serial: 8250_dma: adjust DMA address of the UART

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>
Tested-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
index 122e0e4..c807b73 100644 (file)
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -33,6 +33,11 @@ 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 896e8f4..fdbddbc 100644 (file)
--- a/drivers/tty/serial/8250/8250_dma.c
+++ b/drivers/tty/serial/8250/8250_dma.c
@@ -150,6 +150,10 @@ EXPORT_SYMBOL_GPL(serial8250_rx_dma_flush);
 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;
@@ -157,11 +161,11 @@ 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);