Hi Hari, > -----Original Message----- > From: Kanigeri, Hari > Sent: Thursday, July 01, 2010 6:36 PM > To: Guzman Lugo, Fernando; linux-omap@xxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx > Cc: ohad@xxxxxxxxxx; hiroshi.doyu@xxxxxxxxx; ameya.palande@xxxxxxxxx; > felipe.contreras@xxxxxxxxx; Guzman Lugo, Fernando > Subject: RE: [PATCH 8/9] dspbridge: add map support for big buffers > > Fernando, > > > - for_each_sg(sgt->sgl, sg, sgt->nents, i) > > - sg_set_page(sg, usr_pgs[i], PAGE_SIZE, 0); > > + da = iommu_vmap(mmu, da, sgt, IOVMF_ENDIAN_LITTLE | > > + IOVMF_ELSZ_32); > > -- iommu_vmap does the Kernel mapping to the buffers you are mapping to > DSP MMU. Why do you need Kernel mappings ? > > If there is no benefit in maintaining Kernel mapping I would rather call > iopgtable_store_entry directly to map the entries. Where inside iommu_vmap is the mapping done? I thought the kernel can access to that buffer after get_user_pages() where the user pages are pin and we can get a kernel address. The intention using iommu_vmap was to use api's proved by the iovmmu module. iommu_vmap() it is also tracking the mapped areas, so maybe the next step could be: remove dmm.c/h files and also proc_reserve/unreserved functions. If you think the function is unneeded steps and could affect the performance I can do the change to use only iopgtable_store_entry(). I think a kernel mapping is needed for flush/invalidate api's, please correct me if I am wrong. Regards, Fernando. > > Thank you, > Best regards, Hari -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
