@@ -42,6 +42,7 @@ struct uart_8250_dma {
unsigned char tx_running:1;
unsigned char tx_err: 1;
+ unsigned char rx_running:1;
};
struct old_serial_port {
@@ -60,6 +60,7 @@ static void __dma_rx_do_complete(struct uart_8250_port *p, bool error)
dma_sync_single_for_cpu(dma->rxchan->device->dev, dma->rx_addr,
dma->rx_size, DMA_FROM_DEVICE);
+ dma->rx_running = 0;
dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state);
dmaengine_terminate_all(dma->rxchan);
@@ -162,21 +163,21 @@ int serial8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
{
struct uart_8250_dma *dma = p->dma;
struct dma_async_tx_descriptor *desc;
- struct dma_tx_state state;
- int dma_status;
-
- dma_status = dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state);
switch (iir & 0x3f) {
case UART_IIR_RLSI:
/* 8250_core handles errors and break interrupts */
+ if (dma->rx_running) {
+ dmaengine_pause(dma->rxchan);
+ __dma_rx_do_complete(p, true);
+ }
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_status == DMA_IN_PROGRESS) {
+ if (dma->rx_running) {
dmaengine_pause(dma->rxchan);
__dma_rx_do_complete(p, true);
}
@@ -185,7 +186,7 @@ int serial8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
break;
}
- if (dma_status)
+ if (dma->rx_running)
return 0;
desc = dmaengine_prep_slave_single(dma->rxchan, dma->rx_addr,
@@ -194,6 +195,7 @@ int serial8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
if (!desc)
return -EBUSY;
+ dma->rx_running = 1;
desc->callback = __dma_rx_complete;
desc->callback_param = p;
After dmaengine_terminate_all() has been invoked then both DMA drivers (edma and omap-dma) do not invoke dma_cookie_complete() to mark the transfer as complete. This dma_cookie_complete() is performed by the Synopsys DesignWare driver which is probably the only one that is used by omap8250-dma and hence don't see following problem… …which is that once a RX transfer has been terminated then following query of channel status reports DMA_IN_PROGRESS (again: the actual transfer has been canceled, there is nothing going on anymore). This means that serial8250_rx_dma() never enqueues another DMA transfer because it (wrongly) assumes that there is a transer already pending. Vinod Koul refuses to accept a patch which adds this dma_cookie_complete() to both drivers and so dmaengine_tx_status() would report DMA_COMPLETE instead (and behave like the Synopsys DesignWare driver already does). He argues that I am not allowed to use the cookie to query the status and that the driver already cleaned everything up after the invokation of dmaengine_terminate_all(). To end this I add a bookkeeping whether or not a RX-transfer has been started to the 8250-dma code. It has already been done for the TX side. *Now* we learn about the RX status based on our bookkeeping and don't need dmaengine_tx_status() for this anymore. Cc: vinod.koul@intel.com Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- drivers/tty/serial/8250/8250.h | 1 + drivers/tty/serial/8250/8250_dma.c | 14 ++++++++------ 2 files changed, 9 insertions(+), 6 deletions(-)