[Skiboot] [PATCH v2] libflash/file: greatly increase perf of file_erase()

[Stewart Smith]

Do 4096 byte chunks not 8 byte chunks. A ffspart invocation constructing
a 64MB PNOR goes from a couple of seconds to ~0.1seconds with this
patch.

Signed-off-by: Stewart Smith <stewart at linux.ibm.com>
---
v2: use git properly you git (i.e. don't remove a file)

 libflash/file.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/libflash/file.c b/libflash/file.c
index 49f61778e946..72765b5777f9 100644
--- a/libflash/file.c
+++ b/libflash/file.c
@@ -117,15 +117,17 @@ static int file_write(struct blocklevel_device *bl, uint64_t dst, const void *sr
  */
 static int file_erase(struct blocklevel_device *bl, uint64_t dst, uint64_t len)
 {
-	unsigned long long int d = ULLONG_MAX;
+	char buf[4096];
 	int i = 0;
 	int rc;
 
+	memset(buf, ~0, sizeof(buf));
+
 	while (len - i > 0) {
-		rc = file_write(bl, dst + i, &d, len - i > sizeof(d) ? sizeof(d) : len - i);
+		rc = file_write(bl, dst + i, buf, len - i > sizeof(buf) ? sizeof(buf) : len - i);
 		if (rc)
 			return rc;
-		i += len - i > sizeof(d) ? sizeof(d) : len - i;
+		i += (len - i > sizeof(buf)) ? sizeof(buf) : len - i;
 	}
 
 	return 0;
-- 
2.19.2