Linux reading and writing to the physical memory

curious beast

Other Parts Discussed in Thread: AM5718

Hi Guys,
I have got 0x96000 memory allocated in system ram for audio data.
To read and write I used ioremap, Which while reading back getting
wrong values.

DO I need to use different api's for mapping such a huge physical memory
and acess them in the driver.

over 2 years ago

0 LeonardEllis over 2 years ago

TI__Guru 71516 points

Hello cb,

Please provide more information - what processor are you using?

Thank you,

~Leonard

0 curious beast over 2 years ago

Intellectual 310 points

It is AM5718

0 Suman Anna over 2 years ago in reply to curious beast

TI__Guru* 80245 points

Hi Cb,

What API have you used in your Linux driver? If you have used kmalloc or kzalloc, it is already coming from kernel linear memory, and you need not use ioremap.

ioremap is typically needed only if you use have used a memory carveout.

The API to use also depends on whether you want contiguous memory or not. If there are no restrictions, a normal API to use for large memories is vmalloc().

regards

Suman

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Linux reading and writing to the physical memory