Re: I can't get mapping ram work (Arm kernel 2.4 )

["Antonino A. Daplas" <adaplas@gmail.com>]

ruben quiñones ruiz wrote:
> Hello everybody,
> 
> I'm developing a framebuffer display driver with an armv5 based 
> architecture .
> I've been able to send commands and display what I want using the Ioctl 
> methods (the display works fine).
> 
> But now I want to add the framebuffer funcionality , so I wrote:
> 
> static int slcdc_mmap(struct file *filp, struct vm_area_struct *vma)
> {
>     unsigned long page,pos;
>     unsigned long start = (unsigned long)vma->vm_start;
>     unsigned long size = (unsigned long)(vma->vm_end-vma->vm_start);
>             printk("\nMMAP CALLED");
>     if(size > SLCDC_DATA_MEM_SIZE)
>         return -EINVAL;
>     pos = (unsigned long)slcdc_par.v_screen_start_address;
>     while(size>0){
>         page = virt_to_phys((void*)pos);
>         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
>         // This is an IO map - tell maydump to skip this VMA
>         vma->vm_flags |= VM_IO;
>         vma->vm_flags |= VM_RESERVED;
>         if(remap_page_range(start,page,PAGE_SIZE,PAGE_SHARED)){
>                     printk("\n\nERRORRRR!!!!!!!!");
>             return -EAGAIN;
>         }
>         start+= PAGE_SIZE;
>         pos+= PAGE_SIZE;
>         size-= PAGE_SIZE;
>     }
> 
>     return 0;
> }
> 
> Where slcdc_par.v_screen_start_address; is the virtual adress of the 
> databuffer that must be sent (via a dma provided by the Cpu).

How did you allocate this buffer?  Is is system RAM?  If it's system RAM,
did you use kmalloc, vmalloc or __get_free_pages. (kmalloc, vmalloc usually
do not work, you have to use __get_free_pages).

Tony


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