[PATCH v24 11/11] acpi/arm64: Add SBSA Generic Watchdog support in GTDT driver

fu.wei
2017-04-14T18:43:36Z

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>
Signed-off-by: Mark Rutland <mark.rutland@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 c9ef9c2..6ba47ea 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;
@@ -299,3 +311,94 @@ 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);
--
2.9.3