[OpenBIOS] VESA & DMA

[Clive Jenkins]

After reading your DMA question more carefully, I realise my last
posting did not help. Please ignore it.

Clive Jenkins.

Petazzoni Thomas wrote:
> 
> Hi everybody,
> 
> This has not much to do with the OpenBIOS project, but with low level
> programming. Everyone here seems to know lot of things in this domain,
> that's why i'm asking to all of u those questions :
> 
> 1. Can we setup a VESA 2 (not VESA 3 !) configuration (select video
> mode, and everything) without making a int 0x10 ? We're programming a
> protected mode OS, and switching to VM86 sucks. I know it's possible
> with VESA 3, but with VESA 2 ?
> If yes, do you have any docs about it ?
> Is the int 0x10 VESA code specific to each graphic card ?
> 
> 2. I've got a problem with DMA programming, here's my source :
> 
> const static DmaChannel dmainfo[] = {
>   { 0x87, 0x00, 0x01 },
>   { 0x83, 0x02, 0x03 },
>   { 0x81, 0x04, 0x05 },
>   { 0x82, 0x06, 0x07 }
> };
> 
> void dma_transfer(int channel, long physical_address, unsigned int
> length, unsigned sh
> ort read) {
> 
>   long page, offset;
> 
>   if(channel >= 4)
>    {
>      printk("\nThis function does to manage with channel 4, 5, 6, 7");
>      return ;
>    }
> 
>   page = physical_address >> 16;
>   offset = physical_address & 0xFFFF;
>   length -= 1;
> 
>   // DIsable IRQs
>   outb(0xFF, 0x21);
>   outb(0xFF, 0xA1);
> 
>   // Masking channel (disable)
>   outb(channel | 4, 0x0A);
> 
>   // Reset Flip-Flop
>   outb(0, 0xC0);
> 
>   // Mode
>   outb( (read ? 0x48 : 0x44) | channel, 0x0B);
> 
>   // Page
>   outb(page, dmainfo[channel].page);
> 
>   // Offset
>   outb(offset & 0xFF, dmainfo[channel].offset);
>   outb((offset >> 8) & 0xFF, dmainfo[channel].offset);
> 
>   // Length
>   outb(length & 0xFF, dmainfo[channel].length);
>   outb((length >> 8) & 0xFF, dmainfo[channel].length);
> 
>   // Unmask
>   outb(channel, 0x0A);
> 
>  // Enabling IRQs
>   outb(0, 0x21);
>   outb(0, 0xA1);
> 
> }
> 
> I use it to transfer a sector from the floppy disk. Do you see anything
> wrong in this code ?
> The transfer is not made by the floppy, and i don't know why...
> I don't know if it's in the DMA programming, or in the floppy driver
> ..............
> 
> Help !
> 
> Thanks,
> 
> Thomas, from france
> 
> (If you speak french, you can join the KOS project :
> http://kos.enix.org)
> 
> --
> PETAZZONI Thomas, coordinateur du projet KOS
> thomas.petazzoni at ifrance.com
> ICQ : 34937744
> Home page : http://perso.worldonline.fr/petazzoni/thomas/
> Home Page Projet KOS : http://kos.enix.org
> 
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