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

[Keng-Yu Lin]

On Tue, Jan 15, 2013 at 8:25 PM, Colin King <colin.king at canonical.com> 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)
> --
> 1.8.0
>
Acked-by: Keng-Yu Lin <kengyu at canonical.com>