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Subject[PATCH v14 9/9] 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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