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Subject[PATCH V8 0/7] LPC: legacy ISA I/O support
This patchset supports the IPMI-bt device attached to the Low-Pin-Count
interface implemented on Hisilicon Hip06/Hip07 SoC.
| LPC host|
| |
| |
| 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 pair are based on
MMIO which is not satisfied the I/O mechanism on Hip06/Hip07 LPC.
To solve this issue and keep the relevant existing peripherals' driver
untouched, this patchset implements:
- introduces a generic I/O space management framwork, LIBIO, to support I/O
operations of both MMIO buses and the host controllers which access their
peripherals with host local I/O addresses;
- redefines the in/out accessors to provide unified interfaces for MMIO and
legacy I/O. Based on the LIBIO, the calling of in/out() from upper-layer
drivers, such as ipmi-si, will be redirected to the corresponding
device-specific I/O hooks to perfrom 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.

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;

V7 thread here:
v6 thread here:
v5 thread here:
v4 thread here:
v3 thread here:
v2 thread here:
v1 thread here:

Signed-off-by: Zhichang Yuan <>
zhichang.yuan (6):
LIBIO: 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
LPC: Support the device-tree LPC host on Hip06/Hip07
ACPI: Support the probing on the devices which apply indirect-IO
LPC: Add the ACPI LPC support

.../arm/hisilicon/hisilicon-low-pin-count.txt | 33 ++
arch/arm64/boot/dts/hisilicon/hip06-d03.dts | 4 +
arch/arm64/boot/dts/hisilicon/hip06.dtsi | 14 +
arch/arm64/boot/dts/hisilicon/hip07-d05.dts | 4 +
arch/arm64/boot/dts/hisilicon/hip07.dtsi | 14 +
drivers/acpi/Makefile | 1 +
drivers/acpi/acpi_indirectio.c | 344 +++++++++++++
drivers/acpi/internal.h | 5 +
drivers/acpi/pci_root.c | 8 +-
drivers/acpi/scan.c | 1 +
drivers/bus/Kconfig | 9 +
drivers/bus/Makefile | 1 +
drivers/bus/hisi_lpc.c | 547 +++++++++++++++++++++
drivers/of/address.c | 95 +++-
drivers/pci/pci.c | 104 +---
include/asm-generic/io.h | 50 ++
include/linux/logic_pio.h | 174 +++++++
include/linux/pci.h | 3 +-
lib/Kconfig | 26 +
lib/Makefile | 2 +
lib/logic_pio.c | 413 ++++++++++++++++
22 files changed, 1758 insertions(+), 102 deletions(-)
create mode 100644 Documentation/devicetree/bindings/arm/hisilicon/hisilicon-low-pin-count.txt
create mode 100644 drivers/acpi/acpi_indirectio.c
create mode 100644 drivers/bus/hisi_lpc.c
create mode 100644 include/linux/logic_pio.h
create mode 100644 lib/logic_pio.c


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