Re: 2.6.25-rc3: "__divdi3" [drivers/crypto/hifn_795x.ko] undefined!

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 26 Feb 2008 19:46:35 -0800 (PST)
David Rientjes <rientjes@google.com> wrote:

> On Tue, 26 Feb 2008, Martin Michlmayr wrote:
> 
> > With 2.6.25-rc3 and a config file with
> > 
> > CONFIG_CRYPTO_DEV_HIFN_795X=m
> > CONFIG_CRYPTO_DEV_HIFN_795X_RNG=y
> > 
> > I get the following build error on at least ARM and MIPS:
> > 
> >   Building modules, stage 2.
> >   MODPOST 759 modules
> > ERROR: "__divdi3" [drivers/crypto/hifn_795x.ko] undefined!
> > 
> 
> crypto: use do_div() when registering the rng
> 
> Use do_div() instead of the divide operator.
> 
> Cc: Patrick McHardy <kaber@trash.net>
> Cc: Herbert Xu <herbert@gondor.apana.org.au>
> Signed-off-by: David Rientjes <rientjes@google.com>
> ---
>  Looks like this was triggered by f881d829, which causes this code to be
>  compiled for CONFIG_CRYPTO_DEV_HIFN_795X_RNG.
> 
>  drivers/crypto/hifn_795x.c |    8 +++++---
>  1 files changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/crypto/hifn_795x.c b/drivers/crypto/hifn_795x.c
> --- a/drivers/crypto/hifn_795x.c
> +++ b/drivers/crypto/hifn_795x.c
> @@ -822,12 +822,14 @@ static int hifn_rng_data_read(struct hwrng *rng, u32 *data)
>  
>  static int hifn_register_rng(struct hifn_device *dev)
>  {
> +	unsigned int tmp;
> +
>  	/*
>  	 * We must wait at least 256 Pk_clk cycles between two reads of the rng.
>  	 */
> -	dev->rng_wait_time	= DIV_ROUND_UP(NSEC_PER_SEC, dev->pk_clk_freq) *
> -				  256;
> -
> +	tmp = NSEC_PER_SEC + dev->pk_clk_freq - 1;
> +	do_div(tmp, dev->pk_clk_freq);
> +	dev->rng_wait_time	= tmp * 256;
>  	dev->rng.name		= dev->name;
>  	dev->rng.data_present	= hifn_rng_data_present,
>  	dev->rng.data_read	= hifn_rng_data_read,

do_div takes a u64 as its first arg.  If we're going to make the above
change then we may as well use plain old "/".