It is convenient to write a length value for preceding a block of data.
Of course the length is not known or is hard to calculate a priori. So add
a way to mark the start on a stack, so the length can be updated when
known.
Signed-off-by: Simon Glass <s...@chromium.org>
---
Changes in v1: None
include/acpi/acpigen.h | 3 ++
include/dm/acpi.h | 7 +++++
lib/acpi/acpigen.c | 32 +++++++++++++++++++++
test/dm/acpigen.c | 64 ++++++++++++++++++++++++++++++++++++++++--
4 files changed, 104 insertions(+), 2 deletions(-)
diff --git a/include/acpi/acpigen.h b/include/acpi/acpigen.h
index 7365cce738..31366f5e34 100644
--- a/include/acpi/acpigen.h
+++ b/include/acpi/acpigen.h
@@ -65,4 +65,7 @@ void acpigen_emit_stream(struct acpi_ctx *ctx, const char
*data, int size);
*/
void acpigen_emit_string(struct acpi_ctx *ctx, const char *str);
+void acpigen_write_len_f(struct acpi_ctx *ctx);
+void acpigen_pop_len(struct acpi_ctx *ctx);
+
#endif
diff --git a/include/dm/acpi.h b/include/dm/acpi.h
index 7563a4c60a..2bd03eaa0a 100644
--- a/include/dm/acpi.h
+++ b/include/dm/acpi.h
@@ -22,6 +22,9 @@
/* 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__)
/**
@@ -34,12 +37,16 @@
* 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 *current;
struct acpi_rsdp *rsdp;
struct acpi_rsdt *rsdt;
struct acpi_xsdt *xsdt;
+ char *len_stack[ACPIGEN_LENSTACK_SIZE];
+ int ltop;
};
/**
diff --git a/lib/acpi/acpigen.c b/lib/acpi/acpigen.c
index 1223f0d1c4..8a1c3e8256 100644
--- a/lib/acpi/acpigen.c
+++ b/lib/acpi/acpigen.c
@@ -37,6 +37,38 @@ void acpigen_emit_dword(struct acpi_ctx *ctx, uint data)
acpigen_emit_byte(ctx, (data >> 24) & 0xff);
}
+/*
+ * Maximum length for an ACPI object generated by this code,
+ *
+ * If you need to change this, change acpigen_write_len_f(ctx) and
+ * acpigen_pop_len(ctx)
+ */
+#define ACPIGEN_MAXLEN 0xfffff
+
+void acpigen_write_len_f(struct acpi_ctx *ctx)
+{
+ assert(ctx->ltop < (ACPIGEN_LENSTACK_SIZE - 1));
+ ctx->len_stack[ctx->ltop++] = ctx->current;
+ acpigen_emit_byte(ctx, 0);
+ acpigen_emit_byte(ctx, 0);
+ acpigen_emit_byte(ctx, 0);
+}
+
+void acpigen_pop_len(struct acpi_ctx *ctx)
+{
+ int len;
+ char *p;
+
+ assert(ctx->ltop > 0);
+ p = ctx->len_stack[--ctx->ltop];
+ len = ctx->current - (void *)p;
+ assert(len <= ACPIGEN_MAXLEN);
+ /* generate store length for 0xfffff max */
+ p[0] = (0x80 | (len & 0xf));
+ p[1] = (len >> 4 & 0xff);
+ p[2] = (len >> 12 & 0xff);
+}
+
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 3d580a23a5..f9c15b7503 100644
--- a/test/dm/acpigen.c
+++ b/test/dm/acpigen.c
@@ -22,7 +22,7 @@
#define TEST_STRING "frogmore"
#define TEST_STREAM2 "\xfa\xde"
-static int alloc_context(struct acpi_ctx **ctxp)
+static int alloc_context_size(struct acpi_ctx **ctxp, int size)
{
struct acpi_ctx *ctx;
@@ -30,7 +30,8 @@ static int alloc_context(struct acpi_ctx **ctxp)
ctx = malloc(sizeof(*ctx));
if (!ctx)
return -ENOMEM;
- ctx->current = malloc(150);
+ ctx->current = malloc(size);
+ ctx->ltop = 0;
if (!ctx->current)
return -ENOMEM;
*ctxp = ctx;
@@ -38,6 +39,11 @@ static int alloc_context(struct acpi_ctx **ctxp)
return 0;
}
+static int alloc_context(struct acpi_ctx **ctxp)
+{
+ return alloc_context_size(ctxp, 150);
+}
+
static void free_context(struct acpi_ctx **ctxp)
{
free(*ctxp);
@@ -334,3 +340,57 @@ static int dm_test_acpi_spi(struct unit_test_state *uts)
return 0;
}
DM_TEST(dm_test_acpi_spi, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);
+
+/**
+ * get_length() - decode a three-byte length field
+ *
+ * @ptr: Length encoded as per ACPI
+ * @return decoded length, or -EINVAL on error
+ */
+static int get_length(u8 *ptr)
+{
+ if (!(*ptr & 0x80))
+ return -EINVAL;
+
+ return (*ptr & 0xf) | ptr[1] << 4 | ptr[2] << 12;
+}
+
+/* Test emitting a length */
+static int dm_test_acpi_len(struct unit_test_state *uts)
+{
+ const int size = 0xc0000;
+ struct acpi_ctx *ctx;
+ u8 *ptr;
+ int i;
+
+ ut_assertok(alloc_context_size(&ctx, size));
+
+ ptr = acpigen_get_current(ctx);
+
+ /* Write a byte and a 3-byte length */
+ acpigen_write_len_f(ctx);
+ acpigen_emit_byte(ctx, 0x23);
+ acpigen_pop_len(ctx);
+ ut_asserteq(1 + 3, get_length(ptr));
+
+ /* Write 200 bytes so we need two length bytes */
+ ptr = ctx->current;
+ acpigen_write_len_f(ctx);
+ for (i = 0; i < 200; i++)
+ acpigen_emit_byte(ctx, 0x23);
+ acpigen_pop_len(ctx);
+ ut_asserteq(200 + 3, get_length(ptr));
+
+ /* Write 40KB so we need three length bytes */
+ ptr = ctx->current;
+ acpigen_write_len_f(ctx);
+ for (i = 0; i < 40000; i++)
+ acpigen_emit_byte(ctx, 0x23);
+ acpigen_pop_len(ctx);
+ ut_asserteq(40000 + 3, get_length(ptr));
+
+ free_context(&ctx);
+
+ return 0;
+}
+DM_TEST(dm_test_acpi_len, 0);
--
2.26.2.303.gf8c07b1a785-goog
