Spartan-6 / OMAP-L138 Co-Processing Kit

[pankaj2701]

Hello,

I am trying to write a Linux driver for accessing the FPGA  through the EMIFA bus.

I am unable to access the EMIFA control registers at 0x68000000.

I wrote the following the code:

     resrc=request_mem_region(0x68000000,64,"fpga");  
   
    if (resrc== NULL)
    {
        printk("resource not allocated\n");
        return -1;
       }
   
    location = (unsigned int *)ioremap_nocache(0x68000000,64);
   
    if (!location)
    {
        printk("AEMIFA CTL BASE NOT AVAILABLE\n");
        return 1;
    }
      regval = readl(location);
    printk("Regval %x\n",regval);
    regval = ioread32(location);
    printk("Regval %x\n",regval);

I have tried to use both ioread32 as well as readl functions but I always get 0 as return values.

The value expected is 0x4000 0205h. Its a read only location so there is no question of something else overwriting the register.

I get the correct value when I access the same register in u-boot.

With regards

Pankaj

[professor]

Hi Pankaj,

I was able to recreate the same results as you and I am also perplexed by this behavior.

If I run the following code to read the JTAG ID register:

  jtag_id_reg = ioread32(0xFEC14018);

 printk(KERN_WARNING "Read JTAGID 0x%08X\n",jtag_id_reg);

I observe the expected value of 0x1B7D102F but when reading the EMIFA module ID register I also read back 0x00000000.  One might expect this behavior if the EMIFA controller was powered down or disabled internally.  I tried dumping the PSC0 status registers from the same driver, but I am not sure if all of those values make sense either:

PSC0 REVID: 0x44825A00
PSC0 MDSTAT0: 0x00001E03
PSC0 MDSTAT1: 0x00000E02
PSC0 MDSTAT2: 0x00001E03
PSC0 MDSTAT3: 0x00001E03
PSC0 MDSTAT4: 0x00000E02
PSC0 MDSTAT5: 0x00001E03
PSC0 MDSTAT6: 0x00001E03
PSC0 MDSTAT7: 0x00000000
PSC0 MDSTAT8: 0x00001E03
PSC0 MDSTAT9: 0x00001E03
PSC0 MDSTAT10: 0x00000000
PSC0 MDSTAT11: 0x00000000
PSC0 MDSTAT12: 0x00001E03
PSC0 MDSTAT13: 0x00000000
PSC0 MDSTAT14: 0x00000000
PSC0 MDSTAT15: 0x00000000

From u-boot, I see the power on values as:

01c10000: 44825a00 00000000 00000000 00000000    .Z.D............

01c10800: 00001e03 00001e03 00001e03 00001e03    ................
01c10810: 00001e03 00001e03 00001e03 00001e03    ................
01c10820: 00001e03 00001e03 00001e03 00001e03    ................
01c10830: 00001e03 00000a00 00001f03 00001d03    ................

I would recommend posting this issue to the TI E2E forums to see if there is something obvious that is being overlooked here.

Regards,

-Kevin

P.S. Out of curiousity, what is the value of resrc after your call to request_mem_region()