Re: Question about Talitos Linux driver for MPC885

[leroy christophe <christophe.leroy@c-s.fr>]

Le 28/11/2012 00:11, Kim Phillips a écrit :
> On Fri, 23 Nov 2012 14:51:08 +0100
> leroy christophe <christophe.leroy@c-s.fr> wrote:
>
>> Le 26/09/2012 02:47, Kim Phillips a écrit :
>>> On Tue, 25 Sep 2012 10:45:17 +0200
>>> leroy christophe <christophe.leroy@c-s.fr> wrote:
>>>
>>>> I'm trying to use the Talitos crypto driver with the MPC885
>>>> microcontroller. For the time being, it doesn't work.
>>> yes, they're not exactly compatible...
>>>
>>>> The kernel startup blocks at the test of the DES function.
>>>>
>>>> I have added the following definition in the DTS file:
>>>>
>>>>            crypto@20000 {
>>>>                compatible = "fsl,sec2.0";
>>> interesting, its called "SEC Lite" and its version register does
>>> indeed say 2.  I see it has a single channel FIFO instead of a ring,
>>> that the SEC v1.x (MPC185) used, so you probably don't have to
>>> rewrite talitos_submit.
>> Good news, it was also my understanding.
>>>>                reg = <0x20000 0x8000>;
>>>>                interrupts = <1 1>;
>>> I couldn't find the IRQ line in the MPC855RM - if there's no IRQ
>>> line, then that's a problem.
>> Neither do I on the drawing, however in Table 52-1, there are 3 bits in
>> the CPTR register for defining the interrupt level of the SEC lite, just
>> like you do for the CPM and for the FEC.
> not sure how interrupt _level_ is relevant, but I'm going to assume
> you're saying the SEC's IRQ line is integrated into that of the CPM
> and/or FEC.
>
>> So I believe this should be ok ?
> Assuming the above, the 'interrupts' property above should
> equal that of the CPM and/or FEC, and the IRQ_SHARED flag set in
> request_irq (in both talitos and the CPM and/or FEC drivers).  The
> talitos IRQ handler will return IRQ_NONE if none of the channel
> done/error bits are set in the SEC.
Indeed no. It shares the same registrer (CPTR) as the FEC, but has its 
own bits and its own IRQ line. So it works without having to share the IRQ.
>>>>                interrupt-parent = <&PIC>;
>>>>                fsl,num-channels = <1>;
>>>>                fsl,channel-fifo-len = <24>;
>>>>                fsl,exec-units-mask = <0x4c>;
>>>>                fsl,descriptor-types-mask = <0x301f>;
>>> the descriptor type enumeration isn't uniform across into the mpc8xx
>>> SEC version, e.g., the SEC Lite doesn't support the ipsec_esp
>>> descriptor type, represented in mpc8xxx SEC versions as the second
>>> bit, so this descriptor-types-mask setting should be fixed to at
>>> least omit that since the driver checks for, and uses it if
>>> available.
In fact it looks like the enumeration is uniform as far as what I was 
seen, the different is that on SEC1 it is encoded on 4 bits, while in 
SEC2 it is encoded on 5 bits, and unfortunately it is the least 
significant bit that is missing on SEC1.
So by shifting one bit to the left in matches.
>>>
>>>> Is there anything wrong in what I did ? Or is there something else I
>>>> should do ?
>>> might want to go through the defines in talitos.h, e.g,
>>> TALITOS_MCR_SWR is 0x1 on mpc8xxx vs. 0x10000000 on
>>> mpc8xx (I suppose CONFIG_PPC_8xx can be used as the ifdef, btw).
>> I'm surprised about this, I didn't check the talitos.h file, but had
>> checked the Reference Manual of the MPC 8272.
>> I rechecked yesterday and the SWR bit is at the same place as on the
>> MPC885 which is different from what is defined in talitos.h
> right, for some odd reason the h/w designers decided to scramble
> the bitfield definitions.
Right. In the begining in fact I was wrongly thinking the MPC8282 had 
SEC2 while MPC885 had SEC1, whereas indeed both have SEC1.
Therefore as you suggested I started altering the needed defines inside 
CONFIG_PPC_8xx

I'm now having a driver which starts bubbling, I'm having two issues:
1) One with the interrupt routing of the existing talitos driver. The 
drivers considers that when ISR_LO is non zero, it is an error, whereas 
according to the reference manuels, on both SEC1 (MPC885) and SEC2 
(MPC8323), ISR_LO includes ERR and DONE for the EUs. So when the 
interrupt fires after completion, at least on MPC885, both the Channel 
and the EUs have their DONE bit set.
It there any reason why a non zero ISR_LO is considered as a fault ?
2) I'm having an issue with the MD5 runtime test at startup. The first 
test on MD5 seems to the the hashing of a zero length data. It looks 
like the SEC1 doesn't like this, the kernel remains stuck and nothing 
happens. Looking at the status registers of the crypto channel, status 
is 0x10 meaning Processing Data Pairs, and status2 is 0x00280005.
First, is that correct to try and hash an empty data packet ?
Second, is there a way to workaround this issue ?

Herebelow is the content of /dev/crypto (I have faked the MD5 by setting 
data length to 1 instead of 0, hence the failure)

name         : sha256
driver       : sha256-talitos
module       : kernel
priority     : 3000
refcnt       : 1
selftest     : passed
type         : ahash
async        : yes
blocksize    : 64
digestsize   : 32

name         : sha224
driver       : sha224-talitos
module       : kernel
priority     : 3000
refcnt       : 1
selftest     : passed
type         : ahash
async        : yes
blocksize    : 64
digestsize   : 28

name         : sha1
driver       : sha1-talitos
module       : kernel
priority     : 3000
refcnt       : 1
selftest     : passed
type         : ahash
async        : yes
blocksize    : 64
digestsize   : 20

name         : md5
driver       : md5-talitos
module       : kernel
priority     : 3000
refcnt       : 1
selftest     : unknown
type         : ahash
async        : yes
blocksize    : 64
digestsize   : 16

name         : cbc(des3_ede)
driver       : cbc-3des-talitos
module       : kernel
priority     : 3000
refcnt       : 1
selftest     : passed
type         : ablkcipher
async        : yes
blocksize    : 8
min keysize  : 24
max keysize  : 24
ivsize       : 8
geniv        : eseqiv

name         : cbc(aes)
driver       : cbc-aes-talitos
module       : kernel
priority     : 3000
refcnt       : 1
selftest     : passed
type         : ablkcipher
async        : yes
blocksize    : 16
min keysize  : 16
max keysize  : 32
ivsize       : 16
geniv        : eseqiv

name         : stdrng
driver       : krng
module       : kernel
priority     : 200
refcnt       : 1
selftest     : passed
type         : rng
seedsize     : 0

name         : lzo
driver       : lzo-generic
module       : kernel
priority     : 0
refcnt       : 2
selftest     : passed
type         : compression

name         : aes
driver       : aes-generic
module       : kernel
priority     : 100
refcnt       : 2
selftest     : passed
type         : cipher
blocksize    : 16
min keysize  : 16
max keysize  : 32


Christophe

>
>>> Descriptor header and pointer formats, along with field locations,
>>> sizes, and enumerations may also be different.
>>>
>>> It also appears the SEC Lite doesn't support scatter-gather tables,
>>> which will make performance hurt for fragmented (large) packet sizes.
>> Does it mean something has to be modified if the SW ?
> yes, s/w will have to allocate a new contiguous memory buffer and
> sg_copy_to_buffer() prior to crypto request submission to the h/w,
> and sg_copy_from_buffer() after h/w completion.
>
> Kim
>