[PATCH 01/16] ACPI: GTDT: Parse information related to the EL2 virtual timer

[Marc Zyngier <maz@kernel.org>]

Since ARMv8.1, the architecture has grown an EL2-private virtual
timer. This has been described in ACPI since ACPI v6.3 and revision
3 of the GTDT table.

An aditional structure was added in ACPICA, though in a rather
bizarre way, and merged in v5.1 as 8f5a14d053100 ("ACPICA: ACPI 6.3:
add GTDT Revision 3 support").

Finally plug the table parsing in GTDT, and allow it to be eventually
presented to the architected timer driver.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/acpi/arm64/gtdt.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/acpi/arm64/gtdt.c b/drivers/acpi/arm64/gtdt.c
index ffc867bac2d60..1a58007fccf0a 100644
--- a/drivers/acpi/arm64/gtdt.c
+++ b/drivers/acpi/arm64/gtdt.c
@@ -88,6 +88,19 @@ static int __init map_gt_gsi(u32 interrupt, u32 flags)
 	return acpi_register_gsi(NULL, interrupt, trigger, polarity);
 }
 
+struct gtdt_v3 {
+	struct acpi_table_gtdt	gtdt_v2;
+	struct acpi_gtdt_el2	el2_vtimer;
+};
+
+static struct acpi_gtdt_el2 *gtdt_to_el2_vtimer(struct acpi_table_gtdt *gtdt)
+{
+	if (gtdt->header.revision < 3)
+		return NULL;
+
+	return &container_of(gtdt, struct gtdt_v3, gtdt_v2)->el2_vtimer;
+}
+
 /**
  * acpi_gtdt_map_ppi() - Map the PPIs of per-cpu arch_timer.
  * @type:	the type of PPI.
@@ -101,6 +114,7 @@ static int __init map_gt_gsi(u32 interrupt, u32 flags)
 int __init acpi_gtdt_map_ppi(int type)
 {
 	struct acpi_table_gtdt *gtdt = acpi_gtdt_desc.gtdt;
+	struct acpi_gtdt_el2 *el2_vtimer = gtdt_to_el2_vtimer(gtdt);
 
 	switch (type) {
 	case ARCH_TIMER_PHYS_NONSECURE_PPI:
@@ -113,6 +127,12 @@ int __init acpi_gtdt_map_ppi(int type)
 	case ARCH_TIMER_HYP_PPI:
 		return map_gt_gsi(gtdt->non_secure_el2_interrupt,
 				  gtdt->non_secure_el2_flags);
+	case ARCH_TIMER_HYP_VIRT_PPI:
+		if (el2_vtimer && el2_vtimer->virtual_el2_timer_gsiv)
+			return map_gt_gsi(el2_vtimer->virtual_el2_timer_gsiv,
+					  el2_vtimer->virtual_el2_timer_flags);
+
+		return 0;
 	default:
 		pr_err("Failed to map timer interrupt: invalid type.\n");
 	}
@@ -130,6 +150,7 @@ int __init acpi_gtdt_map_ppi(int type)
 bool __init acpi_gtdt_c3stop(int type)
 {
 	struct acpi_table_gtdt *gtdt = acpi_gtdt_desc.gtdt;
+	struct acpi_gtdt_el2 *el2_vtimer = gtdt_to_el2_vtimer(gtdt);
 
 	switch (type) {
 	case ARCH_TIMER_PHYS_NONSECURE_PPI:
@@ -141,6 +162,10 @@ bool __init acpi_gtdt_c3stop(int type)
 	case ARCH_TIMER_HYP_PPI:
 		return !(gtdt->non_secure_el2_flags & ACPI_GTDT_ALWAYS_ON);
 
+	case ARCH_TIMER_HYP_VIRT_PPI:
+		return el2_vtimer && el2_vtimer->virtual_el2_timer_gsiv &&
+		       !(el2_vtimer->virtual_el2_timer_flags & ACPI_GTDT_ALWAYS_ON);
+
 	default:
 		pr_err("Failed to get c3stop info: invalid type.\n");
 	}
-- 
2.47.3