Serial port console redirection table can be used for default serial
port selection, like chosen stdout-path selection with FDT method.

With acpi SPCR table added, early debug console can be parsed from
SPCR table with simple kernel parameter earlycon rather than
earlycon=uart,mmio,0x1fe001e0

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
---
 hw/loongarch/acpi-build.c | 40 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/hw/loongarch/acpi-build.c b/hw/loongarch/acpi-build.c
index 2638f87434..3912c8d307 100644
--- a/hw/loongarch/acpi-build.c
+++ b/hw/loongarch/acpi-build.c
@@ -241,6 +241,44 @@ build_srat(GArray *table_data, BIOSLinker *linker, MachineState *machine)
     acpi_table_end(linker, &table);
 }
 
+/*
+ * Serial Port Console Redirection Table (SPCR)
+ * https://learn.microsoft.com/en-us/windows-hardware/drivers/serports/serial-port-console-redirection-table
+ */
+static void
+spcr_setup(GArray *table_data, BIOSLinker *linker, MachineState *machine)
+{
+    LoongArchVirtMachineState *lvms;
+    AcpiSpcrData serial = {
+        .interface_type = 0,       /* 16550 compatible */
+        .base_addr.id = AML_AS_SYSTEM_MEMORY,
+        .base_addr.width = 32,
+        .base_addr.offset = 0,
+        .base_addr.size = 1,
+        .base_addr.addr = VIRT_UART_BASE,
+        .interrupt_type = 0,       /* Interrupt not supported */
+        .pc_interrupt = 0,
+        .interrupt = VIRT_UART_IRQ,
+        .baud_rate = 7,            /* 115200 */
+        .parity = 0,
+        .stop_bits = 1,
+        .flow_control = 0,
+        .terminal_type = 3,        /* ANSI */
+        .language = 0,             /* Language */
+        .pci_device_id = 0xffff,   /* not a PCI device*/
+        .pci_vendor_id = 0xffff,   /* not a PCI device*/
+        .pci_bus = 0,
+        .pci_device = 0,
+        .pci_function = 0,
+        .pci_flags = 0,
+        .pci_segment = 0,
+    };
+
+    lvms = LOONGARCH_VIRT_MACHINE(machine);
+    build_spcr(table_data, linker, &serial, 2, lvms->oem_id,
+               lvms->oem_table_id);
+}
+
 typedef
 struct AcpiBuildState {
     /* Copy of table in RAM (for patching). */
@@ -477,6 +515,8 @@ static void acpi_build(AcpiBuildTables *tables, MachineState *machine)
 
     acpi_add_table(table_offsets, tables_blob);
     build_srat(tables_blob, tables->linker, machine);
+    acpi_add_table(table_offsets, tables_blob);
+    spcr_setup(tables_blob, tables->linker, machine);
 
     if (machine->numa_state->num_nodes) {
         if (machine->numa_state->have_numa_distance) {

base-commit: 7b87a25f49a301d3377f3e71e0b4a62540c6f6e4
-- 
2.39.3

在 2024/9/7 下午3:30, Bibo Mao 写道:
> Serial port console redirection table can be used for default serial
> port selection, like chosen stdout-path selection with FDT method.
>
> With acpi SPCR table added, early debug console can be parsed from
> SPCR table with simple kernel parameter earlycon rather than
> earlycon=uart,mmio,0x1fe001e0
>
> Signed-off-by: Bibo Mao <maobibo@loongson.cn>
> ---
>   hw/loongarch/acpi-build.c | 40 +++++++++++++++++++++++++++++++++++++++
>   1 file changed, 40 insertions(+)
Reviewed-by: Song Gao <gaosong@loongson.cn>

Thanks
Song Gao
> diff --git a/hw/loongarch/acpi-build.c b/hw/loongarch/acpi-build.c
> index 2638f87434..3912c8d307 100644
> --- a/hw/loongarch/acpi-build.c
> +++ b/hw/loongarch/acpi-build.c
> @@ -241,6 +241,44 @@ build_srat(GArray *table_data, BIOSLinker *linker, MachineState *machine)
>       acpi_table_end(linker, &table);
>   }
>   
> +/*
> + * Serial Port Console Redirection Table (SPCR)
> + * https://learn.microsoft.com/en-us/windows-hardware/drivers/serports/serial-port-console-redirection-table
> + */
> +static void
> +spcr_setup(GArray *table_data, BIOSLinker *linker, MachineState *machine)
> +{
> +    LoongArchVirtMachineState *lvms;
> +    AcpiSpcrData serial = {
> +        .interface_type = 0,       /* 16550 compatible */
> +        .base_addr.id = AML_AS_SYSTEM_MEMORY,
> +        .base_addr.width = 32,
> +        .base_addr.offset = 0,
> +        .base_addr.size = 1,
> +        .base_addr.addr = VIRT_UART_BASE,
> +        .interrupt_type = 0,       /* Interrupt not supported */
> +        .pc_interrupt = 0,
> +        .interrupt = VIRT_UART_IRQ,
> +        .baud_rate = 7,            /* 115200 */
> +        .parity = 0,
> +        .stop_bits = 1,
> +        .flow_control = 0,
> +        .terminal_type = 3,        /* ANSI */
> +        .language = 0,             /* Language */
> +        .pci_device_id = 0xffff,   /* not a PCI device*/
> +        .pci_vendor_id = 0xffff,   /* not a PCI device*/
> +        .pci_bus = 0,
> +        .pci_device = 0,
> +        .pci_function = 0,
> +        .pci_flags = 0,
> +        .pci_segment = 0,
> +    };
> +
> +    lvms = LOONGARCH_VIRT_MACHINE(machine);
> +    build_spcr(table_data, linker, &serial, 2, lvms->oem_id,
> +               lvms->oem_table_id);
> +}
> +
>   typedef
>   struct AcpiBuildState {
>       /* Copy of table in RAM (for patching). */
> @@ -477,6 +515,8 @@ static void acpi_build(AcpiBuildTables *tables, MachineState *machine)
>   
>       acpi_add_table(table_offsets, tables_blob);
>       build_srat(tables_blob, tables->linker, machine);
> +    acpi_add_table(table_offsets, tables_blob);
> +    spcr_setup(tables_blob, tables->linker, machine);
>   
>       if (machine->numa_state->num_nodes) {
>           if (machine->numa_state->have_numa_distance) {
>
> base-commit: 7b87a25f49a301d3377f3e71e0b4a62540c6f6e4