Physical Memory & Virtual Memory

4 messages

Physical Memory & Virtual Memory

Reply Threaded

Hi All,

I have some very basic / fundamental (may even sound silly) questions:-

How do we determine the values for the following variables in the platform/SoCXX/tools/machines.py file:-

1) memory[physical] .. This value I believe corresponds to RAM (silly question) and probably can be obtained by consulting the TRM of SoCXX. But still, any advise would be helpful.
2) memory[virtual] ... how this value is determined for any particular SoCXX?
3) base_vaddr ... again here, how this value is determined for any particular SoCXX?

4) Based on above values, final memory layout will be reflected in the image.elf file generated. But any basic explanation related to this would be helpful.
5) Also, based on above values, the parameters that we pass to u-boot will also change.

For e.g. consider that an SoCXX has 512MB RAM with address range as : 0x8000 0000 - 0x9FFF FFFF
How do we determine the values of above variables based on this information?

Thanks to all,
Kumar.

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Gabi Voiculescu

Re: Physical Memory & Virtual Memory

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Hi.

I can answer the first part.

In your SoCxxx/tools/machines.py you should have the following line for all your platforms (clases):
memory['physical'] = [Region(0x80000000L, 0xA0000000L)]

I personally do not have an explicit memory['virtual'] entry for my platforms.

If I remember correctly, okl4 usually builds in virtual memory the kernel starting at the base 0xf000.0000, with io sfr's mapped starting from 0xf900.0000. I think memory virtual can influence the kernel's base virtual address but I'm not sure.

Good luck,
Gabi Voiculescu

--- On Tue, 9/15/09, Kumar Sanghvi <[hidden email]> wrote:

From: Kumar Sanghvi <[hidden email]>
Subject: [okl4-developer] Physical Memory & Virtual Memory
To: [hidden email]
Date: Tuesday, September 15, 2009, 6:19 AM

Hi All,

I have some very basic / fundamental (may even sound silly) questions:-

How do we determine the values for the following variables in the platform/SoCXX/tools/machines.py file:-

1) memory[physical] .. This value I believe corresponds to RAM (silly question) and probably can be obtained by consulting the TRM of SoCXX. But still, any advise would be helpful.
2) memory[virtual] ... how this value is determined for any particular SoCXX?
3) base_vaddr ... again here, how this value is determined for any particular SoCXX?

4) Based on above values, final memory layout will be reflected in the image.elf file generated. But any basic explanation related to this would be helpful.
5) Also, based on above values, the parameters that we pass to u-boot will also change.

For e.g. consider that an SoCXX has 512MB RAM with address range as : 0x8000 0000 - 0x9FFF FFFF
How do we determine the values of above variables based on this information?

Thanks to all,
Kumar.

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Kumar Sanghvi

Re: Physical Memory & Virtual Memory

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Hi Gabi,

Thanks for sharing some information on this.

Regards,
Kumar.

On Tue, Sep 15, 2009 at 9:15 PM, Gabi Voiculescu <[hidden email]> wrote:

Hi.

I can answer the first part.

In your SoCxxx/tools/machines.py you should have the following line for all your platforms (clases):
memory['physical'] = [Region(0x80000000L, 0xA0000000L)]

I personally do not have an explicit memory['virtual'] entry for my platforms.

If I remember correctly, okl4 usually builds in virtual memory the kernel starting at the base 0xf000.0000, with io sfr's mapped starting from 0xf900.0000. I think memory virtual can influence the kernel's base virtual address but I'm not sure.

Good luck,
Gabi Voiculescu

--- On Tue, 9/15/09, Kumar Sanghvi <[hidden email]> wrote:

From: Kumar Sanghvi <[hidden email]>
Subject: [okl4-developer] Physical Memory & Virtual Memory
To: [hidden email]
Date: Tuesday, September 15, 2009, 6:19 AM

Hi All,

I have some very basic / fundamental (may even sound silly) questions:-

How do we determine the values for the following variables in the platform/SoCXX/tools/machines.py file:-

1) memory[physical] .. This value I believe corresponds to RAM (silly question) and probably can be obtained by consulting the TRM of SoCXX. But still, any advise would be helpful.
2) memory[virtual] ... how this value is determined for any particular SoCXX?
3) base_vaddr ... again here, how this value is determined for any particular SoCXX?

4) Based on above values, final memory layout will be reflected in the image.elf file generated. But any basic explanation related to this would be helpful.
5) Also, based on above values, the parameters that we pass to u-boot will also change.

For e.g. consider that an SoCXX has 512MB RAM with address range as : 0x8000 0000 - 0x9FFF FFFF
How do we determine the values of above variables based on this information?

Thanks to all,
Kumar.

-----Inline Attachment Follows-----

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Developer mailing list
Developer@...
https://lists.okl4.org/mailman/listinfo/developer

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houwei

Porting Oklinux

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In reply to this post by Kumar Sanghvi

Some javascript/style in this post has been disabled (why?)

Hi All,

I have some questions when porting oklinux.

Now , oklinux has boot to Mount filesysterm, but never display “Linux user startup!”

When I open debug option, I found the problem is that uart is continous printing “uart_open(0) called”, “uart_close(0) called”

I don’t know why linux is never startup, and I hope I can get some useful informations.

Thanks to all!

Hou wei

This is some log information:

………………………..

……………………….

TCP cubic registered

NET: Registered protocol family 1

NET: Registered protocol family 17

driver_probe_done: probe_count = 0

sysfs_read_file: count = 32, ppos = 0, buf = 254:0

VFS: Mounted root (ext2 filesystem) readonly.

uart_open(0) called

uart_close(0) called

uart_wait_until_sent(0), jiffies=4294937469, expire=4294937473...

uart_wait_until_sent(0), jiffies=4294937475, expire=4294937477...

Trying to free already-free IRQ 12

uart_flush_buffer(0) called

uart_open(0) called

uart_close(0) called

uart_wait_until_sent(0), jiffies=4294937824, expire=4294937828...

uart_flush_buffer(0) called

uart_open(0) called

uart_close(0) called

uart_wait_until_sent(0), jiffies=4294937824, expire=4294937828...

uart_flush_buffer(0) called

uart_open(0) called

uart_close(0) called

uart_wait_until_sent(0), jiffies=4294937824, expire=4294937828...

uart_flush_buffer(0) called

………………………………

发件人: [hidden email] [mailto:[hidden email]] 代表 Kumar Sanghvi
发送时间: 2009年9月15日 11:19
收件人: [hidden email]
主题: [okl4-developer] Physical Memory & Virtual Memory

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