• R
    dmaengine: pxa_dma: implement device_synchronize · 7d604663
    Robert Jarzmik 提交于
    Implement the function which wait until a dma channel is stopped to have
    a synchronization point.
    
    This also protects the pxad_remove() from races, such as spurious
    interrupts while removing the driver, because :
     - as long as there is one dma channel requested, ie. dma_chan_get() but
       no dma_chan_put(), the try_module_get() of dma_chan_get() prevents
       the remove() routine from running
     - when the last channel is released, ie. the last dma_chan_put() is
       called, if there is a running DMA, pxad_synchronize() is called
     - pxad_synchronize() waits for the channel to stop, which in turn
       ensures on pxa architecture that the interrupt cannot be fired anymore
    Reported-by: NVinod Koul <vinod.koul@intel.com>
    Signed-off-by: NRobert Jarzmik <robert.jarzmik@free.fr>
    Signed-off-by: NVinod Koul <vinod.koul@intel.com>
    7d604663
pxa_dma.c 41.3 KB