uart issues on coldfire platform

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* uart issues on coldfire platform
@ 2009-07-01  2:20 Lanttor
  2009-07-01  6:30 ` Lanttor
  2009-07-01 13:44 ` Matthew Lear
  0 siblings, 2 replies; 5+ messages in thread
From: Lanttor @ 2009-07-01  2:20 UTC (permalink / raw)
  To: linux-m68k

Hi,

I find one issue of UART on my coldfire platforms (mcf54451evb board).
I use the linux-2.6.29, and use drivers/serial/mcf.c and
drivers/serial/serial_core.c as my uart driver source.

Following is my test steps -- run command: cat /proc/interrupts two
times contiguously.

[root@freescale /]# cat /proc/interrupts
M5445X    *90:       5099 UART*
M5445X    96:       3130 timer0
M5445X    99:          0 timer3
M5445X   100:       1569 fec(TXF)
M5445X   101:          0 fec(TXB)
M5445X   102:          0 fec(TXFIFO)
M5445X   103:          0 fec(TXCR)
M5445X   104:       3098 fec(RXF)
M5445X   105:          0 fec(RXB)
M5445X   106:         41 fec(MII)
M5445X   107:          0 fec(LC)
M5445X   108:          0 fec(HBERR)
M5445X   109:          0 fec(GRA)
M5445X   110:          0 fec(EBERR)
M5445X   111:          0 fec(BABT)
M5445X   112:          0 fec(BABR)
[root@freescale /]# cat /proc/interrupts
M5445X    *90:       5714 UART*
M5445X    96:       3700 timer0
M5445X    99:          1 timer3
M5445X   100:       1574 fec(TXF)
M5445X   101:          0 fec(TXB)
M5445X   102:          0 fec(TXFIFO)
M5445X   103:          0 fec(TXCR)
M5445X   104:       3108 fec(RXF)
M5445X   105:          0 fec(RXB)
M5445X   106:         47 fec(MII)
M5445X   107:          0 fec(LC)
M5445X   108:          0 fec(HBERR)
M5445X   109:          0 fec(GRA)
M5445X   110:          0 fec(EBERR)
M5445X   111:          0 fec(BABT)
M5445X   112:          0 fec(BABR)

I find that the interrupts for above operation is 5714 - 5099 = 605
Is it normal? (my opinion it's too much)

I test it on the mcf5329 board, it has the same-like result (even more 605).
Actually I don't modify any code of mcf.c and serial_core.c, but I don't
know why so much interrupts are occurred through one operation?

Regards,
Lanttor



^ permalink raw reply	[flat|nested] 5+ messages in thread

* uart issues on coldfire platform
  2009-07-01  2:20 uart issues on coldfire platform Lanttor
@ 2009-07-01  6:30 ` Lanttor
  2009-07-02  0:40   ` [uClinux-dev] " Greg Ungerer
  2009-07-01 13:44 ` Matthew Lear
  1 sibling, 1 reply; 5+ messages in thread
From: Lanttor @ 2009-07-01  6:30 UTC (permalink / raw)
  To: uclinux-dev; +Cc: linux-m68k


> Hi,
>
> I find one issue of UART on my coldfire platforms (mcf54451evb board).
> I use the linux-2.6.29, and use drivers/serial/mcf.c and
> drivers/serial/serial_core.c as my uart driver source.
>
> Following is my test steps -- run command: cat /proc/interrupts two
> times contiguously.
>
> [root@freescale /]# cat /proc/interrupts
> M5445X    *90:       5099 UART*
> M5445X    96:       3130 timer0
> M5445X    99:          0 timer3
> M5445X   100:       1569 fec(TXF)
> M5445X   101:          0 fec(TXB)
> M5445X   102:          0 fec(TXFIFO)
> M5445X   103:          0 fec(TXCR)
> M5445X   104:       3098 fec(RXF)
> M5445X   105:          0 fec(RXB)
> M5445X   106:         41 fec(MII)
> M5445X   107:          0 fec(LC)
> M5445X   108:          0 fec(HBERR)
> M5445X   109:          0 fec(GRA)
> M5445X   110:          0 fec(EBERR)
> M5445X   111:          0 fec(BABT)
> M5445X   112:          0 fec(BABR)
> [root@freescale /]# cat /proc/interrupts
> M5445X    *90:       5714 UART*
> M5445X    96:       3700 timer0
> M5445X    99:          1 timer3
> M5445X   100:       1574 fec(TXF)
> M5445X   101:          0 fec(TXB)
> M5445X   102:          0 fec(TXFIFO)
> M5445X   103:          0 fec(TXCR)
> M5445X   104:       3108 fec(RXF)
> M5445X   105:          0 fec(RXB)
> M5445X   106:         47 fec(MII)
> M5445X   107:          0 fec(LC)
> M5445X   108:          0 fec(HBERR)
> M5445X   109:          0 fec(GRA)
> M5445X   110:          0 fec(EBERR)
> M5445X   111:          0 fec(BABT)
> M5445X   112:          0 fec(BABR)
>
> I find that the interrupts for above operation is 5714 - 5099 = 605
> Is it normal? (my opinion it's too much)
>
> I test it on the mcf5329 board, it has the same-like result (even more 605).
> Actually I don't modify any code of mcf.c and serial_core.c, but I don't
> know why so much interrupts are occurred through one operation?
>
> Regards,
> Lanttor
>
>
>
>   

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [uClinux-dev] uart issues on coldfire platform
  2009-07-01  6:30 ` Lanttor
@ 2009-07-02  0:40   ` Greg Ungerer
  2009-07-02  2:21     ` Lanttor
  0 siblings, 1 reply; 5+ messages in thread
From: Greg Ungerer @ 2009-07-02  0:40 UTC (permalink / raw)
  To: uClinux development list; +Cc: linux-m68k

Hi Lanttor,

Lanttor wrote:
>> Hi,
>>
>> I find one issue of UART on my coldfire platforms (mcf54451evb board).
>> I use the linux-2.6.29, and use drivers/serial/mcf.c and
>> drivers/serial/serial_core.c as my uart driver source.
>>
>> Following is my test steps -- run command: cat /proc/interrupts two
>> times contiguously.
>>
>> [root@freescale /]# cat /proc/interrupts
>> M5445X    *90:       5099 UART*
>> M5445X    96:       3130 timer0
>> M5445X    99:          0 timer3
>> M5445X   100:       1569 fec(TXF)
>> M5445X   101:          0 fec(TXB)
>> M5445X   102:          0 fec(TXFIFO)
>> M5445X   103:          0 fec(TXCR)
>> M5445X   104:       3098 fec(RXF)
>> M5445X   105:          0 fec(RXB)
>> M5445X   106:         41 fec(MII)
>> M5445X   107:          0 fec(LC)
>> M5445X   108:          0 fec(HBERR)
>> M5445X   109:          0 fec(GRA)
>> M5445X   110:          0 fec(EBERR)
>> M5445X   111:          0 fec(BABT)
>> M5445X   112:          0 fec(BABR)
>> [root@freescale /]# cat /proc/interrupts
>> M5445X    *90:       5714 UART*
>> M5445X    96:       3700 timer0
>> M5445X    99:          1 timer3
>> M5445X   100:       1574 fec(TXF)
>> M5445X   101:          0 fec(TXB)
>> M5445X   102:          0 fec(TXFIFO)
>> M5445X   103:          0 fec(TXCR)
>> M5445X   104:       3108 fec(RXF)
>> M5445X   105:          0 fec(RXB)
>> M5445X   106:         47 fec(MII)
>> M5445X   107:          0 fec(LC)
>> M5445X   108:          0 fec(HBERR)
>> M5445X   109:          0 fec(GRA)
>> M5445X   110:          0 fec(EBERR)
>> M5445X   111:          0 fec(BABT)
>> M5445X   112:          0 fec(BABR)
>>
>> I find that the interrupts for above operation is 5714 - 5099 = 605
                                                      ^^^^^^^^^^^^^ 615 ?

>> Is it normal? (my opinion it's too much)

Most of the ColdFire UART blocks have no transmit FIFO, so you
are going to get 1 interrupt per character. The above block  has
at least 500 characters in it (including white space).  Then include
the extra command prompt and you typing (receive interrupts) and I
would figure that is going to come to around 600 interrupts.
So, yes, that seems about right.

Check the actual character count using:

   cat /proc/tty/driver/mcf


>> I test it on the mcf5329 board, it has the same-like result (even more 605).
>> Actually I don't modify any code of mcf.c and serial_core.c, but I don't
>> know why so much interrupts are occurred through one operation?

That is the price you pay with no data FIFO's in these UART cores.
(Some of the ColdFire parts support DMA with the UART - the mcf
driver doesn't currently use this though).

Regards
Greg



------------------------------------------------------------------------
Greg Ungerer  --  Principal Engineer        EMAIL:     gerg@snapgear.com
SnapGear Group, McAfee                      PHONE:       +61 7 3435 2888
825 Stanley St,                             FAX:         +61 7 3891 3630
Woolloongabba, QLD, 4102, Australia         WEB: http://www.SnapGear.com

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [uClinux-dev] uart issues on coldfire platform
  2009-07-02  0:40   ` [uClinux-dev] " Greg Ungerer
@ 2009-07-02  2:21     ` Lanttor
  0 siblings, 0 replies; 5+ messages in thread
From: Lanttor @ 2009-07-02  2:21 UTC (permalink / raw)
  To: Greg Ungerer; +Cc: uClinux development list, linux-m68k, Jin Zhengxiong-R64188

Thanks Greg/Matt/Cris' reply. I know it's not the issue now :)

> Most of the ColdFire UART blocks have no transmit FIFO, so you
> are going to get 1 interrupt per character. The above block  has
> at least 500 characters in it (including white space).  Then include
> the extra command prompt and you typing (receive interrupts) and I
> would figure that is going to come to around 600 interrupts.
> So, yes, that seems about right.
>
> Check the actual character count using:
>
>   cat /proc/tty/driver/mcf 
Indeed it is. The UART transmit Buffer in my board is 1 character size
(no FIFO), only receiver has FIFO.

I test command "cat /proc/tty/driver/mcf", the result is as follows:

[root@freescale /]# cat /proc/tty/driver/mcf
serinfo:1.0 driver revision:
0: uart:ColdFire UART mmio:0xFC060000 irq:90 tx:54821 rx:91 RTS|DTR|CD
[root@freescale /]# cat /proc/interrupts
M5445X    90:      55042 UART
M5445X    96:       9962 timer
M5445X    99:          2 timer
M5445X   100:       3761 fec(TXF)
M5445X   101:          0 fec(TXB)
M5445X   102:          0 fec(TXFIFO)
M5445X   103:          0 fec(TXCR)
M5445X   104:       8169 fec(RXF)
M5445X   105:          0 fec(RXB)
M5445X   106:        110 fec(MII)
M5445X   107:          0 fec(LC)
M5445X   108:          0 fec(HBERR)
M5445X   109:          0 fec(GRA)
M5445X   110:          0 fec(EBERR)
M5445X   111:          0 fec(BABT)
M5445X   112:          0 fec(BABR)
[root@freescale /]# cat /proc/tty/driver/mcf
serinfo:1.0 driver revision:
0: uart:ColdFire UART mmio:0xFC060000 irq:90 tx:55603 rx:115 RTS|DTR|CD

Thanks!

Regards,
Lanttor




------------------------------------------------------------------------
*From:* Greg Ungerer <gerg@snapgear.com>
*Sent:* 07/02/2009 8:40:49 AM +0800
*To:* uClinux development list <uclinux-dev@uclinux.org>
*CC:* linux-m68k@vger.kernel.org
*Subject:* [uClinux-dev] uart issues on coldfire platform

> Hi Lanttor,
>
> Lanttor wrote:
>>> Hi,
>>>
>>> I find one issue of UART on my coldfire platforms (mcf54451evb board).
>>> I use the linux-2.6.29, and use drivers/serial/mcf.c and
>>> drivers/serial/serial_core.c as my uart driver source.
>>>
>>> Following is my test steps -- run command: cat /proc/interrupts two
>>> times contiguously.
>>>
>>> [root@freescale /]# cat /proc/interrupts
>>> M5445X    *90:       5099 UART*
>>> M5445X    96:       3130 timer0
>>> M5445X    99:          0 timer3
>>> M5445X   100:       1569 fec(TXF)
>>> M5445X   101:          0 fec(TXB)
>>> M5445X   102:          0 fec(TXFIFO)
>>> M5445X   103:          0 fec(TXCR)
>>> M5445X   104:       3098 fec(RXF)
>>> M5445X   105:          0 fec(RXB)
>>> M5445X   106:         41 fec(MII)
>>> M5445X   107:          0 fec(LC)
>>> M5445X   108:          0 fec(HBERR)
>>> M5445X   109:          0 fec(GRA)
>>> M5445X   110:          0 fec(EBERR)
>>> M5445X   111:          0 fec(BABT)
>>> M5445X   112:          0 fec(BABR)
>>> [root@freescale /]# cat /proc/interrupts
>>> M5445X    *90:       5714 UART*
>>> M5445X    96:       3700 timer0
>>> M5445X    99:          1 timer3
>>> M5445X   100:       1574 fec(TXF)
>>> M5445X   101:          0 fec(TXB)
>>> M5445X   102:          0 fec(TXFIFO)
>>> M5445X   103:          0 fec(TXCR)
>>> M5445X   104:       3108 fec(RXF)
>>> M5445X   105:          0 fec(RXB)
>>> M5445X   106:         47 fec(MII)
>>> M5445X   107:          0 fec(LC)
>>> M5445X   108:          0 fec(HBERR)
>>> M5445X   109:          0 fec(GRA)
>>> M5445X   110:          0 fec(EBERR)
>>> M5445X   111:          0 fec(BABT)
>>> M5445X   112:          0 fec(BABR)
>>>
>>> I find that the interrupts for above operation is 5714 - 5099 = 605
>                                                      ^^^^^^^^^^^^^ 615 ?
>
>>> Is it normal? (my opinion it's too much)
>
> Most of the ColdFire UART blocks have no transmit FIFO, so you
> are going to get 1 interrupt per character. The above block  has
> at least 500 characters in it (including white space).  Then include
> the extra command prompt and you typing (receive interrupts) and I
> would figure that is going to come to around 600 interrupts.
> So, yes, that seems about right.
>
> Check the actual character count using:
>
>   cat /proc/tty/driver/mcf
>
>
>>> I test it on the mcf5329 board, it has the same-like result (even
>>> more 605).
>>> Actually I don't modify any code of mcf.c and serial_core.c, but I
>>> don't
>>> know why so much interrupts are occurred through one operation?
>
> That is the price you pay with no data FIFO's in these UART cores.
> (Some of the ColdFire parts support DMA with the UART - the mcf
> driver doesn't currently use this though).
>
> Regards
> Greg
>
>
>
> ------------------------------------------------------------------------
> Greg Ungerer  --  Principal Engineer        EMAIL:     gerg@snapgear.com
> SnapGear Group, McAfee                      PHONE:       +61 7 3435 2888
> 825 Stanley St,                             FAX:         +61 7 3891 3630
> Woolloongabba, QLD, 4102, Australia         WEB: http://www.SnapGear.com
> -- 
> To unsubscribe from this list: send the line "unsubscribe linux-m68k" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: uart issues on coldfire platform
  2009-07-01  2:20 uart issues on coldfire platform Lanttor
  2009-07-01  6:30 ` Lanttor
@ 2009-07-01 13:44 ` Matthew Lear
  1 sibling, 0 replies; 5+ messages in thread
From: Matthew Lear @ 2009-07-01 13:44 UTC (permalink / raw)
  To: Lanttor; +Cc: linux-m68k

Lanttor wrote:
> Hi,
> 
> I find one issue of UART on my coldfire platforms (mcf54451evb board).
> I use the linux-2.6.29, and use drivers/serial/mcf.c and
> drivers/serial/serial_core.c as my uart driver source.
> 
> Following is my test steps -- run command: cat /proc/interrupts two
> times contiguously.
> 
> [root@freescale /]# cat /proc/interrupts
> M5445X    *90:       5099 UART*
> M5445X    96:       3130 timer0
> M5445X    99:          0 timer3
> M5445X   100:       1569 fec(TXF)
> M5445X   101:          0 fec(TXB)
> M5445X   102:          0 fec(TXFIFO)
> M5445X   103:          0 fec(TXCR)
> M5445X   104:       3098 fec(RXF)
> M5445X   105:          0 fec(RXB)
> M5445X   106:         41 fec(MII)
> M5445X   107:          0 fec(LC)
> M5445X   108:          0 fec(HBERR)
> M5445X   109:          0 fec(GRA)
> M5445X   110:          0 fec(EBERR)
> M5445X   111:          0 fec(BABT)
> M5445X   112:          0 fec(BABR)
> [root@freescale /]# cat /proc/interrupts
> M5445X    *90:       5714 UART*
> M5445X    96:       3700 timer0
> M5445X    99:          1 timer3
> M5445X   100:       1574 fec(TXF)
> M5445X   101:          0 fec(TXB)
> M5445X   102:          0 fec(TXFIFO)
> M5445X   103:          0 fec(TXCR)
> M5445X   104:       3108 fec(RXF)
> M5445X   105:          0 fec(RXB)
> M5445X   106:         47 fec(MII)
> M5445X   107:          0 fec(LC)
> M5445X   108:          0 fec(HBERR)
> M5445X   109:          0 fec(GRA)
> M5445X   110:          0 fec(EBERR)
> M5445X   111:          0 fec(BABT)
> M5445X   112:          0 fec(BABR)
> 
> I find that the interrupts for above operation is 5714 - 5099 = 605
> Is it normal? (my opinion it's too much)
> 
> I test it on the mcf5329 board, it has the same-like result (even more 605).
> Actually I don't modify any code of mcf.c and serial_core.c, but I don't
> know why so much interrupts are occurred through one operation?

By the looks of it, the driver is interrupting per character (ie per
byte). If you copy half your output above into a text editor, and count
the characters, including one byte per line end, you get 605. I can't
speak for the driver implementation, but it sounds fair enough to me.
Cheers,
--  Matt

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2009-07-02  2:21 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2009-07-01  2:20 uart issues on coldfire platform Lanttor
2009-07-01  6:30 ` Lanttor
2009-07-02  0:40   ` [uClinux-dev] " Greg Ungerer
2009-07-02  2:21     ` Lanttor
2009-07-01 13:44 ` Matthew Lear

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