[PATCH 0/4] RISC-V SBI watchdog support

[Prajwal N]

This series introduces support for the RISC-V SBI watchdog extension,
which provides the watchdog functionality for the Supervisor software.

The SBI watchdog extension exposes watchdog functionality including
start, stop, pat, read and write attributes to the S-mode software via
SBI calls. The extension manages the watchdog timer in M-mode using the
system timer.

The S-mode software can also optionally subscribe for
watchdog pretimeout notification which is delivered as a Message
Signaled Interrupt (MSI) before the current watch period expires.
On watchdog expiry, a platform system reset is triggered.

The series consists of the following changes:

- Patch 1 adds helper function to convert timer tick delta to a
  specified time unit and a wrapper to convert the time tick to
  microsecond.

- Patch 2 adds the SBI watchdog extension ID and function IDs
  for supported operations, including start, stop, pat, and
  atrribute read and write.

- Patch 3 implements the SBI watchdog functionality including
  start, stop, pat, read and write attributes, pretimeout and
  timeout handlers.

- Patch 4 implements ecall handler functionality to delegate
  the ecall to SBI watchdog framework

Prajwal N (4):
  lib: sbi: Add timer tick to time conversion helper
  include: sbi: Add SBI watchdog extension definitions
  lib: sbi: Add SBI watchdog framework
  lib: sbi: Add ecall handler for SBI watchdog

 include/sbi/sbi_ecall_interface.h |  33 +++
 include/sbi/sbi_timer.h           |  12 +
 include/sbi/sbi_wdt.h             |  72 +++++
 lib/sbi/Kconfig                   |   4 +
 lib/sbi/objects.mk                |   4 +
 lib/sbi/sbi_ecall_wdt.c           |  79 ++++++
 lib/sbi/sbi_init.c                |   8 +
 lib/sbi/sbi_timer.c               |   5 +
 lib/sbi/sbi_wdt.c                 | 455 ++++++++++++++++++++++++++++++
 9 files changed, 672 insertions(+)
 create mode 100644 include/sbi/sbi_wdt.h
 create mode 100644 lib/sbi/sbi_ecall_wdt.c
 create mode 100644 lib/sbi/sbi_wdt.c

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2.43.0