Add Microchip IPC mailbox

Hello all,

This series adds support for the Microchip Inter-Processor Communication
(IPC) mailbox driver.

Microchip's family of RISC-V SoCs typically has one or more clusters
that can be configured to run in Asymmetric Multi-Processing (AMP) mode.

The Microchip IPC is used to send messages between processors using
an interrupt signaling mechanism. The driver uses the RISC-V Supervisor
Binary Interface (SBI) to communicate with software running in machine
mode (M-mode) to access the IPC hardware block.

Additional details on the Microchip vendor extension and the IPC
function IDs described in the driver can be found in the following
documentation:

https://github.com/linux4microchip/microchip-sbi-ecall-ex...

The PIC64GX MPU has a Mi-V IHC block, this will be added to the PIC64GX
dts after the initial upstreaming [1].

[1] https://patchwork.kernel.org/project/linux-riscv/patch/20...

Changes in v6:
- update bindings to explain why 'reg' is not needed with microchip,sbi-ipc compatible

Changes in v5:
- change interrup-names property to use a list instead of pattern
- move assitionalProperties after allOf : block
- update reg property in dt binding example to use lowercase hex

Changes in v4:
- specify that microchip,miv-ihc-rtl-v2 is intended for use with MIV IHC Soft IP
- drop items array and use const value for compatible strings
- add a contraint to microchip,ihc-chan-disabled-mask property
- minor improvements to "'#mbox-cells' description

Changes in v3:
- Fix incorrent formatting around '=' in dt binding examples
- Add per compatible descriptions in dt binding
- Add '>' in certain dt binding descriptions to keep paragraphs maintained
- export __cpuid_to_hartid_map to compile mailbox driver as module
- Drop unused enum ipc_irq_type
- rename struct mchp_ipc_probe to mchp_ipc_mbox_info
- rename struct ipc_chan_info to mchp_ipc_sbi_chan
- rename struct microchip_ipc to mchp_ipc_sbi_mbox
- use phys_addr_t for __pa()
- drop mchp_ipc_get_chan_id function
- use num_chans in mbox_controller
- Fix buf_base_tx and buf_base_rx sizes using max and kmalloc

Changes in v2:
- use kmalloc and __pa() instead of DMA API
- fix size of buf_base to avoid potential buffer overflow
- add kernel doc for exported functions (mchp_ipc_get_chan_id)
- use EXPORT_SYMBOL_GPL instead of EXPORT_SYMBOL
- drop unnecessary blank line and fix alignment issues
- drop of_match_ptr
- move MODULE_DEVICE_TABLE next to the definition
- reword subject from riscv: asm: vendorid_list to riscv: sbi: vendorid_list
- remove the word "driver" from dt-binding commit subject
- make interrupt-names a required property for all cases
- add dependency on COMPILE_TEST and ARCH_MICROCHIP

Regards,
Valentina

Valentina Fernandez (4):
  riscv: sbi: vendorid_list: Add Microchip Technology to the vendor list
  riscv: export __cpuid_to_hartid_map
  dt-bindings: mailbox: add binding for Microchip IPC mailbox controller
  mailbox: add Microchip IPC support

 .../bindings/mailbox/microchip,sbi-ipc.yaml   | 123 +++++
 arch/riscv/include/asm/vendorid_list.h        |   1 +
 arch/riscv/kernel/smp.c                       |   1 +
 drivers/mailbox/Kconfig                       |  13 +
 drivers/mailbox/Makefile                      |   2 +
 drivers/mailbox/mailbox-mchp-ipc-sbi.c        | 504 ++++++++++++++++++
 include/linux/mailbox/mchp-ipc.h              |  33 ++
 7 files changed, 677 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mailbox/microchip,sbi-ipc.yaml
 create mode 100644 drivers/mailbox/mailbox-mchp-ipc-sbi.c
 create mode 100644 include/linux/mailbox/mchp-ipc.h

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2.34.1