Merge tag 'batadv-net-for-davem-20170125' of git://git.open-mesh.org/linux-merge

[linux-2.6-block.git] / drivers / acpi / sysfs.c

diff --git a/drivers/acpi/sysfs.c b/drivers/acpi/sysfs.c
index 703c26e7022cbf186d9a1ed3a60cd25c6fd1c049..cf05ae973381178cc066e1c235c38afb419e1f01 100644 (file)
--- a/drivers/acpi/sysfs.c
+++ b/drivers/acpi/sysfs.c
@@ -708,6 +708,62 @@ end:
        return result ? result : size;
 }
 
+/*
+ * A Quirk Mechanism for GPE Flooding Prevention:
+ *
+ * Quirks may be needed to prevent GPE flooding on a specific GPE. The
+ * flooding typically cannot be detected and automatically prevented by
+ * ACPI_GPE_DISPATCH_NONE check because there is a _Lxx/_Exx prepared in
+ * the AML tables. This normally indicates a feature gap in Linux, thus
+ * instead of providing endless quirk tables, we provide a boot parameter
+ * for those who want this quirk. For example, if the users want to prevent
+ * the GPE flooding for GPE 00, they need to specify the following boot
+ * parameter:
+ *   acpi_mask_gpe=0x00
+ * The masking status can be modified by the following runtime controlling
+ * interface:
+ *   echo unmask > /sys/firmware/acpi/interrupts/gpe00
+ */
+
+/*
+ * Currently, the GPE flooding prevention only supports to mask the GPEs
+ * numbered from 00 to 7f.
+ */
+#define ACPI_MASKABLE_GPE_MAX  0x80
+
+static u64 __initdata acpi_masked_gpes;
+
+static int __init acpi_gpe_set_masked_gpes(char *val)
+{
+       u8 gpe;
+
+       if (kstrtou8(val, 0, &gpe) || gpe > ACPI_MASKABLE_GPE_MAX)
+               return -EINVAL;
+       acpi_masked_gpes |= ((u64)1<<gpe);
+
+       return 1;
+}
+__setup("acpi_mask_gpe=", acpi_gpe_set_masked_gpes);
+
+void __init acpi_gpe_apply_masked_gpes(void)
+{
+       acpi_handle handle;
+       acpi_status status;
+       u8 gpe;
+
+       for (gpe = 0;
+            gpe < min_t(u8, ACPI_MASKABLE_GPE_MAX, acpi_current_gpe_count);
+            gpe++) {
+               if (acpi_masked_gpes & ((u64)1<<gpe)) {
+                       status = acpi_get_gpe_device(gpe, &handle);
+                       if (ACPI_SUCCESS(status)) {
+                               pr_info("Masking GPE 0x%x.\n", gpe);
+                               (void)acpi_mask_gpe(handle, gpe, TRUE);
+                       }
+               }
+       }
+}
+
 void acpi_irq_stats_init(void)
 {
        acpi_status status;