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 Tested-by: Xiongfeng Wang wangxiongfeng2@huawei.com Reviewed-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com --- drivers/acpi/arm64/gtdt.c | 103 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 103 insertions(+)
diff --git a/drivers/acpi/arm64/gtdt.c b/drivers/acpi/arm64/gtdt.c index 3dd33f3..d73bb16 100644 --- a/drivers/acpi/arm64/gtdt.c +++ b/drivers/acpi/arm64/gtdt.c @@ -15,6 +15,7 @@ #include <linux/init.h> #include <linux/irqdomain.h> #include <linux/kernel.h> +#include <linux/platform_device.h>
#include <clocksource/arm_arch_timer.h>
@@ -60,6 +61,17 @@ static inline bool is_timer_block(void *platform_timer) return gh->type == ACPI_GTDT_TYPE_TIMER_BLOCK; }
+static inline bool is_non_secure_watchdog(void *platform_timer) +{ + struct acpi_gtdt_header *gh = platform_timer; + struct acpi_gtdt_watchdog *wd = platform_timer; + + if (gh->type != ACPI_GTDT_TYPE_WATCHDOG) + return false; + + return !(wd->timer_flags & ACPI_GTDT_WATCHDOG_SECURE); +} + static int __init map_gt_gsi(u32 interrupt, u32 flags) { int trigger, polarity; @@ -301,3 +313,94 @@ int __init acpi_arch_timer_mem_init(struct arch_timer_mem *timer_mem,
return 0; } + +/* + * Initialize a SBSA generic Watchdog platform device info from GTDT + */ +static int __init gtdt_import_sbsa_gwdt(struct acpi_gtdt_watchdog *wd, + int index) +{ + struct platform_device *pdev; + int irq = map_gt_gsi(wd->timer_interrupt, wd->timer_flags); + + /* + * 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), + }; + int nr_res = ARRAY_SIZE(res); + + 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"); + acpi_unregister_gsi(wd->timer_interrupt); + return -EINVAL; + } + + if (irq <= 0) { + pr_warn("failed to map the Watchdog interrupt.\n"); + nr_res--; + } + + /* + * Add a platform device named "sbsa-gwdt" to match the platform driver. + * "sbsa-gwdt": SBSA(Server Base System Architecture) Generic Watchdog + * The platform driver can get device info below by matching this name. + */ + pdev = platform_device_register_simple("sbsa-gwdt", index, res, nr_res); + if (IS_ERR(pdev)) { + acpi_unregister_gsi(wd->timer_interrupt); + return PTR_ERR(pdev); + } + + return 0; +} + +static int __init gtdt_sbsa_gwdt_init(void) +{ + void *platform_timer; + struct acpi_table_header *table; + int ret, timer_count, gwdt_count = 0; + + if (acpi_disabled) + return 0; + + if (ACPI_FAILURE(acpi_get_table(ACPI_SIG_GTDT, 0, &table))) + return -EINVAL; + + /* + * Note: Even though the global variable acpi_gtdt_desc has been + * initialized by acpi_gtdt_init() while initializing the arch timers, + * when we call this function to get SBSA watchdogs info from GTDT, the + * pointers stashed in it are stale (since they are early temporary + * mappings carried out before acpi_permanent_mmap is set) and we need + * to re-initialize them with permanent mapped pointer values to let the + * GTDT parsing possible. + */ + ret = acpi_gtdt_init(table, &timer_count); + if (ret || !timer_count) + return ret; + + for_each_platform_timer(platform_timer) { + if (is_non_secure_watchdog(platform_timer)) { + ret = gtdt_import_sbsa_gwdt(platform_timer, gwdt_count); + if (ret) + break; + gwdt_count++; + } + } + + if (gwdt_count) + pr_info("found %d SBSA generic Watchdog(s).\n", gwdt_count); + + return ret; +} + +device_initcall(gtdt_sbsa_gwdt_init);