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/acpi_gtdt.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++ drivers/watchdog/Kconfig | 1 + 2 files changed, 83 insertions(+)
diff --git a/drivers/acpi/acpi_gtdt.c b/drivers/acpi/acpi_gtdt.c index 4592dba..ab8a822 100644 --- a/drivers/acpi/acpi_gtdt.c +++ b/drivers/acpi/acpi_gtdt.c @@ -15,6 +15,7 @@ #include <linux/init.h> #include <linux/kernel.h> #include <linux/module.h> +#include <linux/platform_device.h>
#include <clocksource/arm_arch_timer.h>
@@ -242,3 +243,84 @@ 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("a Watchdog GT(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 getting the Watchdog GT frame addr.\n"); + return -EINVAL; + } + + if (!wd->timer_interrupt) + pr_warn(FW_BUG "failed getting the Watchdog GT GSIV.\n"); + else if (irq <= 0) + pr_warn("failed to map the Watchdog GT GSIV.\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; + + if (acpi_disabled) + return 0; + + if (ACPI_FAILURE(acpi_get_table(ACPI_SIG_GTDT, 0, &table))) + return -EINVAL; + + if (acpi_gtdt_desc_init(table) < 0) + return -EINVAL; + + for_each_gtdt_watchdog(platform_timer) { + if (!gtdt_import_sbsa_gwdt(platform_timer, index)) + index++; + } + + if (index) + pr_info("found %d SBSA generic Watchdog.\n", index); + + return 0; +} + +device_initcall(gtdt_sbsa_gwdt_init); diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index b4b3e25..105f059 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -207,6 +207,7 @@ config ARM_SBSA_WATCHDOG depends on ARM64 depends on ARM_ARCH_TIMER select WATCHDOG_CORE + select ACPI_GTDT if ACPI help ARM SBSA Generic Watchdog has two stage timeouts: the first signal (WS0) is for alerting the system by interrupt,