spi: rspi: Fix leaking of unused DMA descriptors
If dmaengine_prep_slave_sg() or dmaengine_submit() fail, we may leak unused DMA descriptors. As per Documentation/dmaengine.txt, once a DMA descriptor has been obtained, it must be submitted. Hence: - First prepare and submit all DMA descriptors, - Prepare the SPI controller for DMA, - Start DMA by calling dma_async_issue_pending(), - Make sure to call dmaengine_terminate_all() on all descriptors that haven't completed. Reported-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
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@ -472,25 +472,52 @@ static int rspi_dma_transfer(struct rspi_data *rspi, struct sg_table *tx,
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dma_cookie_t cookie;
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int ret;
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if (tx) {
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desc_tx = dmaengine_prep_slave_sg(rspi->master->dma_tx,
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tx->sgl, tx->nents, DMA_TO_DEVICE,
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DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
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if (!desc_tx)
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goto no_dma;
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irq_mask |= SPCR_SPTIE;
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}
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/* First prepare and submit the DMA request(s), as this may fail */
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if (rx) {
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desc_rx = dmaengine_prep_slave_sg(rspi->master->dma_rx,
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rx->sgl, rx->nents, DMA_FROM_DEVICE,
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DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
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if (!desc_rx)
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goto no_dma;
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if (!desc_rx) {
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ret = -EAGAIN;
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goto no_dma_rx;
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}
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desc_rx->callback = rspi_dma_complete;
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desc_rx->callback_param = rspi;
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cookie = dmaengine_submit(desc_rx);
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if (dma_submit_error(cookie)) {
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ret = cookie;
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goto no_dma_rx;
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}
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irq_mask |= SPCR_SPRIE;
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}
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if (tx) {
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desc_tx = dmaengine_prep_slave_sg(rspi->master->dma_tx,
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tx->sgl, tx->nents, DMA_TO_DEVICE,
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DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
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if (!desc_tx) {
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ret = -EAGAIN;
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goto no_dma_tx;
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}
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if (rx) {
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/* No callback */
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desc_tx->callback = NULL;
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} else {
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desc_tx->callback = rspi_dma_complete;
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desc_tx->callback_param = rspi;
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}
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cookie = dmaengine_submit(desc_tx);
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if (dma_submit_error(cookie)) {
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ret = cookie;
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goto no_dma_tx;
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}
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irq_mask |= SPCR_SPTIE;
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}
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/*
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* DMAC needs SPxIE, but if SPxIE is set, the IRQ routine will be
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* called. So, this driver disables the IRQ while DMA transfer.
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@ -503,34 +530,24 @@ static int rspi_dma_transfer(struct rspi_data *rspi, struct sg_table *tx,
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rspi_enable_irq(rspi, irq_mask);
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rspi->dma_callbacked = 0;
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if (rx) {
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desc_rx->callback = rspi_dma_complete;
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desc_rx->callback_param = rspi;
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cookie = dmaengine_submit(desc_rx);
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if (dma_submit_error(cookie))
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return cookie;
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/* Now start DMA */
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if (rx)
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dma_async_issue_pending(rspi->master->dma_rx);
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}
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if (tx) {
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if (rx) {
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/* No callback */
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desc_tx->callback = NULL;
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} else {
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desc_tx->callback = rspi_dma_complete;
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desc_tx->callback_param = rspi;
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}
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cookie = dmaengine_submit(desc_tx);
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if (dma_submit_error(cookie))
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return cookie;
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if (tx)
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dma_async_issue_pending(rspi->master->dma_tx);
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}
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ret = wait_event_interruptible_timeout(rspi->wait,
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rspi->dma_callbacked, HZ);
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if (ret > 0 && rspi->dma_callbacked)
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ret = 0;
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else if (!ret)
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else if (!ret) {
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dev_err(&rspi->master->dev, "DMA timeout\n");
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ret = -ETIMEDOUT;
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if (tx)
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dmaengine_terminate_all(rspi->master->dma_tx);
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if (rx)
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dmaengine_terminate_all(rspi->master->dma_rx);
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}
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rspi_disable_irq(rspi, irq_mask);
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@ -541,11 +558,16 @@ static int rspi_dma_transfer(struct rspi_data *rspi, struct sg_table *tx,
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return ret;
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no_dma:
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pr_warn_once("%s %s: DMA not available, falling back to PIO\n",
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dev_driver_string(&rspi->master->dev),
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dev_name(&rspi->master->dev));
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return -EAGAIN;
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no_dma_tx:
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if (rx)
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dmaengine_terminate_all(rspi->master->dma_rx);
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no_dma_rx:
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if (ret == -EAGAIN) {
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pr_warn_once("%s %s: DMA not available, falling back to PIO\n",
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dev_driver_string(&rspi->master->dev),
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dev_name(&rspi->master->dev));
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}
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return ret;
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}
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static void rspi_receive_init(const struct rspi_data *rspi)
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