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@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);