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ARM64: kernel: acpi: refactor ACPI tables init and checks 

Current ACPI init code on ARM64 relies on acpi_table_parse() API to
check if the FADT is present and to carry out sanity checks on that.

The handler passed to the acpi_table_parse() function and used to
carry out the parsing on the requested table returns a value that is
ignored by the acpi_table_parse() function, so it is not possible
to propagate errors back to the acpi_table_parse() caller through
the handler.

This forces ARM64 ACPI init code to have disable_acpi() calls scattered
all over the place that makes code unwieldy and not easy to follow.

This patch refactors the ARM64 ACPI init code, by creating a
self-contained function (ie acpi_fadt_sanity_check()) that carries
out the required checks on FADT and returns an adequate return value
to the caller. This allows creating a common error path that disables
ACPI and makes code more readable and easy to parse and change were
further checks FADT to be added in the future.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Lorenzo Pieralisi 2015-03-25 15:13:56 +00:00 committed by Will Deacon
parent d989557187
commit 54971e43b9
1 changed files with 59 additions and 36 deletions
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95
arch/arm64/kernel/acpi.c
View File

@ -218,43 +218,60 @@ void __init acpi_init_cpus(void)
pr_info("%d CPUs enabled, %d CPUs total\n", enabled_cpus, total_cpus);
}
static int __init acpi_parse_fadt(struct acpi_table_header *table)
/*
* 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_fadt *fadt = (struct acpi_table_fadt *)table;
struct acpi_table_header *table;
struct acpi_table_fadt *fadt;
acpi_status status;
acpi_size tbl_size;
int ret = 0;
/*
* FADT is required on arm64; retrieve it to check its presence
* and carry out revision and ACPI HW reduced compliancy tests
*/
status = acpi_get_table_with_size(ACPI_SIG_FADT, 0, &table, &tbl_size);
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;
/*
* Revision in table header is the FADT Major revision, and there
* is a minor revision of FADT which was introduced by ACPI 5.1,
* we only deal with ACPI 5.1 or newer revision to get GIC and SMP
* boot protocol configuration data, or we will disable ACPI.
* boot protocol configuration data.
*/
if (table->revision > 5 ||
(table->revision == 5 && fadt->minor_revision >= 1)) {
if (!acpi_gbl_reduced_hardware) {
pr_err("Not hardware reduced ACPI mode, will not be supported\n");
goto disable_acpi;
}
/*
* ACPI 5.1 only has two explicit methods to boot up SMP,
* PSCI and Parking protocol, but the Parking protocol is
* only specified for ARMv7 now, so make PSCI as the only
* way for the SMP boot protocol before some updates for
* the Parking protocol spec.
*/
if (acpi_psci_present())
return 0;
pr_warn("No PSCI support, will not bring up secondary CPUs\n");
return -EOPNOTSUPP;
if (table->revision < 5 ||
(table->revision == 5 && fadt->minor_revision < 1)) {
pr_err("Unsupported FADT revision %d.%d, should be 5.1+\n",
table->revision, fadt->minor_revision);
ret = -EINVAL;
goto out;
}
pr_warn("Unsupported FADT revision %d.%d, should be 5.1+, will disable ACPI\n",
table->revision, fadt->minor_revision);
if (!(fadt->flags & ACPI_FADT_HW_REDUCED)) {
pr_err("FADT not ACPI hardware reduced compliant\n");
ret = -EINVAL;
}
disable_acpi:
disable_acpi();
return -EINVAL;
out:
/*
* acpi_get_table_with_size() creates FADT table mapping that
* should be released after parsing and before resuming boot
*/
early_acpi_os_unmap_memory(table, tbl_size);
return ret;
}
/*
@ -262,9 +279,13 @@ static int __init acpi_parse_fadt(struct acpi_table_header *table)
* 1. find RSDP and get its address, and then find XSDT
* 2. extract all tables and checksums them all
* 3. check ACPI FADT revision
* 4. check ACPI FADT HW reduced flag
*
* We can parse ACPI boot-time tables such as MADT after
* this function is called.
*
* ACPI is enabled on return if ACPI tables initialized and sanity checks
* passed, disabled otherwise
*/
void __init acpi_boot_table_init(void)
{
@ -278,18 +299,20 @@ void __init acpi_boot_table_init(void)
(!param_acpi_force && of_scan_flat_dt(dt_scan_depth1_nodes, NULL)))
return;
/*
* ACPI is disabled at this point. Enable it in order to parse
* the ACPI tables and carry out sanity checks
*/
enable_acpi();
/* Initialize the ACPI boot-time table parser. */
if (acpi_table_init()) {
/*
* 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_table_init() || acpi_fadt_sanity_check()) {
pr_err("Failed to init ACPI tables\n");
disable_acpi();
return;
}
if (acpi_table_parse(ACPI_SIG_FADT, acpi_parse_fadt)) {
/* disable ACPI if no FADT is found */
disable_acpi();
pr_err("Can't find FADT\n");
}
}