Messages in this thread | | | From | Andy Shevchenko <> | Date | Thu, 22 Nov 2018 13:28:31 +0200 | Subject | Re: using ioremap() memory in dma_map_sg() |
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On Mon, Nov 19, 2018 at 6:31 PM Olga Kitaina <okitain@elvees.com> wrote: > > Hi. > As part of our driver, we want to have some device memory to be > available to other devices via the DMA-BUF subsystem. The device memory > is managed by genpool, and mapped from the sram driver via ioremap_wc(). > We initially used sg_set_buf() with the virtual address returned from > gen_pool_dma_alloc(), but it seems like the wrong thing to do, since the > virt_addr_valid() check fails. Attempting to use vmalloc_to_page() > results in a failure down the line, such as: > > Unable to handle kernel paging request at virtual address ba405000 > Backtrace: > (dma_cache_maint_page) from (__dma_page_dev_to_cpu+0x88/0x108) > (__dma_page_dev_to_cpu) from (arm_dma_map_page+0x5c/0x60) > (arm_dma_unmap_page) from (arm_dma_map_sg+0x64/0x8c) > (arm_dma_unmap_sg) from(foo_dmabuf_map+0x60/0x8c [foo]) > > Is there an appropriate way to put an ioremapped buffer into an SG table?
Olga, I'm not sure you really want DMA-BUF subsystem for your task. Anyway, I Cc'ed to couple of maintainers, hope they can help you.
-- With Best Regards, Andy Shevchenko
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