[PATCH 3/3] lib: fwts_cmos: Use new I/O helpers, add more error checking

[IvanHu]

On 01/15/2013 08:25 PM, Colin King wrote:
> From: Colin Ian King <colin.king at canonical.com>
>
> Use the new I/O helper functions to ensure we catch I/O access errors.
> Also add in sane error handling to undo ioperm, iopl and restore
> interrupt state when an error occurs.
>
> Signed-off-by: Colin Ian King <colin.king at canonical.com>
> ---
>   src/lib/src/fwts_cmos.c | 42 +++++++++++++++++++++++++++++++++---------
>   1 file changed, 33 insertions(+), 9 deletions(-)
>
> diff --git a/src/lib/src/fwts_cmos.c b/src/lib/src/fwts_cmos.c
> index 284e718..fd1f83d 100644
> --- a/src/lib/src/fwts_cmos.c
> +++ b/src/lib/src/fwts_cmos.c
> @@ -30,24 +30,48 @@
>    */
>   int fwts_cmos_read(const uint8_t offset, uint8_t *value)
>   {
> +	int ret = FWTS_OK;
> +
> +	*value = ~0;	/* Default in case of error */
> +
>   	if (ioperm(0x70, 2, 1) < 0)
>   		return FWTS_ERROR;
> -	if (ioperm(0x80, 1, 1) < 0)
> -		return FWTS_ERROR;
> -	if (iopl(3) < 0)	/* Want to disabled interrupts */
> -		return FWTS_ERROR;
> +
> +	if (ioperm(0x80, 1, 1) < 0) {
> +		ret = FWTS_ERROR;
> +		goto tidy0x70;
> +	}
> +	/* Want to disable interrupts */
> +	if (iopl(3) < 0) {
> +		ret = FWTS_ERROR;
> +		goto tidy0x80;
> +	}
>
>   	asm("cli");
> -	outb(offset, 0x70);	/* specify offset to read */
> -	outb(0, 0x80);		/* Small Delay */
> -	*value = inb(0x71);	/* get the value */
> -	asm("sti");
> +	/* specify offset to read */
> +	if (fwts_outb(offset, 0x70) != FWTS_OK) {
> +		ret = FWTS_ERROR;
> +		goto tidy;
> +	}
>
> +	/* Small Delay */
> +	if (fwts_outb(0, 0x80) != FWTS_OK) {
> +		ret = FWTS_ERROR;
> +		goto tidy;
> +	}
> +
> +	/* get the CMOS value */
> +	if (fwts_inb(0x71, value) != FWTS_OK)
> +		ret = FWTS_ERROR;
> +tidy:
> +	asm("sti");
>   	(void)iopl(0);
> +tidy0x80:
>   	(void)ioperm(0x80, 1, 0);
> +tidy0x70:
>   	(void)ioperm(0x70, 2, 0);
>
> -	return FWTS_OK;
> +	return ret;
>   }
>   #else
>   int fwts_cmos_read(const uint8_t offset, uint8_t *value)
>
Acked-by: Ivan Hu <ivan.hu at canonical.com>