[PATCH v7 0/8] Watchdog: introduce ARM SBSA watchdog driver

From: fu . wei
Date: Mon Aug 24 2015 - 13:02:26 EST

From: Fu Wei <fu.wei@xxxxxxxxxx>

This patchset:
(1)Introduce Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt
for FDT info of SBSA Generic Watchdog, and give two examples of
adding SBSA Generic Watchdog device node into the dts files:
foundation-v8.dts and amd-seattle-soc.dtsi.

(2)Introduce "pretimeout" into the watchdog framework, and update
Documentation/watchdog/watchdog-kernel-api.txt to introduce:
(1)the new elements in the watchdog_device and watchdog_ops struct;
(2)the new API "watchdog_init_timeouts".

(3)Introduce ARM SBSA watchdog driver:
a.Use linux kernel watchdog framework;
b.Work with FDT on ARM64;
c.Use "pretimeout" in watchdog framework;
d.Support getting timeout and pretimeout from parameter and FDT
at the driver init stage.
e.In the first timeout, do panic to save system context;
f.In the second stage, user can still feed the dog without
cleaning WS0. By this feature, we can avoid the panic infinite
loops, while backing up a large system context in a server.
g.In the second stage, can trigger WS1 by setting pretimeout = 0
if necessary.

(4)Introduce ACPI GTDT parser: drivers/acpi/gtdt.c
Parse SBSA Generic Watchdog Structure in GTDT table of ACPI,
and create a platform device with that information.
This platform device can be used by This Watchdog driver.
drivers/clocksource/arm_arch_timer.c is simplified by this GTDT support.

This patchset has been tested with watchdog daemon
(ACPI/FDT, module/build-in) on the following platforms:
(1)ARM Foundation v8 model

v7: Rebase to latest kernel version(4.2-rc7).
Improve FDT support: geting resource by order, instead of name.
According to the FDT support, Update the example dts file, gtdt.c
and sbsa_gwdt.c.
Pass the sparse test, and fix the warning.
Fix the max_pretimeout and max_timeout value overflow bug.
Delete the WCV output value.

v6: Improve the dtb example files: reduce the register frame size to 4K.
Improve pretimeout support:
(1) improve watchdog_init_timeouts function
(2) rename watchdog_check_min_max_timeouts back to the original name
(1) improve watchdog_timeout_invalid/watchdog_pretimeout_invalid
Add the new features in the sbsa_gwdt driver:
(1) In the second stage, user can feed the dog without cleaning WS0.
(2) In the second stage, user can trigger WS1 by setting pretimeout = 0.
(3) expand the max value of pretimeout, in case 10 second is not enough
for a kdump kernel reboot in panic.

v5: Improve pretimeout support:
(1)fix typo in documentation and comments.
(2)fix the timeout limits validation bug.
Simplify sbsa_gwdt driver:
(1)integrate all the registers access functions into caller.

v4: Refactor GTDT support code: remove it from arch/arm64/kernel/acpi.c,
put it into drivers/acpi/gtdt.c file.
Integrate the GTDT code of drivers/clocksource/arm_arch_timer.c into
Improve pretimeout support, fix "pretimeout == 0" problem.
Simplify sbsa_gwdt driver:
(1)timeout/pretimeout limits setup;
(2)keepalive function;
(3)delete "clk == 0" check;
(4)delete WS0 status bit check in interrupt routine;
(5)sbsa_gwdt_set_wcv function.

v3: Delete "export arch_timer_get_rate" patch.
Driver back to use arch_timer_get_cntfrq.
Improve watchdog_init_timeouts function and update relevant documentation.
Improve watchdog_timeout_invalid and watchdog_pretimeout_invalid.
Improve foundation-v8.dts: delete the unnecessary tag of device node.
Remove "ARM64 || COMPILE_TEST" from Kconfig.
Add comments in arch/arm64/kernel/acpi.c
Fix typoes and incorrect comments.

v2: Improve watchdog-kernel-api.txt documentation for pretimeout support.
Export "arch_timer_get_rate" in arm_arch_timer.c.
Add watchdog_init_timeouts API for pretimeout support in framework.
Improve suspend and resume foundation in driver
Improve timeout/pretimeout values init code in driver.
Delete unnecessary items of the sbsa_gwdt struct and #define.
Delete all unnecessary debug info in driver.
Fix 64bit division bug.
Use the arch_timer interface to get watchdog clock rate.
Add MODULE_DEVICE_TABLE for platform device id.
Fix typoes.

v1: The first version upstream patchset to linux mailing list.

Fu Wei (8):
Documentation: add sbsa-gwdt.txt documentation
ARM64: add SBSA Generic Watchdog device node in foundation-v8.dts
ARM64: add SBSA Generic Watchdog device node in amd-seattle-soc.dtsi
Watchdog: introdouce "pretimeout" into framework
Watchdog: introduce ARM SBSA watchdog driver
ACPI: add GTDT table parse driver into ACPI driver
Watchdog: enable ACPI GTDT support for ARM SBSA watchdog driver
clocksource: simplify ACPI code in arm_arch_timer.c

.../devicetree/bindings/watchdog/sbsa-gwdt.txt | 32 ++
Documentation/watchdog/watchdog-kernel-api.txt | 47 ++-
arch/arm64/boot/dts/amd/amd-seattle-soc.dtsi | 8 +
arch/arm64/boot/dts/arm/foundation-v8.dts | 7 +
arch/arm64/kernel/time.c | 4 +-
drivers/acpi/Kconfig | 9 +
drivers/acpi/Makefile | 1 +
drivers/acpi/gtdt.c | 178 ++++++++
drivers/clocksource/Kconfig | 1 +
drivers/clocksource/arm_arch_timer.c | 60 +--
drivers/watchdog/Kconfig | 15 +
drivers/watchdog/Makefile | 1 +
drivers/watchdog/sbsa_gwdt.c | 459 +++++++++++++++++++++
drivers/watchdog/watchdog_core.c | 98 +++--
drivers/watchdog/watchdog_dev.c | 53 +++
include/clocksource/arm_arch_timer.h | 8 +
include/linux/acpi.h | 5 +
include/linux/clocksource.h | 4 +-
include/linux/watchdog.h | 39 +-
19 files changed, 939 insertions(+), 90 deletions(-)
create mode 100644 Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt
create mode 100644 drivers/acpi/gtdt.c
create mode 100644 drivers/watchdog/sbsa_gwdt.c


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