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path: root/drivers/dma/of-dma.c
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2013-06-12dma: of: Remove check on always true conditionLars-Peter Clausen
Both of_dma_nbcells field of the of_dma_controller and the args_count field of the dma_spec are initialized by parsing the #dma-cells attribute of their device tree node. So if the device tree nodes of a DMA controller and the dma_spec match this means that of_dma_nbcells and args_count will also match. So the second test in the of_dma_find_controller loop is redundant because given the first test yields true the second test will also yield true. So we can safely remove the test whether of_dma_nbcells matches args_count. Since this was the last user of the of_dma_nbcells field we can remove it altogether. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2013-06-12dma: of: Remove restriction that #dma-cells can't be 0Lars-Peter Clausen
There is no sensible reason why #dma-cells shouldn't be allowed to be 0. It is completely up to the DMA controller how many additional parameters, besides the phandle, it needs to identify a channel. E.g. for DMA controller with only one channel or for DMA controllers which don't have a restriction on which channel can be used for which peripheral it completely legitimate to not require any additional parameters. Also fixes the following warning: drivers/dma/of-dma.c: In function 'of_dma_controller_register': drivers/dma/of-dma.c:67:7: warning: 'nbcells' may be used uninitialized in this function Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2013-05-02dma:of: Use a mutex to protect the of_dma_listLars-Peter Clausen
Currently the OF DMA code uses a spin lock to protect the of_dma_list from concurrent access and a per controller reference count to protect the controller from being freed while a request operation is in progress. If of_dma_controller_free() is called for a controller who's reference count is not zero it will return -EBUSY and not remove the controller. This is fine up until here, but leaves the question what the caller of of_dma_controller_free() is supposed to do if the controller couldn't be freed. The only viable solution for the caller is to spin on of_dma_controller_free() until it returns success. E.g. do { ret = of_dma_controller_free(dev->of_node) } while (ret != -EBUSY); This is rather ugly and unnecessary and none of the current users of of_dma_controller_free() check it's return value anyway. Instead protect the list by a mutex. The mutex will be held as long as a request operation is in progress. So if of_dma_controller_free() is called while a request operation is in progress it will be put to sleep and only wake up once the request operation has finished. This means that it is no longer possible to register or unregister OF DMA controllers from a context where it's not possible to sleep. But I doubt that we'll ever need this. Also rename of_dma_get_controller back to of_dma_find_controller. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2013-05-02dma: of: Fix of_node reference leakLars-Peter Clausen
of_dma_request_slave_channel() currently does not drop the reference to the dma_spec of_node if no DMA controller matching the of_node could be found. This patch fixes it by always calling of_node_put(). Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Acked-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Jon Hunter <jon-hunter@ti.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2013-04-15dma: of: Remove unnecessary list_empty checkLars-Peter Clausen
list_for_each_entry is able to handle empty lists just fine, there is no need to make sure that the list is non empty. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2013-04-15DMA: OF: Check properties value before running be32_to_cpup() on itViresh Kumar
In of_dma_controller_register() routine we are calling of_get_property() as an parameter to be32_to_cpup(). In case the property doesn't exist we will get a crash. This patch changes this code to check if we got a valid property first and then runs be32_to_cpup() on it. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2013-04-15DMA: of: Constant namesMarkus Pargmann
No DMA of-function alters the name, so this patch changes the name arguments to be constant. Most drivers will probably request DMA channels using a constant name. Signed-off-by: Markus Pargmann <mpa@pengutronix.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2013-02-14dma: of-dma: protect list write operation by spin_lockAndy Shevchenko
It's possible to have an inconsistency in the list due to unprotected operation on it. The patch adds a proper locking on the list operation. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Rob Herring <rob.herring@calxeda.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2013-02-14dma: of-dma.c: fix memory leakageCong Ding
The memory allocated to ofdma might be a leakage when error occurs. Signed-off-by: Cong Ding <dinggnu@gmail.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2013-02-13dmaengine: move drivers/of/dma.c -> drivers/dma/of-dma.cVinod Koul
as requested by Rob Suggested-by: Rob Herring <rob.herring@calxeda.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>