diff options
| author | Peter Hurley <peter@hurleysoftware.com> | 2016-04-10 07:14:32 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-04-30 18:26:55 +0200 |
| commit | ec5a11a91eecd81ef19b8044a243b4ea56c809e6 (patch) | |
| tree | 9ddec17e4d8de766912e58be04561eec2d15ee16 /drivers/tty/serial | |
| parent | serial: tegra: Remove unused variable (diff) | |
| download | linux-ec5a11a91eecd81ef19b8044a243b4ea56c809e6.tar.xz linux-ec5a11a91eecd81ef19b8044a243b4ea56c809e6.zip | |
serial: 8250: Validate dmaengine rx chan meets requirements
8250 dma support requires the dmaengine driver support error-free
pause/terminate and better-than-descriptor residue granularity. Query
slave caps to determine if necessary commands/properties are supported;
disable dma if not.
Note this means dmaengine driver must support slave caps reporting
as well.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial')
| -rw-r--r-- | drivers/tty/serial/8250/8250_dma.c | 27 |
1 files changed, 21 insertions, 6 deletions
diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index 78259d3c6a55..cf7a2e3288a6 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -158,6 +158,8 @@ int serial8250_request_dma(struct uart_8250_port *p) { struct uart_8250_dma *dma = p->dma; dma_cap_mask_t mask; + struct dma_slave_caps caps; + int ret; /* Default slave configuration parameters */ dma->rxconf.direction = DMA_DEV_TO_MEM; @@ -178,6 +180,16 @@ int serial8250_request_dma(struct uart_8250_port *p) if (!dma->rxchan) return -ENODEV; + /* 8250 rx dma requires dmaengine driver to support pause/terminate */ + ret = dma_get_slave_caps(dma->rxchan, &caps); + if (ret) + goto release_rx; + if (!caps.cmd_pause || !caps.cmd_terminate || + caps.residue_granularity == DMA_RESIDUE_GRANULARITY_DESCRIPTOR) { + ret = -EINVAL; + goto release_rx; + } + dmaengine_slave_config(dma->rxchan, &dma->rxconf); /* Get a channel for TX */ @@ -185,8 +197,8 @@ int serial8250_request_dma(struct uart_8250_port *p) dma->fn, dma->tx_param, p->port.dev, "tx"); if (!dma->txchan) { - dma_release_channel(dma->rxchan); - return -ENODEV; + ret = -ENODEV; + goto release_rx; } dmaengine_slave_config(dma->txchan, &dma->txconf); @@ -197,8 +209,10 @@ int serial8250_request_dma(struct uart_8250_port *p) dma->rx_buf = dma_alloc_coherent(dma->rxchan->device->dev, dma->rx_size, &dma->rx_addr, GFP_KERNEL); - if (!dma->rx_buf) + if (!dma->rx_buf) { + ret = -ENOMEM; goto err; + } /* TX buffer */ dma->tx_addr = dma_map_single(dma->txchan->device->dev, @@ -208,6 +222,7 @@ int serial8250_request_dma(struct uart_8250_port *p) if (dma_mapping_error(dma->txchan->device->dev, dma->tx_addr)) { dma_free_coherent(dma->rxchan->device->dev, dma->rx_size, dma->rx_buf, dma->rx_addr); + ret = -ENOMEM; goto err; } @@ -215,10 +230,10 @@ int serial8250_request_dma(struct uart_8250_port *p) return 0; err: - dma_release_channel(dma->rxchan); dma_release_channel(dma->txchan); - - return -ENOMEM; +release_rx: + dma_release_channel(dma->rxchan); + return ret; } EXPORT_SYMBOL_GPL(serial8250_request_dma); |