linux-toradex.git/drivers/dma/amba-pl08x.c, branch v3.0.53 Linux kernel for Apalis and Colibri modules ARM: amba: make probe() functions take const id tables 2011-02-23T16:24:14+00:00 Russell King rmk+kernel@arm.linux.org.uk 2011-02-19T15:55:00+00:00 aa25afad2ca60d19457849ea75e9c31236f4e174 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> 
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>
DMA: PL08x: fix channel pausing to timeout rather than lockup 2011-01-31T06:03:47+00:00 Russell King - ARM Linux linux@arm.linux.org.uk 2011-01-27T12:37:44+00:00 8179661694595eb3a4f2ff9bb0b73acbb7d2f4a9 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> 
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>
DMA: PL08x: fix infinite wait when terminating transfers 2011-01-31T06:00:48+00:00 Russell King - ARM Linux linux@arm.linux.org.uk 2011-01-27T12:32:53+00:00 fb526210b2b961b5d590b89fd8f45c0ca5769688 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> 
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>
ARM: PL08x: cleanup comments 2011-01-17T00:55:43+00:00 Russell King - ARM Linux linux@arm.linux.org.uk 2011-01-16T20:18:05+00:00 94ae85220a07d357d4937086c490854f63344de4 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> 
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>
ARM: PL08x: prevent dma_set_runtime_config() reconfiguring memcpy channels 2011-01-05T03:16:14+00:00 Russell King - ARM Linux linux@arm.linux.org.uk 2011-01-03T22:46:17+00:00 b7f758659265c173380b792862aaad1c23c0e004 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> 
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>
ARM: PL08x: allow dma_set_runtime_config() to return errors 2011-01-05T03:16:14+00:00 Russell King - ARM Linux linux@arm.linux.org.uk 2011-01-03T22:45:57+00:00 f0fd944625b6e406dc273b8dffa16e0728c973e6 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> 
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>
ARM: PL08x: fix locking between prepare function and submit function 2011-01-05T03:16:14+00:00 Russell King - ARM Linux linux@arm.linux.org.uk 2011-01-03T22:45:37+00:00 c370e594efe2993620d24d41a78f325102e99d1c 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> 
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>
ARM: PL08x: introduce 'phychan_hold' to hold on to physical channels 2011-01-05T03:16:14+00:00 Russell King - ARM Linux linux@arm.linux.org.uk 2011-01-03T22:45:17+00:00 8087aacda040bdbf84940712d132ce80c30b9d5d 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> 
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>
ARM: PL08x: put txd's on the pending list in pl08x_tx_submit() 2011-01-05T03:16:14+00:00 Russell King - ARM Linux linux@arm.linux.org.uk 2011-01-03T22:44:57+00:00 501e67e82dee68d0a594ec0549f3d6a2943c91f5 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> 
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>
ARM: PL08x: rename 'desc_list' as 'pend_list' 2011-01-05T03:16:14+00:00 Russell King - ARM Linux linux@arm.linux.org.uk 2011-01-03T22:44:36+00:00 15c17232fbd1f7687c740c3c26f9e7f337bd9e36 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> 
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>