From 85b5c1dd04560f95d10c9eee71ba45adaa87deec Mon Sep 17 00:00:00 2001 From: Long Cheng Date: Wed, 5 Dec 2018 16:42:59 +0800 Subject: serial: 8250-mtk: add uart DMA support Modify uart register to support DMA function. Signed-off-by: Long Cheng Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_mtk.c | 210 ++++++++++++++++++++++++++++++++++++- 1 file changed, 209 insertions(+), 1 deletion(-) (limited to 'drivers/tty/serial') diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c index dd5e1cede2b5..1da73e895be6 100644 --- a/drivers/tty/serial/8250/8250_mtk.c +++ b/drivers/tty/serial/8250/8250_mtk.c @@ -14,6 +14,10 @@ #include #include #include +#include +#include +#include +#include #include "8250.h" @@ -22,12 +26,172 @@ #define UART_MTK_SAMPLE_POINT 0x0b /* Sample point register */ #define MTK_UART_RATE_FIX 0x0d /* UART Rate Fix Register */ +#define MTK_UART_DMA_EN 0x13 /* DMA Enable register */ +#define MTK_UART_DMA_EN_TX 0x2 +#define MTK_UART_DMA_EN_RX 0x5 + +#define MTK_UART_TX_SIZE UART_XMIT_SIZE +#define MTK_UART_RX_SIZE 0x8000 +#define MTK_UART_TX_TRIGGER 1 +#define MTK_UART_RX_TRIGGER MTK_UART_RX_SIZE + +#ifdef CONFIG_SERIAL_8250_DMA +enum dma_rx_status { + DMA_RX_START = 0, + DMA_RX_RUNNING = 1, + DMA_RX_SHUTDOWN = 2, +}; +#endif + struct mtk8250_data { int line; + unsigned int rx_pos; struct clk *uart_clk; struct clk *bus_clk; + struct uart_8250_dma *dma; +#ifdef CONFIG_SERIAL_8250_DMA + enum dma_rx_status rx_status; +#endif }; +#ifdef CONFIG_SERIAL_8250_DMA +static void mtk8250_rx_dma(struct uart_8250_port *up); + +static void mtk8250_dma_rx_complete(void *param) +{ + struct uart_8250_port *up = param; + struct uart_8250_dma *dma = up->dma; + struct mtk8250_data *data = up->port.private_data; + struct tty_port *tty_port = &up->port.state->port; + struct dma_tx_state state; + unsigned char *ptr; + int copied; + + dma_sync_single_for_cpu(dma->rxchan->device->dev, dma->rx_addr, + dma->rx_size, DMA_FROM_DEVICE); + + dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); + + if (data->rx_status == DMA_RX_SHUTDOWN) + return; + + if ((data->rx_pos + state.residue) <= dma->rx_size) { + ptr = (unsigned char *)(data->rx_pos + dma->rx_buf); + copied = tty_insert_flip_string(tty_port, ptr, state.residue); + } else { + ptr = (unsigned char *)(data->rx_pos + dma->rx_buf); + copied = tty_insert_flip_string(tty_port, ptr, + dma->rx_size - data->rx_pos); + ptr = (unsigned char *)(dma->rx_buf); + copied += tty_insert_flip_string(tty_port, ptr, + data->rx_pos + state.residue - dma->rx_size); + } + up->port.icount.rx += copied; + + tty_flip_buffer_push(tty_port); + + mtk8250_rx_dma(up); +} + +static void mtk8250_rx_dma(struct uart_8250_port *up) +{ + struct uart_8250_dma *dma = up->dma; + struct mtk8250_data *data = up->port.private_data; + struct dma_async_tx_descriptor *desc; + struct dma_tx_state state; + + desc = dmaengine_prep_slave_single(dma->rxchan, dma->rx_addr, + dma->rx_size, DMA_DEV_TO_MEM, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc) { + pr_err("failed to prepare rx slave single\n"); + return; + } + + desc->callback = mtk8250_dma_rx_complete; + desc->callback_param = up; + + dma->rx_cookie = dmaengine_submit(desc); + + dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); + data->rx_pos = state.residue; + + dma_sync_single_for_device(dma->rxchan->device->dev, dma->rx_addr, + dma->rx_size, DMA_FROM_DEVICE); + + dma_async_issue_pending(dma->rxchan); +} + +static void mtk8250_dma_enable(struct uart_8250_port *up) +{ + struct uart_8250_dma *dma = up->dma; + struct mtk8250_data *data = up->port.private_data; + int lcr = serial_in(up, UART_LCR); + + if (data->rx_status != DMA_RX_START) + return; + + dma->rxconf.direction = DMA_DEV_TO_MEM; + dma->rxconf.src_addr_width = dma->rx_size / 1024; + dma->rxconf.src_addr = dma->rx_addr; + + dma->txconf.direction = DMA_MEM_TO_DEV; + dma->txconf.dst_addr_width = MTK_UART_TX_SIZE / 1024; + dma->txconf.dst_addr = dma->tx_addr; + + serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR | + UART_FCR_CLEAR_XMIT); + serial_out(up, MTK_UART_DMA_EN, + MTK_UART_DMA_EN_RX | MTK_UART_DMA_EN_TX); + + serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); + serial_out(up, UART_EFR, UART_EFR_ECB); + serial_out(up, UART_LCR, lcr); + + if (dmaengine_slave_config(dma->rxchan, &dma->rxconf) != 0) + pr_err("failed to configure rx dma channel\n"); + if (dmaengine_slave_config(dma->txchan, &dma->txconf) != 0) + pr_err("failed to configure tx dma channel\n"); + + data->rx_status = DMA_RX_RUNNING; + data->rx_pos = 0; + mtk8250_rx_dma(up); +} +#endif + +static int mtk8250_startup(struct uart_port *port) +{ +#ifdef CONFIG_SERIAL_8250_DMA + struct uart_8250_port *up = up_to_u8250p(port); + struct mtk8250_data *data = port->private_data; + + /* disable DMA for console */ + if (uart_console(port)) + up->dma = NULL; + + if (up->dma) { + data->rx_status = DMA_RX_START; + uart_circ_clear(&port->state->xmit); + } +#endif + memset(&port->icount, 0, sizeof(port->icount)); + + return serial8250_do_startup(port); +} + +static void mtk8250_shutdown(struct uart_port *port) +{ +#ifdef CONFIG_SERIAL_8250_DMA + struct uart_8250_port *up = up_to_u8250p(port); + struct mtk8250_data *data = port->private_data; + + if (up->dma) + data->rx_status = DMA_RX_SHUTDOWN; +#endif + + return serial8250_do_shutdown(port); +} + static void mtk8250_set_termios(struct uart_port *port, struct ktermios *termios, struct ktermios *old) @@ -36,6 +200,17 @@ mtk8250_set_termios(struct uart_port *port, struct ktermios *termios, unsigned long flags; unsigned int baud, quot; +#ifdef CONFIG_SERIAL_8250_DMA + if (up->dma) { + if (uart_console(port)) { + devm_kfree(up->port.dev, up->dma); + up->dma = NULL; + } else { + mtk8250_dma_enable(up); + } + } +#endif + serial8250_do_set_termios(port, termios, old); /* @@ -143,9 +318,20 @@ mtk8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old) pm_runtime_put_sync_suspend(port->dev); } +#ifdef CONFIG_SERIAL_8250_DMA +static bool mtk8250_dma_filter(struct dma_chan *chan, void *param) +{ + return false; +} +#endif + static int mtk8250_probe_of(struct platform_device *pdev, struct uart_port *p, struct mtk8250_data *data) { +#ifdef CONFIG_SERIAL_8250_DMA + int dmacnt; +#endif + data->uart_clk = devm_clk_get(&pdev->dev, "baud"); if (IS_ERR(data->uart_clk)) { /* @@ -162,7 +348,23 @@ static int mtk8250_probe_of(struct platform_device *pdev, struct uart_port *p, } data->bus_clk = devm_clk_get(&pdev->dev, "bus"); - return PTR_ERR_OR_ZERO(data->bus_clk); + if (IS_ERR(data->bus_clk)) + return PTR_ERR(data->bus_clk); + + data->dma = NULL; +#ifdef CONFIG_SERIAL_8250_DMA + dmacnt = of_property_count_strings(pdev->dev.of_node, "dma-names"); + if (dmacnt == 2) { + data->dma = devm_kzalloc(&pdev->dev, sizeof(*data->dma), + GFP_KERNEL); + data->dma->fn = mtk8250_dma_filter; + data->dma->rx_size = MTK_UART_RX_SIZE; + data->dma->rxconf.src_maxburst = MTK_UART_RX_TRIGGER; + data->dma->txconf.dst_maxburst = MTK_UART_TX_TRIGGER; + } +#endif + + return 0; } static int mtk8250_probe(struct platform_device *pdev) @@ -204,8 +406,14 @@ static int mtk8250_probe(struct platform_device *pdev) uart.port.iotype = UPIO_MEM32; uart.port.regshift = 2; uart.port.private_data = data; + uart.port.shutdown = mtk8250_shutdown; + uart.port.startup = mtk8250_startup; uart.port.set_termios = mtk8250_set_termios; uart.port.uartclk = clk_get_rate(data->uart_clk); +#ifdef CONFIG_SERIAL_8250_DMA + if (data->dma) + uart.dma = data->dma; +#endif /* Disable Rate Fix function */ writel(0x0, uart.port.membase + -- cgit v1.2.3