intel/common: compress VBT

It's pretty well compressible which helps when space is tight.
The code encodes the assumption that the VBT is 8kb or less. Haven't
seen a larger one yet.

BUG=b:77971803,b:78541692
TEST=build, see that vbt.bin is compressed, boot, check log that the
reported VBT size is correct.

Change-Id: Ie25bca21d9edc408f441a292bbe2ab0459948ec4
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: https://review.coreboot.org/25927
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

2 files changed, 15 insertions, 21 deletions

diff --git a/src/drivers/intel/gma/Makefile.inc b/src/drivers/intel/gma/Makefile.inc
index ab799ef99a..0bcf590c55 100644
--- a/src/drivers/intel/gma/Makefile.inc
+++ b/src/drivers/intel/gma/Makefile.inc
@@ -24,6 +24,7 @@ ramstage-$(CONFIG_INTEL_GMA_ACPI) += opregion.c
 cbfs-files-$(CONFIG_INTEL_GMA_ADD_VBT_DATA_FILE) += vbt.bin
 vbt.bin-file := $(call strip_quotes,$(CONFIG_INTEL_GMA_VBT_FILE))
 vbt.bin-type := raw
+vbt.bin-compression := lzma
 
 ifeq ($(CONFIG_MAINBOARD_USE_LIBGFXINIT),y)
 
diff --git a/src/soc/intel/common/vbt.c b/src/soc/intel/common/vbt.c
index 3d8f2bffbe..9e3cb3516b 100644
--- a/src/soc/intel/common/vbt.c
+++ b/src/soc/intel/common/vbt.c
@@ -30,34 +30,35 @@ const char *mainboard_vbt_filename(void)
 	return "vbt.bin";
 }
 
-static struct region_device vbt_rdev;
-static void *vbt_data;
+static char vbt_data[8 * KiB];
+static int vbt_data_used;
 
 void *locate_vbt(void)
 {
 	uint32_t vbtsig = 0;
-	struct cbfsf file_desc;
 
-	if (vbt_data != NULL)
-		return vbt_data;
+	if (vbt_data_used == 1)
+		return (void *)vbt_data;
 
 	const char *filename = mainboard_vbt_filename();
 
-	if (cbfs_boot_locate(&file_desc, filename, NULL) < 0) {
-		printk(BIOS_ERR, "Could not locate a VBT file in in CBFS\n");
-		return NULL;
-	}
+	size_t file_size = cbfs_boot_load_file(filename,
+		vbt_data, sizeof(vbt_data), CBFS_TYPE_RAW);
 
-	cbfs_file_data(&vbt_rdev, &file_desc);
-	rdev_readat(&vbt_rdev, &vbtsig, 0, sizeof(uint32_t));
+	if (file_size == 0)
+		return NULL;
 
+	memcpy(&vbtsig, vbt_data, sizeof(vbtsig));
 	if (vbtsig != VBT_SIGNATURE) {
 		printk(BIOS_ERR, "Missing/invalid signature in VBT data file!\n");
 		return NULL;
 	}
 
-	vbt_data = rdev_mmap_full(&vbt_rdev);
-	return vbt_data;
+	printk(BIOS_INFO, "Found a VBT of %zu bytes after decompression\n",
+		file_size);
+	vbt_data_used = 1;
+
+	return (void *)vbt_data;
 }
 
 void *vbt_get(void)
@@ -73,11 +74,3 @@ void *vbt_get(void)
 		return NULL;
 	return locate_vbt();
 }
-
-static void unmap_vbt(void *unused)
-{
-	if (vbt_data)
-		rdev_munmap(&vbt_rdev, vbt_data);
-}
-BOOT_STATE_INIT_ENTRY(BS_PAYLOAD_LOAD, BS_ON_EXIT, unmap_vbt, NULL);
-BOOT_STATE_INIT_ENTRY(BS_OS_RESUME, BS_ON_ENTRY, unmap_vbt, NULL);