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<br>
Is there a reason you need to map and unmap physical/virtual memory
every time you do a read or write ?<br>
<br>
I think the norm is to map the physical region in your device
driver in its initialization code and unmap it if the driver exits.<br>
<br>
After that you should be able to read and write your chip as you
wish. If the registers are RW then you should be able to "dump" them by
<br>
reading them at whatever later time you choose.<br>
<br>
<br>
<a class="moz-txt-link-abbreviated" href="mailto:jagannathanjay@aim.com">jagannathanjay@aim.com</a>
wrote:
<blockquote cite="mid8C87B6A995C6521-1C74-11273@FWM-M25.sysops.aol.com"
type="cite">
<div>Hi all<br>
<div><span class="406521009-18072006"><font face="Tahoma" size="2"><br>
We are porting third party driver code from vxworks to Embedded linux
in MPC 8260 under a evaluation platform from Embedded Planet in linux
kernel space.<br>
<br>
</font></span>
<div><span class="406521009-18072006"><font face="Tahoma" size="2">The
first step we carried out was reading the chip id and we were able to
read the chip id correctly.</font></span></div>
<div><span class="406521009-18072006"></span> </div>
<div><span class="406521009-18072006"><font face="Tahoma" size="2">For
reading the chip id we used the routine ChipReadMemory in the attached
text and we were able to retrive the chip id successfully.</font></span></div>
<div><span class="406521009-18072006"></span> </div>
<div><span class="406521009-18072006"><font face="Tahoma" size="2">Subsequently
when we write and read from Chip Specific Control Status registers ,it
didn't work.</font></span></div>
<div><span class="406521009-18072006"></span> </div>
<div><span class="406521009-18072006"><font face="Tahoma" size="2">I
checked the manual and the Chip Specific Control Status registers have
RW access.</font></span></div>
<div><span class="406521009-18072006"></span> </div>
<div><span class="406521009-18072006"><font face="Tahoma" size="2">Any
inputs on how to check if the write we made to virtual address succeeds?</font></span></div>
<div><span class="406521009-18072006"></span> </div>
<div><span class="406521009-18072006"><font face="Tahoma" size="2">Is
there a way to dump the linux virtual address and examine the write we
made ?<br>
<br>
Regards<br>
Jay<br>
</font></span></div>
<br>
</div>
</div>
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<pre wrap=""><hr size="4" width="90%">
int ChipReadMemory(unsigned int arg_phys_addr,unsigned int *memValue)
{
void *virt_addr = NULL;
unsigned int phys_addr = 0;
phys_addr = DEVICE_BASE_ADDRESS + arg_phys_addr;
virt_addr = ioremap(phys_addr, 4);
if(virt_addr == NULL)
{
printk("ChipReadMemory: unable to perform ioremap \n");
return -1;
}
*memValue = readl(virt_addr);
iounmap(virt_addr);
return 0;
}
int ChipWriteMemory(unsigned int arg_phys_addr, unsigned int arg_val)
{
void *virt_addr = NULL;
unsigned int phys_addr = 0;
phys_addr = DEVICE_BASE_ADDRESS + arg_phys_addr;
virt_addr = ioremap(phys_addr, 4);
if(virt_addr == NULL)
{
printk("ChipWriteMemory : unable to perform ioremap \n");
return -1;
}
writel(arg_val,virt_addr);
iounmap(virt_addr);
return 0;
}
</pre>
<pre wrap=""><hr size="4" width="90%">
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href="https://ozlabs.org/mailman/listinfo/linuxppc-embedded">https://ozlabs.org/mailman/listinfo/linuxppc-embedded</a></pre>
</blockquote>
<br>
<br>
<pre class="moz-signature" cols="72">--
Dave Lynch DLA Systems
Software Development: Embedded Linux
717.627.3770 <a class="moz-txt-link-abbreviated"
href="mailto:dhlii@dlasys.net">dhlii@dlasys.net</a> <a
class="moz-txt-link-freetext" href="http://www.dlasys.net">http://www.dlasys.net</a>
fax: 1.253.369.9244 Cell: 1.717.587.7774
Over 25 years' experience in platforms, languages, and technologies too numerous to list.
"Any intelligent fool can make things bigger and more complex... It takes a touch of genius - and a lot of courage to move in the opposite direction."
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