qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Qemu-devel] [PATCH v3] ARM: Virt: Don't generate RTC ACPI device when u


From: Shannon Zhao
Subject: [Qemu-devel] [PATCH v3] ARM: Virt: Don't generate RTC ACPI device when using UEFI
Date: Fri, 15 Jan 2016 22:11:31 +0800

When booting the VM with UEFI, UEFI takes ownership of the RTC hardware.
While UEFI can use libfdt to disable the RTC device node in the DTB that
it passes to the OS, it cannot modify AML. Therefore, we won't generate
the RTC ACPI device at all when using UEFI.

Signed-off-by: Shannon Zhao <address@hidden>
Acked-by: Ard Biesheuvel <address@hidden>
Reviewed-by: Laszlo Ersek <address@hidden>
---
V3: add comments to explain why it doesn't generate RTC ACPI device
---
 hw/arm/virt-acpi-build.c | 24 +++++-------------------
 1 file changed, 5 insertions(+), 19 deletions(-)

diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
index 0caf5ce..0d5c635 100644
--- a/hw/arm/virt-acpi-build.c
+++ b/hw/arm/virt-acpi-build.c
@@ -94,23 +94,6 @@ static void acpi_dsdt_add_uart(Aml *scope, const MemMapEntry 
*uart_memmap,
     aml_append(scope, dev);
 }
 
-static void acpi_dsdt_add_rtc(Aml *scope, const MemMapEntry *rtc_memmap,
-                                          uint32_t rtc_irq)
-{
-    Aml *dev = aml_device("RTC0");
-    aml_append(dev, aml_name_decl("_HID", aml_string("LNRO0013")));
-    aml_append(dev, aml_name_decl("_UID", aml_int(0)));
-
-    Aml *crs = aml_resource_template();
-    aml_append(crs, aml_memory32_fixed(rtc_memmap->base,
-                                       rtc_memmap->size, AML_READ_WRITE));
-    aml_append(crs,
-               aml_interrupt(AML_CONSUMER, AML_LEVEL, AML_ACTIVE_HIGH,
-                             AML_EXCLUSIVE, &rtc_irq, 1));
-    aml_append(dev, aml_name_decl("_CRS", crs));
-    aml_append(scope, dev);
-}
-
 static void acpi_dsdt_add_flash(Aml *scope, const MemMapEntry *flash_memmap)
 {
     Aml *dev, *crs;
@@ -571,12 +554,15 @@ build_dsdt(GArray *table_data, GArray *linker, 
VirtGuestInfo *guest_info)
     /* Reserve space for header */
     acpi_data_push(dsdt->buf, sizeof(AcpiTableHeader));
 
+    /* When booting the VM with UEFI, UEFI takes ownership of the RTC hardware.
+     * While UEFI can use libfdt to disable the RTC device node in the DTB that
+     * it passes to the OS, it cannot modify AML. Therefore, we won't generate
+     * the RTC ACPI device at all when using UEFI.
+     */
     scope = aml_scope("\\_SB");
     acpi_dsdt_add_cpus(scope, guest_info->smp_cpus);
     acpi_dsdt_add_uart(scope, &memmap[VIRT_UART],
                        (irqmap[VIRT_UART] + ARM_SPI_BASE));
-    acpi_dsdt_add_rtc(scope, &memmap[VIRT_RTC],
-                      (irqmap[VIRT_RTC] + ARM_SPI_BASE));
     acpi_dsdt_add_flash(scope, &memmap[VIRT_FLASH]);
     acpi_dsdt_add_virtio(scope, &memmap[VIRT_MMIO],
                     (irqmap[VIRT_MMIO] + ARM_SPI_BASE), NUM_VIRTIO_TRANSPORTS);
-- 
2.1.0




reply via email to

[Prev in Thread] Current Thread [Next in Thread]