How to (get a struct device* to) map a DMA buffer for McBSP?

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



I am trying to write a device driver to stream data via a McBSP
module.  Most of it is a pretty thin layer, thanks to all the
framework in plat-omap/mcbsp.c and .../mcbsp.h.  However, I am getting
stuck on the read() and write() implementation -- in particular,
retrieving the device pointer for the DMA mapping functions.

To pick dma_map_single(dev, ptr, size, dir) as an example, the ARM
implementation of dma_map_single() looks like it requires dev != NULL.
 struct omap_mcbsp's "dev" field would be the natural thing to pass,
but the mcbsp_ptr array is not an exported symbol, and there is no
function declared in mcbsp.h that will expose either the omap_mcbsp
struct or the device struct inside it.

Is there a good way to get the right struct device* for the McBSP
module that this device driver is using?  Would a patch be accepted to
add a function that would return the struct device * given the McBSP
id (and if so, should it use EXPORT_SYMBOL() or EXPORT_SYMBOL_GPL())?

Michael Poole
--
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


[Index of Archives]     [Linux Arm (vger)]     [ARM Kernel]     [ARM MSM]     [Linux Tegra]     [Linux WPAN Networking]     [Linux Wireless Networking]     [Maemo Users]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Trails]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux