Re: [Freeipmi-devel] KCS Driver SMS_ATN Register

2010-03-01 Thread Matt Jerdonek 

Al,

Thanks for the clarification.  I see your point and I updated the patch to 
address it.  As with the previous patch, this compiles, but I didn't run it on 
hardware yet because my customer has not yet sent me the KCS hardware.

Thanks again,
-Matt


--- On Thu, 2/25/10, Al Chu ch...@llnl.gov wrote:

From: Al Chu ch...@llnl.gov
Subject: Re: [Freeipmi-devel] KCS Driver  SMS_ATN Register
To: Matt Jerdonek maj1...@yahoo.com
Cc: Anand Babu Periasamy a...@gnu.org.in, freeipmi-devel@gnu.org
Date: Thursday, February 25, 2010, 10:33 AM

Hi Matt,

I don't see it that way.  I could see someone programming a single
thread and only wanting to poll the SMS_ATN bit, and process events as
they occur.  Not doing any other KCS. e.g.

main()
{
   setup_kcs();

   while (1) {
      kcs_wait_for_sms()
      get_message_flags()
      process_event()
   }
}

Maybe I didn't describe it well.  The concern I have with your patch (if
I'm reading it correctly, correct me if I'm wrong) is that the only time
the SMS ATN bit is checked is in _ipmi_kcs_get_status().
_ipmi_kcs_get_status() will only be called through other KCS functions
like ipmi_kcs_read() and ipmi_kcs_write().

So in order for the SMS ATN bit to be checked, ipmi_kcs_read() and
ipmi_kcs_write() have to be called, either by your application or other
IPMI going on in the system, otherwise the SMS_ATN bit will never be
checked.  Correct?  Under your patch, in the above code snippet,
kcs_wait_for_sms() will never return, b/c no other KCS calls are going
on (unless they are other KCS IPMI going on in the system elsewhere). 

Perhaps within your patch, you assumed other IPMI going on in other
parts of the system?

Al

-- 
Albert Chu
ch...@llnl.gov
Computer Scientist
High Performance Systems Division
Lawrence Livermore National Laboratory




  

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Re: [Freeipmi-devel] KCS Driver SMS_ATN Register

2010-02-25 Thread Matt Jerdonek 
Al,

I'm not sure I understand your concern.  Using either the blocking semaphore as 
I suggested, or the blocking polling as you suggested, the application will 
have to create at least 2 threads: one to wait for events, and another to do 
everything else.  Right?

If that's the case, isn't using a semaphore a better approach in that it 
doesn't use as many processor cycles and alerts the application immediately?

Thanks,
-Matt





From: Al Chu ch...@llnl.gov
To: Matt Jerdonek maj1...@yahoo.com
Cc: Anand Babu Periasamy a...@gnu.org.in; freeipmi-devel@gnu.org
Sent: Wed, February 24, 2010 12:49:59 PM
Subject: Re: [Freeipmi-devel] KCS Driver  SMS_ATN Register

Hey Matt,

I noticed one or two minor nits, but I can fix em.  I guess I am only
perplexed by this design choice.  It seems you want to have two threads.
One thread does normal IPMI regularly, and the other thread will wait
for the SMS_ATN bit.  It appears that _ipmi_kcs_get_status() is the only
place that the SMS_ATN bit is checked, so you need to be doing some type
of other KCS in order to ever check for it?

Perhaps it'd be better to just have a function that regularly polls the
SMS_ATN bit, and if it is true, return to the user??  Perhaps something
like:

poll_sms_atn(unsigned int poll_interval, unsigned int max_iterations)
{
  while (count = max_iterations)
  {
  lock_kcs_semaphore();
  if (sms_atn bit set)
  break;
  unlock_kcs_sempahore();  
  sleep (poll_interval);
  }
  unlock_kcs_sempahore();  
}




Al

On Tue, 2010-02-23 at 08:27 -0800, Matt Jerdonek wrote:
 
 
 Please give the attached patch a look.  Since you two didn't like the
 idea of a callback, I created an API to wait for an event and a second
 API to cancel the wait.  Basically the application will be responsible
 for creating a thread which invokes the API.  The API will block the
 application's thread until an event occurs.  The application will be
 responsible for issuing a GET MESSAGE FLAGS command once the thread
 unblocks.
 
 I had to use a semaphore to block the thread, so I made some small
 changes to ipmi-semaphores.c as well.
 
 Note: this compiles, but I didn't try to run it yet.  My customer has
 not yet sent me the hardware with the KCS interface, so I don't have
 hardware to exercise the code.  
 
 Thanks again for your consideration,
 -Matt
 
 
-- 
Albert Chu
ch...@llnl.gov
Computer Scientist
High Performance Systems Division
Lawrence Livermore National Laboratory


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Re: [Freeipmi-devel] KCS Driver SMS_ATN Register

2010-02-23 Thread Matt Jerdonek 


Please give the attached patch a look.  Since you two didn't like the idea of a 
callback, I created an API to wait for an event and a second API to cancel the 
wait.  Basically the application will be responsible for creating a thread 
which invokes the API.  The API will block the application's thread until an 
event occurs.  The application will be responsible for issuing a GET MESSAGE 
FLAGS command once the thread unblocks.

I had to use a semaphore to block the thread, so I made some small changes to 
ipmi-semaphores.c as well.

Note: this compiles, but I didn't try to run it yet.  My customer has not yet 
sent me the hardware with the KCS interface, so I don't have hardware to 
exercise the code.  

Thanks again for your consideration,
-Matt



  

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Re: [Freeipmi-devel] KCS Driver SMS_ATN Register

2010-02-21 Thread Matt Jerdonek 
Before I started looking at the KCS interface, the same customer had me start 
writing a serial interface for FreeIPMI for some different hardware.  That 
project has been abandoned; however, I wanted to point out that the serial 
interface sent an attention character that had the same functionality as the 
SMS_ATN.  So, I think it's in the best interest to create an abstract API.

Since you two appear open to this, please give me a few days to talk to my 
co-workers and develop a patch for this.  You two can then review it and tell 
me if you think I'm in the right direction.

Thanks again for all your comments,
-Matt





From: Al Chu ch...@llnl.gov
To: Anand Babu Periasamy a...@gnu.org.in
Cc: Matt Jerdonek maj1...@yahoo.com; freeipmi-devel@gnu.org
Sent: Sun, February 21, 2010 9:38:27 AM
Subject: Re: [Freeipmi-devel] KCS Driver  SMS_ATN Register

Hey A.B,

 Al, Unfortunately SMS_ATN is KCS specific. So we can't create an 
 abstracted API.

There's no reason other drivers won't have interrupt callbacks in the
future.  We can abstract it by calling the API function something like
interrupt_callback.  The only driver supported with it would be KCS in
the beginning.

Al

On Sun, 2010-02-21 at 04:29 -0800, Anand Babu Periasamy wrote:
 Matt Jerdonek wrote:
  Al  Anand,
  
  Thanks for the quick response.  I'm planning on using libfreeipmi to 
  create a custom application that, among other things, will have to read 
  event flags from the local event log and query sensors on local and 
  remote BMCs.
  
  I looked at the spec, and I think I have a slightly different 
  understanding (I'm not saying I'm right -- I may be misunderstanding the 
  spec).  I don't think SMS_ATN and OBF can be used interchangeably.  
  Here's my understanding:
  1) If the SMS_ATN bit is set the local BMC requires some attention.
  2) A GET MESSAGE FLAGS command should be sent to query the BMC.
  3) If bit 0 is set in the response, that indicates a receive message is 
  available.  From looking at the ipmi_kcs_cmd_api_ipmb code, it appears 
  as if that code polls the local BMC with GET MESSAGE cmds instead of 
  using this bit to indicate when the response from the remote BMC is 
  ready.  While polling may not be ideal, it's certainly ok for my 
  application.
  4) If bit 1 is set in the response, that indicates an event is available.
  5) I'll ignore the pre-watchdog timeout and OEM bits for now ...
  
  I don't understand how libfreeipmi notifies the application that an 
  event is available without monitoring the SMS_ATN bit.  I think I want 
  to create a patch that does the following:
  1) Creates a callback from libfreeapi to the application when an event 
  occurs.
  2) Monitors the SMS_ATN bit.
  3) If set, invokes the callback.
  
  The application would be responsible for issuing the GET MESSAGE FLAGS 
  command and handling the response.  One downside of this approach is 
  that it prevents you from ever making ipmi_kcs_cmd_api_ipmb 
  event-driven.  What do you two think?
  
  Thanks,
  -Matt
  
  *From:* Al Chu ch...@llnl.gov
  *To:* Matt Jerdonek maj1...@yahoo.com
  *Cc:* freeipmi-devel@gnu.org
  *Sent:* Thu, February 18, 2010 10:58:06 AM
  *Subject:* Re: [Freeipmi-devel] KCS Driver  SMS_ATN Register
  
  Hi Matt,
  
  Definitely open to patches.  Looking over the IPMI spec, I agree w/
  A.B., it seems to be more useful for a higher level monitoring, w/ the
  Get Message Flags and similar commands.  I can think of several patch
  ideas:
  
  1) add a KCS driver flag for checking for SMS_ATN in addition to OBF (or
  instead of??).  Flags may be propogated up into higher level APIs too.
  
  2) an additional function that checks for SMS_ATN in addition/or instead
  of OBF that users can call instead.
  
  It would be useful to understand your use case too.  Are you using the
  KCS driver and IPMI bridging commands to bridge from one BMC to another
  BMC?
  
  Thanks,
  
  Al
  
  On Wed, 2010-02-17 at 18:51 -0800, Matt Jerdonek wrote:
Hello,
   
The KCS driver appears to not use the SMS_ATN register.  This register
is useful for BMC-to-BMC communication to know when the remote BMC has
responded.  Are there any plans to monitor this register in future
releases?  If not, are the maintainers open to including a patch?
   
Thanks,
-Matt
 
 I have attached a patch to give you an idea. I did not even compile it yet.
 If ipmi_kcs_read_sms_atn() returns 1, then you should call 
 ipmi_cmd_get_message_flags() 
 function and check what type of event occurred.
 
 nt ipmi_kcs_read_sms_atn (ipmi_kcs_ctx_t ctx);
 int ipmi_cmd_get_message_flags (ipmi_ctx_t ctx, fiid_obj_t obj_cmd_rs);
 Use this tmpl_cmd_get_message_flags_rs to parse the message contents.
 
 All IPMI commands have request (write) and response (read) transaction model. 
 So FreeIPMI 
 drivers doesn't have to  wait for interrupts. All

Re: [Freeipmi-devel] KCS Driver SMS_ATN Register

2010-02-18 Thread Matt Jerdonek 
Al  Anand,

Thanks for the quick response.  I'm planning on using libfreeipmi to create a 
custom application that, among other things, will have to read event flags from 
the local event log and query sensors on local and remote BMCs.

I looked at the spec, and I think I have a slightly different understanding 
(I'm not saying I'm right -- I may be misunderstanding the spec).  I don't 
think SMS_ATN and OBF can be used interchangeably.  Here's my understanding:
1) If the SMS_ATN bit is set the local BMC requires some attention.
2) A GET MESSAGE FLAGS command should be sent to query the BMC.
3) If bit 0 is set in the response, that indicates a receive message is 
available.  From looking at the ipmi_kcs_cmd_api_ipmb code, it appears as if 
that code polls the local BMC with GET MESSAGE cmds instead of using this bit 
to indicate when the response from the remote BMC is ready.  While polling may 
not be ideal, it's certainly ok for my application.
4) If bit 1 is set in the response, that indicates an event is available.
5) I'll ignore the pre-watchdog timeout and OEM bits for now ...

I don't understand how libfreeipmi notifies the application that an event is 
available without monitoring the SMS_ATN bit.  I think I want to create a patch 
that does the following:
1) Creates a callback from libfreeapi to the application when an event occurs.
2) Monitors the SMS_ATN bit.
3) If set, invokes the callback.


The application would be responsible for issuing the GET MESSAGE FLAGS command 
and handling the response.  One downside of this approach is that it prevents 
you from ever making ipmi_kcs_cmd_api_ipmb event-driven.  What do you two think?

Thanks,
-Matt



From: Al Chu ch...@llnl.gov
To: Matt Jerdonek maj1...@yahoo.com
Cc: freeipmi-devel@gnu.org
Sent: Thu, February 18, 2010 10:58:06 AM
Subject: Re: [Freeipmi-devel] KCS Driver  SMS_ATN Register

Hi Matt,

Definitely open to patches.  Looking over the IPMI spec, I agree w/
A.B., it seems to be more useful for a higher level monitoring, w/ the
Get Message Flags and similar commands.  I can think of several patch
ideas:

1) add a KCS driver flag for checking for SMS_ATN in addition to OBF (or
instead of??).  Flags may be propogated up into higher level APIs too.

2) an additional function that checks for SMS_ATN in addition/or instead
of OBF that users can call instead.

It would be useful to understand your use case too.  Are you using the
KCS driver and IPMI bridging commands to bridge from one BMC to another
BMC?

Thanks,

Al

On Wed, 2010-02-17 at 18:51 -0800, Matt Jerdonek wrote:
 Hello,
 
 The KCS driver appears to not use the SMS_ATN register.  This register
 is useful for BMC-to-BMC communication to know when the remote BMC has
 responded.  Are there any plans to monitor this register in future
 releases?  If not, are the maintainers open to including a patch?
 
 Thanks,
 -Matt
 
 
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ch...@llnl.gov
Computer Scientist
High Performance Systems Division
Lawrence Livermore National Laboratory


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[Freeipmi-devel] KCS Driver SMS_ATN Register

2010-02-17 Thread Matt Jerdonek 
Hello,

The KCS driver appears to not use the SMS_ATN register.  This register is 
useful for BMC-to-BMC communication to know when the remote BMC has responded.  
Are there any plans to monitor this register in future releases?  If not, are 
the maintainers open to including a patch?

Thanks,
-Matt



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