[PATCH 1/8] arm64: move acpi/dt decision earlier in boot process

From: Aleksey Makarov
Date: Mon Feb 22 2016 - 08:49:55 EST


From: Leif Lindholm <leif.lindholm@xxxxxxxxxx>

In order to support selecting earlycon via either ACPI or DT, move
the decision on whether to attempt ACPI configuration into the
early_param handling. Then make acpi_boot_table_init() bail out if
acpi_disabled.

Signed-off-by: Leif Lindholm <leif.lindholm@xxxxxxxxxx>
---
arch/arm64/kernel/acpi.c | 54 ++++++++++++++++++++++++++----------------------
1 file changed, 29 insertions(+), 25 deletions(-)

diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index d1ce8e2..7a944f7 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -44,6 +44,19 @@ EXPORT_SYMBOL(acpi_pci_disabled);
static bool param_acpi_off __initdata;
static bool param_acpi_force __initdata;

+static int __init dt_scan_depth1_nodes(unsigned long node,
+ const char *uname, int depth,
+ void *data)
+{
+ /*
+ * Return 1 as soon as we encounter a node at depth 1 that is
+ * not the /chosen node.
+ */
+ if (depth == 1 && (strcmp(uname, "chosen") != 0))
+ return 1;
+ return 0;
+}
+
static int __init parse_acpi(char *arg)
{
if (!arg)
@@ -57,23 +70,27 @@ static int __init parse_acpi(char *arg)
else
return -EINVAL; /* Core will print when we return error */

- return 0;
-}
-early_param("acpi", parse_acpi);
+ /*
+ * Enable ACPI instead of device tree unless
+ * - ACPI has been disabled explicitly (acpi=off), or
+ * - the device tree is not empty (it has more than just a /chosen node)
+ * and ACPI has not been force enabled (acpi=force)
+ */
+ if (param_acpi_off ||
+ (!param_acpi_force && of_scan_flat_dt(dt_scan_depth1_nodes, NULL)))
+ return 0;

-static int __init dt_scan_depth1_nodes(unsigned long node,
- const char *uname, int depth,
- void *data)
-{
/*
- * Return 1 as soon as we encounter a node at depth 1 that is
- * not the /chosen node.
+ * ACPI is disabled at this point. Enable it in order to parse
+ * the ACPI tables and carry out sanity checks
*/
- if (depth == 1 && (strcmp(uname, "chosen") != 0))
- return 1;
+ enable_acpi();
+
return 0;
}

+early_param("acpi", parse_acpi);
+
/*
* __acpi_map_table() will be called before page_init(), so early_ioremap()
* or early_memremap() should be called here to for ACPI table mapping.
@@ -181,23 +198,10 @@ out:
*/
void __init acpi_boot_table_init(void)
{
- /*
- * Enable ACPI instead of device tree unless
- * - ACPI has been disabled explicitly (acpi=off), or
- * - the device tree is not empty (it has more than just a /chosen node)
- * and ACPI has not been force enabled (acpi=force)
- */
- if (param_acpi_off ||
- (!param_acpi_force && of_scan_flat_dt(dt_scan_depth1_nodes, NULL)))
+ if (acpi_disabled)
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.
--
2.7.1