dmaengine: dw: went back to plain {request,free}_irq() calls

The commit dbde5c29 "dw_dmac: use devm_* functions to simplify code" turns
probe function to use devm_* helpers and simultaneously brings a regression. We
need to ensure irq is disabled, followed by ensuring that don't schedule any
more tasklets and then its safe to use tasklet_kill().

The free_irq() will ensure that the irq is disabled and also wait till all
scheduled interrupts are executed by invoking synchronize_irq(). So we need to
only do tasklet_kill() after invoking free_irq().

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: stable@vger.kernel.org # v3.11+
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
index cfdbb92..7a74076 100644 (file)
--- a/drivers/dma/dw/core.c
+++ b/drivers/dma/dw/core.c
@@ -1548,11 +1548,6 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
        /* Disable BLOCK interrupts as well */
        channel_clear_bit(dw, MASK.BLOCK, dw->all_chan_mask);
 
-       err = devm_request_irq(chip->dev, chip->irq, dw_dma_interrupt,
-                              IRQF_SHARED, "dw_dmac", dw);
-       if (err)
-               return err;
-
        /* Create a pool of consistent memory blocks for hardware descriptors */
        dw->desc_pool = dmam_pool_create("dw_dmac_desc_pool", chip->dev,
                                         sizeof(struct dw_desc), 4, 0);
@@ -1563,6 +1558,11 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
 
        tasklet_init(&dw->tasklet, dw_dma_tasklet, (unsigned long)dw);
 
+       err = request_irq(chip->irq, dw_dma_interrupt, IRQF_SHARED,
+                         "dw_dmac", dw);
+       if (err)
+               return err;
+
        INIT_LIST_HEAD(&dw->dma.channels);
        for (i = 0; i < nr_channels; i++) {
                struct dw_dma_chan      *dwc = &dw->chan[i];
@@ -1667,6 +1667,7 @@ int dw_dma_remove(struct dw_dma_chip *chip)
        dw_dma_off(dw);
        dma_async_device_unregister(&dw->dma);
 
+       free_irq(chip->irq, dw);
        tasklet_kill(&dw->tasklet);
 
        list_for_each_entry_safe(dwc, _dwc, &dw->dma.channels,