Re: usage of interruptible_sleep_on( ) function call

I had the same problem with the i2c-algo-8260.c when loading a module. 
It's the __pa() translation. Replace _ALL_ __pa with iopa. It worked for 
me. I discovered it from this link:
http://ozlabs.org/pipermail/linuxppc-dev/2002-February/013260.html

linuxppc-embedded-request@ozlabs.org wrote:

Send Linuxppc-embedded mailing list submissions to
	linuxppc-embedded@ozlabs.org

To subscribe or unsubscribe via the World Wide Web, visit
	https://ozlabs.org/mailman/listinfo/linuxppc-embedded
or, via email, send a message with subject or body 'help' to
	linuxppc-embedded-request@ozlabs.org

You can reach the person managing the list at
	linuxppc-embedded-owner@ozlabs.org

When replying, please edit your Subject line so it is more specific
than "Re: Contents of Linuxppc-embedded digest..."


Today's Topics:

   1. question re usage of  interruptible_sleep_on( ) function call
      in	cpm_iic_tryaddress( ) function (in i2c-algo-8xx.c)
      (Povolotsky, Alexander)


----------------------------------------------------------------------

Message: 1
Date: Sat, 5 Feb 2005 12:30:06 -0500 
From: "Povolotsky, Alexander" <redacted>
Subject: question re usage of  interruptible_sleep_on( ) function call
	in	cpm_iic_tryaddress( ) function (in i2c-algo-8xx.c)
To: "'linuxppc-dev@ozlabs.org'" <redacted>,
	"'linuxppc-embedded@ozlabs.org'" [off-list ref],
	"'etux@embeddedtux.org'" [off-list ref]
Message-ID:
	[ref]
	
Content-Type: text/plain;	charset="ISO-8859-1"

Hello,

quoted

I have MPC880 microprocessor based board with single 24C02 I2C EEPROM,
connected to the I2C bus.

Currently booting of the board hangs in the I2C driver after invocation of
interruptible_sleep_on( )

 function call  in cpm_iic_tryaddress( ) function (in i2c-algo-8xx.c file).

Is it appropriate to use the interruptible_sleep_on( ) function at the
kernel booting stage ?
 (I personally do not think so - since such usage prevents further kernel
booting - as observed).
What should be done in this code to avoid slleping ?

I presume that the usage of the interruptible_sleep_on( ) function would be
appropriate if the 
I2C would be configured as a module (after the kernel booting is completed)
?
Follow up question:  is it really expected to do I2C initialization ONLY as
a module after the kernel booting ?
(is it documented anyplace ?) 

quoted

The (end of) log buffer shows following:
....
<6>i2c /dev entries driver.
<7>device class 'i2c-dev': registering.
<7>bus i2c:add driver dev_driver.
<7>i2c-core: driver dev_driver registered
<6>i2c-rpx: i2c MPC8xx driver.
<7>DEV: registering device: ID ='i2c-0'.
<7>CLASS: registering class device: ID= 'i2c-0'.
<7>i2c_adapter i2c-0:Registered as minor 0.
<7>CLASS:registering class device: ID = 'i2c-0'
<7>i2c_adapter i2c-0: registered as adapter #0.
<4>cpm_iic_init() - iip=fa203c80.
<4>cpm_iic_init[132] Install ISR for IRQ 16.
<6>CPM interrupt c0105d90 replacing c01f7a8c.
<3>request_irq() returned -22  for CPM vector 32.
<6> i2c-algo-8xx.o: scanning bus m8xx........
<4>cpm_iic_tryaddress(cpm=c019b9f8,addr=0).
<4>iip fa203c80, dp_addr 0x800.
<4>iic_tbase 2048, r_tbase 2048
<4>about to sleep
.ABOVE LINE IS THE LAST ENTRY IN THE LOG BUFFER - THE BOOT HANGS
THEREAFTER ... 

Here is the fragment of the cpm_iic_tryaddress( ) function in
i2c-algo-8xx.c,
where the problem takes place:
.... 
//      save_flags(flags); cli();
        i2c->i2c_i2cer = 0xff;
        i2c->i2c_i2cmr = 0x13;  /* Enable some interupts */
        i2c->i2c_i2mod = 1;     /* Enable */
        i2c->i2c_i2com = 0x81;  /* Start master */
//      restore_flags(flags);

        if (cpm_debug > 1) printk("about to sleep\n");

        /* wait for IIC transfer */
interruptible_sleep_on(&iic_wait);
if (signal_pending(current))
        return -EIO;

if (cpm_debug > 1) printk("back from sleep\n");

if (tbdf->cbd_sc & BD_SC_NAK) {
        if (cpm_debug > 1) printk("IIC try; no ack\n");
        return 0;
}

if (tbdf->cbd_sc & BD_SC_READY) {
        printk("IIC try; complete but tbuf ready\n");
}

return 1;

........

quoted

Thanks,
Best Regards,
Alex 

------------------------------

_______________________________________________
Linuxppc-embedded mailing list
Linuxppc-embedded@ozlabs.org
https://ozlabs.org/mailman/listinfo/linuxppc-embedded

End of Linuxppc-embedded Digest, Vol 6, Issue 12
************************************************

-- 
David Bruce
MIT Lincoln Laboratory
244 Wood Street
Lexington, MA 02420
781.981.3863
mailto:dbruce@ll.mit.edu