Re: [PATCH V3 1/2] hw/loongarch: add rtc acpi table

[lixianglai]

Hi Jonathan Cameron :

On Fri, 20 Mar 2026 08:36:52 +0800
Xianglai Li <lixiang...@loongson.cn> wrote:

Add the acpi table to the loongson rtc hardware so that the virtual machine
kernel can use the loongson RTC-related drivers.

Signed-off-by: Xianglai Li <lixiang...@loongson.cn>

Hi

No data updates for

tests/dta/acpi/loongarch64/virt?

Oh! I missed it. I will fix it in the next patch.

Thanks!
Xianglai.

---
Cc: Song Gao <gaos...@loongson.cn>
Cc: Bibo Mao <maob...@loongson.cn>
Cc: Jiaxun Yang <jiaxun.y...@flygoat.com>
Cc: Huacai Chen <zltjiang...@gmail.com>

  hw/loongarch/virt-acpi-build.c | 25 +++++++++++++++++++++++++
  1 file changed, 25 insertions(+)

diff --git a/hw/loongarch/virt-acpi-build.c b/hw/loongarch/virt-acpi-build.c
index 3e34bedcd6..42820001d7 100644
--- a/hw/loongarch/virt-acpi-build.c
+++ b/hw/loongarch/virt-acpi-build.c
@@ -460,6 +460,30 @@ static void acpi_dsdt_add_tpm(Aml *scope, 
LoongArchVirtMachineState *vms)
  }
  #endif

+static void acpi_dsdt_add_rtc(Aml *scope)

+{
+    Aml *dev = aml_device("RTC");
+
+    aml_append(dev, aml_name_decl("_HID", aml_string("LOON0001")));
+    aml_append(dev, aml_name_decl("_UID", aml_int(0)));
+
+    Aml *crs = aml_resource_template();
+    aml_append(crs,
+        aml_qword_memory(AML_POS_DECODE, AML_MIN_FIXED, AML_MAX_FIXED,
+                         AML_NON_CACHEABLE, AML_READ_WRITE,
+                         0, VIRT_RTC_REG_BASE,
+                         VIRT_RTC_REG_BASE + VIRT_RTC_LEN - 1,
+                         0, VIRT_RTC_LEN));
+    /*
+     * The virtual machine model does not support suspend and wake-up,
+     * and rtc is no longer the wake-up source. Therefore, the current
+     * rtc table no longer provides the rtc alarm interrupt number to
+     * avoid the software initializing alarm.
+     */
+    aml_append(dev, aml_name_decl("_CRS", crs));
+    aml_append(scope, dev);
+}
+
  /* build DSDT */
  static void
  build_dsdt(GArray *table_data, BIOSLinker *linker, MachineState *machine)
@@ -475,6 +499,7 @@ build_dsdt(GArray *table_data, BIOSLinker *linker, 
MachineState *machine)
      for (i = 0; i < VIRT_UART_COUNT; i++) {
          build_uart_device_aml(dsdt, i);
      }
+    acpi_dsdt_add_rtc(dsdt);
      build_pci_device_aml(dsdt, lvms);
      build_la_ged_aml(dsdt, machine);
      build_flash_aml(dsdt, lvms);