[PATCH v5 06/11] serial: 8250_dma: adjust DMA address of the UART

Andy Shevchenko
2016-05-06T15:19:07Z

Some UARTs, e.g. one is used in Intel Quark, have a different address base for
DMA operations. Introduce an additional field (per RX and TX DMA channels) in
struct uart_8250_dma to cover those cases.

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
drivers/tty/serial/8250/8250.h | 5 +++++
drivers/tty/serial/8250/8250_dma.c | 8 ++++++--
2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
index 215a992..664232b 100644
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -31,6 +31,11 @@ struct uart_8250_dma {
struct dma_chan *rxchan;
struct dma_chan *txchan;

+ /* Device address base for DMA operations */
+ phys_addr_t rx_dma_addr;
+ phys_addr_t tx_dma_addr;
+
+ /* DMA address of the buffer in memory */
dma_addr_t rx_addr;
dma_addr_t tx_addr;

diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c
index 75c4b40..2db57b0 100644
--- a/drivers/tty/serial/8250/8250_dma.c
+++ b/drivers/tty/serial/8250/8250_dma.c
@@ -149,6 +149,10 @@ void serial8250_rx_dma_flush(struct uart_8250_port *p)
int serial8250_request_dma(struct uart_8250_port *p)
{
struct uart_8250_dma *dma = p->dma;
+ phys_addr_t rx_dma_addr = dma->rx_dma_addr ?
+ dma->rx_dma_addr : p->port.mapbase;
+ phys_addr_t tx_dma_addr = dma->tx_dma_addr ?
+ dma->tx_dma_addr : p->port.mapbase;
dma_cap_mask_t mask;
struct dma_slave_caps caps;
int ret;
@@ -156,11 +160,11 @@ int serial8250_request_dma(struct uart_8250_port *p)
/* Default slave configuration parameters */
dma->rxconf.direction = DMA_DEV_TO_MEM;
dma->rxconf.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
- dma->rxconf.src_addr = p->port.mapbase + UART_RX;
+ dma->rxconf.src_addr = rx_dma_addr + UART_RX;

dma->txconf.direction = DMA_MEM_TO_DEV;
dma->txconf.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
- dma->txconf.dst_addr = p->port.mapbase + UART_TX;
+ dma->txconf.dst_addr = tx_dma_addr + UART_TX;

dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE, mask);
--
2.8.1