On 22/02/16 14:46, Aleksey Makarov wrote:
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();
+
So we only enable ACPI if we pass acpi=force as kernel parameter?
I'm not sure if this is what you wanted to do.
Regards,
Matthias
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