Extend CBFS to support arbitrary ROM source media.

Summary:
	Isolate CBFS underlying I/O to board/arch-specific implementations as
	"media stream", to allow loading and booting romstage on non-x86.

	CBFS functions now all take a new "media source" parameter; use
	CBFS_DEFAULT_MEDIA if you simply want to load from main firmware.
	API Changes:
		cbfs_find => cbfs_get_file.
		cbfs_find_file => cbfs_get_file_content.
		cbfs_get_file => cbfs_get_file_content with correct type.

CBFS used to work only on memory-mapped ROM (all x86). For platforms like ARM,
the ROM may come from USB, UART, or SPI -- any serial devices and not available
for memory mapping.

To support these devices (and allowing CBFS to read from multiple source
at the same time), CBFS operations are now virtual-ized into "cbfs_media".  To
simplify porting existing code, every media source must support both "reading
into pre-allocated memory (read)" and "read and return an allocated buffer
(map)". For devices without native memory-mapped ROM, "cbfs_simple_buffer*"
provides simple memory mapping simulation.

Every CBFS function now takes a cbfs_media* as parameter. CBFS_DEFAULT_MEDIA
is defined for CBFS functions to automatically initialize a per-board default
media (CBFS will internally calls init_default_cbfs_media).  Also revised CBFS
function names relying on memory mapped backend (ex, "cbfs_find" => actually
loads files). Now we only have two getters:
	struct cbfs_file *entry = cbfs_get_file(media, name);
	void *data = cbfs_get_file_content(CBFS_DEFAULT_MEDIA, name, type);

Test results:
 - Verified to work on x86/qemu.
 - Compiles on ARM, and follow up commit will provide working SPI driver.

Change-Id: Iac911ded25a6f2feffbf3101a81364625bb07746
Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-on: http://review.coreboot.org/2182
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/src/drivers/pc80/mc146818rtc.c b/src/drivers/pc80/mc146818rtc.c
index d8d1778b5c..5ffa9d7fc4 100644
--- a/src/drivers/pc80/mc146818rtc.c
+++ b/src/drivers/pc80/mc146818rtc.c
@@ -190,7 +190,8 @@ int get_option(void *dest, const char *name)
 	namelen = strnlen(name, CMOS_MAX_NAME_LENGTH);
 
 	/* find the requested entry record */
-	ct=cbfs_find_file("cmos_layout.bin", CBFS_COMPONENT_CMOS_LAYOUT);
+	ct = cbfs_get_file_content(CBFS_DEFAULT_MEDIA, "cmos_layout.bin",
+				   CBFS_COMPONENT_CMOS_LAYOUT);
 	if (!ct) {
 		printk(BIOS_ERR, "RTC: cmos_layout.bin could not be found. "
 						"Options are disabled\n");
@@ -268,7 +269,8 @@ int set_option(const char *name, void *value)
 	namelen = strnlen(name, CMOS_MAX_NAME_LENGTH);
 
 	/* find the requested entry record */
-	ct=cbfs_find_file("cmos_layout.bin", CBFS_COMPONENT_CMOS_LAYOUT);
+	ct = cbfs_get_file_content(CBFS_DEFAULT_MEDIA, "cmos_layout.bin",
+				   CBFS_COMPONENT_CMOS_LAYOUT);
 	if (!ct) {
 		printk(BIOS_ERR, "cmos_layout.bin could not be found. Options are disabled\n");
 		return(-2);