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authorAaron Durbin <adurbin@chromium.org>2016-08-10 11:42:42 -0500
committerMartin Roth <martinroth@google.com>2016-08-19 03:07:05 +0200
commitdcbccd6a1ef1ee70d6e96f01c55c8ed270f37716 (patch)
tree42b75c89383427f56acc3c2f8a44f0b9d9233232
parente8e118dd324e32070a1550e3f8ff90dd6fad72f8 (diff)
downloadcoreboot-dcbccd6a1ef1ee70d6e96f01c55c8ed270f37716.tar.xz
lib/boot_device: add RW boot device construct
The current boot device usage assumes read-only semantics to the boot device. Any time someone wants to write to the boot device a device-specific API is invoked such as SPI flash. Instead, provide a mechanism to retrieve an object that can be used to perform writes to the boot device. On systems where the implementations are symmetric these devices can be treated one-in-the-same. However, for x86 systems with memory mapped SPI the read-only boot device provides different operations. BUG=chrome-os-partner:55932 Change-Id: I0af324824f9e1a8e897c2453c36e865b59c4e004 Signed-off-by: Aaron Durbin <adurbin@chromium.org> Reviewed-on: https://review.coreboot.org/16194 Tested-by: build bot (Jenkins) Reviewed-by: Furquan Shaikh <furquan@google.com> Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
-rw-r--r--src/include/boot_device.h16
-rw-r--r--src/lib/boot_device.c24
2 files changed, 34 insertions, 6 deletions
diff --git a/src/include/boot_device.h b/src/include/boot_device.h
index 3964a9508c..cc70442e1e 100644
--- a/src/include/boot_device.h
+++ b/src/include/boot_device.h
@@ -18,9 +18,18 @@
#include <commonlib/region.h>
+/*
+ * Please note that the read-only boot device may not be coherent with
+ * the read-write boot device. Thus, mixing mmap() and writeat() is
+ * most likely not to work so don't rely on such semantics.
+ */
+
/* Return the region_device for the read-only boot device. */
const struct region_device *boot_device_ro(void);
+/* Return the region_device for the read-write boot device. */
+const struct region_device *boot_device_rw(void);
+
/*
* Create a sub-region of the read-only boot device.
* Returns 0 on success, < 0 on error.
@@ -29,6 +38,13 @@ int boot_device_ro_subregion(const struct region *sub,
struct region_device *subrd);
/*
+ * Create a sub-region of the read-write boot device.
+ * Returns 0 on success, < 0 on error.
+ */
+int boot_device_rw_subregion(const struct region *sub,
+ struct region_device *subrd);
+
+/*
* Initialize the boot device. This may be called multiple times within
* a stage so boot device implementations should account for this behavior.
**/
diff --git a/src/lib/boot_device.c b/src/lib/boot_device.c
index 42fe5dfd35..e7968f4fa9 100644
--- a/src/lib/boot_device.c
+++ b/src/lib/boot_device.c
@@ -20,18 +20,30 @@ void __attribute__((weak)) boot_device_init(void)
/* Provide weak do-nothing init. */
}
+static int boot_device_subregion(const struct region *sub,
+ struct region_device *subrd,
+ const struct region_device *parent)
+{
+ if (parent == NULL)
+ return -1;
+
+ return rdev_chain(subrd, parent, region_offset(sub), region_sz(sub));
+}
+
int boot_device_ro_subregion(const struct region *sub,
struct region_device *subrd)
{
- const struct region_device *boot_dev;
-
/* Ensure boot device has been initialized at least once. */
boot_device_init();
- boot_dev = boot_device_ro();
+ return boot_device_subregion(sub, subrd, boot_device_ro());
+}
- if (boot_dev == NULL)
- return -1;
+int boot_device_rw_subregion(const struct region *sub,
+ struct region_device *subrd)
+{
+ /* Ensure boot device has been initialized at least once. */
+ boot_device_init();
- return rdev_chain(subrd, boot_dev, region_offset(sub), region_sz(sub));
+ return boot_device_subregion(sub, subrd, boot_device_rw());
}