Commit 5ffd6dc5 authored by Andrey Filippov's avatar Andrey Filippov
Browse files

Using vm_private_data to pass physical address of the mmap-ed area

parent 27abb210

src/drivers/elphel/circbuf.c

+3 −0
Original line number Diff line number Diff line
@@ -861,6 +861,9 @@ int circbuf_mmap(struct file *file, struct vm_area_struct *vma) 
			circbuf_priv[chn].phys_addr >> PAGE_SHIFT,

			vma->vm_end - vma->vm_start,

			vma->vm_page_prot);

    vma->vm_private_data = (void *) circbuf_priv[chn].phys_addr; // for camogm to find phjysical address

	dev_dbg(g_dev_ptr, "added vm_private_data = 0x%lx to tell file write with O_DIRECT physical address\n", \

			(unsigned long) vma->vm_private_data);



	dev_dbg(g_dev_ptr, "remap_pfn_range returned 0x%x\n", ret);

	if (ret) return -EAGAIN;

src/lib/iov_iter.c

+23 −18
Original line number Diff line number Diff line
@@ -1230,23 +1230,33 @@ ssize_t iov_iter_get_pages_elphel(struct iov_iter *i, 
		   struct page **pages, size_t maxsize, unsigned maxpages,

		   size_t *start)

{

	// temporary - fixed physical addresses

	unsigned long circbuf_pa [4]= {0x0ae00000, 0x0ee00000, 0x12e00000, 0x16e00000};

	unsigned long circbuf_pages = 0x4000; // per channel

	int indx, n; // page index

	// just testing, not thread -safe, not locking

	const struct page * circbuf0_page0 = phys_to_page(circbuf_pa[0]);

	size_t len;

	const struct iovec *iov = i->iov; // only use first in array - supposed to be a single-element

	unsigned long paddr = 0; // physical address where to write

	unsigned long addr;

	unsigned long faddr = (unsigned long) iov->iov_base;

	unsigned long vaddr = (unsigned long) iov->iov_base;

	struct vm_area_struct *vm_area;



// *** Putting temporary address here

	struct page * cur_page = (struct page * ) circbuf0_page0;

	pr_debug("circbuf0_page0 = 0x%08x, circbuf0_page0->compound_head=0x%08lx, faddr=0x%08lx, mapcount=%u", \

			(int) circbuf0_page0, circbuf0_page0->compound_head, faddr ,page_mapcount((struct page *) circbuf0_page0));

	addr = 0;

	struct page * cur_page;

//	pr_debug("sizeof(struct vm_area_struct)=%d", sizeof(struct vm_area_struct));

	for (vm_area = current->mm->mmap; vm_area;  vm_area = vm_area-> vm_next) {

		if ((vaddr >= vm_area->vm_start) && (vaddr < vm_area->vm_end)) {

			pr_debug("physical address = 0x%08lx", (unsigned long) vm_area->vm_private_data);

			print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, vm_area, sizeof(struct vm_area_struct));

			paddr = (unsigned long) vm_area->vm_private_data;

			if (paddr) {

				paddr += vaddr - vm_area->vm_start; // added offset within buffer

			}

			break;

		}

	}

	if (!paddr){

		pr_warn("mmap-ed physical address is not specified in vm_area->vm_private_data, aborting");

		return -EINVAL;

	}

	pr_debug("virtual address = 0x%08lx, physical address = 0x%08lx", vaddr, paddr);

	cur_page = phys_to_page(paddr);

	addr = vaddr;

	len = iov->iov_len + (*start = addr & (PAGE_SIZE - 1)); // to inlude beginning of the page - for now 0;

	if (maxsize > i->count)

		maxsize = i->count;
@@ -1264,13 +1274,8 @@ ssize_t iov_iter_get_pages_elphel(struct iov_iter *i, 
	len -= *start;

	pr_debug("iov_iter_get_pages_elphel()->0x%08x, n=%u, current->mm->map_count=%u",\

			len, n, current->mm->map_count);

	pr_debug("sizeof(struct vm_area_struct)=%d", sizeof(struct vm_area_struct));

	for (vm_area = current->mm->mmap; vm_area;  vm_area = vm_area-> vm_next) {

		if ((faddr >= vm_area->vm_start) && (faddr < vm_area->vm_end)) {

			print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, vm_area, sizeof(struct vm_area_struct));

		}

	pr_debug("len=%d", len);



	}

	return len;

}

EXPORT_SYMBOL(iov_iter_get_pages_elphel);