This is a new driver for pxa SoCs, which is also compatible with the former
mmp_pdma.
The rationale behind a new driver (as opposed to incremental patching) was :
- the new driver relies on virt-dma, which obsoletes all the internal
structures of mmp_pdma (sw_desc, hw_desc, ...), and by consequence all the
functions
- mmp_pdma allocates dma coherent descriptors containing not only hardware
descriptors but linked list information
The new driver only puts the dma hardware descriptors (ie. 4 u32) into the
dma pool allocated memory. This changes completely the way descriptors are
handled
- the architecture behind the interrupt/tasklet management was rewritten to be
more conforming to virt-dma
- the buffers alignment is handled differently
The former driver assumed that the DMA channel stopped between each
descriptor. The new one chains descriptors to let the channel running. This
is a necessary guarantee for real-time high bandwidth usecases such as video
capture on "old" architectures such as pxa.
- hot chaining / cold chaining / no chaining
Whenever possible, submitting a descriptor "hot chains" it to a running
channel. There is still no guarantee that the descriptor will be issued, as
the channel might be stopped just before the descriptor is submitted. Yet
this allows to submit several video buffers, and resubmit a buffer while
another is under handling.
As before, dma_async_issue_pending() is the only guarantee to have all the
buffers issued.
When an alignment issue is detected (ie. one address in a descriptor is not
a multiple of 8), if the already running channel is in "aligned mode", the
channel will stop, and restarted in "misaligned mode" to finished the issued
list.
- descriptors reusing
A submitted, issued and completed descriptor can be reused, ie resubmitted if
it was prepared with the proper flag (DMA_PREP_ACK). Only a channel
resources release will in this case release that buffer.
This allows a rolling ring of buffers to be reused, where there are several
thousands of hardware descriptors used (video buffer for example).
Additionally, a set of more casual features is introduced :
- debugging traces
- lockless way to know if a descriptor is terminated or not
The driver was tested on zylonite board (pxa3xx) and mioa701 (pxa27x),
with dmatest, pxa_camera and pxamci.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This patch moves the xilinx_dma.h header file
to the include/linux/dma.
Signed-off-by: Kedareswara rao Appana <appanad@xilinx.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
The HSU DMA is developed to support High Speed UART controllers found in
particular on Intel MID platforms such as Intel Medfield.
The existing implementation is tighten to the drivers/tty/serial/mfd.c driver
and has a lot of disadvantages. Besides that we would like to get rid of the
old HS UART driver in regarding to extending the 8250 which supports generic
DMAEngine API. That's why the current driver has been developed.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The driver library functions can be used directly by the compound devices such
as ADSP or serial driver where DesignWare DMA IP is privately attached to the
main hardware.
Instead of creating a new platform device leaf they may call dw_dma_probe()
with given struct dw_dma_chip directly and make sure that the main device is
DMA capable.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
The introduced include/linux/dma/dw.h is going to contain the private
extensions and structures which are shared for dw_dmac users in the kernel.
Meanwhile include/linux/platform_data/dma-dw.h keeps only platform related data
types and definitions.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
PXA peripherals need to obtain specific DMA request ids which will
eventually be stored in the DRCMR register.
Currently, clients are expected to store that number inside the slave
config block as slave_id, which is unfortunately incompatible with the
way DMA resources are handled in DT environments.
This patch adds a filter function which stores the filter parameter
passed in by of-dma.c into the channel's drcmr register.
For backward compatability, cfg->slave_id is still used if set to
a non-zero value.
Signed-off-by: Daniel Mack <zonque@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
The header ipu.h really belongs to dma subsystem rather than imx
platform. Rename it to ipu-dma.h and put it into include/linux/dma/.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: linux-media@vger.kernel.org
Cc: linux-fbdev@vger.kernel.org
Robert Jarzmik