Some bootmeths support scanning a partition without a filesystem on it. Add a flag to support this.
This will allow the ChromiumOS bootmeth to find kernel partition, which are stored in a special format, without a filesystem.
Signed-off-by: Simon Glass sjg@chromium.org ---
boot/bootdev-uclass.c | 17 ++++++++++++++--- doc/develop/bootstd.rst | 11 ++++++----- include/bootmeth.h | 3 +++ 3 files changed, 23 insertions(+), 8 deletions(-)
diff --git a/boot/bootdev-uclass.c b/boot/bootdev-uclass.c index 00dc28e623a2..eab89088b63d 100644 --- a/boot/bootdev-uclass.c +++ b/boot/bootdev-uclass.c @@ -111,6 +111,8 @@ int bootdev_bind(struct udevice *parent, const char *drv_name, const char *name, int bootdev_find_in_blk(struct udevice *dev, struct udevice *blk, struct bootflow_iter *iter, struct bootflow *bflow) { + struct bootmeth_uc_plat *plat = dev_get_uclass_plat(bflow->method); + bool allow_any_part = plat->flags & BOOTMETHF_ANY_PART; struct blk_desc *desc = dev_get_uclass_plat(blk); struct disk_partition info; char partstr[20]; @@ -142,6 +144,7 @@ int bootdev_find_in_blk(struct udevice *dev, struct udevice *blk, * us whether there is valid media there */ ret = part_get_info(desc, iter->part, &info); + log_debug("part_get_info() returned %d\n", ret); if (!iter->part && ret == -ENOENT) ret = 0;
@@ -154,7 +157,7 @@ int bootdev_find_in_blk(struct udevice *dev, struct udevice *blk, ret = -ESHUTDOWN; else bflow->state = BOOTFLOWST_MEDIA; - if (ret) { + if (ret && !allow_any_part) { /* allow partition 1 to be missing */ if (iter->part == 1) { iter->max_part = 3; @@ -174,9 +177,15 @@ int bootdev_find_in_blk(struct udevice *dev, struct udevice *blk, if (!iter->part) { iter->first_bootable = part_get_bootable(desc); log_debug("checking bootable=%d\n", iter->first_bootable); + } else if (allow_any_part) { + /* + * allow any partition to be scanned, by skipping any checks + * for filesystems or partition contents on this disk + */
/* if there are bootable partitions, scan only those */ - } else if (iter->first_bootable ? !info.bootable : iter->part != 1) { + } else if (iter->first_bootable >= 0 && + (iter->first_bootable ? !info.bootable : iter->part != 1)) { return log_msg_ret("boot", -EINVAL); } else { ret = fs_set_blk_dev_with_part(desc, bflow->part); @@ -193,6 +202,7 @@ int bootdev_find_in_blk(struct udevice *dev, struct udevice *blk, bflow->state = BOOTFLOWST_FS; }
+ log_debug("method %s\n", bflow->method->name); ret = bootmeth_read_bootflow(bflow->method, bflow); if (ret) return log_msg_ret("method", ret); @@ -555,7 +565,8 @@ int bootdev_get_bootflow(struct udevice *dev, struct bootflow_iter *iter, { const struct bootdev_ops *ops = bootdev_get_ops(dev);
- log_debug("->get_bootflow %s=%p\n", dev->name, ops->get_bootflow); + log_debug("->get_bootflow %s,%x=%p\n", dev->name, iter->part, + ops->get_bootflow); bootflow_init(bflow, dev, iter->method); if (!ops->get_bootflow) return default_get_bootflow(dev, iter, bflow); diff --git a/doc/develop/bootstd.rst b/doc/develop/bootstd.rst index 7a2a69fdfcec..23ea46d6c304 100644 --- a/doc/develop/bootstd.rst +++ b/doc/develop/bootstd.rst @@ -677,11 +677,12 @@ Assuming the bootmeth is happy, or at least indicates that it is willing to try partition. If that works it tries to detect a file system. If that works then it calls the bootmeth device once more, this time to read the bootflow.
-Note: At present a filesystem is needed for the bootmeth to be called on block -devices, simply because we don't have any examples where this is not the case. -This feature can be added as needed. Note that sandbox is a special case, since -in that case the host filesystem can be accessed even though the block device -is NULL. +Note: Normally a filesystem is needed for the bootmeth to be called on block +devices, but bootmeths which don't need that can set the BOOTMETHF_ANY_PART +flag to indicate that they can scan any partition. An example is the ChromiumOS +bootmeth which can store a kernel in a raw partition. Note also that sandbox is +a special case, since in that case the host filesystem can be accessed even +though the block device is NULL.
If we take the example of the `bootmeth_extlinux` driver, this call ends up at `extlinux_read_bootflow()`. It has the filesystem ready, so tries various diff --git a/include/bootmeth.h b/include/bootmeth.h index d3d8d608cd78..0fc36104ece0 100644 --- a/include/bootmeth.h +++ b/include/bootmeth.h @@ -16,9 +16,12 @@ struct udevice; * enum bootmeth_flags - Flags for bootmeths * * @BOOTMETHF_GLOBAL: bootmeth handles bootdev selection automatically + * @BOOTMETHF_ANY_PART: bootmeth is willing to check any partition, even if it + * has no filesystem */ enum bootmeth_flags { BOOTMETHF_GLOBAL = BIT(0), + BOOTMETHF_ANY_PART = BIT(1), };
/**