serial: 8250-mtk: add uart DMA support
Modify uart register to support DMA function. Signed-off-by: Long Cheng <long.cheng@mediatek.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Long Cheng
Greg Kroah-Hartman
Родитель
89212465c1
Коммит
85b5c1dd04
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@ -14,6 +14,10 @@
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#include <linux/pm_runtime.h>
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#include <linux/serial_8250.h>
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#include <linux/serial_reg.h>
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#include <linux/console.h>
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#include <linux/dma-mapping.h>
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#include <linux/tty.h>
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#include <linux/tty_flip.h>
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#include "8250.h"
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@ -22,12 +26,172 @@
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#define UART_MTK_SAMPLE_POINT 0x0b /* Sample point register */
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#define MTK_UART_RATE_FIX 0x0d /* UART Rate Fix Register */
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#define MTK_UART_DMA_EN 0x13 /* DMA Enable register */
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#define MTK_UART_DMA_EN_TX 0x2
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#define MTK_UART_DMA_EN_RX 0x5
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#define MTK_UART_TX_SIZE UART_XMIT_SIZE
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#define MTK_UART_RX_SIZE 0x8000
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#define MTK_UART_TX_TRIGGER 1
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#define MTK_UART_RX_TRIGGER MTK_UART_RX_SIZE
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#ifdef CONFIG_SERIAL_8250_DMA
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enum dma_rx_status {
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DMA_RX_START = 0,
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DMA_RX_RUNNING = 1,
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DMA_RX_SHUTDOWN = 2,
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};
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#endif
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struct mtk8250_data {
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int line;
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unsigned int rx_pos;
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struct clk *uart_clk;
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struct clk *bus_clk;
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struct uart_8250_dma *dma;
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#ifdef CONFIG_SERIAL_8250_DMA
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enum dma_rx_status rx_status;
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#endif
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};
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#ifdef CONFIG_SERIAL_8250_DMA
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static void mtk8250_rx_dma(struct uart_8250_port *up);
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static void mtk8250_dma_rx_complete(void *param)
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{
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struct uart_8250_port *up = param;
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struct uart_8250_dma *dma = up->dma;
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struct mtk8250_data *data = up->port.private_data;
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struct tty_port *tty_port = &up->port.state->port;
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struct dma_tx_state state;
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unsigned char *ptr;
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int copied;
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dma_sync_single_for_cpu(dma->rxchan->device->dev, dma->rx_addr,
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dma->rx_size, DMA_FROM_DEVICE);
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dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state);
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if (data->rx_status == DMA_RX_SHUTDOWN)
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return;
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if ((data->rx_pos + state.residue) <= dma->rx_size) {
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ptr = (unsigned char *)(data->rx_pos + dma->rx_buf);
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copied = tty_insert_flip_string(tty_port, ptr, state.residue);
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} else {
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ptr = (unsigned char *)(data->rx_pos + dma->rx_buf);
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copied = tty_insert_flip_string(tty_port, ptr,
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dma->rx_size - data->rx_pos);
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ptr = (unsigned char *)(dma->rx_buf);
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copied += tty_insert_flip_string(tty_port, ptr,
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data->rx_pos + state.residue - dma->rx_size);
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}
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up->port.icount.rx += copied;
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tty_flip_buffer_push(tty_port);
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mtk8250_rx_dma(up);
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}
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static void mtk8250_rx_dma(struct uart_8250_port *up)
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{
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struct uart_8250_dma *dma = up->dma;
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struct mtk8250_data *data = up->port.private_data;
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struct dma_async_tx_descriptor *desc;
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struct dma_tx_state state;
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desc = dmaengine_prep_slave_single(dma->rxchan, dma->rx_addr,
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dma->rx_size, DMA_DEV_TO_MEM,
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DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
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if (!desc) {
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pr_err("failed to prepare rx slave single\n");
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return;
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}
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desc->callback = mtk8250_dma_rx_complete;
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desc->callback_param = up;
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dma->rx_cookie = dmaengine_submit(desc);
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dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state);
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data->rx_pos = state.residue;
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dma_sync_single_for_device(dma->rxchan->device->dev, dma->rx_addr,
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dma->rx_size, DMA_FROM_DEVICE);
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dma_async_issue_pending(dma->rxchan);
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}
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static void mtk8250_dma_enable(struct uart_8250_port *up)
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{
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struct uart_8250_dma *dma = up->dma;
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struct mtk8250_data *data = up->port.private_data;
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int lcr = serial_in(up, UART_LCR);
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if (data->rx_status != DMA_RX_START)
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return;
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dma->rxconf.direction = DMA_DEV_TO_MEM;
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dma->rxconf.src_addr_width = dma->rx_size / 1024;
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dma->rxconf.src_addr = dma->rx_addr;
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dma->txconf.direction = DMA_MEM_TO_DEV;
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dma->txconf.dst_addr_width = MTK_UART_TX_SIZE / 1024;
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dma->txconf.dst_addr = dma->tx_addr;
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serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR |
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UART_FCR_CLEAR_XMIT);
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serial_out(up, MTK_UART_DMA_EN,
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MTK_UART_DMA_EN_RX | MTK_UART_DMA_EN_TX);
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serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
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serial_out(up, UART_EFR, UART_EFR_ECB);
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serial_out(up, UART_LCR, lcr);
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if (dmaengine_slave_config(dma->rxchan, &dma->rxconf) != 0)
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pr_err("failed to configure rx dma channel\n");
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if (dmaengine_slave_config(dma->txchan, &dma->txconf) != 0)
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pr_err("failed to configure tx dma channel\n");
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data->rx_status = DMA_RX_RUNNING;
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data->rx_pos = 0;
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mtk8250_rx_dma(up);
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}
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#endif
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static int mtk8250_startup(struct uart_port *port)
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{
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#ifdef CONFIG_SERIAL_8250_DMA
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struct uart_8250_port *up = up_to_u8250p(port);
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struct mtk8250_data *data = port->private_data;
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/* disable DMA for console */
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if (uart_console(port))
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up->dma = NULL;
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if (up->dma) {
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data->rx_status = DMA_RX_START;
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uart_circ_clear(&port->state->xmit);
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}
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#endif
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memset(&port->icount, 0, sizeof(port->icount));
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return serial8250_do_startup(port);
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}
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static void mtk8250_shutdown(struct uart_port *port)
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{
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#ifdef CONFIG_SERIAL_8250_DMA
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struct uart_8250_port *up = up_to_u8250p(port);
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struct mtk8250_data *data = port->private_data;
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if (up->dma)
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data->rx_status = DMA_RX_SHUTDOWN;
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#endif
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return serial8250_do_shutdown(port);
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}
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static void
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mtk8250_set_termios(struct uart_port *port, struct ktermios *termios,
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struct ktermios *old)
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@ -36,6 +200,17 @@ mtk8250_set_termios(struct uart_port *port, struct ktermios *termios,
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unsigned long flags;
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unsigned int baud, quot;
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#ifdef CONFIG_SERIAL_8250_DMA
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if (up->dma) {
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if (uart_console(port)) {
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devm_kfree(up->port.dev, up->dma);
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up->dma = NULL;
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} else {
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mtk8250_dma_enable(up);
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}
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}
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#endif
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serial8250_do_set_termios(port, termios, old);
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/*
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@ -143,9 +318,20 @@ mtk8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old)
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pm_runtime_put_sync_suspend(port->dev);
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}
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#ifdef CONFIG_SERIAL_8250_DMA
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static bool mtk8250_dma_filter(struct dma_chan *chan, void *param)
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{
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return false;
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}
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#endif
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static int mtk8250_probe_of(struct platform_device *pdev, struct uart_port *p,
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struct mtk8250_data *data)
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{
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#ifdef CONFIG_SERIAL_8250_DMA
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int dmacnt;
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#endif
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data->uart_clk = devm_clk_get(&pdev->dev, "baud");
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if (IS_ERR(data->uart_clk)) {
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/*
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@ -162,7 +348,23 @@ static int mtk8250_probe_of(struct platform_device *pdev, struct uart_port *p,
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}
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data->bus_clk = devm_clk_get(&pdev->dev, "bus");
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return PTR_ERR_OR_ZERO(data->bus_clk);
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if (IS_ERR(data->bus_clk))
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return PTR_ERR(data->bus_clk);
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data->dma = NULL;
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#ifdef CONFIG_SERIAL_8250_DMA
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dmacnt = of_property_count_strings(pdev->dev.of_node, "dma-names");
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if (dmacnt == 2) {
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data->dma = devm_kzalloc(&pdev->dev, sizeof(*data->dma),
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GFP_KERNEL);
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data->dma->fn = mtk8250_dma_filter;
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data->dma->rx_size = MTK_UART_RX_SIZE;
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data->dma->rxconf.src_maxburst = MTK_UART_RX_TRIGGER;
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data->dma->txconf.dst_maxburst = MTK_UART_TX_TRIGGER;
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}
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#endif
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return 0;
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}
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static int mtk8250_probe(struct platform_device *pdev)
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@ -204,8 +406,14 @@ static int mtk8250_probe(struct platform_device *pdev)
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uart.port.iotype = UPIO_MEM32;
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uart.port.regshift = 2;
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uart.port.private_data = data;
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uart.port.shutdown = mtk8250_shutdown;
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uart.port.startup = mtk8250_startup;
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uart.port.set_termios = mtk8250_set_termios;
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uart.port.uartclk = clk_get_rate(data->uart_clk);
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#ifdef CONFIG_SERIAL_8250_DMA
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if (data->dma)
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uart.dma = data->dma;
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#endif
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/* Disable Rate Fix function */
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writel(0x0, uart.port.membase +
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