[PATCH 4/4] fit: Use DM hash driver if supported

[ChiaWei Wang]

Hi Alex,

> From: Alex G. <mr.nuke.me at gmail.com>
> Sent: Friday, September 17, 2021 12:00 AM
> 
> On 7/29/21 8:08 PM, Chia-Wei Wang wrote:
> > Calculate hash using DM driver if supported.
> > For backward compatibility, the call to legacy hash functions is
> > reserved.
> >
> > Signed-off-by: Chia-Wei Wang <chiawei_wang at aspeedtech.com>
> > ---
> >   common/image-fit.c | 30 ++++++++++++++++++++++++++++++
> >   1 file changed, 30 insertions(+)
> >
> > diff --git a/common/image-fit.c b/common/image-fit.c index
> > d6b2c3c7ec..ec2e526356 100644
> > --- a/common/image-fit.c
> > +++ b/common/image-fit.c
> > @@ -25,6 +25,10 @@
> >   #include <asm/io.h>
> >   #include <malloc.h>
> >   #include <asm/global_data.h>
> > +#ifdef CONFIG_DM_HASH
> > +#include <dm.h>
> > +#include <u-boot/hash.h>
> > +#endif
> >   DECLARE_GLOBAL_DATA_PTR;
> >   #endif /* !USE_HOSTCC*/
> >
> > @@ -1214,6 +1218,31 @@ int fit_set_timestamp(void *fit, int noffset,
> time_t timestamp)
> >   int calculate_hash(const void *data, int data_len, const char *algo,
> >   			uint8_t *value, int *value_len)
> >   {
> > +#if !defined(USE_HOSTCC) && defined(CONFIG_DM_HASH)
> 
> This file is shared in its entirety with host tools. There isn't a huge opportunity
> for using a DM-type approach here without #ifndef USE_HOSTCC.
> 

There are still clean up missions to make U-boot bootloader to move on to the DM-based approach.

For instance, when a FIT image is verified by a hash digest, the hash is calculated by calculate_hash() in image-fit.c.
However, when a FIT image is verified by a signature, the hash comes from hash_calculate() in hash-checksum.c.
In my personal opinion, a consistent way to calculate hash for U-Boot bootloader would be better for maintenance.

To make this transition more smoothly, currently the USE_HOSTCC and CONFIG_DM_HASH are added in an ad-hoc way.

Chiawei

> > +	int rc;
> > +	enum HASH_ALGO hash_algo;
> > +	struct udevice *dev;
> > +
> > +	rc = uclass_get_device(UCLASS_HASH, 0, &dev);
> > +	if (rc) {
> > +		debug("failed to get hash device, rc=%d\n", rc);
> > +		return -1;
> > +	}
> > +
> > +	hash_algo = hash_algo_lookup_by_name(algo);
> > +	if (hash_algo == HASH_ALGO_INVALID) {
> > +		debug("Unsupported hash algorithm\n");
> > +		return -1;
> > +	};
> > +
> > +	rc = hash_digest_wd(dev, hash_algo, data, data_len, value, CHUNKSZ);
> > +	if (rc) {
> > +		debug("failed to get hash value, rc=%d\n", rc);
> > +		return -1;
> > +	}
> > +
> > +	*value_len = hash_algo_digest_size(hash_algo); #else
> >   	if (IMAGE_ENABLE_CRC32 && strcmp(algo, "crc32") == 0) {
> >   		*((uint32_t *)value) = crc32_wd(0, data, data_len,
> >   							CHUNKSZ_CRC32);
> > @@ -1242,6 +1271,7 @@ int calculate_hash(const void *data, int data_len,
> const char *algo,
> >   		debug("Unsupported hash alogrithm\n");
> >   		return -1;
> >   	}
> > +#endif
> >   	return 0;
> >   }
> >
> >