[M] Change in flashrom[master]: flashrom.c: Add new erase_by_layout and walk_by_layout implementations

[Edward O'Callaghan (Code Review)]

Attention is currently required from: Simon Buhrow, Thomas Heijligen, Aarya.

Edward O'Callaghan has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/71173 )

Change subject: flashrom.c: Add new erase_by_layout and walk_by_layout implementations
......................................................................

Patch Set 6: Code-Review+2

(13 comments)

File flashrom.c:

https://review.coreboot.org/c/flashrom/+/71173/comment/72895725_cc3f516b 
PS6, Line 1546: , erasefn_count);
`, count_usable_erasers(flashctx));`

https://review.coreboot.org/c/flashrom/+/71173/comment/b706c028_fe325ac0 
PS6, Line 1554: else
you don't need a `else`

https://review.coreboot.org/c/flashrom/+/71173/comment/2c08f614_cc688774 
PS6, Line 1681: int ret = 0;
if you use `ret = 1` as the default you exchange many `ret = 1`'s with one `ret = 0`.

https://review.coreboot.org/c/flashrom/+/71173/comment/e907466c_3313af85 
PS6, Line 1683: const struct romentry *entry = NULL;
pair with while loop construct.

https://review.coreboot.org/c/flashrom/+/71173/comment/a0360be1_3f602b59 
PS6, Line 1684: struct erase_layout *erase_layout = create_erase_layout(flashctx);
If you can help it, pair with the branch below. Don't do C89'ism where you try to put all your declarations at the top.

```
    const struct flashrom_layout *const flash_layout = get_layout(flashctx);
    struct erase_layout *erase_layout = create_erase_layout(flashctx);
    if (!flash_layout || !erase_layout) {
    	goto _ret;
    }
```

https://review.coreboot.org/c/flashrom/+/71173/comment/a6a1ae1a_5a09e89f 
PS6, Line 1685: //no layout
delete

https://review.coreboot.org/c/flashrom/+/71173/comment/cf32f3b3_a90c7fb2 
PS6, Line 1690: //erase layout creation failed
delete

https://review.coreboot.org/c/flashrom/+/71173/comment/b3f6ccca_b995331d 
PS6, Line 1695: 	//not enough memory
              : 	if (!curcontents || !newcontents) {
              : 		ret = 1;
              : 		goto _ret;
              : 	}
delete?

https://review.coreboot.org/c/flashrom/+/71173/comment/896d286e_2f1631ee 
PS6, Line 1701: erase_write(
line-wrap:

```
erase_write(flashctx, entry->region.start,
                      entry->region.end,
                      curcontents, newcontents,
                      erase_layout, all_skipped);
```

https://review.coreboot.org/c/flashrom/+/71173/comment/524ba946_5bf0cc55 
PS6, Line 1701: (uint8_t*)
don't cast, just use the correct type in the first place in the function definition.

https://review.coreboot.org/c/flashrom/+/71173/comment/9243a6b1_20e4d549 
PS6, Line 1703: !!!
one `!` is sufficient or be consistent with the above and have none?

https://review.coreboot.org/c/flashrom/+/71173/comment/f73cbf64_17ae7ac3 
PS6, Line 1708: free_erase_layout(erase_layout, erasefn_count);
`free_erase_layout(erase_layout, count_usable_erasers(flashctx));`

Although I think the API of the free function should not require a length, it should be able to walk the data structure until exhaustion of the `NULL` case.

https://review.coreboot.org/c/flashrom/+/71173/comment/ad55ad7d_3f5f7da1 
PS6, Line 1718: else
ditto