Re: [PATCH v14 0/9] LPC: legacy ISA I/O support

From: Andy Shevchenko
Date: Tue Feb 20 2018 - 09:54:42 EST

On Mon, Feb 19, 2018 at 7:48 PM, John Garry <john.garry@xxxxxxxxxx> wrote:
> This patchset supports the IPMI-bt device attached to the Low-Pin-Count
> interface implemented on Hisilicon Hip06/Hip07 SoC.
> -----------
> | LPC host|
> | |
> -----------
> |
> _____________V_______________LPC
> | |
> V V
> ------------
> | BT(ipmi)|
> ------------
>
> When master accesses those peripherals beneath the Hip06/Hip07 LPC, a specific
> LPC driver is needed to make LPC host generate the standard LPC I/O cycles with
> the target peripherals'I/O port addresses. But on curent arm64 world, there is
> no real I/O accesses. All the I/O operations through in/out accessors are based
> on MMIO ranges; on Hip06/Hip07 LPC the I/O accesses are performed through driver
> specific accessors rather than MMIO.
> To solve this issue and keep the relevant existing peripherals' drivers untouched,
> this patchset:
> - introduces a generic I/O space management framework, logical PIO, to support
> I/O operations on host controllers operating either on MMIO buses or on buses
> requiring specific driver I/O accessors;
> - redefines the in/out accessors to provide a unified interface for both MMIO
> and driver specific I/O operations. Using logical PIO, th call of in/out() from
> the host children drivers, such as ipmi-si, will be redirected to the
> corresponding device-specific I/O hooks to perform the I/O accesses.
>
> Based on this patch-set, all the I/O accesses to Hip06/Hip07 LPC peripherals can
> be supported without any changes on the existing ipmi-si driver.
>
> The whole patchset has been tested on Hip07 D05 board both using DTB and ACPI.
>
> Differences to v13:
> - dropped ACPI scan handler and added patch to not enumerate children
> of indirect IO hosts in ACPI code
> - tidied up logic_pio.c a bit for kerneldoc and made some APIs clearer
> to understand
> - tided (and simplified) hisi_lpc.c and added new ACPI probe code
> (same as previous ACPI scan handler code, so comments from Rafael
> and Andy included)
> - reinstated PCI range upper limit check in pci_pio_to_address()
> - dropped Dann Frazier's "tested-by" tag in light of changes
> - rebase to linuxnext 20180219 (had to fix locally arm64 build issue)
>

Some minor comments per patches, otherwise FWIW

Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>

> Differences to v12:
> - Addressed ACPI comments from Rafael and Andy, including:
> - added SPDX license identifiers (other new files in the series got this also)
> - fixed style issues, like superflous newlines and symbol naming
> - add fuller acpi_indirectio.c patch commit message
> - dropped acpi_indirectio_host_data (author's decision) to simplify
> - added Rob Herring's tag
> - rebase to linux-next 20180212
>
> Differences to v11:
> - fixed build errors for i386, m68k, and tile
> - added a comment in LPC driver commit log why we set
> the kernel config as bool
> - some tidying logic_pio code
>
> Differences to v10:
> - dropped CONFIG_LOGIC_PIO. Reason is that CONFIG_PCI
> depends on this, and CONFIG_PCI is a per-arch CONFIG.
> So we would require all arch's kconfig to select this.
> - Addressed Dann Frazier's comments on LPC driver, and
> sopme other cleanup
> - Moved logic_pio.h to be included in generic asm io.h
> - Fixed ACPI indirect IO host setup to handle >1 child
> - Relocated ACPI indirect IO host setup code to
> drivers/acpi
> - Rebased to linux next-20180118
>
> Changes from v9:
> - patch 2 has been split into 3 patches according to Bjorn comments on
> v9 thread
> - patch 1 has been reworked accordign to Bjorn comments on v9
> - now logic_pio_trans_hwaddr() has a sanity check to make sure the resource
> size fits into the assigned range
> - in patch 5 the MFD framework has been used to probe the LPC children
> according to the suggestion from Mika Westerberg
> - Maintaner has changed to Huawei Linuxarm mailing list
>
> Changes from v8:
> - Simplified LIB IO framewrok
> - Moved INDIRECT PIO ACPI framework under acpi/arm64
> - Renamed occurrences of "lib io" and "indirect io" to "lib pio" and
> "indirect pio" to keep the patchset nomenclature consistent
> - Removed Alignment reuqirements
> - Moved LPC specific code out of ACPI common framework
> - Now PIO indirect HW ranges can overlap
> - Changed HiSilicon LPC driver maintainer (Gabriele Paoloni now) and split
> maintaner file modifications in a separate commit
> - Removed the commit with the DT nodes support for hip06 and hip07 (to be
> pushed separately)
> - Added a checking on ioport_map() not to break that function as Arnd points
> out in V7 review thread;
> - fixed the compile issues on alpha, m68k;
>
> Changes from V7:
> - Based on Arnd's comment, rename the LIBIO as LOGIC_PIO;
> - Improved the mapping process in LOGIC_PIO to gain better efficiency when
> redirecting the I/O accesses to right device driver;
> - To reduce the impact on PCI MMIO to a minimum, add a new
> CONFIG_INDIRECT_PIO for indirect-IO hosts/devices;
> - Added a new ACPI handler for indirect-IO hosts/devices;
> - Fixed the compile issues on V6;
>
> Changes from V6:
> - According to the comments from Bjorn and Alex, merge PCI IO and indirect-IO
> into a generic I/O space management, LIBIO;
> - Adopted the '_DEP' to replace the platform bus notifier. In this way, we can
> ensure the LPC peripherals' I/O resources had been translated to logical IO
> before the LPC peripheral enumeration;
> - Replaced the rwlock with rcu list based on Alex's suggestion;
> - Applied relaxed write/read to LPC driver;
> - Some bugs fixing and some optimazations based on the comments of V6;
>
> Changes from V5:
> - Made the extio driver more generic and locate in lib/;
> - Supported multiple indirect-IO bus instances;
> - Extended the pci_register_io_range() to support indirect-IO, then dropped
> the I/O reservation used in previous patchset;
> - Reimplemented the ACPI LPC support;
> - Fixed some bugs, including the compile error on other archs, the module
> building failure found by Ming Lei, etc;
>
> Changes from V4:
> - Some revises based on the comments from Bjorn, Rob on V4;
> - Fixed the compile error on some platforms, such as openrisc;
>
> Changes from V3:
> - UART support deferred to a separate patchset; This patchset only support
> ipmi device under LPC;
> - LPC bus I/O range is fixed to 0 ~ (PCIBIOS_MIN_IO - 1), which is separeted
> from PCI/PCIE PIO space;
> - Based on Arnd's remarks, removed the ranges property from Hip06 lpc dts and
> added a new fixup function, of_isa_indirect_io(), to get the I/O address
> directly from LPC dts configurations;
> - Support in(w,l)/out(w,l) for Hip06 lpc I/O;
> - Decouple the header file dependency on the gerenic io.h by defining in/out
> as normal functions in c file;
> - removed unused macro definitions in the LPC driver;
>
> Changes from V2:
> - Support the PIO retrieval from the linux PIO generated by
> pci_address_to_pio. This method replace the 4K PIO reservation in V2;
> - Support the flat-tree earlycon;
> - Some revises based on Arnd's remarks;
> - Make sure the linux PIO range allocated to Hip06 LPC peripherals starts
> from non-ZERO;
>
> Changes from V1:
> - Support the ACPI LPC device;
> - Optimize the dts LPC driver in ISA compatible mode;
> - Reserve the IO range below 4K in avoid the possible conflict with PCI host
> IO ranges;
> - Support the LPC uart and relevant earlycon;
>
> V13 thread here: https://lkml.org/lkml/2018/2/13/744
> V12 thread here: https://lkml.org/lkml/2018/1/23/508
> V11 thread here: https://lkml.org/lkml/2018/1/21/38
> V10 thread here: https://lkml.org/lkml/2017/10/27/465
> V9 thread here: https://lkml.org/lkml/2017/5/25/263
> V8 thread here: https://lkml.org/lkml/2017/3/30/619
> V7 thread here: https://lkml.org/lkml/2017/3/12/279
> v6 thread here: https://lkml.org/lkml/2017/1/24/25
> v5 thread here: https://lkml.org/lkml/2016/11/7/955
> v4 thread here: https://lkml.org/lkml/2016/10/20/149
> v3 thread here: https://lkml.org/lkml/2016/9/14/326
> v2 thread here: https://lkml.org/lkml/2016/9/7/356
> v1 thread here: https://lkml.org/lkml/2015/12/29/154
>
> Gabriele Paoloni (2):
> PCI: Remove unused __weak attribute in pci_register_io_range()
> PCI: Add fwnode handler as input param of pci_register_io_range()
>
> John Garry (3):
> ACPI / scan: do not enumerate Indirect IO host children
> HISI LPC: Add ACPI support
> MAINTAINERS: Add maintainer for HiSilicon LPC driver
>
> Zhichang Yuan (4):
> LIB: Introduce a generic PIO mapping method
> PCI: Apply the new generic I/O management on PCI IO hosts
> OF: Add missing I/O range exception for indirect-IO devices
> HISI LPC: Support the LPC host on Hip06/Hip07 with DT bindings
>
> .../arm/hisilicon/hisilicon-low-pin-count.txt | 33 ++
> MAINTAINERS | 7 +
> drivers/acpi/pci_root.c | 8 +-
> drivers/acpi/scan.c | 14 +
> drivers/bus/Kconfig | 8 +
> drivers/bus/Makefile | 1 +
> drivers/bus/hisi_lpc.c | 646 +++++++++++++++++++++
> drivers/of/address.c | 96 ++-
> drivers/pci/pci.c | 95 +--
> include/asm-generic/io.h | 4 +-
> include/linux/logic_pio.h | 131 +++++
> include/linux/pci.h | 3 +-
> lib/Kconfig | 15 +
> lib/Makefile | 2 +
> lib/logic_pio.c | 285 +++++++++
> 15 files changed, 1250 insertions(+), 98 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/arm/hisilicon/hisilicon-low-pin-count.txt
> create mode 100644 drivers/bus/hisi_lpc.c
> create mode 100644 include/linux/logic_pio.h
> create mode 100644 lib/logic_pio.c
>
> --
> 1.9.1
>



--
With Best Regards,
Andy Shevchenko