Unverified Commit 38738947 authored by Sia Jee Heng's avatar Sia Jee Heng Committed by Palmer Dabbelt
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RISC-V: ACPI: Enable SPCR table for console output on RISC-V 



The ACPI SPCR code has been used to enable console output for ARM64 and
X86. The same code can be reused for RISC-V. Furthermore, SPCR table is
mandated for headless system as outlined in the RISC-V BRS
Specification, chapter 6.

Signed-off-by: default avatarSia Jee Heng <jeeheng.sia@starfivetech.com>
Reviewed-by: default avatarSunil V L <sunilvl@ventanamicro.com>
Link: https://lore.kernel.org/r/20240502073751.102093-2-jeeheng.sia@starfivetech.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 1613e604

arch/riscv/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ config RISCV 
	def_bool y

	select ACPI_GENERIC_GSI if ACPI

	select ACPI_REDUCED_HARDWARE_ONLY if ACPI

	select ACPI_SPCR_TABLE if ACPI

	select ARCH_DMA_DEFAULT_COHERENT

	select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION

	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2

arch/riscv/kernel/acpi.c

+11 −1
Original line number Diff line number Diff line
@@ -17,7 +17,9 @@ 
#include <linux/efi.h>

#include <linux/io.h>

#include <linux/memblock.h>

#include <linux/of_fdt.h>

#include <linux/pci.h>

#include <linux/serial_core.h>



int acpi_noirq = 1;		/* skip ACPI IRQ initialization */

int acpi_disabled = 1;
@@ -131,7 +133,7 @@ void __init acpi_boot_table_init(void) 
	if (param_acpi_off ||

	    (!param_acpi_on && !param_acpi_force &&

	     efi.acpi20 == EFI_INVALID_TABLE_ADDR))

		return;

		goto done;



	/*

	 * ACPI is disabled at this point. Enable it in order to parse
@@ -151,6 +153,14 @@ void __init acpi_boot_table_init(void) 
		if (!param_acpi_force)

			disable_acpi();

	}



done:

	if (acpi_disabled) {

		if (earlycon_acpi_spcr_enable)

			early_init_dt_scan_chosen_stdout();

	} else {

		acpi_parse_spcr(earlycon_acpi_spcr_enable, true);

	}

}



static int acpi_parse_madt_rintc(union acpi_subtable_headers *header, const unsigned long end)