[RFC PATCH-for-6.1 00/10] hw/misc: Add memory_region_add_subregion_aliased() helper

[Philippe Mathieu-Daudé]

Hi,

This series introduce the memory_region_add_subregion_aliased()
helper which basically create a device which maps a subregion
multiple times.

Examples are easier, so having a subregion aliased every @span_size
then mapped onto a container at an offset, you get something like:

          ^-----------^
          |           |
          |           |
          | +-------+ |                 +---------+          <--+
          |           |                 +---------+             |
          |           |                 |         |             |
          |           |   +-----------> | alias#3 |             |
          |           |   |             |         |             |
          |           |   |             +---------+             |
          |           |   |             +---------+             |
          |           |   |             |         |             |
          |           |   |   +-------> | alias#2 |             |
          |           |   |   |         |         |             |region
          | container |   |   |         +---------+             | size
          |           |   |   |         +---------+             |
          |           |   |   |         |         |             |
          |           |   |   |  +----> | alias#1 |             |
          |           |   |   |  |      |         |             |
          |           |   |   |  |      +---------+  <--+       |
          |           | +-+---+--+--+   +---------+     |       |
          |           | |           |   |         |     |span   |
          |           | | subregion +-> | alias#0 |     |size   |
   offset |           | |           |   |         |     |       |
   +----> | +-------+ | +-----------+   +---------+  <--+    <--+
   |      |           |
   |      |           |
   |      |           |
   |      |           |
   |      |           |
   |      ^-----------^

I know it need more documentation and tests, but I prefer to send
as draft RFC for early review before spending more time on it.

Based-on: <20210325120921.858993-1-f4bug@amsat.org>
https://www.mail-archive.com/qemu-devel@nongnu.org/msg795218.html

Philippe Mathieu-Daudé (10):
  hw/misc: Add device to help managing aliased memory regions
  hw/arm/musicpal: Open-code pflash_cfi02_register() call
  hw/arm/musicpal: Map flash using memory_region_add_subregion_aliased()
  hw/arm/digic: Open-code pflash_cfi02_register() call
  hw/arm/digic: Map flash using memory_region_add_subregion_aliased()
  hw/block/pflash_cfi02: Remove pflash_setup_mappings()
  hw/block/pflash_cfi02: Simplify pflash_cfi02_register() prototype
  hw/misc/aliased_region: Simplify aliased I/O regions
  hw/m68k/q800: Add MacIO container
  hw/m68k/q800: Map MacIO using memory_region_add_subregion_aliased()

 include/hw/block/flash.h         |   1 -
 include/hw/misc/aliased_region.h |  91 +++++++++++++++
 hw/arm/digic_boards.c            |  28 ++++-
 hw/arm/musicpal.c                |  29 ++++-
 hw/arm/xilinx_zynq.c             |   2 +-
 hw/block/pflash_cfi02.c          |  36 +-----
 hw/lm32/lm32_boards.c            |   4 +-
 hw/m68k/q800.c                   |  61 +++++-----
 hw/misc/aliased_region.c         | 185 +++++++++++++++++++++++++++++++
 hw/ppc/ppc405_boards.c           |   6 +-
 hw/sh4/r2d.c                     |   2 +-
 MAINTAINERS                      |   6 +
 hw/arm/Kconfig                   |   2 +
 hw/m68k/Kconfig                  |   1 +
 hw/misc/Kconfig                  |   3 +
 hw/misc/meson.build              |   1 +
 16 files changed, 375 insertions(+), 83 deletions(-)
 create mode 100644 include/hw/misc/aliased_region.h
 create mode 100644 hw/misc/aliased_region.c

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2.26.2