[PATCH v8 14/35] acpigen: Support writing a package
Simon Glass
sjg at chromium.org
Sun Apr 26 17:25:57 CEST 2020
A package collects together several elements. Add an easy way of writing
a package header and updating its length later.
Signed-off-by: Simon Glass <sjg at chromium.org>
---
Changes in v8: None
Changes in v3: None
Changes in v2: None
include/acpi/acpigen.h | 62 ++++++++++++++++++++++++++++++++++++++++++
lib/acpi/acpigen.c | 12 ++++++++
test/dm/acpigen.c | 27 ++++++++++++++++++
3 files changed, 101 insertions(+)
diff --git a/include/acpi/acpigen.h b/include/acpi/acpigen.h
index 31366f5e34..52e0b75128 100644
--- a/include/acpi/acpigen.h
+++ b/include/acpi/acpigen.h
@@ -14,6 +14,11 @@
struct acpi_ctx;
+/* ACPI Op/Prefix codes */
+enum {
+ PACKAGE_OP = 0x12,
+};
+
/**
* acpigen_get_current() - Get the current ACPI code output pointer
*
@@ -65,7 +70,64 @@ void acpigen_emit_stream(struct acpi_ctx *ctx, const char *data, int size);
*/
void acpigen_emit_string(struct acpi_ctx *ctx, const char *str);
+/**
+ * acpigen_write_len_f() - Write a 'forward' length placeholder
+ *
+ * This adds space for a length value in the ACPI stream and pushes the current
+ * position (before the length) on the stack. After calling this you can write
+ * some data and then call acpigen_pop_len() to update the length value.
+ *
+ * Usage:
+ *
+ * acpigen_write_len_f() ------\
+ * acpigen_write...() |
+ * acpigen_write...() |
+ * acpigen_write_len_f() --\ |
+ * acpigen_write...() | |
+ * acpigen_write...() | |
+ * acpigen_pop_len() ------/ |
+ * acpigen_write...() |
+ * acpigen_pop_len() ----------/
+ *
+ * @ctx: ACPI context pointer
+ */
void acpigen_write_len_f(struct acpi_ctx *ctx);
+
+/**
+ * acpigen_pop_len() - Update the previously stacked length placeholder
+ *
+ * Call this after the data for the block gas been written. It updates the
+ * top length value in the stack and pops it off.
+ *
+ * @ctx: ACPI context pointer
+ */
void acpigen_pop_len(struct acpi_ctx *ctx);
+/**
+ * acpigen_write_package() - Start writing a package
+ *
+ * A package collects together a number of elements in the ACPI code. To write
+ * a package use:
+ *
+ * acpigen_write_package(ctx, 3);
+ * ...write things
+ * acpigen_pop_len()
+ *
+ * If you don't know the number of elements in advance, acpigen_write_package()
+ * returns a pointer to the value so you can update it later:
+ *
+ * char *num_elements = acpigen_write_package(ctx, 0);
+ * ...write things
+ * *num_elements += 1;
+ * ...write things
+ * *num_elements += 1;
+ * acpigen_pop_len()
+ *
+ * @ctx: ACPI context pointer
+ * @nr_el: Number of elements (0 if not known)
+ * @returns pointer to the number of elements, which can be updated by the
+ * caller if needed
+ */
+char *acpigen_write_package(struct acpi_ctx *ctx, int nr_el);
+
#endif
diff --git a/lib/acpi/acpigen.c b/lib/acpi/acpigen.c
index 8a1c3e8256..ca9e96597e 100644
--- a/lib/acpi/acpigen.c
+++ b/lib/acpi/acpigen.c
@@ -69,6 +69,18 @@ void acpigen_pop_len(struct acpi_ctx *ctx)
p[2] = (len >> 12 & 0xff);
}
+char *acpigen_write_package(struct acpi_ctx *ctx, int nr_el)
+{
+ char *p;
+
+ acpigen_emit_byte(ctx, PACKAGE_OP);
+ acpigen_write_len_f(ctx);
+ p = ctx->current;
+ acpigen_emit_byte(ctx, nr_el);
+
+ return p;
+}
+
void acpigen_emit_stream(struct acpi_ctx *ctx, const char *data, int size)
{
int i;
diff --git a/test/dm/acpigen.c b/test/dm/acpigen.c
index f9c15b7503..be81068759 100644
--- a/test/dm/acpigen.c
+++ b/test/dm/acpigen.c
@@ -394,3 +394,30 @@ static int dm_test_acpi_len(struct unit_test_state *uts)
return 0;
}
DM_TEST(dm_test_acpi_len, 0);
+
+/* Test emitting a package */
+static int dm_test_acpi_package(struct unit_test_state *uts)
+{
+ struct acpi_ctx *ctx;
+ char *num_elements;
+ u8 *ptr;
+
+ ut_assertok(alloc_context(&ctx));
+
+ ptr = acpigen_get_current(ctx);
+
+ num_elements = acpigen_write_package(ctx, 3);
+ ut_asserteq_ptr(num_elements, ptr + 4);
+
+ /* For easy of testing, just emit a byte, not valid package contents */
+ acpigen_emit_byte(ctx, 0x23);
+ acpigen_pop_len(ctx);
+ ut_asserteq(PACKAGE_OP, ptr[0]);
+ ut_asserteq(5, get_length(ptr + 1));
+ ut_asserteq(3, ptr[4]);
+
+ free_context(&ctx);
+
+ return 0;
+}
+DM_TEST(dm_test_acpi_package, 0);
--
2.26.2.303.gf8c07b1a785-goog
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