From: Fu Wei <fu.wei@xxxxxxxxxx>
Parse SBSA Generic Watchdog Structure in GTDT table of ACPI,
and create a platform device with that information
This platform device can be used by the ARM SBSA Generic Watchdog driver
Signed-off-by: Fu Wei <fu.wei@xxxxxxxxxx>
---
arch/arm64/kernel/acpi.c | 136 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 136 insertions(+)
diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index 8b83955..1ed11fd 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -23,6 +23,7 @@
#include <linux/irqdomain.h>
#include <linux/memblock.h>
#include <linux/of_fdt.h>
+#include <linux/platform_device.h>
#include <linux/smp.h>
#include <asm/cputype.h>
@@ -343,3 +344,138 @@ void __init acpi_gic_init(void)
early_acpi_os_unmap_memory((char *)table, tbl_size);
}
+
+static int __init acpi_gtdt_import_sbsa_gwdt(struct acpi_gtdt_watchdog *wd,
+ int index)
+{
+ struct platform_device *pdev;
+ struct resource *res;
+ u32 gsi, flags;
+ int irq, trigger, polarity;
+ resource_size_t rf_base_phy, cf_base_phy;
+ int err = -ENOMEM;
+
+ /*
+ * Get SBSA Generic Watchdog info
+ * from a Watchdog GT type structure in GTDT
+ */
+ rf_base_phy = (resource_size_t)wd->refresh_frame_address;
+ cf_base_phy = (resource_size_t)wd->control_frame_address;
+ gsi = wd->timer_interrupt;
+ flags = wd->timer_flags;
+
+ pr_info("GTDT: a Watchdog GT structure(0x%llx/0x%llx gsi:%u flags:0x%x)\n",
+ rf_base_phy, cf_base_phy, gsi, flags);
+
+ if (!(rf_base_phy && cf_base_phy && gsi)) {
+ pr_err("GTDT: failed geting the device info.\n");
+ return -EINVAL;
+ }
+
+ trigger = (flags & ACPI_GTDT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE
+ : ACPI_LEVEL_SENSITIVE;
+ polarity = (flags & ACPI_GTDT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW
+ : ACPI_ACTIVE_HIGH;
+ irq = acpi_register_gsi(NULL, gsi, trigger, polarity);
+ if (irq < 0) {
+ pr_err("GTDT: failed to register GSI of the Watchdog GT.\n");
+ return -EINVAL;
+ }
+
+ pdev = platform_device_alloc("sbsa-gwdt", index);
+ if (!pdev)
+ goto err_unregister_gsi;
+
+ res = kcalloc(3, sizeof(*res), GFP_KERNEL);
+ if (!res)
+ goto err_device_put;
+
+ res[0].start = rf_base_phy;
+ res[0].end = rf_base_phy + SZ_4K - 1;
+ res[0].name = "refresh";
+ res[0].flags = IORESOURCE_MEM;
+
+ res[1].start = cf_base_phy;
+ res[1].end = cf_base_phy + SZ_4K - 1;
+ res[1].name = "control";
+ res[1].flags = IORESOURCE_MEM;
+
+ res[2].start = irq;
+ res[2].end = res[2].start;
+ res[2].name = "ws0";
+ res[2].flags = IORESOURCE_IRQ;
+
+ err = platform_device_add_resources(pdev, res, 3);
+ if (err)
+ goto err_free_res;
+
+ err = platform_device_add(pdev);
+ if (err)
+ goto err_free_res;
+
+ return 0;
+
+err_free_res:
+ kfree(res);
+err_device_put:
+ platform_device_put(pdev);
+err_unregister_gsi:
+ acpi_unregister_gsi(gsi);
+
+ return err;
+}
+
+/* Initialize SBSA generic Watchdog platform device info from GTDT */
+static int __init acpi_gtdt_sbsa_gwdt_init(struct acpi_table_header *table)
+{
+ struct acpi_table_gtdt *gtdt;
+ struct acpi_gtdt_header *header;
+ void *gtdt_subtable;
+ int i, gwdt_index;
+ int ret = 0;
+
+ if (table->revision < 2) {
+ pr_info("GTDT: Revision:%d doesn't support Platform Timers.\n",
+ table->revision);
+ return 0;
+ }
+
+ gtdt = container_of(table, struct acpi_table_gtdt, header);
+ if (!gtdt->platform_timer_count) {
+ pr_info("GTDT: No Platform Timer structures.\n");
+ return 0;
+ }
+
+ gtdt_subtable = (void *)gtdt + gtdt->platform_timer_offset;
+
+ for (i = 0, gwdt_index = 0; i < gtdt->platform_timer_count; i++) {
+ if (gtdt_subtable > (void *)table + table->length) {
+ pr_err("GTDT: subtable pointer overflows, bad table\n");
+ return -EINVAL;
+ }
+ header = (struct acpi_gtdt_header *)gtdt_subtable;
+ if (header->type == ACPI_GTDT_TYPE_WATCHDOG) {
+ ret = acpi_gtdt_import_sbsa_gwdt(gtdt_subtable,
+ gwdt_index);
+ if (ret)
+ pr_err("GTDT: failed to import subtable %d\n",
+ i);
+ else
+ gwdt_index++;
+ }
+ gtdt_subtable += header->length;
+ }
+
+ return ret;
+}
+
+/* Initialize the SBSA Generic Watchdog presented in GTDT */
+static int __init acpi_gtdt_init(void)
+{
+ if (acpi_disabled)
+ return 0;
+
+ return acpi_table_parse(ACPI_SIG_GTDT, acpi_gtdt_sbsa_gwdt_init);
+}
+
+arch_initcall(acpi_gtdt_init);
--
1.9.1
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