[v3] Add CONFIG_SYSTEM_SUSPEND and SCIF UART suspend/resume handlers

[PATCH v3 0/2] Add CONFIG_SYSTEM_SUSPEND and SCIF UART suspend/resume handlers

Mykola Kvach posted 2 patches 4 months, 3 weeks ago

Diff against v2
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git fetch https://gitlab.com/xen-project/patchew/xen tags/patchew/cover.1749204282.git.mykola._5Fkvach@epam.com

xen/arch/x86/Kconfig         |  1 +
xen/common/Kconfig           | 18 ++++++++++++++++
xen/drivers/char/scif-uart.c | 40 ++++++++++++++++++++++++++++++++++--
3 files changed, 57 insertions(+), 2 deletions(-)

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[PATCH v3 0/2] Add CONFIG_SYSTEM_SUSPEND and SCIF UART suspend/resume handlers

Posted by Mykola Kvach 4 months, 3 weeks ago

From: Mykola Kvach <mykola_kvach@epam.com>

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.

Changes introduced in v3:
- select HAS_SYSTEM_SUSPEND from SYSTEM_SUSPEND_ALWAYS_ON
- drop selecting HAS_SYSTEM_SUSPEND from X86
- simplify default setting in SYSTEM_SUSPEND
- hide prompt of SYSTEM_SUSPEND when SYSTEM_SUSPEND_ALWAYS_ON is enabled
- move HAS_SYSTEM_SUSPEND alongside other HAS_* configs

Best regards,
Mykola Kvach

Mykyta Poturai (1):
  xen: Introduce system suspend config option

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

 xen/arch/x86/Kconfig         |  1 +
 xen/common/Kconfig           | 18 ++++++++++++++++
 xen/drivers/char/scif-uart.c | 40 ++++++++++++++++++++++++++++++++++--
 3 files changed, 57 insertions(+), 2 deletions(-)

-- 
2.48.1