[Skiboot] [PATCH 1/2] libflash: don't use the low level interface if it doesn't exist

[Cyril Bur]

During init libflash calls low level functions without checking.

libflash states to backends that if they implement all the higher level
functions the lower level functions are optional (from libflash-priv.h):
  If all functions of the high level interface are
  implemented then the low level one is optional. A
  controller can implement some of the high level one
  in which case the missing ones will be handled by
  libflash using the low level interface.

Signed-off-by: Cyril Bur <cyril.bur at au1.ibm.com>
---
 libflash/libflash.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/libflash/libflash.c b/libflash/libflash.c
index 5b8a0ac..bb6f097 100644
--- a/libflash/libflash.c
+++ b/libflash/libflash.c
@@ -668,6 +668,10 @@ static int flash_set_4b(struct flash_chip *c, bool enable)
 	struct spi_flash_ctrl *ct = c->ctrl;
 	int rc;
 
+	/* Don't have low level interface, assume all is well */
+	if (!ct->cmd_wr)
+		return 0;
+
 	/* Some flash chips want this */
 	rc = fl_wren(ct);
 	if (rc) {
@@ -676,7 +680,6 @@ static int flash_set_4b(struct flash_chip *c, bool enable)
 	}
 
 	/* Ignore error in case chip is write protected */
-
 	return ct->cmd_wr(ct, enable ? CMD_EN4B : CMD_EX4B, false, 0, NULL, 0);
 }
 
@@ -758,7 +761,6 @@ static int flash_configure(struct flash_chip *c)
 				return rc;
 			}
 		}
-
 		/* Set controller to 3b mode if mode switch is supported */
 		if (ct->set_4b) {
 			FL_DBG("LIBFLASH: Disabling controller 4B mode...\n");
-- 
1.9.1