Comments for Embedded Bits

Comment on Turning on an ARM MMU and Living to tell the tale: The code by Andrew Murray

Andrew Murray — Wed, 28 Mar 2012 18:19:23 +0000

Hi Igor,

The start of the page table is 0×40200000, each entry is 4 bytes long and each entry corresponds to a 1MB section of memory. The first entry in the page table (0×40200000) represents what happens when you try to access memory between the range of 0×00000000 to 0×00100000, the second entry (4 bytes into the table at 0×40200004) represents the memory range 0×00100000 to 0×00200000, etc.

Therefore to find the page table associated with area of memory 0×40200000 to 0×40200000+1MB (which is the 402nd MB of memory) – you need to traverse the page table list by 402 entries – but each entry is 4 bytes long therefore you need to time this number by 4.

Does that make sense?

Andy

Comment on Turning on an ARM MMU and Living to tell the tale: The code by Igor

Igor — Sun, 18 Mar 2012 12:39:08 +0000

Hi… thx for ur work.. I m a noob (and maybe a bit stupid too…) but really I don’t understand the:
“the destination address is the offset in the page table which corresponds to the 1MB of memory which includes the SRAM (table base + 0×402 * 4).”

I thought the first entry should be on the :
“tlb_l1_base: .word 0×40200000″

And so, where that 0×402*4 comes from??

Did I miss something? Thank u very much..

Comment on Writing an MLO for a BeagleBoard XM by johnson

johnson — Thu, 23 Feb 2012 06:37:48 +0000

I like details,It really shot me!

Comment on cat /proc/meminfo : MemTotal by Linux系统内存相关信息获取 | Erlang非业余研究

Linux系统内存相关信息获取 | Erlang非业余研究 — Sun, 19 Feb 2012 06:09:02 +0000

[...] 详细描述可参考这里比如： NUMA: Using 30 for the hash shift. Bootmem setup node 0 0000000000000000-0000000340000000 [...]

Comment on Hardware Environment for a BeagleBoard XM with JTAG by Suresh Acharya

Suresh Acharya — Thu, 16 Feb 2012 07:44:13 +0000

For the beagleboard Xm – do we have any startup initialization code to flash using xds100, if we are not using any bootloader or linux image and want to perform some board diagnostics?

Comment on I2C in the 2.6.32 Linux Kernel by kakaburra

kakaburra — Wed, 15 Feb 2012 16:51:27 +0000

thanks a lot .. it cleared up a lot of doubts

Comment on I2C in the 2.6.32 Linux Kernel by Vinesh Balan

Vinesh Balan — Fri, 27 Jan 2012 11:31:10 +0000

Nice one, I’ve been pondering for the basics of I2C for a while, got it finally. Thanks a ton!

Comment on Init Call Mechanism in the Linux Kernel by Nobel

Nobel — Sat, 14 Jan 2012 12:11:52 +0000

Nice Blog for Linus’s beginners

Comment on I2C in the 2.6.32 Linux Kernel by Michel Benoit

Michel Benoit — Fri, 09 Dec 2011 12:00:19 +0000

Thanks for the article. It saved me a lot of time …

Comment on I2C in the 2.6.32 Linux Kernel by ebanezar

ebanezar — Tue, 06 Dec 2011 13:21:38 +0000

nice article……..Thanks for it….