Re: [PATCH 08/10] crypto: omap-aes: gmc: Add algo info

[Lokesh Vutla <lokeshvutla@ti.com>]

On Thursday 02 July 2015 01:30 PM, Stephan Mueller wrote:
> Am Donnerstag, 2. Juli 2015, 10:48:38 schrieb Lokesh Vutla:
> 
> Hi Lokesh,
> 
>> Now the driver supports gcm mode, add omap-aes-gcm
>> algo info to omap-aes driver.
>>
>> Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
>> ---
>> drivers/crypto/omap-aes.c |   22 ++++++++++++++++++++++
>> 1 file changed, 22 insertions(+)
>>
>> diff --git a/drivers/crypto/omap-aes.c b/drivers/crypto/omap-aes.c
>> index e5e9a19..11f3850 100644
>> --- a/drivers/crypto/omap-aes.c
>> +++ b/drivers/crypto/omap-aes.c
>> @@ -789,6 +789,28 @@ static struct crypto_alg algs_ctr[] = {
>> 		.decrypt	= omap_aes_ctr_decrypt,
>> 	}
>> },
>> +{
>> +	.cra_name		= "gcm(aes)",
>> +	.cra_driver_name	= "gcm-aes-omap",
>> +	.cra_priority		= 100,
> 
> Why did you choose the priority 100? The software implementations commonly use 
> 100. crypto/gcm.c uses the prio of the underlying cipher. In case of ARM, 
> there seem to be assembler implementations of AES which have the prio of 200 
> or 300. So, such software implementation of gcm(aes) would have a higher 
> precedence than your hw implementation.
Yes, you are right.
Other hw algos in omap-aes also uses priority 100.
Only sw and hw implementations are enabled right now and both are at same priority.
And till now its lucky enough that hw algo gets picked.

Ill change the priority to 300 for all the modes.
Thanks for pointing it.

Regards,
Lokesh
> 
> So, if a user would use gcm(aes), isn't it more likely that he gets the 
> software implementation?
> 
>> +	.cra_flags		= CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_ASYNC |
>> +				  CRYPTO_ALG_KERN_DRIVER_ONLY,
>> +	.cra_blocksize		= AES_BLOCK_SIZE,
>> +	.cra_ctxsize		= sizeof(struct omap_aes_ctx),
>> +	.cra_alignmask		= 0xf,
>> +	.cra_type		= &crypto_aead_type,
>> +	.cra_module		= THIS_MODULE,
>> +	.cra_init		= omap_aes_gcm_cra_init,
>> +	.cra_exit		= omap_aes_cra_exit,
>> +	.cra_u.aead = {
>> +		.maxauthsize	= AES_BLOCK_SIZE,
>> +		.geniv		= "eseqiv",
>> +		.ivsize		= AES_BLOCK_SIZE,
>> +		.setkey		= omap_aes_gcm_setkey,
>> +		.encrypt	= omap_aes_gcm_encrypt,
>> +		.decrypt	= omap_aes_gcm_decrypt,
>> +	}
>> +},
>> };
>>
>> static struct omap_aes_algs_info omap_aes_algs_info_ecb_cbc[] = {
> 
> 
> Ciao
> Stephan
>