RE: Requested feedback on V4L2 driver design

2010-02-26 Thread Maupin, Chase
Laurent,

Responses inline.

Sincerely,
Chase Maupin
Software Applications
Catalog DSP Products
e-mail: chase.mau...@ti.com
phone: (281) 274-3285

For support:
Forums - http://community.ti.com/forums/
Wiki - http://wiki.davincidsp.com/

 -Original Message-
 From: Laurent Pinchart [mailto:laurent.pinch...@ideasonboard.com]
 Sent: Thursday, February 25, 2010 6:35 PM
 To: Maupin, Chase
 Cc: Hans Verkuil; sakari.ai...@maxwell.research.nokia.com;
 mche...@infradead.org; vpss_driver_des...@list.ti.com - This list is to
 discuss the VPSS driver design (May contain non-TIers); linux-
 me...@vger.kernel.org
 Subject: Re: Requested feedback on V4L2 driver design
 
 Hi Chase,
 
 On Tuesday 16 February 2010 14:00:11 Maupin, Chase wrote:
  Laurent,
 
  To follow up with some of the comments I made before I got additional
  clarification about the commands supported by the proxy driver running
 on
  the VPSS MCU.  The proxy will support all of the commands used by V4L2
 as
  well as those proposed extensions to V4L2 that Hans has mentioned.
  Basically, the list of commands supported at initial release is not only
  those required today, but a full set for all the features of the VPSS.
 In
  this was as new APIs are added to V4L2 the support for those features
 will
  already be supported by the VPSS MCU proxy driver.
 
 Thank you for the clarification.
 
 A few things are still uncleared to me, as stated in my previous mail
 (from a
 few minutes ago). My main question is, if the VPSS API is full-featured
 and
 accessible from the master CPU, why do we need a proxy driver in the
 firmware
 at all ?

The proxy driver is the piece of code in the firmware that is actually exposing 
the VPSS API to the master CPU.  It is responsible for listening for requests 
from the master CPU and then executing those requests on the VPSS CPU.  Without 
the proxy there is no way to tell the VPSS CPU which functions to execute.

 
  As for the license of the firmware this is still being worked.  It is
  currently under TI proprietary license and will be distributed as binary
  under Technical Software Publicly Available (TSPA) which means it can be
  obtained by anyone.  If you feel that source code is required for the
  firmware at launch to gain acceptance please let us know and we can
 start
  working that issue.
 
 I think it would definitely help keeping the Linux driver and the VPSS
 firmware in sync if the VPSS firmware source was available. The firmware
 source code could even be distributed along with the Linux driver.

Thanks for the input.  We'll keep this in mind and see what we can do.

 
 By the way, will the firmware be loaded at runtime by the driver, or will
 it
 be stored internally in the chip ?

The firmware will not be stored internally on the chip and will have to be 
loaded at runtime.  We have not settled on how the loading will be done.  
Currently we are thinking on loading it from u-boot similar to an FPGA firmware 
load but it could also be done from the kernel.

 
 --
 Regards,
 
 Laurent Pinchart
--
To unsubscribe from this list: send the line unsubscribe linux-media in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html


RE: Requested feedback on V4L2 driver design

2010-02-26 Thread Maupin, Chase
Laurent,

Responses inline

Puru,

There is a question for you below.  Can you look at it and provide an answer?

Sincerely,
Chase Maupin
Software Applications
Catalog DSP Products
e-mail: chase.mau...@ti.com
phone: (281) 274-3285

For support:
Forums - http://community.ti.com/forums/
Wiki - http://wiki.davincidsp.com/

 -Original Message-
 From: Laurent Pinchart [mailto:laurent.pinch...@ideasonboard.com]
 Sent: Thursday, February 25, 2010 6:32 PM
 To: Maupin, Chase
 Cc: Hans Verkuil; sakari.ai...@maxwell.research.nokia.com;
 mche...@infradead.org; vpss_driver_des...@list.ti.com - This list is to
 discuss the VPSS driver design (May contain non-TIers); linux-
 me...@vger.kernel.org; Kamoolkar, Mugdha
 Subject: Re: Requested feedback on V4L2 driver design

 Hi Chase,

 On Friday 12 February 2010 17:46:55 Maupin, Chase wrote:
  Laurent,
 
  First let me thank you for taking time to review this.

 You're welcome.

 [snip]

   -Original Message-
   From: Laurent Pinchart [mailto:laurent.pinch...@ideasonboard.com]
   Sent: Thursday, February 11, 2010 7:23 PM
  
   On Monday 08 February 2010 16:08:37 Maupin, Chase wrote:

 [snip]

If you have additional questions or need more information please
 feel
free to contact us (we have setup a mailing list at
vpss_driver_des...@list.ti.com) so we can answer them.
  
   I'll answer here as the instructions provided in the wiki to subscribe
 to
   the vpss_driver_design mailing list are incorrect (http://list.ti.com/
   isn't accessible, the name has no A record associated to it). I've
 CC'ed
   the list in case subscription wouldn't be required to post.
 
  The page for subscribing to the list requires a my.TI login which you
 can
  setup at
 
 https://myportal.ti.com/portal/dt?provider=TIPassLoginSingleContainerlt=m
  ytij5=2j3=1goto=https%3A%2F%2Fmy.ti.com%3A443%2Fcgi-
 bin%2Fhome.pl%3FDCMP
  %3DTIHeaderTracking%26HQS%3DOther%2BOT%2Bhdr_my_ti.
  However, your reply to the list should be fine without subscribing.

 Thanks for the information, but http://list.ti.com/ still can't be
 accessed.
 The host list.ti.com has no A record, an HTTP connection can't thus be
 established.

I'm not sure what is going on here.  Let me file a ticket with our IT group and 
see if they can fix the problem.


   1. Multi-core design
   
  
   OMAP3 was already a dual-core system, OMAP4 (I assume all this is
 about
   the OMAP4 processors family) seems to push the concept one step
 further.
  
   With its heterogeneous multi-core design (ARM master CPU and slave
 DSPs),
   the OMAP architecture delivers high performances at the cost of higher
   development time and effort as users need to write software for
 completely
   different cores, usually using different toolchains. This is in my
 opinion
   a good (or at least acceptable) trade-off between CPU power,
 development
   time and power consumption (DSPs being more efficient at signal
 processing
   at the cost of a higher development complexity).
  
   I'm a bit puzzled, however, by how the VPSS MCU will help improving
 the
   situation compared to the OMAP3 design. The VPSS MCU will provide an
 API
   that will expose a fixed subset of the hardware capabilities. This is
 only
   a guess, but I suppose the firmware will be fairly generic, and that
 TI
   will provide customized versions to big customers tailored for their
 needs
   and use cases. The official kernel drivers will then need to be
 changed,
   and those changes will have no chance to be accepted in the mainline
   kernel. This will lead to forks and fragmentation of the developers
 base
   among the big players in the embedded markets. What will be the
   compensation for that ? How will the VPSS MCU provide higher
 performances
   than the OMAP3 model ?
 
  The firmware on the VPSS MCU will be able to configure/control all of
 the
  functionality that the VPSS MCU has and will be the same for all
  customers. The only part that may change is the proxy driver of the
  firmware. The proxy driver is the piece that will be responsible for
  taking the commands from the driver and telling the firmware to execute
  the operation.

 As the proxy is the tip of the firmware iceberg, it will be all the
 Linux
 driver will care about. Whether the firmware backend is able to
 configure
 and control all of the functionality that the VPSS MCU offers is then
 irrelevant, as the Linux driver will have no way to access that backend
 directly. Is my understanding correct ?

As you saw in my follow-up e-mail the proxy will support all the VPSS APIs so 
my statement was misleading.


  The initial version of the proxy will support all the standard V4L2
  operations.  As new operations (such as on the fly video scaling) are
 added
  to the V4L2 API the firmware may require an update to the proxy driver
 to
  handle these requests, but the underlying code will remain the same.

 Different proxy versions will need different version of the Linux

RE: Requested feedback on V4L2 driver design

2010-02-25 Thread Maupin, Chase
Laurent,

Some additional information from the syslink team.

Yes, the current Notify code is indeed going over the kernel mailbox code.
You can find this code in 
drivers/dsp/syslink/notify_ducatidriver/notify_ducati.c.

We have already pushed some mailbox patches specific to the new mailbox 
register set in OMAP4/Netra to kernel. These patches are available starting in 
2.6.33. On our tree, we currently have some custom patches some of which were 
pushed to upstream and in the process of getting rolled into the upcoming 
2.6.34 releases.

Sincerely,
Chase Maupin
Software Applications
Catalog DSP Products
e-mail: chase.mau...@ti.com
phone: (281) 274-3285

For support:
Forums - http://community.ti.com/forums/
Wiki - http://wiki.davincidsp.com/

 -Original Message-
 From: Kamoolkar, Mugdha
 Sent: Wednesday, February 24, 2010 9:05 PM
 To: Maupin, Chase; Laurent Pinchart
 Cc: Hans Verkuil; sakari.ai...@maxwell.research.nokia.com;
 mche...@infradead.org; vpss_driver_des...@list.ti.com - This list is to
 discuss the VPSS driver design (May contain non-TIers); linux-
 me...@vger.kernel.org; Kanigeri, Hari; Shah, Bhavin; Anna, Suman
 Subject: RE: Requested feedback on V4L2 driver design

 Chase, Laurent,

 Sorry for the extreme delay in my response ...
 From the code available currently on omapzoom, our plans are to eventually
 have only the Notify module in kernel-space. All the other code in
 multicore_ipc will actually move to user-side. The Notify module gives
 additional functionality over the basic mailbox driver to abstract the
 single physical event into multiple logical events. This enables multiple
 clients (one of which is the DSS driver) to use the single physical
 interrupt for multiple different purposes in a fully modular manner. We
 will ensure that the kernel-side Notify module is fully integrated into
 the kernel in the proper way and still meets our functionality
 requirements, taking feedback from the community into account.

 We are also making several changes in the APIs for all modules to make
 them much easier to use. A lot of the complexity as seen by the user will
 vanish underneath. This is still under progress, so it's not out on
 omapzoom yet, but will definitely be done.


 As soon as this is done, we will work on moving most of the modules
 (except Notify) fully from kernel-user space. Once our kernel-user work
 has at least gone far enough ahead to allow us to make a design proposal,
 we will push it out for review to get your valuable feedback.

 I have also looped in the TI engineers who have worked on and pushed out
 the omapzoom SysLink code.

 Regards,
 Mugdha

 -Original Message-
 From: Maupin, Chase
 Sent: Friday, February 12, 2010 10:17 PM
 To: Laurent Pinchart
 Cc: Hans Verkuil; sakari.ai...@maxwell.research.nokia.com;
 mche...@infradead.org; vpss_driver_des...@list.ti.com - This list is to
 discuss the VPSS driver design (May contain non-TIers); linux-
 me...@vger.kernel.org; Kamoolkar, Mugdha
 Subject: RE: Requested feedback on V4L2 driver design

 Laurent,

 First let me thank you for taking time to review this.  I have made
 comments below to address your concerns.

 Sincerely,
 Chase Maupin
 Software Applications
 Catalog DSP Products
 e-mail: chase.mau...@ti.com
 phone: (281) 274-3285

 For support:
 Forums - http://community.ti.com/forums/
 Wiki - http://wiki.davincidsp.com/

  -Original Message-
  From: Laurent Pinchart [mailto:laurent.pinch...@ideasonboard.com]
  Sent: Thursday, February 11, 2010 7:23 PM
  To: Maupin, Chase
  Cc: Hans Verkuil; sakari.ai...@maxwell.research.nokia.com;
  mche...@infradead.org; vpss_driver_des...@list.ti.com - This list is to
  discuss the VPSS driver design (May contain non-TIers); linux-
  me...@vger.kernel.org
  Subject: Re: Requested feedback on V4L2 driver design
 
  Hi Chase,
 
  On Monday 08 February 2010 16:08:37 Maupin, Chase wrote:
   All,
  
   Texas Instruments (TI) is working on the design for the V4L2 capture
 and
   display drivers for our next generation system-on-chip (SoC) processor
  and
   would like to solicit your feedback.
 
  Thank you very much for requesting feedback on the system design. I
  personally
  appreciate this, and I'm pretty sure that the feeling is shared by most
 of
  the
  Linux kernel developers.
 
   If you have additional questions or need more information please feel
  free
   to contact us (we have setup a mailing list at
   vpss_driver_des...@list.ti.com) so we can answer them.
 
  I'll answer here as the instructions provided in the wiki to subscribe
 to
  the
  vpss_driver_design mailing list are incorrect (http://list.ti.com/ isn't
  accessible, the name has no A record associated to it). I've CC'ed the
  list in
  case subscription wouldn't be required to post.

 The page for subscribing to the list requires a my.TI login which you can
 setup at
 https://myportal.ti.com/portal/dt?provider=TIPassLoginSingleContainerlt=m
 ytij5=2j3=1goto=https%3A%2F%2Fmy.ti.com

RE: Requested feedback on V4L2 driver design

2010-02-24 Thread Maupin, Chase
Hans,

Some follow-up from the syslink team about the driver code in the git tree.

The only code to be referred on omapzoom that will actually be in the kernel is 
the Notify module. All the other code in multicore_ipc will actually move to 
user-side. The Notify module gives additional functionality over the basic 
mailbox driver to abstract the single physical event into multiple logical 
events. This enables multiple clients (one of which is the DSS driver) to use 
the single physical interrupt for multiple different purposes in a fully 
modular manner.

Sincerely,
Chase Maupin
Software Applications
Catalog DSP Products
e-mail: chase.mau...@ti.com
phone: (281) 274-3285

For support:
Forums - http://community.ti.com/forums/
Wiki - http://wiki.davincidsp.com/

 -Original Message-
 From: Hans Verkuil [mailto:hverk...@xs4all.nl]
 Sent: Tuesday, February 09, 2010 1:52 AM
 To: Mauro Carvalho Chehab; laurent.pinch...@ideasonboard.com
 Cc: Maupin, Chase; sakari.ai...@maxwell.research.nokia.com;
 vpss_driver_des...@list.ti.com - This list is to discuss the VPSS driver
 design (May contain non-TIers); linux-media@vger.kernel.org
 Subject: Re: Requested feedback on V4L2 driver design
 
 On Monday 08 February 2010 21:23:00 Mauro Carvalho Chehab wrote:
  Maupin, Chase wrote:
   All,
  
   Texas Instruments (TI) is working on the design for the V4L2 capture
 and display drivers for our next generation system-on-chip (SoC) processor
 and would like to solicit your feedback.  Our new SoCs have been improved
 to allow for higher video resolutions and greater frame rates.  To this
 end the display hardware has been moved to a separate processing block
 called the video processing subsystem (VPSS).  The VPSS will be running a
 firmware image that controls the capture/display hardware and services
 requests from one or more host processors.
  
   Moving to a remote processor for the processing of video input and
 output data requires that commands to control the hardware be passed to
 this processing block using some form of inter-processor communication
 (IPC).  TI would like to solicit your feedback on proposal for the V4L2
 driver design to get a feel for whether or not this design would be
 accepted into the Linux kernel.  To this end we have put together an
 overview of the design and usage on our wiki at
 http://wiki.davincidsp.com/index.php/Video_Processing_Subsystem_Driver_Des
 ign.  We would greatly appreciate feedback from community members on the
 acceptability of our driver design.
  
   If you have additional questions or need more information please feel
 free to contact us (we have setup a mailing list at
 vpss_driver_des...@list.ti.com) so we can answer them.
  
 
  Hi Chase,
 
  I'm not sure if I got all the details on your proposal, so let me try to
 give my
  understanding.
 
  First of all, for normal usage (e.g. capturing a stream or sending an
 stream
  to an output device), the driver should work with only the standard V4L2
 API.
  I'm assuming that the driver will provide this capability.
 
  I understand that, being a SoC hardware, there are much more that can be
 done
  than just doing the normal stream capture/output, already supported by
 V4L2 API.
 
  For such advanced usages, we're open to a proposal to enhance the
 existing API
  to support the needs. There are some important aspects that need to be
 considered
  when designing any Linux userspace API's:
 
 The full functionality of this device can be handled by the proposals made
 during
 last year's LPC and that are currently being implemented/prototyped for
 omap3.
 That's no coincidence, by the way :-)
 
 
  1) kernel-userspace API's are forever. So, they need to be designed
 in
  a way that new technology changes won't break the old API;
 
  2) API's are meant to be generic. So, they needed to be designed in
 a way
  that, if another hardware with similar features require an API, the
 planned one
  should fit;
 
  3) The API's should be, as much as possible, independent of the
 hardware
  architecture. You'll see that even low-level architecture dependent
 stuff, like
  bus drivers are designed in a way that they are not bound to a
 particular hardware,
  but instead provide the same common methods to interact with the
 hardware to other
  device drivers.
 
  That's said, it would be interesting if you could give us a more deep
 detail on
  what kind of functionalities and how do you think you'll be implementing
 them.
 
 For me the core issue will be the communication between the main ARM and
 the ARM
 controlling the VPSS. Looking at the syslink part of the git tree it all
 looks
 way overengineered to me. In particular the multicore_ipc directory. Is
 all that
 code involved in setting up the communication path between the main and
 VPSS ARM?
 Is there some more detailed document describing how the syslink code
 works?
 
 What I would expect to see is standard mailbox functionality that is used
 in other
 places

RE: Requested feedback on V4L2 driver design

2010-02-16 Thread Maupin, Chase
Laurent,

To follow up with some of the comments I made before I got additional 
clarification about the commands supported by the proxy driver running on the 
VPSS MCU.  The proxy will support all of the commands used by V4L2 as well as 
those proposed extensions to V4L2 that Hans has mentioned.  Basically, the list 
of commands supported at initial release is not only those required today, but 
a full set for all the features of the VPSS.  In this was as new APIs are added 
to V4L2 the support for those features will already be supported by the VPSS 
MCU proxy driver.

As for the license of the firmware this is still being worked.  It is currently 
under TI proprietary license and will be distributed as binary under Technical 
Software Publicly Available (TSPA) which means it can be obtained by anyone.  
If you feel that source code is required for the firmware at launch to gain 
acceptance please let us know and we can start working that issue.

Sincerely,
Chase Maupin
Software Applications
Catalog DSP Products
e-mail: chase.mau...@ti.com
phone: (281) 274-3285

For support:
Forums - http://community.ti.com/forums/
Wiki - http://wiki.davincidsp.com/

 -Original Message-
 From: Laurent Pinchart [mailto:laurent.pinch...@ideasonboard.com]
 Sent: Thursday, February 11, 2010 7:23 PM
 To: Maupin, Chase
 Cc: Hans Verkuil; sakari.ai...@maxwell.research.nokia.com;
 mche...@infradead.org; vpss_driver_des...@list.ti.com - This list is to
 discuss the VPSS driver design (May contain non-TIers); linux-
 me...@vger.kernel.org
 Subject: Re: Requested feedback on V4L2 driver design
 
 Hi Chase,
 
 On Monday 08 February 2010 16:08:37 Maupin, Chase wrote:
  All,
 
  Texas Instruments (TI) is working on the design for the V4L2 capture and
  display drivers for our next generation system-on-chip (SoC) processor
 and
  would like to solicit your feedback.
 
 Thank you very much for requesting feedback on the system design. I
 personally
 appreciate this, and I'm pretty sure that the feeling is shared by most of
 the
 Linux kernel developers.
 
  If you have additional questions or need more information please feel
 free
  to contact us (we have setup a mailing list at
  vpss_driver_des...@list.ti.com) so we can answer them.
 
 I'll answer here as the instructions provided in the wiki to subscribe to
 the
 vpss_driver_design mailing list are incorrect (http://list.ti.com/ isn't
 accessible, the name has no A record associated to it). I've CC'ed the
 list in
 case subscription wouldn't be required to post.
 
 1. Multi-core design
 
 
 OMAP3 was already a dual-core system, OMAP4 (I assume all this is about
 the
 OMAP4 processors family) seems to push the concept one step further.
 
 With its heterogeneous multi-core design (ARM master CPU and slave DSPs),
 the
 OMAP architecture delivers high performances at the cost of higher
 development
 time and effort as users need to write software for completely different
 cores, usually using different toolchains. This is in my opinion a good
 (or at
 least acceptable) trade-off between CPU power, development time and power
 consumption (DSPs being more efficient at signal processing at the cost of
 a
 higher development complexity).
 
 I'm a bit puzzled, however, by how the VPSS MCU will help improving the
 situation compared to the OMAP3 design. The VPSS MCU will provide an API
 that
 will expose a fixed subset of the hardware capabilities. This is only a
 guess,
 but I suppose the firmware will be fairly generic, and that TI will
 provide
 customized versions to big customers tailored for their needs and use
 cases.
 The official kernel drivers will then need to be changed, and those
 changes
 will have no chance to be accepted in the mainline kernel. This will lead
 to
 forks and fragmentation of the developers base among the big players in
 the
 embedded markets. What will be the compensation for that ? How will the
 VPSS
 MCU provide higher performances than the OMAP3 model ?
 
 2. VPSS firmware and API
 
 
 The wiki doesn't state under which license the VPSS MCU firmware will be
 released, but I suppose it won't be open sourced. The VPSS API, which
 seems
 from the information provided in the wiki to mimic the V4L2 API at least
 for
 video capture and output, will thus be controlled by TI and pretty much
 set
 into stone. This means future extensions to the V4L2 API that will provide
 more control over the devices to userspace applications will be stuck with
 access to a limited subset of the hardware capabilities, and users will
 not be
 able to use the full potential of the system.
 
 This goes in the opposite direction of what the Linux media community is
 trying to do today. For the past 6 months now we have been working on
 additions to the V4L2 subsystem to create a complete media framework,
 targeted
 at both desktop and embedded use cases. The new APIs that we are
 developing
 will let userspace applications discover

RE: Requested feedback on V4L2 driver design

2010-02-12 Thread Maupin, Chase
Laurent,

First let me thank you for taking time to review this.  I have made comments 
below to address your concerns.

Sincerely,
Chase Maupin
Software Applications
Catalog DSP Products
e-mail: chase.mau...@ti.com
phone: (281) 274-3285

For support:
Forums - http://community.ti.com/forums/
Wiki - http://wiki.davincidsp.com/

 -Original Message-
 From: Laurent Pinchart [mailto:laurent.pinch...@ideasonboard.com]
 Sent: Thursday, February 11, 2010 7:23 PM
 To: Maupin, Chase
 Cc: Hans Verkuil; sakari.ai...@maxwell.research.nokia.com;
 mche...@infradead.org; vpss_driver_des...@list.ti.com - This list is to
 discuss the VPSS driver design (May contain non-TIers); linux-
 me...@vger.kernel.org
 Subject: Re: Requested feedback on V4L2 driver design
 
 Hi Chase,
 
 On Monday 08 February 2010 16:08:37 Maupin, Chase wrote:
  All,
 
  Texas Instruments (TI) is working on the design for the V4L2 capture and
  display drivers for our next generation system-on-chip (SoC) processor
 and
  would like to solicit your feedback.
 
 Thank you very much for requesting feedback on the system design. I
 personally
 appreciate this, and I'm pretty sure that the feeling is shared by most of
 the
 Linux kernel developers.
 
  If you have additional questions or need more information please feel
 free
  to contact us (we have setup a mailing list at
  vpss_driver_des...@list.ti.com) so we can answer them.
 
 I'll answer here as the instructions provided in the wiki to subscribe to
 the
 vpss_driver_design mailing list are incorrect (http://list.ti.com/ isn't
 accessible, the name has no A record associated to it). I've CC'ed the
 list in
 case subscription wouldn't be required to post.

The page for subscribing to the list requires a my.TI login which you can setup 
at 
https://myportal.ti.com/portal/dt?provider=TIPassLoginSingleContainerlt=mytij5=2j3=1goto=https%3A%2F%2Fmy.ti.com%3A443%2Fcgi-bin%2Fhome.pl%3FDCMP%3DTIHeaderTracking%26HQS%3DOther%2BOT%2Bhdr_my_ti.
  However, your reply to the list should be fine without subscribing.

 
 1. Multi-core design
 
 
 OMAP3 was already a dual-core system, OMAP4 (I assume all this is about
 the
 OMAP4 processors family) seems to push the concept one step further.
 
 With its heterogeneous multi-core design (ARM master CPU and slave DSPs),
 the
 OMAP architecture delivers high performances at the cost of higher
 development
 time and effort as users need to write software for completely different
 cores, usually using different toolchains. This is in my opinion a good
 (or at
 least acceptable) trade-off between CPU power, development time and power
 consumption (DSPs being more efficient at signal processing at the cost of
 a
 higher development complexity).
 
 I'm a bit puzzled, however, by how the VPSS MCU will help improving the
 situation compared to the OMAP3 design. The VPSS MCU will provide an API
 that
 will expose a fixed subset of the hardware capabilities. This is only a
 guess,
 but I suppose the firmware will be fairly generic, and that TI will
 provide
 customized versions to big customers tailored for their needs and use
 cases.
 The official kernel drivers will then need to be changed, and those
 changes
 will have no chance to be accepted in the mainline kernel. This will lead
 to
 forks and fragmentation of the developers base among the big players in
 the
 embedded markets. What will be the compensation for that ? How will the
 VPSS
 MCU provide higher performances than the OMAP3 model ?

The firmware on the VPSS MCU will be able to configure/control all of the 
functionality that the VPSS MCU has and will be the same for all customers.  
The only part that may change is the proxy driver of the firmware.  The proxy 
driver is the piece that will be responsible for taking the commands from the 
driver and telling the firmware to execute the operation.  The initial version 
of the proxy will support all the standard V4L2 operations.  As new operations 
(such as on the fly video scaling) are added to the V4L2 API the firmware may 
require an update to the proxy driver to handle these requests, but the 
underlying code will remain the same.  

For customers who wish to use features of the VPSS that are not supported by 
the current V4L2 APIs there are OpenMax components being developed that can 
also talk to the VPSS and support the full set of features of the VPSS.  These 
components allow for additional use cases such as transferring data directly 
from other processing blocks such as the DSP to the VPSS without ever returning 
to the host processor (tunneling).  However, the OpenMax API does not integrate 
with most existing software such as applications that use V4L2 drivers for 
video capture and display.

What this means is that we will not be creating a bunch of one-off drivers for 
customers who want to use features that are not part of the V4L2 APIs.  Instead 
those customers will be able to use the OpenMax components.  The Linux V4L2

RE: Requested feedback on V4L2 driver design

2010-02-09 Thread Maupin, Chase

 -Original Message-
 From: Hans Verkuil [mailto:hverk...@xs4all.nl]
 Sent: Tuesday, February 09, 2010 1:52 AM
 To: Mauro Carvalho Chehab; laurent.pinch...@ideasonboard.com
 Cc: Maupin, Chase; sakari.ai...@maxwell.research.nokia.com;
 vpss_driver_des...@list.ti.com - This list is to discuss the VPSS driver
 design (May contain non-TIers); linux-media@vger.kernel.org
 Subject: Re: Requested feedback on V4L2 driver design
 
 On Monday 08 February 2010 21:23:00 Mauro Carvalho Chehab wrote:
  Maupin, Chase wrote:
   All,
  
   Texas Instruments (TI) is working on the design for the V4L2 capture
 and display drivers for our next generation system-on-chip (SoC) processor
 and would like to solicit your feedback.  Our new SoCs have been improved
 to allow for higher video resolutions and greater frame rates.  To this
 end the display hardware has been moved to a separate processing block
 called the video processing subsystem (VPSS).  The VPSS will be running a
 firmware image that controls the capture/display hardware and services
 requests from one or more host processors.
  
   Moving to a remote processor for the processing of video input and
 output data requires that commands to control the hardware be passed to
 this processing block using some form of inter-processor communication
 (IPC).  TI would like to solicit your feedback on proposal for the V4L2
 driver design to get a feel for whether or not this design would be
 accepted into the Linux kernel.  To this end we have put together an
 overview of the design and usage on our wiki at
 http://wiki.davincidsp.com/index.php/Video_Processing_Subsystem_Driver_Des
 ign.  We would greatly appreciate feedback from community members on the
 acceptability of our driver design.
  
   If you have additional questions or need more information please feel
 free to contact us (we have setup a mailing list at
 vpss_driver_des...@list.ti.com) so we can answer them.
  
 
  Hi Chase,
 
  I'm not sure if I got all the details on your proposal, so let me try to
 give my
  understanding.
 
  First of all, for normal usage (e.g. capturing a stream or sending an
 stream
  to an output device), the driver should work with only the standard V4L2
 API.
  I'm assuming that the driver will provide this capability.
 
  I understand that, being a SoC hardware, there are much more that can be
 done
  than just doing the normal stream capture/output, already supported by
 V4L2 API.
 
  For such advanced usages, we're open to a proposal to enhance the
 existing API
  to support the needs. There are some important aspects that need to be
 considered
  when designing any Linux userspace API's:
 
 The full functionality of this device can be handled by the proposals made
 during
 last year's LPC and that are currently being implemented/prototyped for
 omap3.
 That's no coincidence, by the way :-)

Our initial goal is to enable the current V4L2 APIs and functionality that 
exist today and then to continue working to add new features that use new 
functionality as it becomes available.  Of course we will be working with the 
V4L2 community on these features.

 
 
  1) kernel-userspace API's are forever. So, they need to be designed
 in
  a way that new technology changes won't break the old API;
 
  2) API's are meant to be generic. So, they needed to be designed in
 a way
  that, if another hardware with similar features require an API, the
 planned one
  should fit;
 
  3) The API's should be, as much as possible, independent of the
 hardware
  architecture. You'll see that even low-level architecture dependent
 stuff, like
  bus drivers are designed in a way that they are not bound to a
 particular hardware,
  but instead provide the same common methods to interact with the
 hardware to other
  device drivers.
 
  That's said, it would be interesting if you could give us a more deep
 detail on
  what kind of functionalities and how do you think you'll be implementing
 them.
 
 For me the core issue will be the communication between the main ARM and
 the ARM
 controlling the VPSS. Looking at the syslink part of the git tree it all
 looks
 way overengineered to me. In particular the multicore_ipc directory. Is
 all that
 code involved in setting up the communication path between the main and
 VPSS ARM?
 Is there some more detailed document describing how the syslink code
 works?

Agreed.  The most important aspect that we are hoping to get feedback on is 
using the syslink notify IPC for communication between the cores.  In this use 
case much of the functionality of syslink is un-needed.  The focus for this 
driver will be on using simple IPC where events are registered to send data 
between the host MCU and the VPSS.  I'll get someone from the syslink team to 
comment here with more details but the basic idea is that the host MCU and the 
VPSS will have an event configured for handling requests.  When the host MCU 
wants to sent a request to the VPSS it will create

RE: Requested feedback on V4L2 driver design

2010-02-09 Thread Maupin, Chase

 -Original Message-
 From: Hans Verkuil [mailto:hverk...@xs4all.nl]
 Sent: Tuesday, February 09, 2010 1:52 AM
 To: Mauro Carvalho Chehab; laurent.pinch...@ideasonboard.com
 Cc: Maupin, Chase; sakari.ai...@maxwell.research.nokia.com;
 vpss_driver_des...@list.ti.com - This list is to discuss the VPSS driver
 design (May contain non-TIers); linux-media@vger.kernel.org
 Subject: Re: Requested feedback on V4L2 driver design
 
 On Monday 08 February 2010 21:23:00 Mauro Carvalho Chehab wrote:
  Maupin, Chase wrote:
   All,
  
   Texas Instruments (TI) is working on the design for the V4L2 capture
 and display drivers for our next generation system-on-chip (SoC) processor
 and would like to solicit your feedback.  Our new SoCs have been improved
 to allow for higher video resolutions and greater frame rates.  To this
 end the display hardware has been moved to a separate processing block
 called the video processing subsystem (VPSS).  The VPSS will be running a
 firmware image that controls the capture/display hardware and services
 requests from one or more host processors.
  
   Moving to a remote processor for the processing of video input and
 output data requires that commands to control the hardware be passed to
 this processing block using some form of inter-processor communication
 (IPC).  TI would like to solicit your feedback on proposal for the V4L2
 driver design to get a feel for whether or not this design would be
 accepted into the Linux kernel.  To this end we have put together an
 overview of the design and usage on our wiki at
 http://wiki.davincidsp.com/index.php/Video_Processing_Subsystem_Driver_Des
 ign.  We would greatly appreciate feedback from community members on the
 acceptability of our driver design.
  
   If you have additional questions or need more information please feel
 free to contact us (we have setup a mailing list at
 vpss_driver_des...@list.ti.com) so we can answer them.
  
 
  Hi Chase,
 
  I'm not sure if I got all the details on your proposal, so let me try to
 give my
  understanding.
 
  First of all, for normal usage (e.g. capturing a stream or sending an
 stream
  to an output device), the driver should work with only the standard V4L2
 API.
  I'm assuming that the driver will provide this capability.
 
  I understand that, being a SoC hardware, there are much more that can be
 done
  than just doing the normal stream capture/output, already supported by
 V4L2 API.
 
  For such advanced usages, we're open to a proposal to enhance the
 existing API
  to support the needs. There are some important aspects that need to be
 considered
  when designing any Linux userspace API's:
 
 The full functionality of this device can be handled by the proposals made
 during
 last year's LPC and that are currently being implemented/prototyped for
 omap3.
 That's no coincidence, by the way :-)
 
 
  1) kernel-userspace API's are forever. So, they need to be designed
 in
  a way that new technology changes won't break the old API;
 
  2) API's are meant to be generic. So, they needed to be designed in
 a way
  that, if another hardware with similar features require an API, the
 planned one
  should fit;
 
  3) The API's should be, as much as possible, independent of the
 hardware
  architecture. You'll see that even low-level architecture dependent
 stuff, like
  bus drivers are designed in a way that they are not bound to a
 particular hardware,
  but instead provide the same common methods to interact with the
 hardware to other
  device drivers.
 
  That's said, it would be interesting if you could give us a more deep
 detail on
  what kind of functionalities and how do you think you'll be implementing
 them.
 
 For me the core issue will be the communication between the main ARM and
 the ARM
 controlling the VPSS. Looking at the syslink part of the git tree it all
 looks
 way overengineered to me. In particular the multicore_ipc directory. Is
 all that
 code involved in setting up the communication path between the main and
 VPSS ARM?
 Is there some more detailed document describing how the syslink code
 works?

I uploaded a preliminary version of the syslink User's Guide to the wiki page 
in the syslink section.  You can find the pdf at 
http://wiki.davincidsp.com/images/3/30/Sprugo6a.pdf.  Section 3.7 covers the 
Notify functionality and usage.

Please note that for these video drivers much of the communication settings 
would be static (i.e. the even number).  This configuration would be done by 
the driver and would not require the user to set it up.

 
 What I would expect to see is standard mailbox functionality that is used
 in other
 places as well. I gather that at the bottom there actually seems to be a
 mailbox
 involved with syslink, but there also seems to be a lot of layers on top
 of that.
 
 Regards,
 
   Hans
 
 --
 Hans Verkuil - video4linux developer - sponsored by TANDBERG
--
To unsubscribe from this list: send the line unsubscribe linux

Requested feedback on V4L2 driver design

2010-02-08 Thread Maupin, Chase
All,

Texas Instruments (TI) is working on the design for the V4L2 capture and 
display drivers for our next generation system-on-chip (SoC) processor and 
would like to solicit your feedback.  Our new SoCs have been improved to allow 
for higher video resolutions and greater frame rates.  To this end the display 
hardware has been moved to a separate processing block called the video 
processing subsystem (VPSS).  The VPSS will be running a firmware image that 
controls the capture/display hardware and services requests from one or more 
host processors.

Moving to a remote processor for the processing of video input and output data 
requires that commands to control the hardware be passed to this processing 
block using some form of inter-processor communication (IPC).  TI would like to 
solicit your feedback on proposal for the V4L2 driver design to get a feel for 
whether or not this design would be accepted into the Linux kernel.  To this 
end we have put together an overview of the design and usage on our wiki at 
http://wiki.davincidsp.com/index.php/Video_Processing_Subsystem_Driver_Design.  
We would greatly appreciate feedback from community members on the 
acceptability of our driver design.

If you have additional questions or need more information please feel free to 
contact us (we have setup a mailing list at vpss_driver_des...@list.ti.com) so 
we can answer them.

Sincerely,
Chase Maupin
Software Applications
Catalog DSP Products
e-mail: chase.mau...@ti.com

For support:
Forums - http://community.ti.com/forums/
Wiki - http://wiki.davincidsp.com/

--
To unsubscribe from this list: send the line unsubscribe linux-media in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html