Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Sat, 21 Nov 2020 17:10:27 -0800
From:   Moritz Fischer <mdf@kernel.org>
To:     Richard Gong <richard.gong@linux.intel.com>
Cc:     Moritz Fischer <mdf@kernel.org>, gregkh@linuxfoundation.org,
        trix@redhat.com, linux-fpga@vger.kernel.org,
        linux-kernel@vger.kernel.org, dinguyen@kernel.org,
        sridhar.rajagopal@intel.com, richard.gong@intel.com
Subject: Re: [PATCHv2 1/5] firmware: stratix10-svc: add
 COMMAND_AUTHENTICATE_BITSTREAM flag
Message-ID: <X7m6gy/B8DiafyYQ@archbook>
References: <1605709753-7800-1-git-send-email-richard.gong@linux.intel.com>
 <1605709753-7800-2-git-send-email-richard.gong@linux.intel.com>
 <X7U+BTkW7ZmsMByV@epycbox.lan>
 <d8b58b40-63c6-115e-8e61-f092e3f050b3@linux.intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <d8b58b40-63c6-115e-8e61-f092e3f050b3@linux.intel.com>
Precedence: bulk

Richard,

On Wed, Nov 18, 2020 at 12:16:09PM -0600, Richard Gong wrote:

> > > -#define COMMAND_RECONFIG_FLAG_PARTIAL	1
> > > +#define COMMAND_RECONFIG_FLAG_PARTIAL	0
> > > +#define COMMAND_AUTHENTICATE_BITSTREAM	1
> > 
> > Can you explain how this commit by itself doesn't break things?
> > 
> > Before this change firmware expected BIT(0) to be set for partial
> > reconfiguration, now BIT(0) suddenly means authentication? How doest his
> > work? :)
> >  > Was there a firmware version change? Did this never work before?
> > 
> > If this is version depenedent for firmware, then this might need a
> > different compatible string / id / some form of probing?
> > 
> > Entirely possible that I'm missing something, but it doesn't *seem*
> > right.
> 
> It did work before.
> 
> Before this change, firmware only checks if the received flag value is zero.
> If the value is zero, it preforms full reconfiguration. Otherwise it does
> partial reconfiguration.
> 
> To support bitstream authentication feature, firmware is updated to check
> the received flag value as below:
> 	0	--- full reconfiguration
> 	BIT(0) 	--- partial reconfiguration
> 	BIT(1) 	--- bitstream authentication

So there are two different versions of firmware involved that behave
differently? 

Old firmware:
- ctype.flags  = 0x0 -> Full reconfig
- ctype.flags != 0 -> Partial reconfig

New firmware:
- ctype.flags = 0x0 -> Full reconfig
- ctype.flags = 0x1 -> Partial reconfig
- ctype.flags = 0x2 -> Authenticate

Old software:
- Send 0x0 for Full
- Send 0x1 for Partial

New software:
- Send 0x0 for Full
- Send 0x1 for Partial
- Send 0x2 for Auth

If I send request for authentication BIT(1) (new software) to old
firmware it'd try and attempt a partial reconfiguration with the data I
send? Is that safe?

Is there a way for software to figure out the firmware version and do
the right thing?

> Therefore I have updated the command flag setting at Intel service layer
> driver to align with firmware.
> 
> Regards,
> Richard
> 
> > >   /**
> > >    * Timeout settings for service clients:
> > > -- 
> > > 2.7.4
> > > 
> > 
> > Cheers,
> > Moritz
> > 

Thanks,
Moritz