Re: [PATCH v15 0/9] LPC: legacy ISA I/O support

[Andy Shevchenko]

On Tue, 2018-02-27 at 00:40 +0800, John Garry 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.
> 

I did a review and don't see the patch 8 is ready to go.

So, to move things forward I may suggest to reorder series that some
small preparation stuff can go first w/o dependency to the actual Logic
PIO / LPC.

> Differences to v14:
> - addressed coding style comments from Andy
> - applied tags from Rafael, Andy, and Dann
> - rebased to linux next 20180223 (had to fix locally arm64 build
> issue)
> 
> 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)
> 
> 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;
> 
> V14 thread here: https://lkml.org/lkml/2018/2/19/460
> 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                               |   2 +
>  drivers/bus/hisi_lpc.c                             | 624
> +++++++++++++++++++++
>  drivers/of/address.c                               |  96 +++-
>  drivers/pci/pci.c                                  |  95 +---
>  include/asm-generic/io.h                           |   4 +-
>  include/linux/logic_pio.h                          | 127 +++++
>  include/linux/pci.h                                |   3 +-
>  lib/Kconfig                                        |  15 +
>  lib/Makefile                                       |   2 +
>  lib/logic_pio.c                                    | 285 ++++++++++
>  15 files changed, 1225 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
> 

-- 
Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Intel Finland Oy