[PATCH v2 0/2] Add CONFIG_SYSTEM_SUSPEND and SCIF UART suspend/resume handlers

[Mykola Kvach <xakep.amatop@xxxxxxxxx>]

From: Mykola Kvach <mykola_kvach@xxxxxxxx>

Hi all,

This patch series introduces CONFIG_SYSTEM_SUSPEND to Xen and implements
suspend/resume handlers for the SCIF UART driver. These changes address
feedback and discussions on the Xen-devel mailing list:

    https://lists.xenproject.org/archives/html/xen-devel/2025-03/msg00169.html
    https://lists.xenproject.org/archives/html/xen-devel/2025-03/msg02188.html

I am marking this series as v2, as it is a logical continuation of the
discussion linked above regarding the SCIF driver changes.

Patch 1:
  Introduces the CONFIG_SYSTEM_SUSPEND infrastructure, which enables Xen to
support suspend-to-RAM functionality. It adds three new Kconfig options:
    - HAS_SYSTEM_SUSPEND: Indicates whether the architecture supports suspend.
    - SYSTEM_SUSPEND_ALWAYS_ON: Forces suspend support on platforms that
      require it (e.g., x86).
    - SYSTEM_SUSPEND: The user-facing option to enable suspend support,
      enabled by default when SYSTEM_SUSPEND_ALWAYS_ON is set.
      
  This approach is intended to be easily extendable to other architectures in
the future.

Patch 2:
  Implements suspend/resume callbacks for the SCIF UART driver. These functions
ensure proper shutdown and reinitialization of the UART hardware across
suspend/resume cycles. Their inclusion is gated by the CONFIG_SYSTEM_SUSPEND
option.
  The SCIF suspend/resume functionality has been tested on the Renesas R-Car H3
Starter Kit board.
  Compared to v1, the main change in this version is the addition of a
CONFIG_SYSTEM_SUSPEND check around the SCIF driver's suspend/resume logic.

Best regards,
Mykola Kvach


Mykola Kvach (1):
  xen: Introduce system suspend config option

Volodymyr Babchuk (1):
  xen/char: implement suspend/resume calls for SCIF driver

 xen/arch/x86/Kconfig         |  2 ++
 xen/common/Kconfig           | 17 +++++++++++++++
 xen/drivers/char/scif-uart.c | 40 ++++++++++++++++++++++++++++++++++--
 3 files changed, 57 insertions(+), 2 deletions(-)

-- 
2.48.1