On Tue, 2013-01-29 at 20:57 +0530, Viresh Kumar wrote: > On Tue, Jan 29, 2013 at 10:52 AM, Mika Westerberg > <mika.westerb...@linux.intel.com> wrote: > > We had a discusssion about this with Andy as well. The thing is that there > > is no way in current resource to pass DMA request line numbers supported by > > the controller to the driver in a generic way. We on the other hand have to > > deal this somehow as we have a shared DMA controller on Lynxpoint where the > > offset will start from 16 (but it might be something else as well). > > > > Is there something which limits the usage of IORESOUCE_DMA to be only > > usable for ISA DMA channels? > > Andy, > > Why do we need this request_line_base? Why not program the actual value > directly into the slave structure (base + offset)?
Slave device exactly has knowledge about this number slave_id = (base +offset). However... > In case it is required, add it in platform data field or can add DT > binding for it. We get a device from the ACPI CSRT table. During enumeration we don't know what kind of the device it is. From the enumeration point of view each device enumerated from CSRT is a platform device (see drivers/acpi/csrt.c for the details). That's why we have to pass this info somehow to the DMAC driver. And like Mika already mentioned we have no other generic way except IORESOURCE_DMA. If you have something better in mind, please share. We could adopt our code then. -- Andy Shevchenko <andriy.shevche...@linux.intel.com> Intel Finland Oy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/