If we fail to allocate the LLI, the prep_* function will return NULL.
However, the TXD we allocated will not be placed on any list, nor
will it be freed - we'll just drop all references to it.  Make sure
we free it rather than leaking TXDs.
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>

Tasklets are run from an interruptible context.  The slave DMA functions
can be called from within IRQ handlers.  Taking the spinlock without
disabling interrupts allows an interrupt handler to run, which may try
to take the spinlock again, resulting in deadlock.  Fix this by using
the irqsave spinlocks.
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>

If maxburst was passed in as zero, we would overflow the burst_sizes[]
array.  Fix this by checking for this condition, and defaulting to
single transfer 'bursts'.

Improve the readability of the loop using a for() loop rather than
a while() loop with the iterator initialized far from the loop.
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>

Correct mis-spellings in comments and printk strings.
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>