[PATCH v2 1/8] arm64: move acpi/dt decision earlier in boot process

[Aleksey Makarov]

From: Leif Lindholm <leif.lindholm at linaro.org>

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 at linaro.org>
Signed-off-by: Aleksey Makarov <aleksey.makarov at linaro.org>
---
 arch/arm64/kernel/acpi.c | 62 +++++++++++++++++++++++-------------------------
 1 file changed, 30 insertions(+), 32 deletions(-)

diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index d1ce8e2..3faa323 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -41,26 +41,8 @@ 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_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, "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);
-
 static int __init dt_scan_depth1_nodes(unsigned long node,
 				       const char *uname, int depth,
 				       void *data)
@@ -74,6 +56,35 @@ static int __init dt_scan_depth1_nodes(unsigned long node,
 	return 0;
 }
 
+static int __init parse_acpi(char *arg)
+{
+	if (!arg)
+		return -EINVAL;
+
+	/*
+	 * 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 (strcmp(arg, "off") == 0)
+		return 0;
+	else if (strcmp(arg, "force") == 0)
+		param_acpi_force = true;
+	else if (of_scan_flat_dt(dt_scan_depth1_nodes, NULL))
+		return 0;
+
+	/*
+	 * ACPI is disabled at this point. Enable it in order to parse
+	 * the ACPI tables and carry out sanity checks
+	 */
+	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 +192,10 @@ 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