[U-Boot] [PATCH 1/4 v3] Exynos: Add hardware accelerated SHA 256

[Kim Phillips]

On Fri, 1 Mar 2013 11:16:22 -0500
Akshay Saraswat <akshay.s at samsung.com> wrote:

> SHA-256 and SHA-1 accelerated using ACE hardware.

curious about the rationale: how much faster is this than software?

> ---
> Changes since v2:
> 	- Added falling back to software sha256 in case length exceeds buffer limit.
> 	- Reduced one tab at lines 533, 559 and 571 in this patch.
> 	- Removed space after a cast at line 506 in this patch.
> 	- Removed blank line at line 561 in this patch.
> 	- Removed space before semicolon at line 576 in this patch.

you should retain the list of changes since v1 here.  Read:

http://www.denx.de/wiki/view/U-Boot/Patches#Sending_updated_patch_versions

> +/* Hash status */
> +#define ACE_HASH_BUFRDY_MASK		(1 << 0)
> +#define ACE_HASH_BUFRDY_OFF		(0 << 0)
> +#define ACE_HASH_BUFRDY_ON		(1 << 0)
> +#define ACE_HASH_SEEDSETTING_MASK	(1 << 1)
> +#define ACE_HASH_SEEDSETTING_OFF	(0 << 1)
> +#define ACE_HASH_SEEDSETTING_ON		(1 << 1)
> +#define ACE_HASH_PRNGBUSY_MASK		(1 << 2)
> +#define ACE_HASH_PRNGBUSY_OFF		(0 << 2)
> +#define ACE_HASH_PRNGBUSY_ON		(1 << 2)
> +#define ACE_HASH_PARTIALDONE_MASK	(1 << 4)
> +#define ACE_HASH_PARTIALDONE_OFF	(0 << 4)
> +#define ACE_HASH_PARTIALDONE_ON		(1 << 4)

based on the nomenclature of the above definitions, this hardware
obviously has support for breaking up hash requests into multiple
buffer submissions, so do that, and not this:

> +	} else if (buf_len > BUF_LIMIT) {
> +		/*
> +		 * ACE H/W cannot compute hash value for buffer > 8 MB.
> +		 * Falling back to software.
> +		 */
> +		if (hash_type == ACE_SHA_TYPE_SHA1)
> +			sha1_csum_wd(pbuf, buf_len, pout, CHUNKSZ_SHA1);
> +		else
> +			sha256_csum_wd(pbuf, buf_len, pout, CHUNKSZ_SHA256);
> +		return 0;
> +	}

Kim