2013/7/14 Gerhard Sittig <gsi@xxxxxxx>:
> this series
> - introduces slave s/g support (that's support for DMA transfers which
> involve peripherals in contrast to mem-to-mem transfers)
> - adds device tree based lookup support for DMA channels
> - combines floating patches and related feedback which already covered
> several aspects of what the suggested LPB driver needs, to demonstrate
> how integration might be done
> - carries Q&D SD card support to enable another DMA client during test,
> while this patch needs to get dropped upon pickup
Changes in v2:
> - re-order mpc8308 related code paths for improved readability, no
> change in behaviour, introduction of symbolic channel names here
> already
> - squash 'execute() start condition' and 'terminate all' into the
> introduction of 'slave s/g prep' and 'device control' support; refuse
> s/g lists with more than one item since slave support is operational
> yet proper s/g support is missing (can get addressed later)
> - always start transfers from software on MPC8308 as there are no
> external request lines for peripheral flow control
> - drop dt-bindings header file and symbolic channel names in OF nodes
Changes in v3 and v4:
Part 1/5:
- use #define instead of enum since individual channels don't require
special handling.
Part 2/5:
- add a flag "will_access_peripheral" to DMA transfer descriptor
according recommendations of Gerhard Sittig.
This flag is set in mpc_dma_prep_memcpy() and mpc_dma_prep_slave_sg()
and is evaluated in mpc_dma_execute() to choose a type of start for
the transfer.
- prevent descriptors of transfers which involve peripherals from
being chained together;
each of such transfers needs hardware initiated start.
- add locking while working with struct mpc_dma_chan
according recommendations of Lars-Peter Clausen.
- remove default nbytes value. Client kernel modules must set
src_maxburst and dst_maxburst fields of struct dma_slave_config (dmaengine.h).
Changes in v5:
Part 2/5:
- add and improve comments;
- improve the code moving transfer descriptors from 'queued' to 'active' list
in mpc_dma_execute();
- allow mpc_dma_prep_slave_sg() to run with non-empty 'active' list;
- take 'mdesc' back to 'free' list in case of error in mpc_dma_prep_slave_sg();
- improve checks of the transfer parameters;
- provide the default value for 'maxburst' in mpc_dma_device_control().
Changes in v6:
Part 2/5:
- remove doubtful comment;
- fix coding style issues;
- set default value for 'maxburst' to 1 which applies to most cases;
Part 3/5:
- use dma_get_slave_channel() instead of dma_request_channel()
in new function of_dma_xlate_by_chan_id() according recommendations of
Arnd Bergmann;
Part 4/5:
- set DMA_PRIVATE flag for MPC512x DMA controller since its driver relies on
of_dma_xlate_by_chan_id() which doesn't use dma_request_channel()
any more; (removed in v7)
- resolve little patch conflict;
Part 5/5:
- resolve little patch conflict;
Changes in v7:
Part 2:
- improve comment;
Part 4:
- split in two separate patches. Part 4/6 contains device tree
binding document and in part 5/6 MPC512x DMA controller is registered
for device tree channel lookup;
- remove setting DMA_PRIVATE flag for MPC512x DMA controller from part 5/6;
Changes in v8:
Part 2:
- improve comments;
- fix style issues;
Part 6:
- remove since it has become obsolete;
Changes in v9:
A new patch (part 3/6) is added to this series according the
feedback of Andy Shevchenko.
Part 2/6:
- keep style of the comments;
- use is_slave_direction() instead of manual checks;
- remove redundant else branches of the conditions;
- make mpc_dma_device_control() return -ENXIO for unknown command;
Part 6/6:
- change according the new part 3/6;
- fix style issues;
Changes in v10:
Part 2/6:
- don't use direction field of dma_slave_config in mpc_dma_device_control()
but store settings in mpc_dma_chan for both DMA_DEV_TO_MEM and
DMA_MEM_TO_DEV cases; then retrieve the needed values in
mpc_dma_prep_slave_sg();
- fix style issue and put 2014 instead of 2013;
Part 3/6:
- fix mpc_dma_probe() error path and mpc_dma_remove(): manually free IRQs and
dispose IRQ mappings before devm_* takes care of other resources;
Part 6/6:
- change according the new part 3/6;
- fix style issue;
Changes in v11:
Part 5/6:
- remake device tree binding document according the recommendations of
Gerhard Sittig, Mark Rutland and Arnd Bergmann;
> known issues:
> - it's yet to get confirmed whether MPC8308 can use slave support or
> whether the DMA controller's driver shall actively reject it, the
> information that's available so far suggests that peripheral transfers
> to IP bus attached I/O is useful and shall not get blocked right away
- adding support for transfers which don't increment the RAM address or
do increment the peripheral "port's" address is easy with
this implementation; but which options of the common API
should be used for specifying such transfers?
Alexander Popov (6):
dma: mpc512x: reorder mpc8308 specific instructions
dma: mpc512x: add support for peripheral transfers
dma: mpc512x: fix freeing resources in mpc_dma_probe() and
mpc_dma_remove()
dma: of: Add common xlate function for matching by channel id
dma: mpc512x: add device tree binding document
dma: mpc512x: register for device tree channel lookup
.../devicetree/bindings/dma/mpc512x-dma.txt | 51 +++
arch/powerpc/boot/dts/mpc5121.dtsi | 1 +
drivers/dma/mpc512x_dma.c | 345 ++++++++++++++++++---
drivers/dma/of-dma.c | 35 +++
include/linux/of_dma.h | 4 +
5 files changed, 398 insertions(+), 38 deletions(-)
create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt
--
1.8.4.2
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