From: Fu Wei fu.wei@linaro.org
This driver adds support for parsing SBSA Generic Watchdog timer in GTDT, parse all info in SBSA Generic Watchdog Structure in GTDT, and creating a platform device with that information.
This allows the operating system to obtain device data from the resource of platform device. The platform device named "sbsa-gwdt" can be used by the ARM SBSA Generic Watchdog driver.
Signed-off-by: Fu Wei fu.wei@linaro.org Signed-off-by: Hanjun Guo hanjun.guo@linaro.org --- drivers/acpi/arm64/acpi_gtdt.c | 88 ++++++++++++++++++++++++++++++++++++++++++ drivers/watchdog/Kconfig | 1 + 2 files changed, 89 insertions(+)
diff --git a/drivers/acpi/arm64/acpi_gtdt.c b/drivers/acpi/arm64/acpi_gtdt.c index b48e443..45ac0f8 100644 --- a/drivers/acpi/arm64/acpi_gtdt.c +++ b/drivers/acpi/arm64/acpi_gtdt.c @@ -14,6 +14,7 @@ #include <linux/acpi.h> #include <linux/init.h> #include <linux/kernel.h> +#include <linux/platform_device.h>
#include <clocksource/arm_arch_timer.h>
@@ -222,3 +223,90 @@ int __init gtdt_arch_timer_mem_init(struct gt_block_data *data)
return index; } + +/* + * Initialize a SBSA generic Watchdog platform device info from GTDT + */ +static int __init gtdt_import_sbsa_gwdt(void *platform_timer, int index) +{ + struct platform_device *pdev; + struct acpi_gtdt_watchdog *wd = platform_timer; + int irq = map_generic_timer_interrupt(wd->timer_interrupt, + wd->timer_flags); + int no_irq = 1; + + /* + * According to SBSA specification the size of refresh and control + * frames of SBSA Generic Watchdog is SZ_4K(Offset 0x000 – 0xFFF). + */ + struct resource res[] = { + DEFINE_RES_MEM(wd->control_frame_address, SZ_4K), + DEFINE_RES_MEM(wd->refresh_frame_address, SZ_4K), + DEFINE_RES_IRQ(irq), + }; + + pr_debug("found a Watchdog (0x%llx/0x%llx gsi:%u flags:0x%x).\n", + wd->refresh_frame_address, wd->control_frame_address, + wd->timer_interrupt, wd->timer_flags); + + if (!(wd->refresh_frame_address && wd->control_frame_address)) { + pr_err(FW_BUG "failed to get the Watchdog base address.\n"); + return -EINVAL; + } + + if (!wd->timer_interrupt) + pr_warn(FW_BUG "failed to get the Watchdog interrupt.\n"); + else if (irq <= 0) + pr_warn("failed to map the Watchdog interrupt.\n"); + else + no_irq = 0; + + /* + * Add a platform device named "sbsa-gwdt" to match the platform driver. + * "sbsa-gwdt": SBSA(Server Base System Architecture) Generic Watchdog + * The platform driver (like drivers/watchdog/sbsa_gwdt.c)can get device + * info below by matching this name. + */ + pdev = platform_device_register_simple("sbsa-gwdt", index, res, + ARRAY_SIZE(res) - no_irq); + if (IS_ERR(pdev)) { + acpi_unregister_gsi(wd->timer_interrupt); + return PTR_ERR(pdev); + } + + return 0; +} + +static int __init gtdt_sbsa_gwdt_init(void) +{ + struct acpi_table_header *table; + void *platform_timer; + int index = 0; + int ret; + + if (acpi_disabled) + return 0; + + if (ACPI_FAILURE(acpi_get_table(ACPI_SIG_GTDT, 0, &table))) + return -EINVAL; + + ret = acpi_gtdt_init(table); + if (ret <= 0) + return ret; + + for_each_platform_timer(platform_timer) { + if (!is_watchdog(platform_timer)) + continue; + ret = gtdt_import_sbsa_gwdt(platform_timer, index); + if (ret) + break; + index++; + } + + if (index) + pr_info("found %d SBSA generic Watchdog(s).\n", index); + + return ret; +} + +device_initcall(gtdt_sbsa_gwdt_init); diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index b4b3e25..4019792 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -206,6 +206,7 @@ config ARM_SBSA_WATCHDOG tristate "ARM SBSA Generic Watchdog" depends on ARM64 depends on ARM_ARCH_TIMER + depends on ACPI_GTDT || !ACPI select WATCHDOG_CORE help ARM SBSA Generic Watchdog has two stage timeouts: