[PATCH v4 32/35] x86: Allow devices to write to DSDT

[Simon Glass]

Call the new core function to inject ASL programmatically into the DSDT.
This is made up of fragments generated by devices that have the
inject_dsdt() method. The normal, compiled ASL file is added after this.

Signed-off-by: Simon Glass <sjg at chromium.org>
Reviewed-by: Wolfgang Wallner <wolfgang.wallner at br-automation.com>
Reviewed-by: Bin Meng <bmeng.cn at gmail.com>
---

(no changes since v3)

Changes in v3:
- Refactor the code to remove the extra memcpy()
- Recalculate the DSDT checksum only once
- Add a comment as to why the checksum byte is set to 0

 arch/x86/lib/acpi_table.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/arch/x86/lib/acpi_table.c b/arch/x86/lib/acpi_table.c
index 4658d88351..eeacfe9b06 100644
--- a/arch/x86/lib/acpi_table.c
+++ b/arch/x86/lib/acpi_table.c
@@ -406,11 +406,20 @@ ulong write_acpi_tables(ulong start_addr)
 
 	debug("ACPI:    * DSDT\n");
 	dsdt = ctx->current;
+
+	/* Put the table header first */
 	memcpy(dsdt, &AmlCode, sizeof(struct acpi_table_header));
 	acpi_inc(ctx, sizeof(struct acpi_table_header));
+
+	/* If the table is not empty, allow devices to inject things */
+	if (dsdt->length >= sizeof(struct acpi_table_header))
+		acpi_inject_dsdt(ctx);
+
+	/* Copy in the AML code itself if any (after the header) */
 	memcpy(ctx->current,
 	       (char *)&AmlCode + sizeof(struct acpi_table_header),
 	       dsdt->length - sizeof(struct acpi_table_header));
+
 	acpi_inc_align(ctx, dsdt->length - sizeof(struct acpi_table_header));
 
 	/* Pack GNVS into the ACPI table area */
@@ -425,7 +434,12 @@ ulong write_acpi_tables(ulong start_addr)
 		}
 	}
 
-	/* Update DSDT checksum since we patched the GNVS address */
+	/*
+	 * Recalculate the length and update the DSDT checksum since we patched
+	 * the GNVS address. Set the checksum to zero since it is part of the
+	 * region being checksummed.
+	 */
+	dsdt->length = ctx->current - (void *)dsdt;
 	dsdt->checksum = 0;
 	dsdt->checksum = table_compute_checksum((void *)dsdt, dsdt->length);
 
-- 
2.27.0.383.g050319c2ae-goog