Linux with MMU on NEEK

Hi,

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But the new confusion was that nothing appeared on the screen and Nano-X seemed running correctly:

/#  nano-X &
 686 nano-X
/#  nanowm &
 687 nanowm
/#  nxclock &
 688 nxclock

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Have you revised that the all DMA descriptors use physical addresses? For example,

} __attribute__ ((packed)) sgdma_desc;
# include <asm/cacheflush.h>  // <-- to use 'flush_cache_all()'
static int altfb_dma_start(unsigned long start, unsigned long len)
{
    unsigned long base =
        (unsigned long)ioremap(SGDMABASE, ALTERA_SGDMA_IO_EXTENT);
    sgdma_desc *desc, *desc1;
    int ndesc = (len + DISPLAY_BYTES_PER_DESC - 1) / DISPLAY_BYTES_PER_DESC;
    int ndesc_size = sizeof(sgdma_desc) * ndesc;
    int i;
    writel(ALTERA_SGDMA_CONTROL_SOFTWARERESET_MSK,
           base + ALTERA_SGDMA_CONTROL);    /* halt current transfer */
    writel(0, base + ALTERA_SGDMA_CONTROL);    /* disable interrupts */
    writel(0xff, base + ALTERA_SGDMA_STATUS);    /* clear status */
    /* assume cache line size is 32, which is required by sgdma desc */
    desc1 = kzalloc(ndesc_size, GFP_KERNEL);
    if (desc1 == NULL)
        return -ENOMEM;
//    desc1 = ioremap((unsigned long)desc1, ndesc_size);
    for (i = 0, desc = desc1; i < ndesc; i++, desc++) {
        unsigned ctrl = ALTERA_SGDMA_DESCRIPTOR_CONTROL_OWNED_BY_HW_MSK;
        desc->read_addr = (void *)start;
        if (i == (ndesc - 1)) {
//            desc->next = (void *)desc1;
            desc->next = (void *)virt_to_phys(desc1);
            desc->bytes_to_transfer = len;
            ctrl |=
                ALTERA_SGDMA_DESCRIPTOR_CONTROL_GENERATE_EOP_MSK;
        } else {
//            desc->next = (void *)(desc + 1);
            desc->next = (void *)virt_to_phys((desc + 1));
            desc->bytes_to_transfer = DISPLAY_BYTES_PER_DESC;
        }
        if (i == 0)
            ctrl |=
                ALTERA_SGDMA_DESCRIPTOR_CONTROL_GENERATE_SOP_MSK;
        desc->control = ctrl;
        start += DISPLAY_BYTES_PER_DESC;
        len -= DISPLAY_BYTES_PER_DESC;
    }
//    writel((unsigned long)desc1, base + ALTERA_SGDMA_NEXT_DESC_POINTER);
    writel(((unsigned long)virt_to_phys(desc1)), base + ALTERA_SGDMA_NEXT_DESC_POINTER);
    writel(ALTERA_SGDMA_CONTROL_RUN_MSK | ALTERA_SGDMA_CONTROL_PARK_MSK,
           base + ALTERA_SGDMA_CONTROL);    /* start */
    flush_cache_all();   // <- To flush descriptors from the cache.  Indeed, it's enough to flush the D-cache.
    return 0;
}# else
static int altfb_dma_start(unsigned long start, unsigned long len)

Kazu