Device Driver for Reserved Memory

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I am trying to develop a simple character device driver that access the reserved memory region as described in the site: http://www.wiki.xilinx.com/Linux+Reserved+Memory

/* Get reserved memory region from Device-tree */

np = of_parse_phandle(dev->of_node, "memory-region", 0);

if (!np) {
    dev_err(dev, "No %s specified\n", "memory-region");
    goto error1;
}

rc = of_address_to_resource(np, 0, &r);

if (rc) {
  dev_err(dev, "No memory address assigned to the region\n");  
  goto error1;
}

lp->paddr = r.start;
lp->vaddr = memremap(r.start, resource_size(&r), MEMREMAP_WB);

dev_info(dev, "Allocated reserved memory, vaddr: 0x%0llX, paddr: 0x%0llX\n", (u64)lp->vaddr, lp->paddr);

The site does not give any information regarding lp->paddr and lp->vaddr

What is the datatype of lp ?

reserved embedded-linux linux-device-driver memory linux-kernel
1 Answers

I think "lp" is not a predefined variable. I have declared my own struct with vaddr and paddr as struct elements and defined lp as the struct variable and it worked.

static struct addr_map
{
   __u32 paddr,vaddr;
   ssize_t size;
}*lp;
user_81924340
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