diff options
| -rw-r--r-- | drivers/tty/serial/samsung.c | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c index 7196a3e586cf..825c8192b944 100644 --- a/drivers/tty/serial/samsung.c +++ b/drivers/tty/serial/samsung.c @@ -28,6 +28,9 @@ #define SUPPORT_SYSRQ #endif +#include <linux/dmaengine.h> +#include <linux/dma-mapping.h> +#include <linux/slab.h> #include <linux/module.h> #include <linux/ioport.h> #include <linux/io.h> @@ -453,6 +456,93 @@ static void s3c24xx_serial_break_ctl(struct uart_port *port, int break_state) spin_unlock_irqrestore(&port->lock, flags); } +static int s3c24xx_serial_request_dma(struct s3c24xx_uart_port *p) +{ + struct s3c24xx_uart_dma *dma = p->dma; + dma_cap_mask_t mask; + unsigned long flags; + + /* Default slave configuration parameters */ + dma->rx_conf.direction = DMA_DEV_TO_MEM; + dma->rx_conf.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; + dma->rx_conf.src_addr = p->port.mapbase + S3C2410_URXH; + dma->rx_conf.src_maxburst = 16; + + dma->tx_conf.direction = DMA_MEM_TO_DEV; + dma->tx_conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; + dma->tx_conf.dst_addr = p->port.mapbase + S3C2410_UTXH; + if (dma_get_cache_alignment() >= 16) + dma->tx_conf.dst_maxburst = 16; + else + dma->tx_conf.dst_maxburst = 1; + + dma_cap_zero(mask); + dma_cap_set(DMA_SLAVE, mask); + + dma->rx_chan = dma_request_slave_channel_compat(mask, dma->fn, + dma->rx_param, p->port.dev, "rx"); + if (!dma->rx_chan) + return -ENODEV; + + dmaengine_slave_config(dma->rx_chan, &dma->rx_conf); + + dma->tx_chan = dma_request_slave_channel_compat(mask, dma->fn, + dma->tx_param, p->port.dev, "tx"); + if (!dma->tx_chan) { + dma_release_channel(dma->rx_chan); + return -ENODEV; + } + + dmaengine_slave_config(dma->tx_chan, &dma->tx_conf); + + /* RX buffer */ + dma->rx_size = PAGE_SIZE; + + dma->rx_buf = kmalloc(dma->rx_size, GFP_KERNEL); + + if (!dma->rx_buf) { + dma_release_channel(dma->rx_chan); + dma_release_channel(dma->tx_chan); + return -ENOMEM; + } + + dma->rx_addr = dma_map_single(dma->rx_chan->device->dev, dma->rx_buf, + dma->rx_size, DMA_FROM_DEVICE); + + spin_lock_irqsave(&p->port.lock, flags); + + /* TX buffer */ + dma->tx_addr = dma_map_single(dma->tx_chan->device->dev, + p->port.state->xmit.buf, + UART_XMIT_SIZE, DMA_TO_DEVICE); + + spin_unlock_irqrestore(&p->port.lock, flags); + + return 0; +} + +static void s3c24xx_serial_release_dma(struct s3c24xx_uart_port *p) +{ + struct s3c24xx_uart_dma *dma = p->dma; + + if (dma->rx_chan) { + dmaengine_terminate_all(dma->rx_chan); + dma_unmap_single(dma->rx_chan->device->dev, dma->rx_addr, + dma->rx_size, DMA_FROM_DEVICE); + kfree(dma->rx_buf); + dma_release_channel(dma->rx_chan); + dma->rx_chan = NULL; + } + + if (dma->tx_chan) { + dmaengine_terminate_all(dma->tx_chan); + dma_unmap_single(dma->tx_chan->device->dev, dma->tx_addr, + UART_XMIT_SIZE, DMA_TO_DEVICE); + dma_release_channel(dma->tx_chan); + dma->tx_chan = NULL; + } +} + static void s3c24xx_serial_shutdown(struct uart_port *port) { struct s3c24xx_uart_port *ourport = to_ourport(port); @@ -478,6 +568,10 @@ static void s3c24xx_serial_shutdown(struct uart_port *port) wr_regl(port, S3C64XX_UINTP, 0xf); wr_regl(port, S3C64XX_UINTM, 0xf); } + + if (ourport->dma) + s3c24xx_serial_release_dma(ourport); + } static int s3c24xx_serial_startup(struct uart_port *port) @@ -535,6 +629,13 @@ static int s3c64xx_serial_startup(struct uart_port *port) port, (unsigned long long)port->mapbase, port->membase); wr_regl(port, S3C64XX_UINTM, 0xf); + if (ourport->dma) { + ret = s3c24xx_serial_request_dma(ourport); + if (ret < 0) { + dev_warn(port->dev, "DMA request failed\n"); + return ret; + } + } ret = request_irq(port->irq, s3c64xx_serial_handle_irq, IRQF_SHARED, s3c24xx_serial_portname(port), ourport); |