diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/acpi/acpigen.h | 41 | ||||
| -rw-r--r-- | include/dm/acpi.h | 9 |
2 files changed, 49 insertions, 1 deletions
diff --git a/include/acpi/acpigen.h b/include/acpi/acpigen.h index 9c1faf7bf2..18409b613c 100644 --- a/include/acpi/acpigen.h +++ b/include/acpi/acpigen.h @@ -14,6 +14,9 @@ struct acpi_ctx; +/* Top 4 bits of the value used to indicate a three-byte length value */ +#define ACPI_PKG_LEN_3_BYTES 0x80 + /** * acpigen_get_current() - Get the current ACPI code output pointer * @@ -65,4 +68,42 @@ 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() ----------/ + * + * See ACPI 6.3 section 20.2.4 Package Length Encoding + * + * This implementation always uses a 3-byte packet length for simplicity. It + * could be adjusted to support other lengths. + * + * @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 has 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); + #endif diff --git a/include/dm/acpi.h b/include/dm/acpi.h index 696b1a96a0..dfda88e493 100644 --- a/include/dm/acpi.h +++ b/include/dm/acpi.h @@ -16,12 +16,15 @@ #define ACPI_OPS_PTR(_ptr) #endif -/* Length of an ACPI name string, excluding nul terminator */ +/* Length of an ACPI name string, excluding null terminator */ #define ACPI_NAME_LEN 4 /* Length of an ACPI name string including nul terminator */ #define ACPI_NAME_MAX (ACPI_NAME_LEN + 1) +/* Number of nested objects supported */ +#define ACPIGEN_LENSTACK_SIZE 10 + #if !defined(__ACPI__) /** @@ -35,6 +38,8 @@ * adding a new table. The RSDP holds pointers to the RSDT and XSDT. * @rsdt: Pointer to the Root System Description Table * @xsdt: Pointer to the Extended System Description Table + * @len_stack: Stack of 'length' words to fix up later + * @ltop: Points to current top of stack (0 = empty) */ struct acpi_ctx { void *base; @@ -42,6 +47,8 @@ struct acpi_ctx { struct acpi_rsdp *rsdp; struct acpi_rsdt *rsdt; struct acpi_xsdt *xsdt; + char *len_stack[ACPIGEN_LENSTACK_SIZE]; + int ltop; }; /** |