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RISC-V: Add ACPI initialization in setup_arch()

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Initialize the ACPI core for RISC-V during boot.

ACPI tables and interpreter are initialized based on
the information passed from the firmware and the value of
the kernel parameter 'acpi'.

With ACPI support added for RISC-V, the kernel parameter 'acpi'
is also supported on RISC-V. Hence, update the documentation.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230515054928.2079268-9-sunilvl@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Sunil V L 2023-05-15 11:19:15 +05:30 committed by Palmer Dabbelt
parent 8b7809e289
commit 724f4c0df7
No known key found for this signature in database
GPG Key ID: 2E1319F35FBB1889
3 changed files with 135 additions and 4 deletions
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8
Documentation/admin-guide/kernel-parameters.txt
View File

@ -1,17 +1,17 @@
acpi= [HW,ACPI,X86,ARM64]
acpi= [HW,ACPI,X86,ARM64,RISCV64]
Advanced Configuration and Power Interface
Format: { force | on | off | strict | noirq | rsdt |
copy_dsdt }
force -- enable ACPI if default was off
on -- enable ACPI but allow fallback to DT [arm64]
on -- enable ACPI but allow fallback to DT [arm64,riscv64]
off -- disable ACPI if default was on
noirq -- do not use ACPI for IRQ routing
strict -- Be less tolerant of platforms that are not
strictly ACPI specification compliant.
rsdt -- prefer RSDT over (default) XSDT
copy_dsdt -- copy DSDT to memory
For ARM64, ONLY "acpi=off", "acpi=on" or "acpi=force"
are available
For ARM64 and RISCV64, ONLY "acpi=off", "acpi=on" or
"acpi=force" are available
See also Documentation/power/runtime_pm.rst, pci=noacpi

126
arch/riscv/kernel/acpi.c
View File

@ -16,6 +16,7 @@
#include <linux/acpi.h>
#include <linux/io.h>
#include <linux/pci.h>
#include <linux/efi.h>
int acpi_noirq = 1; /* skip ACPI IRQ initialization */
int acpi_disabled = 1;
@ -24,6 +25,131 @@ EXPORT_SYMBOL(acpi_disabled);
int acpi_pci_disabled = 1; /* skip ACPI PCI scan and IRQ initialization */
EXPORT_SYMBOL(acpi_pci_disabled);
static bool param_acpi_off __initdata;
static bool param_acpi_on __initdata;
static bool param_acpi_force __initdata;
static int __init parse_acpi(char *arg)
{
if (!arg)
return -EINVAL;
/* "acpi=off" disables both ACPI table parsing and interpreter */
if (strcmp(arg, "off") == 0)
param_acpi_off = true;
else if (strcmp(arg, "on") == 0) /* prefer ACPI over DT */
param_acpi_on = true;
else if (strcmp(arg, "force") == 0) /* force ACPI to be enabled */
param_acpi_force = true;
else
return -EINVAL; /* Core will print when we return error */
return 0;
}
early_param("acpi", parse_acpi);
/*
* acpi_fadt_sanity_check() - Check FADT presence and carry out sanity
* checks on it
*
* Return 0 on success, <0 on failure
*/
static int __init acpi_fadt_sanity_check(void)
{
struct acpi_table_header *table;
struct acpi_table_fadt *fadt;
acpi_status status;
int ret = 0;
/*
* FADT is required on riscv; retrieve it to check its presence
* and carry out revision and ACPI HW reduced compliancy tests
*/
status = acpi_get_table(ACPI_SIG_FADT, 0, &table);
if (ACPI_FAILURE(status)) {
const char *msg = acpi_format_exception(status);
pr_err("Failed to get FADT table, %s\n", msg);
return -ENODEV;
}
fadt = (struct acpi_table_fadt *)table;
/*
* The revision in the table header is the FADT's Major revision. The
* FADT also has a minor revision, which is stored in the FADT itself.
*
* TODO: Currently, we check for 6.5 as the minimum version to check
* for HW_REDUCED flag. However, once RISC-V updates are released in
* the ACPI spec, we need to update this check for exact minor revision
*/
if (table->revision < 6 || (table->revision == 6 && fadt->minor_revision < 5))
pr_err(FW_BUG "Unsupported FADT revision %d.%d, should be 6.5+\n",
table->revision, fadt->minor_revision);
if (!(fadt->flags & ACPI_FADT_HW_REDUCED)) {
pr_err("FADT not ACPI hardware reduced compliant\n");
ret = -EINVAL;
}
/*
* acpi_get_table() creates FADT table mapping that
* should be released after parsing and before resuming boot
*/
acpi_put_table(table);
return ret;
}
/*
* acpi_boot_table_init() called from setup_arch(), always.
* 1. find RSDP and get its address, and then find XSDT
* 2. extract all tables and checksums them all
* 3. check ACPI FADT HW reduced flag
*
* We can parse ACPI boot-time tables such as MADT after
* this function is called.
*
* On return ACPI is enabled if either:
*
* - ACPI tables are initialized and sanity checks passed
* - acpi=force was passed in the command line and ACPI was not disabled
* explicitly through acpi=off command line parameter
*
* ACPI is disabled on function return otherwise
*/
void __init acpi_boot_table_init(void)
{
/*
* Enable ACPI instead of device tree unless
* - ACPI has been disabled explicitly (acpi=off), or
* - firmware has not populated ACPI ptr in EFI system table
* and ACPI has not been [force] enabled (acpi=on|force)
*/
if (param_acpi_off ||
(!param_acpi_on && !param_acpi_force &&
efi.acpi20 == EFI_INVALID_TABLE_ADDR))
return;
/*
* ACPI is disabled at this point. Enable it in order to parse
* the ACPI tables and carry out sanity checks
*/
enable_acpi();
/*
* If ACPI tables are initialized and FADT sanity checks passed,
* leave ACPI enabled and carry on booting; otherwise disable ACPI
* on initialization error.
* If acpi=force was passed on the command line it forces ACPI
* to be enabled even if its initialization failed.
*/
if (acpi_table_init() || acpi_fadt_sanity_check()) {
pr_err("Failed to init ACPI tables\n");
if (!param_acpi_force)
disable_acpi();
}
}
/*
* __acpi_map_table() will be called before paging_init(), so early_ioremap()
* or early_memremap() should be called here to for ACPI table mapping.

5
arch/riscv/kernel/setup.c
View File

@ -8,6 +8,7 @@
* Nick Kossifidis <mick@ics.forth.gr>
*/
#include <linux/acpi.h>
#include <linux/cpu.h>
#include <linux/init.h>
#include <linux/mm.h>
@ -276,6 +277,10 @@ void __init setup_arch(char **cmdline_p)
efi_init();
paging_init();
/* Parse the ACPI tables for possible boot-time configuration */
acpi_boot_table_init();
#if IS_ENABLED(CONFIG_BUILTIN_DTB)
unflatten_and_copy_device_tree();
#else