diff options
Diffstat (limited to 'drivers/tty/serial/mxs-auart.c')
| -rw-r--r-- | drivers/tty/serial/mxs-auart.c | 451 |
1 files changed, 409 insertions, 42 deletions
diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c index 55fd362b987..86de4477d98 100644 --- a/drivers/tty/serial/mxs-auart.c +++ b/drivers/tty/serial/mxs-auart.c @@ -32,10 +32,14 @@ #include <linux/clk.h> #include <linux/delay.h> #include <linux/io.h> +#include <linux/of_device.h> +#include <linux/dma-mapping.h> +#include <linux/dmaengine.h> #include <asm/cacheflush.h> #define MXS_AUART_PORTS 5 +#define MXS_AUART_FIFO_SIZE 16 #define AUART_CTRL0 0x00000000 #define AUART_CTRL0_SET 0x00000004 @@ -69,8 +73,18 @@ #define AUART_CTRL0_SFTRST (1 << 31) #define AUART_CTRL0_CLKGATE (1 << 30) +#define AUART_CTRL0_RXTO_ENABLE (1 << 27) +#define AUART_CTRL0_RXTIMEOUT(v) (((v) & 0x7ff) << 16) +#define AUART_CTRL0_XFER_COUNT(v) ((v) & 0xffff) + +#define AUART_CTRL1_XFER_COUNT(v) ((v) & 0xffff) + +#define AUART_CTRL2_DMAONERR (1 << 26) +#define AUART_CTRL2_TXDMAE (1 << 25) +#define AUART_CTRL2_RXDMAE (1 << 24) #define AUART_CTRL2_CTSEN (1 << 15) +#define AUART_CTRL2_RTSEN (1 << 14) #define AUART_CTRL2_RTS (1 << 11) #define AUART_CTRL2_RXE (1 << 9) #define AUART_CTRL2_TXE (1 << 8) @@ -108,29 +122,165 @@ #define AUART_STAT_BERR (1 << 18) #define AUART_STAT_PERR (1 << 17) #define AUART_STAT_FERR (1 << 16) +#define AUART_STAT_RXCOUNT_MASK 0xffff static struct uart_driver auart_driver; +enum mxs_auart_type { + IMX23_AUART, + IMX28_AUART, +}; + struct mxs_auart_port { struct uart_port port; - unsigned int flags; +#define MXS_AUART_DMA_ENABLED 0x2 +#define MXS_AUART_DMA_TX_SYNC 2 /* bit 2 */ +#define MXS_AUART_DMA_RX_READY 3 /* bit 3 */ +#define MXS_AUART_RTSCTS 4 /* bit 4 */ + unsigned long flags; unsigned int ctrl; + enum mxs_auart_type devtype; unsigned int irq; struct clk *clk; struct device *dev; + + /* for DMA */ + struct scatterlist tx_sgl; + struct dma_chan *tx_dma_chan; + void *tx_dma_buf; + + struct scatterlist rx_sgl; + struct dma_chan *rx_dma_chan; + void *rx_dma_buf; +}; + +static struct platform_device_id mxs_auart_devtype[] = { + { .name = "mxs-auart-imx23", .driver_data = IMX23_AUART }, + { .name = "mxs-auart-imx28", .driver_data = IMX28_AUART }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(platform, mxs_auart_devtype); + +static struct of_device_id mxs_auart_dt_ids[] = { + { + .compatible = "fsl,imx28-auart", + .data = &mxs_auart_devtype[IMX28_AUART] + }, { + .compatible = "fsl,imx23-auart", + .data = &mxs_auart_devtype[IMX23_AUART] + }, { /* sentinel */ } }; +MODULE_DEVICE_TABLE(of, mxs_auart_dt_ids); + +static inline int is_imx28_auart(struct mxs_auart_port *s) +{ + return s->devtype == IMX28_AUART; +} + +static inline bool auart_dma_enabled(struct mxs_auart_port *s) +{ + return s->flags & MXS_AUART_DMA_ENABLED; +} static void mxs_auart_stop_tx(struct uart_port *u); #define to_auart_port(u) container_of(u, struct mxs_auart_port, port) -static inline void mxs_auart_tx_chars(struct mxs_auart_port *s) +static void mxs_auart_tx_chars(struct mxs_auart_port *s); + +static void dma_tx_callback(void *param) +{ + struct mxs_auart_port *s = param; + struct circ_buf *xmit = &s->port.state->xmit; + + dma_unmap_sg(s->dev, &s->tx_sgl, 1, DMA_TO_DEVICE); + + /* clear the bit used to serialize the DMA tx. */ + clear_bit(MXS_AUART_DMA_TX_SYNC, &s->flags); + smp_mb__after_atomic(); + + /* wake up the possible processes. */ + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + uart_write_wakeup(&s->port); + + mxs_auart_tx_chars(s); +} + +static int mxs_auart_dma_tx(struct mxs_auart_port *s, int size) +{ + struct dma_async_tx_descriptor *desc; + struct scatterlist *sgl = &s->tx_sgl; + struct dma_chan *channel = s->tx_dma_chan; + u32 pio; + + /* [1] : send PIO. Note, the first pio word is CTRL1. */ + pio = AUART_CTRL1_XFER_COUNT(size); + desc = dmaengine_prep_slave_sg(channel, (struct scatterlist *)&pio, + 1, DMA_TRANS_NONE, 0); + if (!desc) { + dev_err(s->dev, "step 1 error\n"); + return -EINVAL; + } + + /* [2] : set DMA buffer. */ + sg_init_one(sgl, s->tx_dma_buf, size); + dma_map_sg(s->dev, sgl, 1, DMA_TO_DEVICE); + desc = dmaengine_prep_slave_sg(channel, sgl, + 1, DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc) { + dev_err(s->dev, "step 2 error\n"); + return -EINVAL; + } + + /* [3] : submit the DMA */ + desc->callback = dma_tx_callback; + desc->callback_param = s; + dmaengine_submit(desc); + dma_async_issue_pending(channel); + return 0; +} + +static void mxs_auart_tx_chars(struct mxs_auart_port *s) { struct circ_buf *xmit = &s->port.state->xmit; + if (auart_dma_enabled(s)) { + u32 i = 0; + int size; + void *buffer = s->tx_dma_buf; + + if (test_and_set_bit(MXS_AUART_DMA_TX_SYNC, &s->flags)) + return; + + while (!uart_circ_empty(xmit) && !uart_tx_stopped(&s->port)) { + size = min_t(u32, UART_XMIT_SIZE - i, + CIRC_CNT_TO_END(xmit->head, + xmit->tail, + UART_XMIT_SIZE)); + memcpy(buffer + i, xmit->buf + xmit->tail, size); + xmit->tail = (xmit->tail + size) & (UART_XMIT_SIZE - 1); + + i += size; + if (i >= UART_XMIT_SIZE) + break; + } + + if (uart_tx_stopped(&s->port)) + mxs_auart_stop_tx(&s->port); + + if (i) { + mxs_auart_dma_tx(s, i); + } else { + clear_bit(MXS_AUART_DMA_TX_SYNC, &s->flags); + smp_mb__after_atomic(); + } + return; + } + + while (!(readl(s->port.membase + AUART_STAT) & AUART_STAT_TXFF)) { if (s->port.x_char) { @@ -209,7 +359,6 @@ out: static void mxs_auart_rx_chars(struct mxs_auart_port *s) { - struct tty_struct *tty = s->port.state->port.tty; u32 stat = 0; for (;;) { @@ -220,7 +369,7 @@ static void mxs_auart_rx_chars(struct mxs_auart_port *s) } writel(stat, s->port.membase + AUART_STAT); - tty_flip_buffer_push(tty); + tty_flip_buffer_push(&s->port.state->port); } static int mxs_auart_request_port(struct uart_port *u) @@ -257,9 +406,14 @@ static void mxs_auart_set_mctrl(struct uart_port *u, unsigned mctrl) u32 ctrl = readl(u->membase + AUART_CTRL2); - ctrl &= ~AUART_CTRL2_RTS; - if (mctrl & TIOCM_RTS) - ctrl |= AUART_CTRL2_RTS; + ctrl &= ~(AUART_CTRL2_RTSEN | AUART_CTRL2_RTS); + if (mctrl & TIOCM_RTS) { + if (tty_port_cts_enabled(&u->state->port)) + ctrl |= AUART_CTRL2_RTSEN; + else + ctrl |= AUART_CTRL2_RTS; + } + s->ctrl = mctrl; writel(ctrl, u->membase + AUART_CTRL2); } @@ -281,10 +435,136 @@ static u32 mxs_auart_get_mctrl(struct uart_port *u) return mctrl; } +static int mxs_auart_dma_prep_rx(struct mxs_auart_port *s); +static void dma_rx_callback(void *arg) +{ + struct mxs_auart_port *s = (struct mxs_auart_port *) arg; + struct tty_port *port = &s->port.state->port; + int count; + u32 stat; + + dma_unmap_sg(s->dev, &s->rx_sgl, 1, DMA_FROM_DEVICE); + + stat = readl(s->port.membase + AUART_STAT); + stat &= ~(AUART_STAT_OERR | AUART_STAT_BERR | + AUART_STAT_PERR | AUART_STAT_FERR); + + count = stat & AUART_STAT_RXCOUNT_MASK; + tty_insert_flip_string(port, s->rx_dma_buf, count); + + writel(stat, s->port.membase + AUART_STAT); + tty_flip_buffer_push(port); + + /* start the next DMA for RX. */ + mxs_auart_dma_prep_rx(s); +} + +static int mxs_auart_dma_prep_rx(struct mxs_auart_port *s) +{ + struct dma_async_tx_descriptor *desc; + struct scatterlist *sgl = &s->rx_sgl; + struct dma_chan *channel = s->rx_dma_chan; + u32 pio[1]; + + /* [1] : send PIO */ + pio[0] = AUART_CTRL0_RXTO_ENABLE + | AUART_CTRL0_RXTIMEOUT(0x80) + | AUART_CTRL0_XFER_COUNT(UART_XMIT_SIZE); + desc = dmaengine_prep_slave_sg(channel, (struct scatterlist *)pio, + 1, DMA_TRANS_NONE, 0); + if (!desc) { + dev_err(s->dev, "step 1 error\n"); + return -EINVAL; + } + + /* [2] : send DMA request */ + sg_init_one(sgl, s->rx_dma_buf, UART_XMIT_SIZE); + dma_map_sg(s->dev, sgl, 1, DMA_FROM_DEVICE); + desc = dmaengine_prep_slave_sg(channel, sgl, 1, DMA_DEV_TO_MEM, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc) { + dev_err(s->dev, "step 2 error\n"); + return -1; + } + + /* [3] : submit the DMA, but do not issue it. */ + desc->callback = dma_rx_callback; + desc->callback_param = s; + dmaengine_submit(desc); + dma_async_issue_pending(channel); + return 0; +} + +static void mxs_auart_dma_exit_channel(struct mxs_auart_port *s) +{ + if (s->tx_dma_chan) { + dma_release_channel(s->tx_dma_chan); + s->tx_dma_chan = NULL; + } + if (s->rx_dma_chan) { + dma_release_channel(s->rx_dma_chan); + s->rx_dma_chan = NULL; + } + + kfree(s->tx_dma_buf); + kfree(s->rx_dma_buf); + s->tx_dma_buf = NULL; + s->rx_dma_buf = NULL; +} + +static void mxs_auart_dma_exit(struct mxs_auart_port *s) +{ + + writel(AUART_CTRL2_TXDMAE | AUART_CTRL2_RXDMAE | AUART_CTRL2_DMAONERR, + s->port.membase + AUART_CTRL2_CLR); + + mxs_auart_dma_exit_channel(s); + s->flags &= ~MXS_AUART_DMA_ENABLED; + clear_bit(MXS_AUART_DMA_TX_SYNC, &s->flags); + clear_bit(MXS_AUART_DMA_RX_READY, &s->flags); +} + +static int mxs_auart_dma_init(struct mxs_auart_port *s) +{ + if (auart_dma_enabled(s)) + return 0; + + /* init for RX */ + s->rx_dma_chan = dma_request_slave_channel(s->dev, "rx"); + if (!s->rx_dma_chan) + goto err_out; + s->rx_dma_buf = kzalloc(UART_XMIT_SIZE, GFP_KERNEL | GFP_DMA); + if (!s->rx_dma_buf) + goto err_out; + + /* init for TX */ + s->tx_dma_chan = dma_request_slave_channel(s->dev, "tx"); + if (!s->tx_dma_chan) + goto err_out; + s->tx_dma_buf = kzalloc(UART_XMIT_SIZE, GFP_KERNEL | GFP_DMA); + if (!s->tx_dma_buf) + goto err_out; + + /* set the flags */ + s->flags |= MXS_AUART_DMA_ENABLED; + dev_dbg(s->dev, "enabled the DMA support."); + + /* The DMA buffer is now the FIFO the TTY subsystem can use */ + s->port.fifosize = UART_XMIT_SIZE; + + return 0; + +err_out: + mxs_auart_dma_exit_channel(s); + return -EINVAL; + +} + static void mxs_auart_settermios(struct uart_port *u, struct ktermios *termios, struct ktermios *old) { + struct mxs_auart_port *s = to_auart_port(u); u32 bm, ctrl, ctrl2, div; unsigned int cflag, baud; @@ -324,7 +604,7 @@ static void mxs_auart_settermios(struct uart_port *u, if (termios->c_iflag & INPCK) u->read_status_mask |= AUART_STAT_PERR; - if (termios->c_iflag & (BRKINT | PARMRK)) + if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK)) u->read_status_mask |= AUART_STAT_BERR; /* @@ -356,10 +636,24 @@ static void mxs_auart_settermios(struct uart_port *u, ctrl |= AUART_LINECTRL_STP2; /* figure out the hardware flow control settings */ - if (cflag & CRTSCTS) - ctrl2 |= AUART_CTRL2_CTSEN; - else - ctrl2 &= ~AUART_CTRL2_CTSEN; + if (cflag & CRTSCTS) { + /* + * The DMA has a bug(see errata:2836) in mx23. + * So we can not implement the DMA for auart in mx23, + * we can only implement the DMA support for auart + * in mx28. + */ + if (is_imx28_auart(s) + && test_bit(MXS_AUART_RTSCTS, &s->flags)) { + if (!mxs_auart_dma_init(s)) + /* enable DMA tranfer */ + ctrl2 |= AUART_CTRL2_TXDMAE | AUART_CTRL2_RXDMAE + | AUART_CTRL2_DMAONERR; + } + ctrl2 |= AUART_CTRL2_CTSEN | AUART_CTRL2_RTSEN; + } else { + ctrl2 &= ~(AUART_CTRL2_CTSEN | AUART_CTRL2_RTSEN); + } /* set baud rate */ baud = uart_get_baud_rate(u, termios, old, 0, u->uartclk); @@ -369,15 +663,37 @@ static void mxs_auart_settermios(struct uart_port *u, writel(ctrl, u->membase + AUART_LINECTRL); writel(ctrl2, u->membase + AUART_CTRL2); + + uart_update_timeout(u, termios->c_cflag, baud); + + /* prepare for the DMA RX. */ + if (auart_dma_enabled(s) && + !test_and_set_bit(MXS_AUART_DMA_RX_READY, &s->flags)) { + if (!mxs_auart_dma_prep_rx(s)) { + /* Disable the normal RX interrupt. */ + writel(AUART_INTR_RXIEN | AUART_INTR_RTIEN, + u->membase + AUART_INTR_CLR); + } else { + mxs_auart_dma_exit(s); + dev_err(s->dev, "We can not start up the DMA.\n"); + } + } } static irqreturn_t mxs_auart_irq_handle(int irq, void *context) { - u32 istatus, istat; + u32 istat; struct mxs_auart_port *s = context; u32 stat = readl(s->port.membase + AUART_STAT); - istatus = istat = readl(s->port.membase + AUART_INTR); + istat = readl(s->port.membase + AUART_INTR); + + /* ack irq */ + writel(istat & (AUART_INTR_RTIS + | AUART_INTR_TXIS + | AUART_INTR_RXIS + | AUART_INTR_CTSMIS), + s->port.membase + AUART_INTR_CLR); if (istat & AUART_INTR_CTSMIS) { uart_handle_cts_change(&s->port, stat & AUART_STAT_CTS); @@ -387,7 +703,8 @@ static irqreturn_t mxs_auart_irq_handle(int irq, void *context) } if (istat & (AUART_INTR_RTIS | AUART_INTR_RXIS)) { - mxs_auart_rx_chars(s); + if (!auart_dma_enabled(s)) + mxs_auart_rx_chars(s); istat &= ~(AUART_INTR_RTIS | AUART_INTR_RXIS); } @@ -396,12 +713,6 @@ static irqreturn_t mxs_auart_irq_handle(int irq, void *context) istat &= ~AUART_INTR_TXIS; } - writel(istatus & (AUART_INTR_RTIS - | AUART_INTR_TXIS - | AUART_INTR_RXIS - | AUART_INTR_CTSMIS), - s->port.membase + AUART_INTR_CLR); - return IRQ_HANDLED; } @@ -423,9 +734,12 @@ static void mxs_auart_reset(struct uart_port *u) static int mxs_auart_startup(struct uart_port *u) { + int ret; struct mxs_auart_port *s = to_auart_port(u); - clk_prepare_enable(s->clk); + ret = clk_prepare_enable(s->clk); + if (ret) + return ret; writel(AUART_CTRL0_CLKGATE, u->membase + AUART_CTRL0_CLR); @@ -434,6 +748,9 @@ static int mxs_auart_startup(struct uart_port *u) writel(AUART_INTR_RXIEN | AUART_INTR_RTIEN | AUART_INTR_CTSMIEN, u->membase + AUART_INTR); + /* Reset FIFO size (it could have changed if DMA was enabled) */ + u->fifosize = MXS_AUART_FIFO_SIZE; + /* * Enable fifo so all four bytes of a DMA word are written to * output (otherwise, only the LSB is written, ie. 1 in 4 bytes) @@ -447,13 +764,16 @@ static void mxs_auart_shutdown(struct uart_port *u) { struct mxs_auart_port *s = to_auart_port(u); - writel(AUART_CTRL2_UARTEN, u->membase + AUART_CTRL2_CLR); + if (auart_dma_enabled(s)) + mxs_auart_dma_exit(s); - writel(AUART_CTRL0_CLKGATE, u->membase + AUART_CTRL0_SET); + writel(AUART_CTRL2_UARTEN, u->membase + AUART_CTRL2_CLR); writel(AUART_INTR_RXIEN | AUART_INTR_RTIEN | AUART_INTR_CTSMIEN, u->membase + AUART_INTR_CLR); + writel(AUART_CTRL0_CLKGATE, u->membase + AUART_CTRL0_SET); + clk_disable_unprepare(s->clk); } @@ -541,9 +861,9 @@ auart_console_write(struct console *co, const char *str, unsigned int count) struct mxs_auart_port *s; struct uart_port *port; unsigned int old_ctrl0, old_ctrl2; - unsigned int to = 1000; + unsigned int to = 20000; - if (co->index > MXS_AUART_PORTS || co->index < 0) + if (co->index >= MXS_AUART_PORTS || co->index < 0) return; s = auart_port[co->index]; @@ -562,18 +882,23 @@ auart_console_write(struct console *co, const char *str, unsigned int count) uart_console_write(port, str, count, mxs_auart_console_putchar); - /* - * Finally, wait for transmitter to become empty - * and restore the TCR - */ + /* Finally, wait for transmitter to become empty ... */ while (readl(port->membase + AUART_STAT) & AUART_STAT_BUSY) { + udelay(1); if (!to--) break; - udelay(1); } - writel(old_ctrl0, port->membase + AUART_CTRL0); - writel(old_ctrl2, port->membase + AUART_CTRL2); + /* + * ... and restore the TCR if we waited long enough for the transmitter + * to be idle. This might keep the transmitter enabled although it is + * unused, but that is better than to disable it while it is still + * transmitting. + */ + if (!(readl(port->membase + AUART_STAT) & AUART_STAT_BUSY)) { + writel(old_ctrl0, port->membase + AUART_CTRL0); + writel(old_ctrl2, port->membase + AUART_CTRL2); + } clk_disable(s->clk); } @@ -635,7 +960,9 @@ auart_console_setup(struct console *co, char *options) if (!s) return -ENODEV; - clk_prepare_enable(s->clk); + ret = clk_prepare_enable(s->clk); + if (ret) + return ret; if (options) uart_parse_options(options, &baud, &parity, &bits, &flow); @@ -672,8 +999,37 @@ static struct uart_driver auart_driver = { #endif }; -static int __devinit mxs_auart_probe(struct platform_device *pdev) +/* + * This function returns 1 if pdev isn't a device instatiated by dt, 0 if it + * could successfully get all information from dt or a negative errno. + */ +static int serial_mxs_probe_dt(struct mxs_auart_port *s, + struct platform_device *pdev) { + struct device_node *np = pdev->dev.of_node; + int ret; + + if (!np) + /* no device tree device */ + return 1; + + ret = of_alias_get_id(np, "serial"); + if (ret < 0) { + dev_err(&pdev->dev, "failed to get alias id: %d\n", ret); + return ret; + } + s->port.line = ret; + + if (of_get_property(np, "fsl,uart-has-rtscts", NULL)) + set_bit(MXS_AUART_RTSCTS, &s->flags); + + return 0; +} + +static int mxs_auart_probe(struct platform_device *pdev) +{ + const struct of_device_id *of_id = + of_match_device(mxs_auart_dt_ids, &pdev->dev); struct mxs_auart_port *s; u32 version; int ret = 0; @@ -685,6 +1041,17 @@ static int __devinit mxs_auart_probe(struct platform_device *pdev) goto out; } + ret = serial_mxs_probe_dt(s, pdev); + if (ret > 0) + s->port.line = pdev->id < 0 ? 0 : pdev->id; + else if (ret < 0) + goto out_free; + + if (of_id) { + pdev->id_entry = of_id->data; + s->devtype = pdev->id_entry->driver_data; + } + s->clk = clk_get(&pdev->dev, NULL); if (IS_ERR(s->clk)) { ret = PTR_ERR(s->clk); @@ -701,13 +1068,11 @@ static int __devinit mxs_auart_probe(struct platform_device *pdev) s->port.membase = ioremap(r->start, resource_size(r)); s->port.ops = &mxs_auart_ops; s->port.iotype = UPIO_MEM; - s->port.line = pdev->id < 0 ? 0 : pdev->id; - s->port.fifosize = 16; + s->port.fifosize = MXS_AUART_FIFO_SIZE; s->port.uartclk = clk_get_rate(s->clk); s->port.type = PORT_IMX; - s->port.dev = s->dev = get_device(&pdev->dev); + s->port.dev = s->dev = &pdev->dev; - s->flags = 0; s->ctrl = 0; s->irq = platform_get_irq(pdev, 0); @@ -718,7 +1083,7 @@ static int __devinit mxs_auart_probe(struct platform_device *pdev) platform_set_drvdata(pdev, s); - auart_port[pdev->id] = s; + auart_port[s->port.line] = s; mxs_auart_reset(&s->port); @@ -744,7 +1109,7 @@ out: return ret; } -static int __devexit mxs_auart_remove(struct platform_device *pdev) +static int mxs_auart_remove(struct platform_device *pdev) { struct mxs_auart_port *s = platform_get_drvdata(pdev); @@ -761,10 +1126,11 @@ static int __devexit mxs_auart_remove(struct platform_device *pdev) static struct platform_driver mxs_auart_driver = { .probe = mxs_auart_probe, - .remove = __devexit_p(mxs_auart_remove), + .remove = mxs_auart_remove, .driver = { .name = "mxs-auart", .owner = THIS_MODULE, + .of_match_table = mxs_auart_dt_ids, }, }; @@ -797,3 +1163,4 @@ module_init(mxs_auart_init); module_exit(mxs_auart_exit); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("Freescale MXS application uart driver"); +MODULE_ALIAS("platform:mxs-auart"); |
