> -----Original Message----- > From: Kanigeri, Hari > Sent: Monday, May 03, 2010 2:09 PM > To: Aguirre, Sergio; Hiroshi DOYU > Cc: linux-omap@xxxxxxxxxxxxxxx > Subject: RE: [Query][omap iommu] Consulting iommu if a physical region is > "mappable" before actually mapping it > > Sergio, > > > > > Can the iommu driver be "consulted" if a certain area (contiguous or > not) > > can be mapped or not, before even trying to do it? > > > > -- As long as there are physical pages backing the area it should be > mappable right ? Ok, well.. maybe my question was more about that, if the ISP MMU has some kind of limited translation table size, in which it has a limited of pages to map to device addresses that the ISP can use. The need for this is that, in camera, there's a Video4Linux2 IOCTL to know if a certain amount of buffers can be handled (and that includes if they could be mapped or not), even before actually doing the whole allocation/mapping. If there's no limitation in the translation table size, then I guess the only concern is to ensure we have enough free RAM to use. (Which I'll like to think that an userspace resource manager will be able to figure out for the camera application, which is the one allocating the buffers.) Please correct me if there's something wrong in my reasoning... Regards, Sergio > > 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
