecc.txt > delete mode 100644 Documentation/devicetree/bindings/ata/sata_highbank.txt > delete mode 100644 Documentation/devicetree/bindings/clock/calxeda.txt > delete mode 100644 Documentation/devicetree/bindings/memory-controllers/calxeda-ddr-ctrlr.txt > delete mode 100644 Documentation/devicetree/bindings/net/calxeda-xgmac.txt > delete mode 100644 Documentation/devicetree/bindings/phy/calxeda-combophy.txt > delete mode 100644 arch/arm/boot/dts/ecx-2000.dts > delete mode 100644 arch/arm/boot/dts/ecx-common.dtsi > delete mode 100644 arch/arm/boot/dts/highbank.dts > delete mode 100644 arch/arm/mach-highbank/Kconfig > delete mode 100644 arch/arm/mach-highbank/Makefile > delete mode 100644 arch/arm/mach-highbank/core.h > delete mode 100644 arch/arm/mach-highbank/highbank.c > delete mode 100644 arch/arm/mach-highbank/pm.c > delete mode 100644 arch/arm/mach-highbank/smc.S > delete mode 100644 arch/arm/mach-highbank/sysregs.h > delete mode 100644 arch/arm/mach-highbank/system.c > delete mode 100644 drivers/ata/sata_highbank.c > delete mode 100644 drivers/clk/clk-highbank.c > delete mode 100644 drivers/cpufreq/highbank-cpufreq.c > delete mode 100644 drivers/cpuidle/cpuidle-calxeda.c > delete mode 100644 drivers/edac/highbank_l2_edac.c > delete mode 100644 drivers/edac/highbank_mc_edac.c > delete mode 100644 drivers/net/ethernet/calxeda/Kconfig > delete mode 100644 drivers/net/ethernet/calxeda/Makefile > delete mode 100644 drivers/net/ethernet/calxeda/xgmac.c > delete mode 100644 drivers/vfio/platform/reset/vfio_platform_calxedaxgmac.c > > > base-commit: 11a48a5a18c63fd7621bb050228cebf13566e4d8 > -- > 2.20.1
On Tue, Feb 18, 2020 at 12:14 PM Andre Przywara <andre.przywara@arm.com> wrote: > > On Tue, 18 Feb 2020 11:13:10 -0600 > Rob Herring <robh@kernel.org> wrote: > > Hi, > > > Calxeda has been defunct for 6 years now. Use of Calxeda servers carried > > on for some time afterwards primarily as distro builders for 32-bit ARM. > > AFAIK, those systems have been retired in favor of 32-bit VMs on 64-bit > > hosts. > > > > The other use of Calxeda Midway I'm aware of was testing 32-bit ARM KVM > > support as there are few or no other systems with enough RAM and LPAE. Now > > 32-bit KVM host support is getting removed[1]. > > > > While it's not much maintenance to support, I don't care to convert the > > Calxeda DT bindings to schema nor fix any resulting errors in the dts files > > (which already don't exactly match what's shipping in firmware). > > While every kernel maintainer seems always happy to take patches with a negative diffstat, I wonder if this is really justification enough to remove a perfectly working platform. I don't really know about any active users, but experience tells that some platforms really are used for quite a long time, even if they are somewhat obscure. N900 or Netwinder, anyone? > > So to not give the impression that actually *everyone* (from that small subset of people actively reading the kernel list) is happy with that, I think that having support for at least Midway would be useful. On the one hand it's a decent LPAE platform (with memory actually exceeding 4GB), and on the other hand it's something with capable I/O (SATA) and networking, so one can actually stress test the system. Which is the reason I was using that for KVM testing, but even with that probably going away now there remain still some use cases, and be it for general ARM(32) testing. Does LPAE with more than 4GB actually need to work if there's not another platform out there? > I don't particularly care about the more optional parts like EDAC, cpuidle, or cpufreq, but I wonder if keeping in at least the rather small SATA and XGMAC drivers and basic platform support is feasible. cpuidle isn't actually stable from what I remember. I think without cpufreq, we default to 1.1GHz instead of 1.4. > If YAML DT bindings are used as an excuse, I am more than happy to convert those over. Thanks! > > And if anyone has any particular gripes with some code, maybe there is a way to fix that instead of removing it? I was always wondering if we could get rid of the mach-highbank directory, for instance. I think most of it is Highbank (Cortex-A9) related. All the reset/suspend/poweroff and coherency parts are shared. The SCU and L2 parts could be removed, but not really worth the surgery IMO. Rob
On 2/18/20 10:40 AM, Rob Herring wrote: > On Tue, Feb 18, 2020 at 12:14 PM Andre Przywara <andre.przywara@arm.com> wrote: >> >> On Tue, 18 Feb 2020 11:13:10 -0600 >> Rob Herring <robh@kernel.org> wrote: >> >> Hi, >> >>> Calxeda has been defunct for 6 years now. Use of Calxeda servers carried >>> on for some time afterwards primarily as distro builders for 32-bit ARM. >>> AFAIK, those systems have been retired in favor of 32-bit VMs on 64-bit >>> hosts. >>> >>> The other use of Calxeda Midway I'm aware of was testing 32-bit ARM KVM >>> support as there are few or no other systems with enough RAM and LPAE. Now >>> 32-bit KVM host support is getting removed[1]. >>> >>> While it's not much maintenance to support, I don't care to convert the >>> Calxeda DT bindings to schema nor fix any resulting errors in the dts files >>> (which already don't exactly match what's shipping in firmware). >> >> While every kernel maintainer seems always happy to take patches with a negative diffstat, I wonder if this is really justification enough to remove a perfectly working platform. I don't really know about any active users, but experience tells that some platforms really are used for quite a long time, even if they are somewhat obscure. N900 or Netwinder, anyone? >> >> So to not give the impression that actually *everyone* (from that small subset of people actively reading the kernel list) is happy with that, I think that having support for at least Midway would be useful. On the one hand it's a decent LPAE platform (with memory actually exceeding 4GB), and on the other hand it's something with capable I/O (SATA) and networking, so one can actually stress test the system. Which is the reason I was using that for KVM testing, but even with that probably going away now there remain still some use cases, and be it for general ARM(32) testing. > > Does LPAE with more than 4GB actually need to work if there's not > another platform out there? There are ARCH_BRCMSTB platforms that are 32-bit only and have 6GB of DRAM populated, and those continue to work just fine, though there is no known use for KVM AFAICT.
Hi, On Tue, Feb 18, 2020 at 10:14 AM Andre Przywara <andre.przywara@arm.com> wrote: > > On Tue, 18 Feb 2020 11:13:10 -0600 > Rob Herring <robh@kernel.org> wrote: > > Hi, > > > Calxeda has been defunct for 6 years now. Use of Calxeda servers carried > > on for some time afterwards primarily as distro builders for 32-bit ARM. > > AFAIK, those systems have been retired in favor of 32-bit VMs on 64-bit > > hosts. > > > > The other use of Calxeda Midway I'm aware of was testing 32-bit ARM KVM > > support as there are few or no other systems with enough RAM and LPAE. Now > > 32-bit KVM host support is getting removed[1]. > > > > While it's not much maintenance to support, I don't care to convert the > > Calxeda DT bindings to schema nor fix any resulting errors in the dts files > > (which already don't exactly match what's shipping in firmware). > > While every kernel maintainer seems always happy to take patches with a negative diffstat, I wonder if this is really justification enough to remove a perfectly working platform. I don't really know about any active users, but experience tells that some platforms really are used for quite a long time, even if they are somewhat obscure. N900 or Netwinder, anyone? One of the only ways we know to confirm whether there are active users or not, is to propose removing a platform. The good news is that if/when you do, and someone cares enough about it to want to keep it alive, they should also have access to hardware and can help out in maintaining it and keeping it in a working state. For some hardware platforms, at some point in time it no longer makes sense to keep the latest kernel available on them, especially if maintainers and others no longer have easy access to hardware and resources/time to keep it functional. It's really more about "If you care about this enough to keep it going, please speak up and help out". > So to not give the impression that actually *everyone* (from that small subset of people actively reading the kernel list) is happy with that, I think that having support for at least Midway would be useful. On the one hand it's a decent LPAE platform (with memory actually exceeding 4GB), and on the other hand it's something with capable I/O (SATA) and networking, so one can actually stress test the system. Which is the reason I was using that for KVM testing, but even with that probably going away now there remain still some use cases, and be it for general ARM(32) testing. How many bugs have you found on this platform that you would not have on a more popular one? And, how many of those bugs only affected this platform, i.e. just adding onto the support burden without positive impact to the broader community? > I don't particularly care about the more optional parts like EDAC, cpuidle, or cpufreq, but I wonder if keeping in at least the rather small SATA and XGMAC drivers and basic platform support is feasible. At what point are you better off just running under QEMU/virtualization? > If YAML DT bindings are used as an excuse, I am more than happy to convert those over. > > And if anyone has any particular gripes with some code, maybe there is a way to fix that instead of removing it? I was always wondering if we could get rid of the mach-highbank directory, for instance. I think most of it is Highbank (Cortex-A9) related. Again, how do you fix it if nobody has signed up for maintaining and keeping it working? Doing blind changes that might or might not work is not a way to keep a platform supported. Just because code is removed, it doesn't mean it can't be reintroduced when someone comes along and wants to do that. Look at some of the recent additions of old OLPC hardware support, for example. But there's a difference between this and keeping the code around hoping that someone will care about it. It's not lost, and it's easy to bring back. -Olof
On 19/02/2020 22:54, Olof Johansson wrote: Hi, > On Tue, Feb 18, 2020 at 10:14 AM Andre Przywara <andre.przywara@arm.com> wrote: >> >> On Tue, 18 Feb 2020 11:13:10 -0600 >> Rob Herring <robh@kernel.org> wrote: >> >> Hi, >> >>> Calxeda has been defunct for 6 years now. Use of Calxeda servers carried >>> on for some time afterwards primarily as distro builders for 32-bit ARM. >>> AFAIK, those systems have been retired in favor of 32-bit VMs on 64-bit >>> hosts. >>> >>> The other use of Calxeda Midway I'm aware of was testing 32-bit ARM KVM >>> support as there are few or no other systems with enough RAM and LPAE. Now >>> 32-bit KVM host support is getting removed[1]. >>> >>> While it's not much maintenance to support, I don't care to convert the >>> Calxeda DT bindings to schema nor fix any resulting errors in the dts files >>> (which already don't exactly match what's shipping in firmware). >> >> While every kernel maintainer seems always happy to take patches with a negative diffstat, I wonder if this is really justification enough to remove a perfectly working platform. I don't really know about any active users, but experience tells that some platforms really are used for quite a long time, even if they are somewhat obscure. N900 or Netwinder, anyone? > > One of the only ways we know to confirm whether there are active users > or not, is to propose removing a platform. > > The good news is that if/when you do, and someone cares enough about > it to want to keep it alive, they should also have access to hardware > and can help out in maintaining it and keeping it in a working state. > > For some hardware platforms, at some point in time it no longer makes > sense to keep the latest kernel available on them, especially if > maintainers and others no longer have easy access to hardware and > resources/time to keep it functional. > > It's really more about "If you care about this enough to keep it > going, please speak up and help out". I understand that, hence this email ;-) I just wanted to avoid the impression that, by looking at the replies on the list, *everybody* seems to be happy with the removal and it just goes ahead. I have no idea how many actual *users* read this list and this email. >> So to not give the impression that actually *everyone* (from that small subset of people actively reading the kernel list) is happy with that, I think that having support for at least Midway would be useful. On the one hand it's a decent LPAE platform (with memory actually exceeding 4GB), and on the other hand it's something with capable I/O (SATA) and networking, so one can actually stress test the system. Which is the reason I was using that for KVM testing, but even with that probably going away now there remain still some use cases, and be it for general ARM(32) testing. > > How many bugs have you found on this platform that you would not have > on a more popular one? And, how many of those bugs only affected this > platform, i.e. just adding onto the support burden without positive > impact to the broader community? I have found and helped fixing (or fixed myself) multiple bugs on the Midway in the past. The mixture of decent I/O and 8GB of DRAM seemed to be unique enough to spot bugs that didn't easily show on other systems. Most were on KVM, but some were generic, and I remember at least one LPAE related. And some bugs only showed under stress, because you can actually run something useful on that machine before it goes on its knees. >> I don't particularly care about the more optional parts like EDAC, cpuidle, or cpufreq, but I wonder if keeping in at least the rather small SATA and XGMAC drivers and basic platform support is feasible. > > At what point are you better off just running under QEMU/virtualization? For many things we are looking at that's not really an option. If it would be very involved or painful to keep the support alive (as in the KVM/arm32 case), I would see your point, but just some isolated drivers (really a few and mostly quite small) don't justify a removal, IMHO. I think we have far worse and older code in the kernel to worry about. >> If YAML DT bindings are used as an excuse, I am more than happy to convert those over. >> >> And if anyone has any particular gripes with some code, maybe there is a way to fix that instead of removing it? I was always wondering if we could get rid of the mach-highbank directory, for instance. I think most of it is Highbank (Cortex-A9) related. > > Again, how do you fix it if nobody has signed up for maintaining and > keeping it working? Doing blind changes that might or might not work > is not a way to keep a platform supported. > > Just because code is removed, it doesn't mean it can't be reintroduced > when someone comes along and wants to do that. Look at some of the > recent additions of old OLPC hardware support, for example. But > there's a difference between this and keeping the code around hoping > that someone will care about it. It's not lost, and it's easy to bring > back. OK, maybe I should have been more explicit: If Rob does not want to maintain it anymore, I am happy to throw my hat in the ring. I have a working Midway system under my desk, with at least four working nodes, two of them have an SSD connected and are running some off-the-shelf Ubuntu 18.04 or Debian userland. I mostly run mainline kernels, but try the distro kernels as well from time to time. Routinely I test at least every -rc1 for regressions. I also have updates to the A-15 firmware parts (U-Boot and PSCI runtime, including PSCI 1.0 support and a Spectre V2 workaround), and have a working setup to either chainload or actually update the firmware on the flash. Happy to share that if someone is interested. For U-Boot I wanted to send updates anyway. I also have an old Highbank system lying around, but haven't turned that on in years. So would just a patch to MAINTAINERS be a solution? Cheers, Andre