Cleanup the formatting of comments, remove some which don't make sense
anymore.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
[fix conflict with 96a608a4]
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

drivers/dma/amba-pl08x.c: In function 'pl08x_start_txd':
drivers/dma/amba-pl08x.c:205: warning: dereferencing 'void *' pointer

We never dereference llis_va aside from assigning it to a struct
pl08x_lli pointer or calculating the address of array element 0.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The PL08x driver holds on to the channel lock with interrupts disabled
between the prepare and the subsequent submit API functions.  This
means that the locking state when the prepare function returns is
dependent on whether it suceeeds or not.

It did this to ensure that the physical channel wasn't released, and
as it used to add the descriptor onto the pending list at prepare time
rather than submit time.

Now that we have reorganized the code to remove those reasons, we can
now safely release the spinlock at the end of preparation and reacquire
it in our submit function.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: NLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Introduce 'phychan_hold' to hold on to physical DMA channels while we're
preparing a new descriptor for it.  This will be incremented when we
allocate a physical channel and set the MUX registers during the
preparation of the TXD, and will only be decremented when the TXD is
submitted.

This prevents the physical channel being given up before the new TXD
is placed on the queue.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: NLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

This 'desc_list' is actually a list of pending descriptors, so name
it after its function (pending list) rather than what it contains
(descriptors).
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: NLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

We only need to store the dma address.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: NLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Platforms need to be able to control which AHB master interface is used,
as each AHB master interface may be asymetric.  Allow the interfaces
used for fetching LLIs, memory, and each peripheral to be configured
individually.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: NLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Rather than modifying platform data while preparing a transfer, copy
the cctl value into the txd structure and modify the value there.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: NLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The ccfg register is used to configure the channel parameters - the type
and direction of transfer, the flow control signal and IRQ mask enables.
The type and direction of transfer is known in the relevent prep_*
function where a txd is created.  The IRQ mask enables are always set,
and the flow control signals are always set when we start processing a
txd according to phychan->signal.

If we store the ccfg value in the txd structure, we can avoid modifying
platform data - and even having it in platform data at all.

So, remove it from platform data too.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: NLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

As we now have all the code accessing the phychan {csrc,cdst,clli,cctl,
ccfg} members in one function, there's no point storing the data into
the struct.  Get rid of the struct members.  Re-order the register dump
in the dev_dbg() to reflect the order we write the registers to the DMA
device.

The txd {csrc,cdst,clli,cctl} values are duplicates of the lli[0]
values, so there's no point duplicating these either.  Program the DMAC
registers directly from the lli[0] values.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: NLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Use size_t for variables denoting lengths throughout, and use the 'z'
qualifier for printing the value.  For safety, add a BUG_ON() in
pl08x_fill_lli_for_desc() to catch the remainder potentially becoming
negative.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: NLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Avoid using 'void *' struct fields when the structs are not defined
in linux/amba/pl08x.h - instead, forward declare the struct names, and
use these instead.  This ensures we have proper typechecking.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: NLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The last_issued variable uses an atomic type, which is only
incremented inside a protected region, and then read.  Everywhere else
only reads the value, so it isn't using atomic_t correctly, and it
doesn't even need to.  Moreover, the DMA engine code provides us with
a variable for this already - chan.cookie.  Use chan.cookie instead.

Also, avoid negative dma_cookie_t values - negative returns from
tx_submit() mean failure, yet in reality we always succeed.  Restart
from cookie 1, just like other DMA engine drivers do.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: NLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

This creates a DMAengine driver for the ARM PL080/PL081 PrimeCells
based on the implementation earlier submitted by Peter Pearse.
This is working like a charm for memcpy and slave DMA to the PL011
PrimeCell on the PB11MPCore.

This DMA controller is used in mostly unmodified form in the ARM
RealView and Versatile platforms, in the ST-Ericsson Nomadik, and
in the ST SPEAr platform.

It has been converted to use the header from the Samsung PL080
derivate instead of its own defintions. The Samsungs have a custom
driver in their mach-* folders though, atleast we can share the
register definitions.

Cc: Peter Pearse <peter.pearse@arm.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Alessandro Rubini <rubini@unipv.it>
Acked-by: NViresh Kumar <viresh.kumar@st.com>
Signed-off-by: NLinus Walleij <linus.walleij@stericsson.com>
[GFP_KERNEL to GFP_NOWAIT in pl08x_prep_dma_memcpy]
Signed-off-by: NDan Williams <dan.j.williams@intel.com>