diff options
Diffstat (limited to 'drivers/tty/serial/mxs-auart.c')
-rw-r--r-- | drivers/tty/serial/mxs-auart.c | 380 |
1 files changed, 364 insertions, 16 deletions
diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c index 6db3baa..e55615e 100644 --- a/drivers/tty/serial/mxs-auart.c +++ b/drivers/tty/serial/mxs-auart.c @@ -34,6 +34,8 @@ #include <linux/io.h> #include <linux/pinctrl/consumer.h> #include <linux/of_device.h> +#include <linux/dma-mapping.h> +#include <linux/fsl/mxs-dma.h> #include <asm/cacheflush.h> @@ -71,6 +73,15 @@ #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) @@ -111,29 +122,170 @@ #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_CONFIG 0x1 +#define MXS_AUART_DMA_ENABLED 0x2 +#define MXS_AUART_DMA_TX_SYNC 2 /* bit 2 */ +#define MXS_AUART_DMA_RX_READY 3 /* bit 3 */ + unsigned long flags; unsigned int ctrl; + enum mxs_auart_type devtype; unsigned int irq; struct clk *clk; struct device *dev; + + /* for DMA */ + struct mxs_dma_data dma_data; + int dma_channel_rx, dma_channel_tx; + int dma_irq_rx, dma_irq_tx; + int dma_channel; + + 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_clear_bit(); + + /* 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_clear_bit(); + } + return; + } + + while (!(readl(s->port.membase + AUART_STAT) & AUART_STAT_TXFF)) { if (s->port.x_char) { @@ -260,10 +412,12 @@ static void mxs_auart_set_mctrl(struct uart_port *u, unsigned mctrl) u32 ctrl = readl(u->membase + AUART_CTRL2); - ctrl &= ~AUART_CTRL2_RTSEN; + 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; @@ -287,10 +441,159 @@ static u32 mxs_auart_get_mctrl(struct uart_port *u) return mctrl; } +static bool mxs_auart_dma_filter(struct dma_chan *chan, void *param) +{ + struct mxs_auart_port *s = param; + + if (!mxs_dma_is_apbx(chan)) + return false; + + if (s->dma_channel == chan->chan_id) { + chan->private = &s->dma_data; + return true; + } + return false; +} + +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_struct *tty = s->port.state->port.tty; + 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(tty, s->rx_dma_buf, count); + + writel(stat, s->port.membase + AUART_STAT); + tty_flip_buffer_push(tty); + + /* 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) +{ + dma_cap_mask_t mask; + + if (auart_dma_enabled(s)) + return 0; + + /* We do not get the right DMA channels. */ + if (s->dma_channel_rx == -1 || s->dma_channel_rx == -1) + return -EINVAL; + + /* init for RX */ + dma_cap_zero(mask); + dma_cap_set(DMA_SLAVE, mask); + s->dma_channel = s->dma_channel_rx; + s->dma_data.chan_irq = s->dma_irq_rx; + s->rx_dma_chan = dma_request_channel(mask, mxs_auart_dma_filter, s); + 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->dma_channel = s->dma_channel_tx; + s->dma_data.chan_irq = s->dma_irq_tx; + s->tx_dma_chan = dma_request_channel(mask, mxs_auart_dma_filter, s); + 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."); + + 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; @@ -362,10 +665,23 @@ static void mxs_auart_settermios(struct uart_port *u, ctrl |= AUART_LINECTRL_STP2; /* figure out the hardware flow control settings */ - if (cflag & CRTSCTS) + 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) && (s->flags & MXS_AUART_DMA_CONFIG)) { + 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 + } else { ctrl2 &= ~(AUART_CTRL2_CTSEN | AUART_CTRL2_RTSEN); + } /* set baud rate */ baud = uart_get_baud_rate(u, termios, old, 0, u->uartclk); @@ -377,6 +693,19 @@ static void mxs_auart_settermios(struct uart_port *u, 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) @@ -395,7 +724,8 @@ 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); } @@ -455,6 +785,9 @@ static void mxs_auart_shutdown(struct uart_port *u) { struct mxs_auart_port *s = to_auart_port(u); + if (auart_dma_enabled(s)) + mxs_auart_dma_exit(s); + writel(AUART_CTRL2_UARTEN, u->membase + AUART_CTRL2_CLR); writel(AUART_INTR_RXIEN | AUART_INTR_RTIEN | AUART_INTR_CTSMIEN, @@ -688,6 +1021,7 @@ static int serial_mxs_probe_dt(struct mxs_auart_port *s, struct platform_device *pdev) { struct device_node *np = pdev->dev.of_node; + u32 dma_channel[2]; int ret; if (!np) @@ -701,11 +1035,27 @@ static int serial_mxs_probe_dt(struct mxs_auart_port *s, } s->port.line = ret; + s->dma_irq_rx = platform_get_irq(pdev, 1); + s->dma_irq_tx = platform_get_irq(pdev, 2); + + ret = of_property_read_u32_array(np, "fsl,auart-dma-channel", + dma_channel, 2); + if (ret == 0) { + s->dma_channel_rx = dma_channel[0]; + s->dma_channel_tx = dma_channel[1]; + + s->flags |= MXS_AUART_DMA_CONFIG; + } else { + s->dma_channel_rx = -1; + s->dma_channel_tx = -1; + } return 0; } -static int __devinit mxs_auart_probe(struct platform_device *pdev) +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; @@ -730,6 +1080,11 @@ static int __devinit mxs_auart_probe(struct platform_device *pdev) 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); @@ -751,7 +1106,6 @@ static int __devinit mxs_auart_probe(struct platform_device *pdev) s->port.type = PORT_IMX; s->port.dev = s->dev = get_device(&pdev->dev); - s->flags = 0; s->ctrl = 0; s->irq = platform_get_irq(pdev, 0); @@ -789,7 +1143,7 @@ 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); @@ -805,15 +1159,9 @@ static int __devexit mxs_auart_remove(struct platform_device *pdev) return 0; } -static struct of_device_id mxs_auart_dt_ids[] = { - { .compatible = "fsl,imx23-auart", }, - { /* sentinel */ } -}; -MODULE_DEVICE_TABLE(of, mxs_auart_dt_ids); - 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, |