Commit Graph

53 Commits

Author SHA1 Message Date
Russell King aa25afad2c ARM: amba: make probe() functions take const id tables
Make Primecell driver probe functions take a const pointer to their
ID tables.  Drivers should never modify their ID tables in their
probe handler.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2011-02-23 16:24:14 +00:00
Russell King - ARM Linux 8179661694 DMA: PL08x: fix channel pausing to timeout rather than lockup
If a transfer is initiated from memory to a peripheral, then data is
fetched and the channel is marked busy.  This busy status persists until
the HALT bit is set and the queued data has been transfered to the
peripheral.  Waiting indefinitely after setting the HALT bit results in
system lockups.  Timeout this operation, and print an error when this
happens.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-30 22:03:47 -08:00
Russell King - ARM Linux fb526210b2 DMA: PL08x: fix infinite wait when terminating transfers
If we try to pause a channel when terminating a transfer, we could end
up spinning for it to become inactive indefinitely, and can result in
an uninterruptible wait requiring a reset to recover from.

Terminating a transfer is supposed to take effect immediately, but may
result in data loss.

To make this clear, rename the function to pl08x_terminate_phy_chan().
Also, make sure it is always consistently called - with the spinlock
held and IRQs disabled, and ensure that the TC and ERR interrupt status
is always cleared.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-30 22:00:48 -08:00
Russell King - ARM Linux 94ae85220a ARM: PL08x: cleanup comments
Cleanup the formatting of comments, remove some which don't make sense
anymore.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
[fix conflict with 96a608a4]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-16 16:55:43 -08:00
Russell King - ARM Linux b7f7586592 ARM: PL08x: prevent dma_set_runtime_config() reconfiguring memcpy channels
Prevent dma_set_runtime_config() being used to alter the configuration
supplied by the platform for memcpy channel configuration.  No one
should be trying to change this configuration.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:14 -08:00
Russell King - ARM Linux f0fd944625 ARM: PL08x: allow dma_set_runtime_config() to return errors
There are cases in dma_set_runtime_config() where we fail to perform
the requested action - and we just issue a KERN_ERR message in that
case.  We have the facility to return an error to the caller, so that
is what we should do.

When we encounter an error due to invalid parameters, we should not
modify driver state.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:14 -08:00
Russell King - ARM Linux c370e594ef ARM: PL08x: fix locking between prepare function and submit function
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: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:14 -08:00
Russell King - ARM Linux 8087aacda0 ARM: PL08x: introduce 'phychan_hold' to hold on to physical channels
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: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:14 -08:00
Russell King - ARM Linux 501e67e82d ARM: PL08x: put txd's on the pending list in pl08x_tx_submit()
Don't place TXDs on the pending list when they're prepared - place
them on the list when they're ready to be submitted.  Also, only
place memcpy requests in the wait state when they're submitted and
don't have a physical channel associated.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:14 -08:00
Russell King - ARM Linux 15c17232fb ARM: PL08x: rename 'desc_list' as 'pend_list'
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: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:14 -08:00
Russell King - ARM Linux 3d992e1a6f ARM: PL08x: implement unmapping of memcpy buffers
The DMA engine API requires DMA engine implementations to unmap buffers
passed into the non-slave DMA methods unless the relevant completion
flag is set.  We aren't doing this, so implement this facility.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:14 -08:00
Russell King - ARM Linux c04287948e ARM: PL08x: store prep_* flags in async_tx structure
Like other DMA engine drivers do, store the passed flags into the
async_tx structure, so they can be checked when the operation
completes.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:13 -08:00
Russell King - ARM Linux d7244e9a27 ARM: PL08x: shrink srcbus/dstbus in txd structure
We only need to store the dma address.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:13 -08:00
Russell King - ARM Linux 542361f8e3 ARM: PL08x: don't manipulate txd->srcbus or txd->dstbus during LLI fill
Don't alter any txd->srcbus or txd->dstbus values while building the
LLI list.  This allows us to see the original dma_addr_t values passed
in via the prep_memcpy() method.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:13 -08:00
Russell King - ARM Linux 5f638b4f31 ARM: PL08x: fix fill_bytes calculation
The number of bytes we want to fill into any LLI is the minimum of:
- number of bytes remaining in the transfer
- number of bytes we can transfer in a single LLI
- number of bytes we can transfer without overflowing the source boundary
- number of bytes we can transfer without overflowing the destination boundary

The minimum of the first two is already calculated (target_len).  We
limit the boundary calculations to this number of bytes, which will
then give us the number of bytes we can place into this LLI.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:13 -08:00
Russell King - ARM Linux d6cf7b597f ARM: PL08x: use min() to calculate target_len
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:13 -08:00
Russell King - ARM Linux b61be8d728 ARM: PL08x: ensure pl08x_pre_boundary() works for any value of addr
pl08x_pre_boundary() was unsafe with addresses towards the top of
memory space:

	boundary = ((addr >> PL08X_BOUNDARY_SHIFT) + 1)
			<< PL08X_BOUNDARY_SHIFT;

This can overflow a 32-bit number, producing zero.  When it does:

	if (boundary < addr + len)
		return boundary - addr;
	else
		return len;

results in (boundary - addr) returning either a large positive value.
Also if addr + len overflows, this calculation also fails.

We can fix this trivially as the only thing we're actually interested
in is the value of the least significant PL08X_BOUNDARY_SHIFT bits:

	boundary_len = PL08X_BOUNDARY_SIZE -
		(addr & (PL08X_BOUNDARY_SIZE - 1));

gives us the number of bytes before 'addr' becomes a multiple of
PL08X_BOUNDARY_SIZE.  We can then just take the min() of the two
calculated lengths.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:13 -08:00
Russell King - ARM Linux 0059005f2c ARM: PL08x: make pl08x_fill_lli_for_desc() return void
We don't need pl08x_fill_lli_for_desc() to return num_llis + 1 as
we know that's what it always does.  We can just pass in num_llis
and use post-increment in the caller.

This makes the code slightly easier to read.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:13 -08:00
Russell King - ARM Linux 858c21c0f3 ARM: PL08x: move callback outside spinlock'd region
Calling the callback handler with spinlocks in the tasklet held leads
to deadlock when dmaengine functions are called:

BUG: spinlock lockup on CPU#0, sh/417, c1870a08
Backtrace:
...
[<c017b408>] (do_raw_spin_lock+0x0/0x154) from [<c02c4b98>] (_raw_spin_lock_irqsave+0x54/0x60)
[<c02c4b44>] (_raw_spin_lock_irqsave+0x0/0x60) from [<c01f5828>] (pl08x_prep_channel_resources+0x718/0x8b4)
[<c01f5110>] (pl08x_prep_channel_resources+0x0/0x8b4) from [<c01f5bb4>] (pl08x_prep_slave_sg+0x120/0x19c)
[<c01f5a94>] (pl08x_prep_slave_sg+0x0/0x19c) from [<c01be7a0>] (pl011_dma_tx_refill+0x164/0x224)
[<c01be63c>] (pl011_dma_tx_refill+0x0/0x224) from [<c01bf1c8>] (pl011_dma_tx_callback+0x7c/0xc4)
[<c01bf14c>] (pl011_dma_tx_callback+0x0/0xc4) from [<c01f4d34>] (pl08x_tasklet+0x60/0x368)
[<c01f4cd4>] (pl08x_tasklet+0x0/0x368) from [<c004d978>] (tasklet_action+0xa0/0x100)

Dan quoted the documentation:
> 2/ Completion callback routines cannot submit new operations.  This
>    results in recursion in the synchronous case and spin_locks being
>    acquired twice in the asynchronous case.

but then followed up to say:
> I should clarify, this is the async_memcpy() api requirement which is
> not used outside of md/raid5.  DMA drivers can and do allow new
> submissions from callbacks, and the ones that do so properly move the
> callback outside of the driver lock.

So let's fix it by moving the callback out of the spinlocked region.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:13 -08:00
Russell King - ARM Linux 30749cb4a4 ARM: PL08x: allow AHB master port selection to be configured
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: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:13 -08:00
Russell King - ARM Linux c7da9a56d6 ARM: PL08x: move AHB master port selection into prep_* functions
As we initialize the default cctl value in the prep_* functions along
with the increment settings, we don't need to repeat the selection of
the AHB ports each time we create a LLI entry.  Do this in the prep_*
functions once per transfer.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:13 -08:00
Russell King - ARM Linux 1cae78f120 ARM: PL08x: move cctl increment and protection setup to prep_slave_sg
We don't need to initialize the cctl increment and protection values
in the runtime_config method - we have all the inforamtion to setup
these values in prep_slave_sg().  Move their initialization there.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:13 -08:00
Russell King - ARM Linux 70b5ed6b6d ARM: PL08x: move default cctl into txd structure
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: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:12 -08:00
Russell King - ARM Linux 09b3c32333 ARM: PL08x: assign ccfg DMA request signal in prep_phy_channel()
There is no need to wait until we start processing a tx descriptor
before setting up the DMA request selection in the ccfg register.
We know which channel and request will be used in prep_phy_channel(),
so setup the ccfg request selection at txd creation time in
prep_phy_channel().

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:12 -08:00
Russell King - ARM Linux 4983a04fd2 ARM: PL08x: move ccfg into txd structure
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: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:12 -08:00
Russell King - ARM Linux 19524d77ec ARM: PL08x: avoid duplicating registers in txd and phychan structures
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: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:12 -08:00
Russell King - ARM Linux c885bee4f1 ARM: PL08x: combine functions to start DMA into one function
There is no need for pl08x_config_phychan_for_txd(), pl08x_set_cregs()
and pl08x_enable_phy_chan() to be separate - they are always called in
sequence.  Combine them into one function.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:12 -08:00
Russell King - ARM Linux db9f136a60 ARM: PL08x: clean up LLI lookup
As the LLI list is an array, we can use maths to locate which LLI
index we're currently at, and then sum up the remaining LLI entries
until we reach the end of the list.

This makes the code much easier to read, and much less susceptible
to falling off the end of the array.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:12 -08:00
Russell King - ARM Linux bfddfb4505 ARM: PL08x: rename lli.next to lli.lli
The LLI pointer in the documentation is placed into the LLI register,
so name it LLI rather than 'next'.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:12 -08:00
Russell King - ARM Linux e25761d72c ARM: PL08x: use 'u32' for LLI structure members, not dma_addr_t
Use 'u32' for the LLI structure members, which are defined by hardware
to be 32-bit.  dma_addr_t is much more vague about its actual size.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:12 -08:00
Russell King - ARM Linux cace658572 ARM: PL08x: use 'size_t' for lengths
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: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:12 -08:00
Russell King - ARM Linux 56b618820c ARM: PL08x: don't try to use llis_bus as a pointer
llis_bus is the DMA address of the LLI array.  Casting it to be a
pointer just to be able to use pointer arithmetic on it is not nice.
We can trivially deal with the places where we do arithmetic on it,
and it's actually cleaner this way.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:12 -08:00
Russell King - ARM Linux 4c0df6a3ce ARM: PL08x: don't assume that the LLI pointer has the bus bit clear
We only want use the address of the LLI pointer when locating the
corresponding structure in memory, so clear the master bus selection
bit.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:11 -08:00
Russell King - ARM Linux 19386b3234 ARM: PL08x: ensure loops use cpu_relax()
Tight loops should use cpu_relax() to allow CPUs to reduce power
consumption while waiting for events.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:11 -08:00
Russell King - ARM Linux 8c8cc2b104 ARM: PL08x: consolidate physical channel release code
Consolidate duplicated channel release code into release_phy_channel()

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:11 -08:00
Russell King - ARM Linux ac3cd20df9 ARM: PL08x: consolidate common txd initialization
Consolidate code which allocates and initializes txds.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:11 -08:00
Russell King - ARM Linux 7cb72ad959 ARM: PL08x: avoid 'void *' struct fields when we can type them properly
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: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:11 -08:00
Russell King - ARM Linux f96ca9ec27 ARM: PL08x: constify vendor data pointers
We should never modify the vendor data structure so make it const.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:11 -08:00
Russell King - ARM Linux b58b6b5bed ARM: PL08x: remove circular buffer support
The driver already won't initialize a channel with a circular buffer;
the check in pl08x_prep_channel_resources() sees to that.  Remove
circular buffer support for the time being.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:11 -08:00
Russell King - ARM Linux ad0a3ad33c ARM: PL08x: remove unnecessary NULL and BUG checks
The tasklet always is initialized with a non-NULL data argument.  It
is not possible for it to be called with a NULL data argument (unless
something is very wrong in the tasklet code - in which case lots of
stuff will break).  Therefore, as plchan can never be NULL, remove
this unnecessary BUG check.

In pl08x_tasklet(), we've already dereferenced plchan->at, so it can't
be NULL here.  Remove this unnecessary BUG check.

pl08x_fill_llis_for_desc() and pl08x_free_txd() are always called with
a non-NULL txd argument - either as a consequence of the code paths or
as a result of other checks already in place.  We don't need to repeat
the non-NULL check in these functions.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:11 -08:00
Russell King - ARM Linux 730404ac1c ARM: PL08x: remove unnecessary includes
We don't need to include linux/pci.h as we aren't a PCI driver.  We
aren't doing any processor specific functions, so asm/processor.h is
not required.  asm/cacheflush.h shouldn't be used, we have the DMA API
for this.  DMA interfaces aren't required as we're only implementing
the dmaengine API and not a platform-private DMA API.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:11 -08:00
Russell King - ARM Linux 9c13299268 ARM: PL08x: prefix hex numbers with 0x
A driver which emits both decimal and hex numbers in its printk
creates confusion as to what is what.  Prefix hex numbers with 0x.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:11 -08:00
Russell King - ARM Linux b05cd8f4c0 ARM: PL08x: improve the announcement printk
Include the revision number of the PL08x primecell in the boot-time
printk to allow proper identification of the peripheral.  Reformat
the announcement printk format reflect what we do for other primecell
drivers - generally "PLXXX revX at 0xNNNNNNNN irq X".

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:11 -08:00
Russell King - ARM Linux 9dc2c200a0 ARM: PL08x: add comment explaining the flow control methods
Explain the two flow control methods which the PL08x implements, along
with the problem which peripheral flow control presents.  This helps
people understand why we are unable to use these DMA controllers with
(eg) the MMCI.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:10 -08:00
Russell King - ARM Linux 3e2a037c1d ARM: PL08x: fix sparse warnings
drivers/dma/amba-pl08x.c:1895:40: warning: Unknown escape '%'
drivers/dma/amba-pl08x.c:1903:40: warning: Unknown escape '%'
drivers/dma/amba-pl08x.c:513:6: warning: symbol 'pl08x_choose_master_bus' was not declared. Should it be static?
drivers/dma/amba-pl08x.c:604:5: warning: symbol 'pl08x_fill_llis_for_desc' was not declared. Should it be static?
drivers/dma/amba-pl08x.c:1442:32: warning: symbol 'pl08x_prep_slave_sg' was not declared. Should it be static?

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:10 -08:00
Russell King - ARM Linux 98838f90d9 ARM: PL08x: fix deadlock in terminate_all
Trying to disable a tasklet while holding a spinlock which the tasklet
will take is a recipe for deadlock - tasklet_disable() will wait for the
tasklet to finish running, which it will never do.  In any case, there
is not a corresponding tasklet_enable(), so once the tasklet is disabled,
it will never run again until reboot.

It's safe to just remove the tasklet_disable() as we remove all current
and pending descriptors before releasing this spinlock.  This means that
the tasklet will find no remaining work if it subsequently runs.

The only remaining issue is that the callback for an already submitted
txd may be in progress, or even called after terminate_all() returns.
There's not much that can be done about that as waiting for the callback
to complete before returning will also lead to deadlocks.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:10 -08:00
Russell King - ARM Linux 9c0bb43bbd ARM: PL08x: fix missed spin-unlock in pl08x_issue_pending()
pl08x_issue_pending() returns with the spinlock locked and interrupts
disabled if the channel is waiting for a physical DMA to become free.
This is wrong - especially as pl08x_issue_pending() is an API function
as it leads to deadlocks.  Fix it to always return with the spinlock
unlocked.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:10 -08:00
Russell King - ARM Linux dafa73171b ARM: PL08x: fix a leak when preparing TXDs
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: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:10 -08:00
Russell King - ARM Linux bf072af461 ARM: PL08x: fix locking in tasklet
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: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:10 -08:00
Russell King - ARM Linux 91aa5fadb8 ARM: PL08x: fix atomic_t usage and tx_submit() return value range
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: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-01-04 19:16:10 -08:00