From dcbccd6a1ef1ee70d6e96f01c55c8ed270f37716 Mon Sep 17 00:00:00 2001 From: Aaron Durbin Date: Wed, 10 Aug 2016 11:42:42 -0500 Subject: 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 Reviewed-on: https://review.coreboot.org/16194 Tested-by: build bot (Jenkins) Reviewed-by: Furquan Shaikh Reviewed-by: Paul Menzel --- src/include/boot_device.h | 16 ++++++++++++++++ src/lib/boot_device.c | 24 ++++++++++++++++++------ 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 +/* + * 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. @@ -28,6 +37,13 @@ const struct region_device *boot_device_ro(void); 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()); } -- cgit v1.2.3