[U-Boot] [PATCH 1/4 v7] Exynos: Add hardware accelerated SHA256 and SHA1

[Kim Phillips]

On Mon, 18 Mar 2013 02:06:15 -0400
Akshay Saraswat <akshay.s at samsung.com> wrote:

> SHA-256 and SHA-1 accelerated using ACE hardware.
> 
> Signed-off-by: ARUN MANKUZHI <arun.m at samsung.com>
> Signed-off-by: Akshay Saraswat <akshay.s at samsung.com>
> Acked-by: Simon Glass <sjg at chromium.org>
> ---
> +++ b/arch/arm/include/asm/arch-exynos/ace_sha.h

ace_sha.h belongs in drivers/crypto/

> +#define ACE_FC_SELBC_AES		(0 << 2)	/* AES */
> +#define ACE_FC_SELBC_DES		(1 << 2)	/* DES */

nit: comments seem a bit redundant

> +#define ACE_FC_BRDMACARPROT_OFS		(2)
> +#define ACE_FC_BRDMACARCACHE_OFS	(5)
> +#define ACE_FC_BTDMACAWPROT_OFS		(2)
> +#define ACE_FC_BTDMACAWCACHE_OFS	(5)
> +#define ACE_FC_HRDMACARPROT_OFS		(2)
> +#define ACE_FC_HRDMACARCACHE_OFS	(5)
> +#define ACE_FC_SRAMOFFSET_MASK		(0xfff)

no parens.

> +/**
> + * Computes hash value of input pbuf using ACE
> + *
> + * @param in_addr	A pointer to the input buffer
> + * @param bufleni	Byte length of input buffer
> + * @param out_addr	A pointer to the output buffer. When complete
> + *			32 bytes are copied to pout[0]...pout[31]. Thus, a user
> + *			should allocate at least 32 bytes at pOut in advance.
> + * @param hash_type SHA1 or SHA256
> + *
> + * @return		0 on Success, -1 on Failure (Timeout)
...
> +	/* Check if status changes within given time limit */

leftovers from timeout implementation?

> +	while ((readl(&ace_sha_reg->hash_status) & ACE_HASH_MSGDONE_MASK) ==
> +		ACE_HASH_MSGDONE_OFF) {
> +		/*
> +		 * PRNG error bit goes HIGH if a PRNG request occurs without
> +		 * a complete seed setup. We are using this bit to check h/w
> +		 * because proper setup is not expected in that case.
> +		 */
> +		if ((readl(&ace_sha_reg->hash_status)
> +			& ACE_HASH_PRNGERROR_MASK) == ACE_HASH_PRNGERROR_ON)
> +			break;
> +	}

so we have:

whilst (not_done)
	if (PRNGERROR_ON)
		break;

...and then success-assuming code flow continues after this.  What
value is this check for PRNGERROR_ON, if the code isn't going to do
anything differently?  And what does the status of the RNG have to
do with keyless hashing?  It sounds like a check for proper
initialization (RNG got seeded) is in order here, but only if it's
required for the given hash operations (I doubt it, but the h/w
might be fussy).

Kim