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path: root/drivers/tty/serial/8250/8250_dma.c
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Diffstat (limited to 'drivers/tty/serial/8250/8250_dma.c')
-rw-r--r--drivers/tty/serial/8250/8250_dma.c68
1 files changed, 42 insertions, 26 deletions
diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c
index 78259d3..7f33d1c 100644
--- a/drivers/tty/serial/8250/8250_dma.c
+++ b/drivers/tty/serial/8250/8250_dma.c
@@ -110,30 +110,11 @@ err:
return ret;
}
-int serial8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
+int serial8250_rx_dma(struct uart_8250_port *p)
{
struct uart_8250_dma *dma = p->dma;
struct dma_async_tx_descriptor *desc;
- switch (iir & 0x3f) {
- case UART_IIR_RLSI:
- /* 8250_core handles errors and break interrupts */
- return -EIO;
- case UART_IIR_RX_TIMEOUT:
- /*
- * If RCVR FIFO trigger level was not reached, complete the
- * transfer and let 8250_core copy the remaining data.
- */
- if (dma->rx_running) {
- dmaengine_pause(dma->rxchan);
- __dma_rx_complete(p);
- dmaengine_terminate_all(dma->rxchan);
- }
- return -ETIMEDOUT;
- default:
- break;
- }
-
if (dma->rx_running)
return 0;
@@ -154,10 +135,23 @@ int serial8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
return 0;
}
+void serial8250_rx_dma_flush(struct uart_8250_port *p)
+{
+ struct uart_8250_dma *dma = p->dma;
+
+ if (dma->rx_running) {
+ dmaengine_pause(dma->rxchan);
+ __dma_rx_complete(p);
+ dmaengine_terminate_all(dma->rxchan);
+ }
+}
+
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 +172,16 @@ 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 +189,17 @@ 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;
+ }
+
+ /* 8250 tx dma requires dmaengine driver to support terminate */
+ ret = dma_get_slave_caps(dma->txchan, &caps);
+ if (ret)
+ goto err;
+ if (!caps.cmd_terminate) {
+ ret = -EINVAL;
+ goto err;
}
dmaengine_slave_config(dma->txchan, &dma->txconf);
@@ -197,8 +210,10 @@ 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 +223,7 @@ 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 +231,10 @@ 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);
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