In principle, ioremap() will return 0x00000000 if the physical address passed is of memory.<br>I just want you to double check the address you have passed to ioremap().<br>In my experiment on x86 Desktop machine with 2GB RAM. I passed a physical address 0x63ACD000. As expected it returned 0x00000000. I am running linux version 3.5.1.<br>
<br><div><br>Regards,<br>Prabhunath G<br>Linux Trainer<br>Bangalore<br></div>
<br><br><div class="gmail_quote">On Fri, Mar 1, 2013 at 5:57 PM, sandeep kumar <span dir="ltr"><<a href="mailto:coolsandyforyou@gmail.com" target="_blank">coolsandyforyou@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr"><div class="im"><span style="font-family:arial,sans-serif;font-size:13px">>Looks like you are trying to pass the address of physical memory to this function as a parameter and it is screwing up. </span><br>
</div><div><font face="arial, sans-serif">Yes, i intentionally gave some physical address which is part of system memory.</font></div>
<div><font face="arial, sans-serif">My problem infact is, it is not screwing up. It is allowing me to do that. Its not 'panic'ing</font></div></div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br>
<br><div class="gmail_quote">
On Fri, Mar 1, 2013 at 4:58 PM, Prabhu nath <span dir="ltr"><<a href="mailto:gprabhunath@gmail.com" target="_blank">gprabhunath@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br><br><div class="gmail_quote"><div><div>On Fri, Mar 1, 2013 at 4:48 PM, sandeep kumar <span dir="ltr"><<a href="mailto:coolsandyforyou@gmail.com" target="_blank">coolsandyforyou@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">Hi All<div>I am using ARM based board.</div><div>In mine, </div><div>i did the following...</div><div><br clear="all"><div><font face="courier new, monospace"> void __iomem *tcpm_base = ioremap_nocache(0x03B00000, 10*SZ_3MB);</font><br>
</div><div><font face="courier new, monospace"><br></font></div><div><font face="arial, helvetica, sans-serif">Actually i didnt reserve the 30MB memory @ 0x3B00000. But still the call is succesful and i am able to read the memory.</font></div>
<div><font face="arial, helvetica, sans-serif"><br></font></div><div><font face="arial, helvetica, sans-serif">In the logs it is just showing a warning, to fix my driver as i am calling ioremap() on system memory.</font></div>
<div><font face="arial, helvetica, sans-serif"><br></font></div><div><font face="arial, helvetica, sans-serif">However if i try to write something on that memory, then only it is calling panic()..</font></div>
<div><font face="arial, helvetica, sans-serif"><br></font></div><div><font face="arial, helvetica, sans-serif">Don't you think it should throw panic()while calling the ioremap() itself. Because this sounds like a serious violation...</font></div>
<div><font face="arial, helvetica, sans-serif"><br></font></div><div><font face="arial, helvetica, sans-serif">What say?</font></div></div></div></blockquote></div></div><div><br>To my knowledge, ioremap is used only to map the device related physical address to kernel virtual address. i.e. this function will only map either device registers or device memory to kernel virtual address. <br>
<br>Looks like you are trying to pass the address of physical memory to this function as a parameter and it is screwing up. <br><br>Please verify. <br><br>Regards,<br>Prabhu<br><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<div dir="ltr"><div><span><font color="#888888">-- <br>With regards,<br>Sandeep Kumar Anantapalli,<br>
</font></span></div></div>
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<br></blockquote></div><br>
</blockquote></div><br><br clear="all"><div><br></div>-- <br>With regards,<br>Sandeep Kumar Anantapalli,<br>
</div>
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