Re: How accessing to my IP registers from Linux

["Ludovic Desroches" <ludovic.desroches@gmail.com>]

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Thanks for your answer, unfortunately it doesn't work. I'm doing this :

static unsigned int *virtual_base = 0;
static unsigned long mem_addr = 0x70001e00;
static unsigned long mem_size = 0x100;
static unsigned int reg3 = 0;

static int __init gpio_init(void) {

    printk("<1>gpio: init_module\n");
    if(check_mem_region(mem_addr,mem_size))
    {
        printk("gpio: memory already in use\n");
        return -EBUSY;
    }
    // request memory for the device
    request_mem_region(mem_addr,mem_size,"gpio");
    // remap
    virtual_base = ioremap_nocache(mem_addr,mem_size);
    printk("ioremap: Virtual Address %08x\n",(unsigned int)virtual_base);
    printk("Physical Address %08x\n",(unsigned
int)virt_to_phys(virtual_base));
    if( virtual_base==0 )
    {
        printk("ioremap failed\n");
        return -EBUSY ;
    }
    else
    {
        reg3 = XIo_Out32(virtual_base);
        printk("Result of GPIO_DATA = %08x\n",reg3) ;
        reg3 = XIo_Out32(virtual_base+4);
        printk("Result of GPIO_TRI = %08x\n",reg3) ;

        printk("Xio_Out32\n");
        XIo_Out32(virtual_base, 0x00);
    }
    return 0;
}

the result is :

gpio: init_module
ioremap: Virtual Address c500ee00
Physical Address 0500ee00
Xio_Out32

The LEDs stay ON. I find strange having physical address different from the
physical adress I wanted to map. Can I have a problem with my MMU ? As other
devices are working, I am not sure it's the MMU for exemple during boot :
eth0: Xilinx 10/100 EMAC at 0x80400000 mapped to 0xC5020000, irq=1 and
Ethernet is working so the MMU seems to be ok.


Thanks

Ludovic Desroches


2008/6/3 A. Nolson <alohanono@gmail.com>:

> Hi,
>
> I have recently developed a similar driver for that. Your IO memory
> remapping should look like similar to this in your module_init:
>
> -------
>
>   if ( (lcd_remap_address = (u32) ioremap(LCD_BASE, LCD_END - LCD_BASE +1
> )) == 0) {
>       printk(KERN_ERR "Couldn't ioremap memory at 0x%08lX\n",
>              (unsigned long) LCD_BASE);
>       return -EFAULT;         }
>     // Configure the IO as outputs
>   XIo_Out32(lcd_remap_address  + 0x4,0x00);
> -------
> /A
>
> Ludovic Desroches wrote:
>
>>
>> Hi,
>>
>>
>> I have put xilinx kernel on my board : a memec FX12 based on a Virtex 4
>> FX. Everything thing is OK, I have my serial console, Ethernet is also OK.
>>
>> I have to make some drivers. For example one for the LCD screen. It is my
>> first driver so I want to try with something easier like LEDs. I know there
>> is a driver from Xilinx but I want to do it by myself. Moreover it is only a
>> file to adapt Xilinx standelone driver for Kernel.
>>
>>
>> I try to read and to write the registers of my GPIO IP which is working, I
>> have made some tests in standelone. How accessing to these registers ?
>>
>> I have tried with this for example but without success :
>>
>>    ptr = ioremap_nocache(0x70001e00,0x00000004);
>>    printk("GPIO_DATA (readl): %u\n",readl(ptr));
>>
>>
>> readl, outl, ioread32 : same result.
>>
>>
>> Thanks
>>
>>
>> Best Regards
>>
>>
>> --
>> Ludovic Desroches
>> Ingénieur ESIEE 2008
>> mobile : 06 19 21 02 08
>> http://www.odulo.net
>> ------------------------------------------------------------------------
>>
>> _______________________________________________
>> Linuxppc-embedded mailing list
>> Linuxppc-embedded@ozlabs.org
>> https://ozlabs.org/mailman/listinfo/linuxppc-embedded
>>
>
>


-- 
Ludovic Desroches
Ingénieur ESIEE 2008
mobile : 06 19 21 02 08
http://www.odulo.net

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