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

[Cyril Bur]

I'll rebase these onto master, sorry.

On Wed, 2015-04-01 at 16:51 +1100, Cyril Bur wrote:
> 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");