[PATCH v2 0/5] aspeed: LPC peripheral controller devices

[Andrew Jeffery]

Hello,

This series adds support for some of the LPC[1] peripherals found in Aspeed BMC
SoCs.

v2 addresses some minor feedback from Philippe and Cédric. v1 can be found here:

20210226065758.547824-1-andrew@aj.id.au/T/#m28b4392d0672e85fbfaaf6565a2da2e82de1691d">https://lore.kernel.org/qemu-devel/20210226065758.547824-1-andrew@aj.id.au/T/#m28b4392d0672e85fbfaaf6565a2da2e82de1691d

BMCs typically provide a number of features to their host via LPC that include
but are not limited to:

1. Mapping LPC firmware cycles to BMC-controlled flash devices
2. UART(s) for system console routing
3. POST code routing
4. Keyboard-Controller-Style (KCS) IPMI devices
5. Block Transfer (BT) IPMI devices
6. A SuperIO controller for management of LPC devices and miscellaneous
   functionality

[1] 
https://www.intel.com/content/dam/www/program/design/us/en/documents/low-pin-count-interface-specification.pdf

Specifically, this series adds basic support for functions 1 and 4 above,
handling the BMC firmware configuring the bridge mapping LPC firmware cycles
onto its AHB as well as support for four KCS devices.

Aspeed's LPC controller is not a straight-forward device by any stretch. It
contains at least the capabilities outlined above, in the sense that it's not
possible to cleanly separate the different functions into distinct MMIO
sub-regions: Registers for the various bits of functionality have the feel of
arbitrary placement with a nod to feature-creep and backwards compatibility.
Further, the conceptually coherent pieces of functionality often come with the
ability to issue interrupts, though for the AST2400 and AST2500 there is one
shared VIC IRQ for all LPC "subdevices". By contrast the AST2600 gives each
subdevice a distinct IRQ via the GIC.

All this combined leads to some complexity regarding the interrupts and handling
the MMIO accesses (in terms of mapping the access back to the function it's
affecting).

Finally, as a point of clarity, Aspeed BMCs also contain an LPC Host Controller
to drive the LPC bus. This series does not concern itself with the LPC Host
Controller function, only with a subset of the peripheral devices the BMC
presents to the host.

I've tested the series using a combination of the ast2600-evb, witherspoon-bmc
and romulus-bmc machines along with a set of recently-posted patches for
Linux[2].

Please review!

Andrew

[2] 
https://lore.kernel.org/openbmc/20210219142523.3464540-1-andrew@aj.id.au/T/#m1e2029e7aa2be3056320e8d46b3b5b1539a776b4

Andrew Jeffery (4):
  arm: ast2600: Force a multiple of 32 of IRQs for the GIC
  hw/arm: ast2600: Set AST2600_MAX_IRQ to value from datasheet
  hw/arm: ast2600: Correct the iBT interrupt ID
  hw/misc: Model KCS devices in the Aspeed LPC controller

Cédric Le Goater (1):
  hw/misc: Add a basic Aspeed LPC controller model

 docs/system/arm/aspeed.rst   |   2 +-
 hw/arm/aspeed_ast2600.c      |  44 +++-
 hw/arm/aspeed_soc.c          |  34 ++-
 hw/misc/aspeed_lpc.c         | 486 +++++++++++++++++++++++++++++++++++
 hw/misc/meson.build          |   7 +-
 include/hw/arm/aspeed_soc.h  |   3 +
 include/hw/misc/aspeed_lpc.h |  47 ++++
 7 files changed, 616 insertions(+), 7 deletions(-)
 create mode 100644 hw/misc/aspeed_lpc.c
 create mode 100644 include/hw/misc/aspeed_lpc.h


base-commit: 51db2d7cf26d05a961ec0ee0eb773594b32cc4a1
-- 
2.27.0