Re: how to allocate 9MB of memory in kernel ?
From: Misbah khan <hidden>
Date: 2008-07-23 07:30:39
If you SDRAM is you main memory, you need vmalloc and remap_vmalloc_range. If the SDRAM is not your main memory but some I/O attached buffer, you need ioremap/of_iomap and remap_pfn_range. My SDRAM is the main memory of which 9MB i have to allocate in the driver. If i allocate 9BM using vmalloc and remap to user space how should it address to the 9MB SDRAM contigues address which i need to map for user access ? Arnd Bergmann wrote:
On Tuesday 22 July 2008, Misbah khan wrote:quoted
First of all let me thank you for your valuable suggessions ... 1. I wanted to allocate 9MB in kernel and wanted that memory to be mapped to the physically continews SDRAM memory. but till now i could not found a way to do so ??? 2. So i thought to use ioremap to map SDRAM and make it accessible to user using mmap technique but there is only one doubt and that is will it be secure and stable and whether it is a right way of doing ???As I have told you a few times now, you *either* allocate the memory *or* ioremap it, NOT BOTH!!! If you SDRAM is you main memory, you need vmalloc and remap_vmalloc_range. If the SDRAM is not your main memory but some I/O attached buffer, you need ioremap/of_iomap and remap_pfn_range. Arnd <>< _______________________________________________ Linuxppc-embedded mailing list Linuxppc-embedded@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-embedded
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