[coreboot-gerrit] Change in coreboot[master]: acpigen: Add option for reserved bits in Field

[Duncan Laurie (Code Review)]

Duncan Laurie has submitted this change. ( https://review.coreboot.org/c/coreboot/+/46254 )

Change subject: acpigen: Add option for reserved bits in Field
......................................................................

acpigen: Add option for reserved bits in Field

Add an option for unused/reserved bits in a Field definition,
allowing for declarations that do not start at bit 0:

Field (UART, AnyAcc, NoLock, Preserve)
{
    , 7,  /* RESERVED */
    BITF, /* Used bit */
}

These just use byte 0 instead of a name.

Change-Id: I86b54685dbdebacb0834173857c9341ea9fa9a46
Signed-off-by: Duncan Laurie 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/46254
Reviewed-by: Furquan Shaikh 
Tested-by: build bot (Jenkins) 
---
M src/acpi/acpigen.c
M src/include/acpi/acpigen.h
2 files changed, 18 insertions(+), 1 deletion(-)

Approvals:
  build bot (Jenkins): Verified
  Furquan Shaikh: Looks good to me, approved

diff --git a/src/acpi/acpigen.c b/src/acpi/acpigen.c
index 5b45ebd..a3beb10 100644
--- a/src/acpi/acpigen.c
+++ b/src/acpi/acpigen.c
@@ -505,6 +505,12 @@
    acpigen_write_field_length(size);
 }

+static void acpigen_write_field_reserved(uint32_t size)
+{
+	acpigen_emit_byte(0);
+	acpigen_write_field_length(size);
+}
+
 /*
  * Generate ACPI AML code for Field
  * Arg0: region name
@@ -515,6 +521,7 @@
  * struct fieldlist l[] = {
  *	FIELDLIST_OFFSET(0x84),
  *	FIELDLIST_NAMESTR("PMCS", 2),
+ *	FIELDLIST_RESERVED(6),
  *	};
  * acpigen_write_field("UART", l, ARRAY_SIZE(l), FIELD_ANYACC | FIELD_NOLOCK |
  *								FIELD_PRESERVE);
@@ -522,7 +529,8 @@
  * Field (UART, AnyAcc, NoLock, Preserve)
  *	{
  *		Offset (0x84),
- *		PMCS,   2
+ *		PMCS,   2,
+ *              , 6,
  *	}
  */
 void acpigen_write_field(const char *name, const struct fieldlist *l, size_t count,
@@ -546,6 +554,10 @@
    		acpigen_write_field_name(l[i].name, l[i].bits);
    		current_bit_pos += l[i].bits;
    		break;
+		case RESERVED:
+			acpigen_write_field_reserved(l[i].bits);
+			current_bit_pos += l[i].bits;
+			break;
    	case OFFSET:
    		acpigen_write_field_offset(l[i].bits, current_bit_pos);
    		current_bit_pos = l[i].bits;
diff --git a/src/include/acpi/acpigen.h b/src/include/acpi/acpigen.h
index c30f844..10e328b 100644
--- a/src/include/acpi/acpigen.h
+++ b/src/include/acpi/acpigen.h
@@ -158,6 +158,10 @@
    				  .name = X, \
    				  .bits = Y, \
    				}
+#define FIELDLIST_RESERVED(X)		{ .type = RESERVED, \
+					  .name = "", \
+					  .bits = X, \
+					}

#define FIELD_ANYACC			0
 #define FIELD_BYTEACC			1
@@ -174,6 +178,7 @@
 enum field_type {
    OFFSET,
    NAME_STRING,
+	RESERVED,
    FIELD_TYPE_MAX,
 };