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    Subject[PATCH v12 8/8] acpi/arm64: Add SBSA Generic Watchdog support in GTDT driver
    Date
    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/gtdt.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++
    drivers/watchdog/Kconfig | 1 +
    2 files changed, 88 insertions(+)

    diff --git a/drivers/acpi/arm64/gtdt.c b/drivers/acpi/arm64/gtdt.c
    index b6021db..6d9fdd3 100644
    --- a/drivers/acpi/arm64/gtdt.c
    +++ b/drivers/acpi/arm64/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>

    @@ -220,3 +221,89 @@ 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(struct acpi_gtdt_watchdog *wd,
    + int index)
    +{
    + struct platform_device *pdev;
    + int irq = map_gt_gsi(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 1bffe00..341964a 100644
    --- a/drivers/watchdog/Kconfig
    +++ b/drivers/watchdog/Kconfig
    @@ -205,6 +205,7 @@ 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:
    --
    2.7.4
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