libflash/blocklevel: add blocklevel flags.

It has become apparent that communication between blocklevel and its
backend may be necessarily, at least so that the backend can inform
blocklevel as to if an erase must be done before a write.

An erase before flag isn't strictly necessary as erases can be performed
regardless of whether they need to be or not, however, the caveat with that
is that when erases don't need to be performed, this is likely due to the
backend not having erase blocks and therefore it may be impossible to set a
sane value for erase blocks which would be used to erase before write.

This flag saves backends that don't need erases before write to have to lie
about an erase block size.

Reviewed-By: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Cyril Bur <cyril.bur@au1.ibm.com>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

2 files changed, 6 insertions, 0 deletions

diff --git a/libflash/blocklevel.h b/libflash/blocklevel.h
index 837e67e..310e274 100644
--- a/libflash/blocklevel.h
+++ b/libflash/blocklevel.h
@@ -29,6 +29,10 @@ struct blocklevel_range {
 	int total_prot;
 };
 
+enum blocklevel_flags {
+	WRITE_NEED_ERASE = 1,
+};
+
 /*
  * libffs may be used with different backends, all should provide these for
  * libflash to get the information it needs
@@ -45,6 +49,7 @@ struct blocklevel_device {
 	 * Keep the erase mask so that blocklevel_erase() can do sanity checking
 	 */
 	uint32_t erase_mask;
+	enum blocklevel_flags flags;
 
 	struct blocklevel_range ecc_prot;
 };
diff --git a/libflash/libflash.c b/libflash/libflash.c
index a142e17..55eafbe 100644
--- a/libflash/libflash.c
+++ b/libflash/libflash.c
@@ -838,6 +838,7 @@ bail:
 	c->bl.erase = &flash_erase;
 	c->bl.get_info = &flash_get_info;
 	c->bl.erase_mask = c->min_erase_mask;
+	c->bl.flags = WRITE_NEED_ERASE;
 
 	*bl = &(c->bl);
 	return 0;