Re: [PATCH V2] hw/loongarch: add rtc acpi table

[lixianglai]

Hi gaosong:

在 2026/3/12 上午10:13, Xianglai Li 写道:

Add the acpi table to the loongson rtc hardware so that the virtual machine

kernel can use the loongson RTC-related drivers.

Delete the interrupt information in the rtc fdt table.

Signed-off-by: Xianglai Li <lixiang...@loongson.cn>
---
Cc: Song Gao <gaos...@loongson.cn>
Cc: Bibo Mao <maob...@loongson.cn>
Cc: Jiaxun Yang <jiaxun.y...@flygoat.com>

change:
V1->V2:

1.Add a comment to explain why the acpi table no longer provides interrupt numbers

2.Delete the interrupt number from the rtc fdt table

It would be better to move point 2 to the new patch.

Ok!!!

Thanks.
Song Gao

  hw/loongarch/virt-acpi-build.c | 25 +++++++++++++++++++++++++
  hw/loongarch/virt-fdt-build.c  | 16 ++++++++--------
  2 files changed, 33 insertions(+), 8 deletions(-)

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);

diff --git a/hw/loongarch/virt-fdt-build.c b/hw/loongarch/virt-fdt-build.c

index 6c06b36fca..42f014a7bd 100644
--- a/hw/loongarch/virt-fdt-build.c
+++ b/hw/loongarch/virt-fdt-build.c

@@ -458,8 +458,7 @@ static void fdt_add_uart_node(LoongArchVirtMachineState *lvms,

      g_free(nodename);
  }
  -static void fdt_add_rtc_node(LoongArchVirtMachineState *lvms,
-                             uint32_t *pch_pic_phandle)
+static void fdt_add_rtc_node(LoongArchVirtMachineState *lvms)
  {
      char *nodename;
      hwaddr base = VIRT_RTC_REG_BASE;

@@ -470,12 +469,13 @@ static void fdt_add_rtc_node(LoongArchVirtMachineState *lvms,

      qemu_fdt_add_subnode(ms->fdt, nodename);
      qemu_fdt_setprop_string(ms->fdt, nodename, "compatible",
                              "loongson,ls7a-rtc");
+    /*
+     * 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.
+     */

      qemu_fdt_setprop_sized_cells(ms->fdt, nodename, "reg", 2, base, 2, size);

-    qemu_fdt_setprop_cells(ms->fdt, nodename, "interrupts",
-                           VIRT_RTC_IRQ - VIRT_GSI_BASE ,
-                           FDT_IRQ_TYPE_LEVEL_HIGH);
-    qemu_fdt_setprop_cell(ms->fdt, nodename, "interrupt-parent",
-                          *pch_pic_phandle);
      g_free(nodename);
  }

  @@ -550,7 +550,7 @@ void virt_fdt_setup(LoongArchVirtMachineState *lvms)

          fdt_add_uart_node(lvms, &pch_pic_phandle, base, irq, i == 0);
      }
  -    fdt_add_rtc_node(lvms, &pch_pic_phandle);
+    fdt_add_rtc_node(lvms);
      fdt_add_ged_reset(lvms);
      platform_bus_add_all_fdt_nodes(machine->fdt, "/platic",
VIRT_PLATFORM_BUS_BASEADDRESS,