diff options
author | Geert Uytterhoeven <geert+renesas@glider.be> | 2014-08-06 12:59:03 (GMT) |
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committer | Mark Brown <broonie@linaro.org> | 2014-08-16 22:13:14 (GMT) |
commit | 3e81b59208fa4697c6c3b6eefb92892b47f8b1e7 (patch) | |
tree | 9553dd8862a015ff91b0d26e24bc3be042552b9b /drivers/spi/spi-sh-msiof.c | |
parent | 7d1311b93e58ed55f3a31cc8f94c4b8fe988a2b9 (diff) | |
download | linux-3e81b59208fa4697c6c3b6eefb92892b47f8b1e7.tar.xz |
spi: sh-msiof: 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>
Diffstat (limited to 'drivers/spi/spi-sh-msiof.c')
-rw-r--r-- | drivers/spi/spi-sh-msiof.c | 71 |
1 files changed, 38 insertions, 33 deletions
diff --git a/drivers/spi/spi-sh-msiof.c b/drivers/spi/spi-sh-msiof.c index 2a4354d..887c208 100644 --- a/drivers/spi/spi-sh-msiof.c +++ b/drivers/spi/spi-sh-msiof.c @@ -636,48 +636,38 @@ static int sh_msiof_dma_once(struct sh_msiof_spi_priv *p, const void *tx, dma_cookie_t cookie; int ret; - if (tx) { - ier_bits |= IER_TDREQE | IER_TDMAE; - dma_sync_single_for_device(p->master->dma_tx->device->dev, - p->tx_dma_addr, len, DMA_TO_DEVICE); - desc_tx = dmaengine_prep_slave_single(p->master->dma_tx, - p->tx_dma_addr, len, DMA_TO_DEVICE, - DMA_PREP_INTERRUPT | DMA_CTRL_ACK); - if (!desc_tx) - return -EAGAIN; - } - + /* First prepare and submit the DMA request(s), as this may fail */ if (rx) { ier_bits |= IER_RDREQE | IER_RDMAE; desc_rx = dmaengine_prep_slave_single(p->master->dma_rx, p->rx_dma_addr, len, DMA_FROM_DEVICE, DMA_PREP_INTERRUPT | DMA_CTRL_ACK); - if (!desc_rx) - return -EAGAIN; - } - - /* 1 stage FIFO watermarks for DMA */ - sh_msiof_write(p, FCTR, FCTR_TFWM_1 | FCTR_RFWM_1); - - /* setup msiof transfer mode registers (32-bit words) */ - sh_msiof_spi_set_mode_regs(p, tx, rx, 32, len / 4); - - sh_msiof_write(p, IER, ier_bits); - - reinit_completion(&p->done); + if (!desc_rx) { + ret = -EAGAIN; + goto no_dma_rx; + } - if (rx) { desc_rx->callback = sh_msiof_dma_complete; desc_rx->callback_param = p; cookie = dmaengine_submit(desc_rx); if (dma_submit_error(cookie)) { ret = cookie; - goto stop_ier; + goto no_dma_rx; } - dma_async_issue_pending(p->master->dma_rx); } if (tx) { + ier_bits |= IER_TDREQE | IER_TDMAE; + dma_sync_single_for_device(p->master->dma_tx->device->dev, + p->tx_dma_addr, len, DMA_TO_DEVICE); + desc_tx = dmaengine_prep_slave_single(p->master->dma_tx, + p->tx_dma_addr, len, DMA_TO_DEVICE, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc_tx) { + ret = -EAGAIN; + goto no_dma_tx; + } + if (rx) { /* No callback */ desc_tx->callback = NULL; @@ -688,15 +678,30 @@ static int sh_msiof_dma_once(struct sh_msiof_spi_priv *p, const void *tx, cookie = dmaengine_submit(desc_tx); if (dma_submit_error(cookie)) { ret = cookie; - goto stop_rx; + goto no_dma_tx; } - dma_async_issue_pending(p->master->dma_tx); } + /* 1 stage FIFO watermarks for DMA */ + sh_msiof_write(p, FCTR, FCTR_TFWM_1 | FCTR_RFWM_1); + + /* setup msiof transfer mode registers (32-bit words) */ + sh_msiof_spi_set_mode_regs(p, tx, rx, 32, len / 4); + + sh_msiof_write(p, IER, ier_bits); + + reinit_completion(&p->done); + + /* Now start DMA */ + if (tx) + dma_async_issue_pending(p->master->dma_rx); + if (rx) + dma_async_issue_pending(p->master->dma_tx); + ret = sh_msiof_spi_start(p, rx); if (ret) { dev_err(&p->pdev->dev, "failed to start hardware\n"); - goto stop_tx; + goto stop_dma; } /* wait for tx fifo to be emptied / rx fifo to be filled */ @@ -726,14 +731,14 @@ static int sh_msiof_dma_once(struct sh_msiof_spi_priv *p, const void *tx, stop_reset: sh_msiof_reset_str(p); sh_msiof_spi_stop(p, rx); -stop_tx: +stop_dma: if (tx) dmaengine_terminate_all(p->master->dma_tx); -stop_rx: +no_dma_tx: if (rx) dmaengine_terminate_all(p->master->dma_rx); -stop_ier: sh_msiof_write(p, IER, 0); +no_dma_rx: return ret; } |