The hardware automatically disables further interrupts after each event
until rearmed. This allows a delay to be injected between the occurence
of the interrupt and the running of the cleanup routine. The delay is
scaled by the descriptor backlog and then written to the INTRDELAY
register which specifies the number of microseconds to hold off
interrupt delivery after an interrupt event occurs. According to
powertop this reduces the interrupt rate from ~5000 intr/s to ~150
intr/s per without affecting throughput (simple dd to a raid6 array).
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Since ioat_cleanup_preamble() and the update of the last completed
descriptor are not synchronized there is a chance that two cleanup threads
can see descriptors to clean. If the first cleans up all pending
descriptors then the second will trigger the BUG_ON.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
We already disallow raid operations while DCA is globally enabled, so
having it locally enabled is a nop and confusing when reading the code.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Put the ioat2 and ioat3 state machines in the halted state with all
errors cleared.
The ioat1 init path is not disturbed for stability, there are no
reported ioat1 initiaization issues.
Cc: <stable@kernel.org>
Reported-by: Roland Dreier <rdreier@cisco.com>
Tested-by: Roland Dreier <rdreier@cisco.com>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
When continuing a pq calculation the driver needs 3 extra sources. The
driver can perform a 3 source calculation with a single descriptor, but
needs an extended descriptor to process up to 8 sources in one
operation. However, in the p-disabled case only one extra source is
needed. When continuing a p-disabled operation there are occasions
(i.e. 0 < src_cnt % 8 < 3) where the tail operation does not need an
extended descriptor. Properly account for this fact otherwise invalid
'dmacount' values will be written to hardware usually causing the
channel to halt with 'invalid descriptor' errors.
Cc: <stable@kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
The completion of a pq operation is notified with a null descriptor
appended to the end of the chain. This descriptor needs to be visible
to dma clients otherwise the client is precluded from ensuring all
operations are quiesced before freeing channel resources, i.e. due to
descriptor polling it may get the completion notification ahead of the
interrupt delivered by the null descriptor.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
ioat3.2 does not support asynchronous error notifications which makes
the driver experience latencies when non-zero pq validate results are
expected. Provide a mechanism for turning off async_xor_val and
async_syndrome_val via Kconfig. This approach is generally useful for
any driver that specifies ASYNC_TX_DISABLE_CHANNEL_SWITCH and would like
to force the async_tx api to fall back to the synchronous path for
certain operations.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
RAID operations cause a system hang on platforms with DCA
(Direct-Cache-Access) enabled. So turn off RAID capabilities in this
case.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
drivers/dma/ioat/dma_v3.c: In function 'ioat3_prep_memset_lock':
drivers/dma/ioat/dma_v3.c:439: warning: 'fill' may be used uninitialized in this function
drivers/dma/ioat/dma_v3.c:437: warning: 'desc' may be used uninitialized in this function
drivers/dma/ioat/dma_v3.c: In function '__ioat3_prep_xor_lock':
drivers/dma/ioat/dma_v3.c:489: warning: 'xor' may be used uninitialized in this function
drivers/dma/ioat/dma_v3.c:486: warning: 'desc' may be used uninitialized in this function
drivers/dma/ioat/dma_v3.c: In function '__ioat3_prep_pq_lock':
drivers/dma/ioat/dma_v3.c:631: warning: 'pq' may be used uninitialized in this function
drivers/dma/ioat/dma_v3.c:628: warning: 'desc' may be used uninitialized in this function
gcc-4.0, unlike gcc-4.3, does not see that these variables are
initialized before use. Convert the descriptor loops to do-while make
this initialization apparent.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
The cleanup routine for the raid cases imposes extra checks for handling
raid descriptors and extended descriptors. If the channel does not
support raid it can avoid this extra overhead by using the ioat2 cleanup
path.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
The async_tx api uses the DMA_INTERRUPT operation type to terminate a
chain of issued operations with a callback routine.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
If a platform advertises pq capabilities, but not xor, then use
ioat3_prep_pqxor and ioat3_prep_pqxor_val to simulate xor support.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
ioat3.2 adds support for raid6 syndrome generation (xor sum of galois
field multiplication products) using up to 8 sources. It can also
perform an pq-zero-sum operation to validate whether the syndrome for a
given set of sources matches a previously computed syndrome.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This adds a hardware specific self test to be called from ioat_probe.
In the ioat3 case we will have tests for all the different raid
operations, while ioat1 and ioat2 will continue to just test memcpy.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
ioat3.2 adds xor offload support for up to 8 sources. It can also
perform an xor-zero-sum operation to validate whether all given sources
sum to zero, without writing to a destination. Xor descriptors differ
from memcpy in that one operation may require multiple descriptors
depending on the number of sources. When the number of sources exceeds
5 an extended descriptor is needed. These descriptors need to be
accounted for when updating the DMA_COUNT register.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Tag completion writes for direct cache access to reduce the latency of
checking for descriptor completions.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Export driver attributes for diagnostic purposes:
'ring_size': total number of descriptors available to the engine
'ring_active': number of descriptors in-flight
'capabilities': supported operation types for this channel
'version': Intel(R) QuickData specfication revision
This also allows some chattiness to be removed from the driver startup
as this information is now available via sysfs.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Up until this point the driver for Intel(R) QuickData Technology
engines, specification versions 2 and 3, were mostly identical save for
a few quirks. Version 3.2 hardware adds many new capabilities (like
raid offload support) requiring some infrastructure that is not relevant
for v2. For better code organization of the new funcionality move v3
and v3.2 support to its own file dma_v3.c, and export some routines from
the base files (dma.c and dma_v2.c) that can be reused directly.
The first new capability included in this code reorganization is support
for v3.2 memset operations.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Dan Williams