/* * Driver for Motorola/Freescale IMX serial ports * * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o. * * Author: Sascha Hauer * Copyright (C) 2004 Pengutronix * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #if defined(CONFIG_SERIAL_IMX_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) #define SUPPORT_SYSRQ #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "serial_mctrl_gpio.h" /* Register definitions */ #define URXD0 0x0 /* Receiver Register */ #define URTX0 0x40 /* Transmitter Register */ #define UCR1 0x80 /* Control Register 1 */ #define UCR2 0x84 /* Control Register 2 */ #define UCR3 0x88 /* Control Register 3 */ #define UCR4 0x8c /* Control Register 4 */ #define UFCR 0x90 /* FIFO Control Register */ #define USR1 0x94 /* Status Register 1 */ #define USR2 0x98 /* Status Register 2 */ #define UESC 0x9c /* Escape Character Register */ #define UTIM 0xa0 /* Escape Timer Register */ #define UBIR 0xa4 /* BRM Incremental Register */ #define UBMR 0xa8 /* BRM Modulator Register */ #define UBRC 0xac /* Baud Rate Count Register */ #define IMX21_ONEMS 0xb0 /* One Millisecond register */ #define IMX1_UTS 0xd0 /* UART Test Register on i.mx1 */ #define IMX21_UTS 0xb4 /* UART Test Register on all other i.mx*/ /* UART Control Register Bit Fields.*/ #define URXD_DUMMY_READ (1<<16) #define URXD_CHARRDY (1<<15) #define URXD_ERR (1<<14) #define URXD_OVRRUN (1<<13) #define URXD_FRMERR (1<<12) #define URXD_BRK (1<<11) #define URXD_PRERR (1<<10) #define URXD_RX_DATA (0xFF<<0) #define UCR1_ADEN (1<<15) /* Auto detect interrupt */ #define UCR1_ADBR (1<<14) /* Auto detect baud rate */ #define UCR1_TRDYEN (1<<13) /* Transmitter ready interrupt enable */ #define UCR1_IDEN (1<<12) /* Idle condition interrupt */ #define UCR1_ICD_REG(x) (((x) & 3) << 10) /* idle condition detect */ #define UCR1_RRDYEN (1<<9) /* Recv ready interrupt enable */ #define UCR1_RDMAEN (1<<8) /* Recv ready DMA enable */ #define UCR1_IREN (1<<7) /* Infrared interface enable */ #define UCR1_TXMPTYEN (1<<6) /* Transimitter empty interrupt enable */ #define UCR1_RTSDEN (1<<5) /* RTS delta interrupt enable */ #define UCR1_SNDBRK (1<<4) /* Send break */ #define UCR1_TDMAEN (1<<3) /* Transmitter ready DMA enable */ #define IMX1_UCR1_UARTCLKEN (1<<2) /* UART clock enabled, i.mx1 only */ #define UCR1_ATDMAEN (1<<2) /* Aging DMA Timer Enable */ #define UCR1_DOZE (1<<1) /* Doze */ #define UCR1_UARTEN (1<<0) /* UART enabled */ #define UCR2_ESCI (1<<15) /* Escape seq interrupt enable */ #define UCR2_IRTS (1<<14) /* Ignore RTS pin */ #define UCR2_CTSC (1<<13) /* CTS pin control */ #define UCR2_CTS (1<<12) /* Clear to send */ #define UCR2_ESCEN (1<<11) /* Escape enable */ #define UCR2_PREN (1<<8) /* Parity enable */ #define UCR2_PROE (1<<7) /* Parity odd/even */ #define UCR2_STPB (1<<6) /* Stop */ #define UCR2_WS (1<<5) /* Word size */ #define UCR2_RTSEN (1<<4) /* Request to send interrupt enable */ #define UCR2_ATEN (1<<3) /* Aging Timer Enable */ #define UCR2_TXEN (1<<2) /* Transmitter enabled */ #define UCR2_RXEN (1<<1) /* Receiver enabled */ #define UCR2_SRST (1<<0) /* SW reset */ #define UCR3_DTREN (1<<13) /* DTR interrupt enable */ #define UCR3_PARERREN (1<<12) /* Parity enable */ #define UCR3_FRAERREN (1<<11) /* Frame error interrupt enable */ #define UCR3_DSR (1<<10) /* Data set ready */ #define UCR3_DCD (1<<9) /* Data carrier detect */ #define UCR3_RI (1<<8) /* Ring indicator */ #define UCR3_ADNIMP (1<<7) /* Autobaud Detection Not Improved */ #define UCR3_RXDSEN (1<<6) /* Receive status interrupt enable */ #define UCR3_AIRINTEN (1<<5) /* Async IR wake interrupt enable */ #define UCR3_AWAKEN (1<<4) /* Async wake interrupt enable */ #define UCR3_DTRDEN (1<<3) /* Data Terminal Ready Delta Enable. */ #define IMX21_UCR3_RXDMUXSEL (1<<2) /* RXD Muxed Input Select */ #define UCR3_INVT (1<<1) /* Inverted Infrared transmission */ #define UCR3_BPEN (1<<0) /* Preset registers enable */ #define UCR4_CTSTL_SHF 10 /* CTS trigger level shift */ #define UCR4_CTSTL_MASK 0x3F /* CTS trigger is 6 bits wide */ #define UCR4_INVR (1<<9) /* Inverted infrared reception */ #define UCR4_ENIRI (1<<8) /* Serial infrared interrupt enable */ #define UCR4_WKEN (1<<7) /* Wake interrupt enable */ #define UCR4_REF16 (1<<6) /* Ref freq 16 MHz */ #define UCR4_IDDMAEN (1<<6) /* DMA IDLE Condition Detected */ #define UCR4_IRSC (1<<5) /* IR special case */ #define UCR4_TCEN (1<<3) /* Transmit complete interrupt enable */ #define UCR4_BKEN (1<<2) /* Break condition interrupt enable */ #define UCR4_OREN (1<<1) /* Receiver overrun interrupt enable */ #define UCR4_DREN (1<<0) /* Recv data ready interrupt enable */ #define UFCR_RXTL_SHF 0 /* Receiver trigger level shift */ #define UFCR_DCEDTE (1<<6) /* DCE/DTE mode select */ #define UFCR_RFDIV (7<<7) /* Reference freq divider mask */ #define UFCR_RFDIV_REG(x) (((x) < 7 ? 6 - (x) : 6) << 7) #define UFCR_TXTL_SHF 10 /* Transmitter trigger level shift */ #define USR1_PARITYERR (1<<15) /* Parity error interrupt flag */ #define USR1_RTSS (1<<14) /* RTS pin status */ #define USR1_TRDY (1<<13) /* Transmitter ready interrupt/dma flag */ #define USR1_RTSD (1<<12) /* RTS delta */ #define USR1_ESCF (1<<11) /* Escape seq interrupt flag */ #define USR1_FRAMERR (1<<10) /* Frame error interrupt flag */ #define USR1_RRDY (1<<9) /* Receiver ready interrupt/dma flag */ #define USR1_AGTIM (1<<8) /* Ageing timer interrupt flag */ #define USR1_DTRD (1<<7) /* DTR Delta */ #define USR1_RXDS (1<<6) /* Receiver idle interrupt flag */ #define USR1_AIRINT (1<<5) /* Async IR wake interrupt flag */ #define USR1_AWAKE (1<<4) /* Aysnc wake interrupt flag */ #define USR2_ADET (1<<15) /* Auto baud rate detect complete */ #define USR2_TXFE (1<<14) /* Transmit buffer FIFO empty */ #define USR2_DTRF (1<<13) /* DTR edge interrupt flag */ #define USR2_IDLE (1<<12) /* Idle condition */ #define USR2_RIDELT (1<<10) /* Ring Interrupt Delta */ #define USR2_RIIN (1<<9) /* Ring Indicator Input */ #define USR2_IRINT (1<<8) /* Serial infrared interrupt flag */ #define USR2_WAKE (1<<7) /* Wake */ #define USR2_DCDIN (1<<5) /* Data Carrier Detect Input */ #define USR2_RTSF (1<<4) /* RTS edge interrupt flag */ #define USR2_TXDC (1<<3) /* Transmitter complete */ #define USR2_BRCD (1<<2) /* Break condition */ #define USR2_ORE (1<<1) /* Overrun error */ #define USR2_RDR (1<<0) /* Recv data ready */ #define UTS_FRCPERR (1<<13) /* Force parity error */ #define UTS_LOOP (1<<12) /* Loop tx and rx */ #define UTS_TXEMPTY (1<<6) /* TxFIFO empty */ #define UTS_RXEMPTY (1<<5) /* RxFIFO empty */ #define UTS_TXFULL (1<<4) /* TxFIFO full */ #define UTS_RXFULL (1<<3) /* RxFIFO full */ #define UTS_SOFTRST (1<<0) /* Software reset */ /* We've been assigned a range on the "Low-density serial ports" major */ #define SERIAL_IMX_MAJOR 207 #define MINOR_START 16 #define DEV_NAME "ttymxc" /* * This determines how often we check the modem status signals * for any change. They generally aren't connected to an IRQ * so we have to poll them. We also check immediately before * filling the TX fifo incase CTS has been dropped. */ #define MCTRL_TIMEOUT (250*HZ/1000) #define DRIVER_NAME "IMX-uart" #define UART_NR 8 /* i.MX21 type uart runs on all i.mx except i.MX1 and i.MX6q */ enum imx_uart_type { IMX1_UART, IMX21_UART, IMX53_UART, IMX6Q_UART, }; /* device type dependent stuff */ struct imx_uart_data { unsigned uts_reg; enum imx_uart_type devtype; }; struct imx_port { struct uart_port port; struct timer_list timer; unsigned int old_status; unsigned int have_rtscts:1; unsigned int have_rtsgpio:1; unsigned int dte_mode:1; unsigned int irda_inv_rx:1; unsigned int irda_inv_tx:1; unsigned short trcv_delay; /* transceiver delay */ struct clk *clk_ipg; struct clk *clk_per; const struct imx_uart_data *devdata; struct mctrl_gpios *gpios; /* DMA fields */ unsigned int dma_is_inited:1; unsigned int dma_is_enabled:1; unsigned int dma_is_rxing:1; unsigned int dma_is_txing:1; struct dma_chan *dma_chan_rx, *dma_chan_tx; struct scatterlist rx_sgl, tx_sgl[2]; void *rx_buf; struct circ_buf rx_ring; unsigned int rx_periods; dma_cookie_t rx_cookie; unsigned int tx_bytes; unsigned int dma_tx_nents; wait_queue_head_t dma_wait; unsigned int saved_reg[10]; bool context_saved; }; struct imx_port_ucrs { unsigned int ucr1; unsigned int ucr2; unsigned int ucr3; }; static struct imx_uart_data imx_uart_devdata[] = { [IMX1_UART] = { .uts_reg = IMX1_UTS, .devtype = IMX1_UART, }, [IMX21_UART] = { .uts_reg = IMX21_UTS, .devtype = IMX21_UART, }, [IMX53_UART] = { .uts_reg = IMX21_UTS, .devtype = IMX53_UART, }, [IMX6Q_UART] = { .uts_reg = IMX21_UTS, .devtype = IMX6Q_UART, }, }; static const struct platform_device_id imx_uart_devtype[] = { { .name = "imx1-uart", .driver_data = (kernel_ulong_t) &imx_uart_devdata[IMX1_UART], }, { .name = "imx21-uart", .driver_data = (kernel_ulong_t) &imx_uart_devdata[IMX21_UART], }, { .name = "imx53-uart", .driver_data = (kernel_ulong_t) &imx_uart_devdata[IMX53_UART], }, { .name = "imx6q-uart", .driver_data = (kernel_ulong_t) &imx_uart_devdata[IMX6Q_UART], }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(platform, imx_uart_devtype); static const struct of_device_id imx_uart_dt_ids[] = { { .compatible = "fsl,imx6q-uart", .data = &imx_uart_devdata[IMX6Q_UART], }, { .compatible = "fsl,imx53-uart", .data = &imx_uart_devdata[IMX53_UART], }, { .compatible = "fsl,imx1-uart", .data = &imx_uart_devdata[IMX1_UART], }, { .compatible = "fsl,imx21-uart", .data = &imx_uart_devdata[IMX21_UART], }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, imx_uart_dt_ids); static inline unsigned uts_reg(struct imx_port *sport) { return sport->devdata->uts_reg; } static inline int is_imx1_uart(struct imx_port *sport) { return sport->devdata->devtype == IMX1_UART; } static inline int is_imx21_uart(struct imx_port *sport) { return sport->devdata->devtype == IMX21_UART; } static inline int is_imx53_uart(struct imx_port *sport) { return sport->devdata->devtype == IMX53_UART; } static inline int is_imx6q_uart(struct imx_port *sport) { return sport->devdata->devtype == IMX6Q_UART; } /* * Save and restore functions for UCR1, UCR2 and UCR3 registers */ #if defined(CONFIG_SERIAL_IMX_CONSOLE) static void imx_port_ucrs_save(struct uart_port *port, struct imx_port_ucrs *ucr) { /* save control registers */ ucr->ucr1 = readl(port->membase + UCR1); ucr->ucr2 = readl(port->membase + UCR2); ucr->ucr3 = readl(port->membase + UCR3); } static void imx_port_ucrs_restore(struct uart_port *port, struct imx_port_ucrs *ucr) { /* restore control registers */ writel(ucr->ucr1, port->membase + UCR1); writel(ucr->ucr2, port->membase + UCR2); writel(ucr->ucr3, port->membase + UCR3); } #endif static void imx_port_rts_active(struct imx_port *sport, unsigned long *ucr2) { *ucr2 &= ~(UCR2_CTSC | UCR2_CTS); mctrl_gpio_set(sport->gpios, sport->port.mctrl | TIOCM_RTS); } static void imx_port_rts_inactive(struct imx_port *sport, unsigned long *ucr2) { *ucr2 &= ~UCR2_CTSC; *ucr2 |= UCR2_CTS; mctrl_gpio_set(sport->gpios, sport->port.mctrl & ~TIOCM_RTS); } static void imx_port_rts_auto(struct imx_port *sport, unsigned long *ucr2) { *ucr2 |= UCR2_CTSC; } /* * interrupts disabled on entry */ static void imx_stop_tx(struct uart_port *port) { struct imx_port *sport = (struct imx_port *)port; unsigned long temp; /* * We are maybe in the SMP context, so if the DMA TX thread is running * on other cpu, we have to wait for it to finish. */ if (sport->dma_is_enabled && sport->dma_is_txing) return; temp = readl(port->membase + UCR1); writel(temp & ~UCR1_TXMPTYEN, port->membase + UCR1); /* in rs485 mode disable transmitter if shifter is empty */ if (port->rs485.flags & SER_RS485_ENABLED && readl(port->membase + USR2) & USR2_TXDC) { temp = readl(port->membase + UCR2); if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND) imx_port_rts_active(sport, &temp); else imx_port_rts_inactive(sport, &temp); temp |= UCR2_RXEN; writel(temp, port->membase + UCR2); temp = readl(port->membase + UCR4); temp &= ~UCR4_TCEN; writel(temp, port->membase + UCR4); } } /* * interrupts disabled on entry */ static void imx_stop_rx(struct uart_port *port) { struct imx_port *sport = (struct imx_port *)port; unsigned long temp; if (sport->dma_is_enabled && sport->dma_is_rxing) { if (sport->port.suspended) { dmaengine_terminate_all(sport->dma_chan_rx); sport->dma_is_rxing = 0; } else { return; } } temp = readl(sport->port.membase + UCR2); writel(temp & ~UCR2_RXEN, sport->port.membase + UCR2); /* disable the `Receiver Ready Interrrupt` */ temp = readl(sport->port.membase + UCR1); writel(temp & ~UCR1_RRDYEN, sport->port.membase + UCR1); } /* * Set the modem control timer to fire immediately. */ static void imx_enable_ms(struct uart_port *port) { struct imx_port *sport = (struct imx_port *)port; mod_timer(&sport->timer, jiffies); mctrl_gpio_enable_ms(sport->gpios); } static void imx_dma_tx(struct imx_port *sport); static inline void imx_transmit_buffer(struct imx_port *sport) { struct circ_buf *xmit = &sport->port.state->xmit; unsigned long temp; if (sport->port.x_char) { /* Send next char */ writel(sport->port.x_char, sport->port.membase + URTX0); sport->port.icount.tx++; sport->port.x_char = 0; return; } if (uart_circ_empty(xmit) || uart_tx_stopped(&sport->port)) { imx_stop_tx(&sport->port); return; } if (sport->dma_is_enabled) { /* * We've just sent a X-char Ensure the TX DMA is enabled * and the TX IRQ is disabled. **/ temp = readl(sport->port.membase + UCR1); temp &= ~UCR1_TXMPTYEN; if (sport->dma_is_txing) { temp |= UCR1_TDMAEN; writel(temp, sport->port.membase + UCR1); } else { writel(temp, sport->port.membase + UCR1); imx_dma_tx(sport); } } while (!uart_circ_empty(xmit) && !(readl(sport->port.membase + uts_reg(sport)) & UTS_TXFULL)) { /* send xmit->buf[xmit->tail] * out the port here */ writel(xmit->buf[xmit->tail], sport->port.membase + URTX0); xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); sport->port.icount.tx++; } if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(&sport->port); if (uart_circ_empty(xmit)) imx_stop_tx(&sport->port); } static void dma_tx_callback(void *data) { struct imx_port *sport = data; struct scatterlist *sgl = &sport->tx_sgl[0]; struct circ_buf *xmit = &sport->port.state->xmit; unsigned long flags; unsigned long temp; spin_lock_irqsave(&sport->port.lock, flags); dma_unmap_sg(sport->port.dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE); temp = readl(sport->port.membase + UCR1); temp &= ~UCR1_TDMAEN; writel(temp, sport->port.membase + UCR1); /* update the stat */ xmit->tail = (xmit->tail + sport->tx_bytes) & (UART_XMIT_SIZE - 1); sport->port.icount.tx += sport->tx_bytes; dev_dbg(sport->port.dev, "we finish the TX DMA.\n"); sport->dma_is_txing = 0; spin_unlock_irqrestore(&sport->port.lock, flags); if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(&sport->port); if (waitqueue_active(&sport->dma_wait)) { wake_up(&sport->dma_wait); dev_dbg(sport->port.dev, "exit in %s.\n", __func__); return; } spin_lock_irqsave(&sport->port.lock, flags); if (!uart_circ_empty(xmit) && !uart_tx_stopped(&sport->port)) imx_dma_tx(sport); spin_unlock_irqrestore(&sport->port.lock, flags); } static void imx_dma_tx(struct imx_port *sport) { struct circ_buf *xmit = &sport->port.state->xmit; struct scatterlist *sgl = sport->tx_sgl; struct dma_async_tx_descriptor *desc; struct dma_chan *chan = sport->dma_chan_tx; struct device *dev = sport->port.dev; unsigned long temp; int ret; if (sport->dma_is_txing) return; sport->tx_bytes = uart_circ_chars_pending(xmit); if (xmit->tail < xmit->head) { sport->dma_tx_nents = 1; sg_init_one(sgl, xmit->buf + xmit->tail, sport->tx_bytes); } else { sport->dma_tx_nents = 2; sg_init_table(sgl, 2); sg_set_buf(sgl, xmit->buf + xmit->tail, UART_XMIT_SIZE - xmit->tail); sg_set_buf(sgl + 1, xmit->buf, xmit->head); } ret = dma_map_sg(dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE); if (ret == 0) { dev_err(dev, "DMA mapping error for TX.\n"); return; } desc = dmaengine_prep_slave_sg(chan, sgl, sport->dma_tx_nents, DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT); if (!desc) { dma_unmap_sg(dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE); dev_err(dev, "We cannot prepare for the TX slave dma!\n"); return; } desc->callback = dma_tx_callback; desc->callback_param = sport; dev_dbg(dev, "TX: prepare to send %lu bytes by DMA.\n", uart_circ_chars_pending(xmit)); temp = readl(sport->port.membase + UCR1); temp |= UCR1_TDMAEN; writel(temp, sport->port.membase + UCR1); /* fire it */ sport->dma_is_txing = 1; dmaengine_submit(desc); dma_async_issue_pending(chan); return; } /* * interrupts disabled on entry */ static void imx_start_tx(struct uart_port *port) { struct imx_port *sport = (struct imx_port *)port; unsigned long temp; if (port->rs485.flags & SER_RS485_ENABLED) { temp = readl(port->membase + UCR2); if (port->rs485.flags & SER_RS485_RTS_ON_SEND) imx_port_rts_active(sport, &temp); else imx_port_rts_inactive(sport, &temp); if (!(port->rs485.flags & SER_RS485_RX_DURING_TX)) temp &= ~UCR2_RXEN; writel(temp, port->membase + UCR2); /* enable transmitter and shifter empty irq */ temp = readl(port->membase + UCR4); temp |= UCR4_TCEN; writel(temp, port->membase + UCR4); } if (!sport->dma_is_enabled) { temp = readl(sport->port.membase + UCR1); writel(temp | UCR1_TXMPTYEN, sport->port.membase + UCR1); } if (sport->dma_is_enabled) { if (sport->port.x_char) { /* We have X-char to send, so enable TX IRQ and * disable TX DMA to let TX interrupt to send X-char */ temp = readl(sport->port.membase + UCR1); temp &= ~UCR1_TDMAEN; temp |= UCR1_TXMPTYEN; writel(temp, sport->port.membase + UCR1); return; } if (!uart_circ_empty(&port->state->xmit) && !uart_tx_stopped(port)) imx_dma_tx(sport); return; } } static irqreturn_t imx_rtsint(int irq, void *dev_id) { struct imx_port *sport = dev_id; unsigned int val; unsigned long flags; spin_lock_irqsave(&sport->port.lock, flags); writel(USR1_RTSD, sport->port.membase + USR1); val = readl(sport->port.membase + USR1) & USR1_RTSS; uart_handle_cts_change(&sport->port, !!val); wake_up_interruptible(&sport->port.state->port.delta_msr_wait); spin_unlock_irqrestore(&sport->port.lock, flags); return IRQ_HANDLED; } static irqreturn_t imx_txint(int irq, void *dev_id) { struct imx_port *sport = dev_id; unsigned long flags; spin_lock_irqsave(&sport->port.lock, flags); imx_transmit_buffer(sport); spin_unlock_irqrestore(&sport->port.lock, flags); return IRQ_HANDLED; } static irqreturn_t imx_rxint(int irq, void *dev_id) { struct imx_port *sport = dev_id; unsigned int rx, flg, ignored = 0; struct tty_port *port = &sport->port.state->port; unsigned long flags, temp; spin_lock_irqsave(&sport->port.lock, flags); while (readl(sport->port.membase + USR2) & USR2_RDR) { flg = TTY_NORMAL; sport->port.icount.rx++; rx = readl(sport->port.membase + URXD0); temp = readl(sport->port.membase + USR2); if (temp & USR2_BRCD) { writel(USR2_BRCD, sport->port.membase + USR2); if (uart_handle_break(&sport->port)) continue; } if (uart_handle_sysrq_char(&sport->port, (unsigned char)rx)) continue; if (unlikely(rx & URXD_ERR)) { if (rx & URXD_BRK) sport->port.icount.brk++; else if (rx & URXD_PRERR) sport->port.icount.parity++; else if (rx & URXD_FRMERR) sport->port.icount.frame++; if (rx & URXD_OVRRUN) sport->port.icount.overrun++; if (rx & sport->port.ignore_status_mask) { if (++ignored > 100) goto out; continue; } rx &= (sport->port.read_status_mask | 0xFF); if (rx & URXD_BRK) flg = TTY_BREAK; else if (rx & URXD_PRERR) flg = TTY_PARITY; else if (rx & URXD_FRMERR) flg = TTY_FRAME; if (rx & URXD_OVRRUN) flg = TTY_OVERRUN; #ifdef SUPPORT_SYSRQ sport->port.sysrq = 0; #endif } if (sport->port.ignore_status_mask & URXD_DUMMY_READ) goto out; if (tty_insert_flip_char(port, rx, flg) == 0) sport->port.icount.buf_overrun++; } out: spin_unlock_irqrestore(&sport->port.lock, flags); tty_flip_buffer_push(port); return IRQ_HANDLED; } static void imx_disable_rx_int(struct imx_port *sport) { unsigned long temp; sport->dma_is_rxing = 1; /* disable the receiver ready and aging timer interrupts */ temp = readl(sport->port.membase + UCR1); temp &= ~(UCR1_RRDYEN); writel(temp, sport->port.membase + UCR1); temp = readl(sport->port.membase + UCR2); temp &= ~(UCR2_ATEN); writel(temp, sport->port.membase + UCR2); /* disable the rx errors interrupts */ temp = readl(sport->port.membase + UCR4); temp &= ~UCR4_OREN; writel(temp, sport->port.membase + UCR4); } static void clear_rx_errors(struct imx_port *sport); static int start_rx_dma(struct imx_port *sport); /* * If the RXFIFO is filled with some data, and then we * arise a DMA operation to receive them. */ static void imx_dma_rxint(struct imx_port *sport) { unsigned long temp; unsigned long flags; spin_lock_irqsave(&sport->port.lock, flags); temp = readl(sport->port.membase + USR2); if ((temp & USR2_RDR) && !sport->dma_is_rxing) { imx_disable_rx_int(sport); /* tell the DMA to receive the data. */ start_rx_dma(sport); } spin_unlock_irqrestore(&sport->port.lock, flags); } /* * We have a modem side uart, so the meanings of RTS and CTS are inverted. */ static unsigned int imx_get_hwmctrl(struct imx_port *sport) { unsigned int tmp = TIOCM_DSR; unsigned usr1 = readl(sport->port.membase + USR1); unsigned usr2 = readl(sport->port.membase + USR2); if (usr1 & USR1_RTSS) tmp |= TIOCM_CTS; /* in DCE mode DCDIN is always 0 */ if (!(usr2 & USR2_DCDIN)) tmp |= TIOCM_CAR; if (sport->dte_mode) if (!(readl(sport->port.membase + USR2) & USR2_RIIN)) tmp |= TIOCM_RI; return tmp; } /* * Handle any change of modem status signal since we were last called. */ static void imx_mctrl_check(struct imx_port *sport) { unsigned int status, changed; status = imx_get_hwmctrl(sport); changed = status ^ sport->old_status; if (changed == 0) return; sport->old_status = status; if (changed & TIOCM_RI && status & TIOCM_RI) sport->port.icount.rng++; if (changed & TIOCM_DSR) sport->port.icount.dsr++; if (changed & TIOCM_CAR) uart_handle_dcd_change(&sport->port, status & TIOCM_CAR); if (changed & TIOCM_CTS) uart_handle_cts_change(&sport->port, status & TIOCM_CTS); wake_up_interruptible(&sport->port.state->port.delta_msr_wait); } static irqreturn_t imx_int(int irq, void *dev_id) { struct imx_port *sport = dev_id; unsigned int sts; unsigned int sts2; irqreturn_t ret = IRQ_NONE; sts = readl(sport->port.membase + USR1); sts2 = readl(sport->port.membase + USR2); if (sts & (USR1_RRDY | USR1_AGTIM)) { if (sport->dma_is_enabled) imx_dma_rxint(sport); else imx_rxint(irq, dev_id); ret = IRQ_HANDLED; } if ((sts & USR1_TRDY && readl(sport->port.membase + UCR1) & UCR1_TXMPTYEN) || (sts2 & USR2_TXDC && readl(sport->port.membase + UCR4) & UCR4_TCEN)) { imx_txint(irq, dev_id); ret = IRQ_HANDLED; } if (sts & USR1_DTRD) { unsigned long flags; if (sts & USR1_DTRD) writel(USR1_DTRD, sport->port.membase + USR1); spin_lock_irqsave(&sport->port.lock, flags); imx_mctrl_check(sport); spin_unlock_irqrestore(&sport->port.lock, flags); ret = IRQ_HANDLED; } if (sts & USR1_RTSD) { imx_rtsint(irq, dev_id); ret = IRQ_HANDLED; } if (sts & USR1_AWAKE) { writel(USR1_AWAKE, sport->port.membase + USR1); ret = IRQ_HANDLED; } if (sts2 & USR2_ORE) { sport->port.icount.overrun++; writel(USR2_ORE, sport->port.membase + USR2); ret = IRQ_HANDLED; } return ret; } /* * Return TIOCSER_TEMT when transmitter is not busy. */ static unsigned int imx_tx_empty(struct uart_port *port) { struct imx_port *sport = (struct imx_port *)port; unsigned int ret; ret = (readl(sport->port.membase + USR2) & USR2_TXDC) ? TIOCSER_TEMT : 0; /* If the TX DMA is working, return 0. */ if (sport->dma_is_enabled && sport->dma_is_txing) ret = 0; return ret; } static unsigned int imx_get_mctrl(struct uart_port *port) { struct imx_port *sport = (struct imx_port *)port; unsigned int ret = imx_get_hwmctrl(sport); mctrl_gpio_get(sport->gpios, &ret); return ret; } static void imx_set_mctrl(struct uart_port *port, unsigned int mctrl) { struct imx_port *sport = (struct imx_port *)port; unsigned long temp; if (!(port->rs485.flags & SER_RS485_ENABLED)) { temp = readl(sport->port.membase + UCR2); temp &= ~(UCR2_CTS | UCR2_CTSC); if (mctrl & TIOCM_RTS) temp |= UCR2_CTS | UCR2_CTSC; writel(temp, sport->port.membase + UCR2); } temp = readl(sport->port.membase + UCR3) & ~UCR3_DSR; if (!(mctrl & TIOCM_DTR)) temp |= UCR3_DSR; writel(temp, sport->port.membase + UCR3); temp = readl(sport->port.membase + uts_reg(sport)) & ~UTS_LOOP; if (mctrl & TIOCM_LOOP) temp |= UTS_LOOP; writel(temp, sport->port.membase + uts_reg(sport)); mctrl_gpio_set(sport->gpios, mctrl); } /* * Interrupts always disabled. */ static void imx_break_ctl(struct uart_port *port, int break_state) { struct imx_port *sport = (struct imx_port *)port; unsigned long flags, temp; spin_lock_irqsave(&sport->port.lock, flags); temp = readl(sport->port.membase + UCR1) & ~UCR1_SNDBRK; if (break_state != 0) temp |= UCR1_SNDBRK; writel(temp, sport->port.membase + UCR1); spin_unlock_irqrestore(&sport->port.lock, flags); } /* * This is our per-port timeout handler, for checking the * modem status signals. */ static void imx_timeout(unsigned long data) { struct imx_port *sport = (struct imx_port *)data; unsigned long flags; if (sport->port.state) { spin_lock_irqsave(&sport->port.lock, flags); imx_mctrl_check(sport); spin_unlock_irqrestore(&sport->port.lock, flags); mod_timer(&sport->timer, jiffies + MCTRL_TIMEOUT); } } #define RX_BUF_SIZE (PAGE_SIZE) /* * There are two kinds of RX DMA interrupts(such as in the MX6Q): * [1] the RX DMA buffer is full. * [2] the aging timer expires * * Condition [2] is triggered when a character has been sitting in the FIFO * for at least 8 byte durations. */ static void dma_rx_callback(void *data) { struct imx_port *sport = data; struct dma_chan *chan = sport->dma_chan_rx; struct scatterlist *sgl = &sport->rx_sgl; struct tty_port *port = &sport->port.state->port; struct dma_tx_state state; struct circ_buf *rx_ring = &sport->rx_ring; enum dma_status status; unsigned int w_bytes = 0; unsigned int r_bytes; unsigned int bd_size; status = dmaengine_tx_status(chan, (dma_cookie_t)0, &state); if (status == DMA_ERROR) { dev_err(sport->port.dev, "DMA transaction error.\n"); clear_rx_errors(sport); return; } if (!(sport->port.ignore_status_mask & URXD_DUMMY_READ)) { /* * The state-residue variable represents the empty space * relative to the entire buffer. Taking this in consideration * the head is always calculated base on the buffer total * length - DMA transaction residue. The UART script from the * SDMA firmware will jump to the next buffer descriptor, * once a DMA transaction if finalized (IMX53 RM - A.4.1.2.4). * Taking this in consideration the tail is always at the * beginning of the buffer descriptor that contains the head. */ /* Calculate the head */ rx_ring->head = sg_dma_len(sgl) - state.residue; /* Calculate the tail. */ bd_size = sg_dma_len(sgl) / sport->rx_periods; rx_ring->tail = ((rx_ring->head-1) / bd_size) * bd_size; if (rx_ring->head <= sg_dma_len(sgl) && rx_ring->head > rx_ring->tail) { /* Move data from tail to head */ r_bytes = rx_ring->head - rx_ring->tail; /* CPU claims ownership of RX DMA buffer */ dma_sync_sg_for_cpu(sport->port.dev, sgl, 1, DMA_FROM_DEVICE); w_bytes = tty_insert_flip_string(port, sport->rx_buf + rx_ring->tail, r_bytes); /* UART retrieves ownership of RX DMA buffer */ dma_sync_sg_for_device(sport->port.dev, sgl, 1, DMA_FROM_DEVICE); if (w_bytes != r_bytes) sport->port.icount.buf_overrun++; sport->port.icount.rx += w_bytes; } else { WARN_ON(rx_ring->head > sg_dma_len(sgl)); WARN_ON(rx_ring->head <= rx_ring->tail); } } if (w_bytes) { tty_flip_buffer_push(port); dev_dbg(sport->port.dev, "We get %d bytes.\n", w_bytes); } } /* RX DMA buffer periods */ #define RX_DMA_PERIODS 4 static int start_rx_dma(struct imx_port *sport) { struct scatterlist *sgl = &sport->rx_sgl; struct dma_chan *chan = sport->dma_chan_rx; struct device *dev = sport->port.dev; struct dma_async_tx_descriptor *desc; int ret; sport->rx_ring.head = 0; sport->rx_ring.tail = 0; sport->rx_periods = RX_DMA_PERIODS; sg_init_one(sgl, sport->rx_buf, RX_BUF_SIZE); ret = dma_map_sg(dev, sgl, 1, DMA_FROM_DEVICE); if (ret == 0) { dev_err(dev, "DMA mapping error for RX.\n"); return -EINVAL; } desc = dmaengine_prep_dma_cyclic(chan, sg_dma_address(sgl), sg_dma_len(sgl), sg_dma_len(sgl) / sport->rx_periods, DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT); if (!desc) { dma_unmap_sg(dev, sgl, 1, DMA_FROM_DEVICE); dev_err(dev, "We cannot prepare for the RX slave dma!\n"); return -EINVAL; } desc->callback = dma_rx_callback; desc->callback_param = sport; dev_dbg(dev, "RX: prepare for the DMA.\n"); sport->rx_cookie = dmaengine_submit(desc); dma_async_issue_pending(chan); return 0; } static void clear_rx_errors(struct imx_port *sport) { unsigned int status_usr1, status_usr2; status_usr1 = readl(sport->port.membase + USR1); status_usr2 = readl(sport->port.membase + USR2); if (status_usr2 & USR2_BRCD) { sport->port.icount.brk++; writel(USR2_BRCD, sport->port.membase + USR2); } else if (status_usr1 & USR1_FRAMERR) { sport->port.icount.frame++; writel(USR1_FRAMERR, sport->port.membase + USR1); } else if (status_usr1 & USR1_PARITYERR) { sport->port.icount.parity++; writel(USR1_PARITYERR, sport->port.membase + USR1); } if (status_usr2 & USR2_ORE) { sport->port.icount.overrun++; writel(USR2_ORE, sport->port.membase + USR2); } } #define TXTL_DEFAULT 2 /* reset default */ #define RXTL_DEFAULT 1 /* reset default */ #define TXTL_DMA 8 /* DMA burst setting */ #define RXTL_DMA 9 /* DMA burst setting */ static void imx_setup_ufcr(struct imx_port *sport, unsigned char txwl, unsigned char rxwl) { unsigned int val; /* set receiver / transmitter trigger level */ val = readl(sport->port.membase + UFCR) & (UFCR_RFDIV | UFCR_DCEDTE); val |= txwl << UFCR_TXTL_SHF | rxwl; writel(val, sport->port.membase + UFCR); } static void imx_uart_dma_exit(struct imx_port *sport) { if (sport->dma_chan_rx) { dmaengine_terminate_sync(sport->dma_chan_rx); dma_release_channel(sport->dma_chan_rx); sport->dma_chan_rx = NULL; sport->rx_cookie = -EINVAL; kfree(sport->rx_buf); sport->rx_buf = NULL; } if (sport->dma_chan_tx) { dmaengine_terminate_sync(sport->dma_chan_tx); dma_release_channel(sport->dma_chan_tx); sport->dma_chan_tx = NULL; } sport->dma_is_inited = 0; } static int imx_uart_dma_init(struct imx_port *sport) { struct dma_slave_config slave_config = {}; struct device *dev = sport->port.dev; int ret; /* Prepare for RX : */ sport->dma_chan_rx = dma_request_slave_channel(dev, "rx"); if (!sport->dma_chan_rx) { dev_dbg(dev, "cannot get the DMA channel.\n"); ret = -EINVAL; goto err; } slave_config.direction = DMA_DEV_TO_MEM; slave_config.src_addr = sport->port.mapbase + URXD0; slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; /* one byte less than the watermark level to enable the aging timer */ slave_config.src_maxburst = RXTL_DMA - 1; ret = dmaengine_slave_config(sport->dma_chan_rx, &slave_config); if (ret) { dev_err(dev, "error in RX dma configuration.\n"); goto err; } sport->rx_buf = kzalloc(PAGE_SIZE, GFP_KERNEL); if (!sport->rx_buf) { ret = -ENOMEM; goto err; } sport->rx_ring.buf = sport->rx_buf; /* Prepare for TX : */ sport->dma_chan_tx = dma_request_slave_channel(dev, "tx"); if (!sport->dma_chan_tx) { dev_err(dev, "cannot get the TX DMA channel!\n"); ret = -EINVAL; goto err; } slave_config.direction = DMA_MEM_TO_DEV; slave_config.dst_addr = sport->port.mapbase + URTX0; slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; slave_config.dst_maxburst = TXTL_DMA; ret = dmaengine_slave_config(sport->dma_chan_tx, &slave_config); if (ret) { dev_err(dev, "error in TX dma configuration."); goto err; } sport->dma_is_inited = 1; return 0; err: imx_uart_dma_exit(sport); return ret; } static void imx_enable_dma(struct imx_port *sport) { unsigned long temp; init_waitqueue_head(&sport->dma_wait); /* set UCR1 */ temp = readl(sport->port.membase + UCR1); temp |= UCR1_RDMAEN | UCR1_TDMAEN | UCR1_ATDMAEN; writel(temp, sport->port.membase + UCR1); temp = readl(sport->port.membase + UCR2); temp |= UCR2_ATEN; writel(temp, sport->port.membase + UCR2); imx_setup_ufcr(sport, TXTL_DMA, RXTL_DMA); sport->dma_is_enabled = 1; } static void imx_disable_dma(struct imx_port *sport) { unsigned long temp; /* clear UCR1 */ temp = readl(sport->port.membase + UCR1); temp &= ~(UCR1_RDMAEN | UCR1_TDMAEN | UCR1_ATDMAEN); writel(temp, sport->port.membase + UCR1); /* clear UCR2 */ temp = readl(sport->port.membase + UCR2); temp &= ~(UCR2_CTSC | UCR2_CTS | UCR2_ATEN); writel(temp, sport->port.membase + UCR2); imx_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT); sport->dma_is_enabled = 0; } /* half the RX buffer size */ #define CTSTL 16 static int imx_startup(struct uart_port *port) { struct imx_port *sport = (struct imx_port *)port; int retval, i; unsigned long flags, temp; retval = clk_prepare_enable(sport->clk_per); if (retval) return retval; retval = clk_prepare_enable(sport->clk_ipg); if (retval) { clk_disable_unprepare(sport->clk_per); return retval; } imx_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT); /* disable the DREN bit (Data Ready interrupt enable) before * requesting IRQs */ temp = readl(sport->port.membase + UCR4); /* set the trigger level for CTS */ temp &= ~(UCR4_CTSTL_MASK << UCR4_CTSTL_SHF); temp |= CTSTL << UCR4_CTSTL_SHF; writel(temp & ~UCR4_DREN, sport->port.membase + UCR4); /* Can we enable the DMA support? */ if (!uart_console(port) && !sport->dma_is_inited) imx_uart_dma_init(sport); spin_lock_irqsave(&sport->port.lock, flags); /* Reset fifo's and state machines */ i = 100; temp = readl(sport->port.membase + UCR2); temp &= ~UCR2_SRST; writel(temp, sport->port.membase + UCR2); while (!(readl(sport->port.membase + UCR2) & UCR2_SRST) && (--i > 0)) udelay(1); /* * Finally, clear and enable interrupts */ writel(USR1_RTSD | USR1_DTRD, sport->port.membase + USR1); writel(USR2_ORE, sport->port.membase + USR2); if (sport->dma_is_inited && !sport->dma_is_enabled) imx_enable_dma(sport); temp = readl(sport->port.membase + UCR1); temp |= UCR1_RRDYEN | UCR1_RTSDEN | UCR1_UARTEN; writel(temp, sport->port.membase + UCR1); temp = readl(sport->port.membase + UCR4); temp |= UCR4_OREN; writel(temp, sport->port.membase + UCR4); temp = readl(sport->port.membase + UCR2); temp |= (UCR2_RXEN | UCR2_TXEN); if (!sport->have_rtscts) temp |= UCR2_IRTS; /* * make sure the edge sensitive RTS-irq is disabled, * we're using RTSD instead. */ if (!is_imx1_uart(sport)) temp &= ~UCR2_RTSEN; writel(temp, sport->port.membase + UCR2); if (!is_imx1_uart(sport)) { temp = readl(sport->port.membase + UCR3); temp |= UCR3_DTRDEN | UCR3_RI | UCR3_DCD; if (sport->dte_mode) /* disable broken interrupts */ temp &= ~(UCR3_RI | UCR3_DCD); writel(temp, sport->port.membase + UCR3); } /* * Enable modem status interrupts */ imx_enable_ms(&sport->port); /* * If the serial port is opened for reading start RX DMA immediately * instead of waiting for RX FIFO interrupts. In our iMX53 the average * delay for the first reception dropped from approximately 35000 * microseconds to 1000 microseconds. */ if (sport->dma_is_enabled) { struct tty_struct *tty = sport->port.state->port.tty; struct tty_file_private *file_priv; int readcnt = 0; spin_lock(&tty->files_lock); if (!list_empty(&tty->tty_files)) list_for_each_entry(file_priv, &tty->tty_files, list) if (!(file_priv->file->f_flags & O_WRONLY)) readcnt++; spin_unlock(&tty->files_lock); if (readcnt > 0) { imx_disable_rx_int(sport); start_rx_dma(sport); } } spin_unlock_irqrestore(&sport->port.lock, flags); return 0; } static void imx_shutdown(struct uart_port *port) { struct imx_port *sport = (struct imx_port *)port; unsigned long temp; unsigned long flags; if (sport->dma_is_enabled) { sport->dma_is_rxing = 0; sport->dma_is_txing = 0; dmaengine_terminate_sync(sport->dma_chan_tx); dmaengine_terminate_sync(sport->dma_chan_rx); spin_lock_irqsave(&sport->port.lock, flags); imx_stop_tx(port); imx_stop_rx(port); imx_disable_dma(sport); spin_unlock_irqrestore(&sport->port.lock, flags); imx_uart_dma_exit(sport); } mctrl_gpio_disable_ms(sport->gpios); spin_lock_irqsave(&sport->port.lock, flags); temp = readl(sport->port.membase + UCR2); temp &= ~(UCR2_TXEN); writel(temp, sport->port.membase + UCR2); spin_unlock_irqrestore(&sport->port.lock, flags); /* * Stop our timer. */ del_timer_sync(&sport->timer); /* * Disable all interrupts, port and break condition. */ spin_lock_irqsave(&sport->port.lock, flags); temp = readl(sport->port.membase + UCR1); temp &= ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN | UCR1_UARTEN); writel(temp, sport->port.membase + UCR1); spin_unlock_irqrestore(&sport->port.lock, flags); clk_disable_unprepare(sport->clk_per); clk_disable_unprepare(sport->clk_ipg); } static void imx_flush_buffer(struct uart_port *port) { struct imx_port *sport = (struct imx_port *)port; struct scatterlist *sgl = &sport->tx_sgl[0]; unsigned long temp; int i = 100, ubir, ubmr, uts; if (!sport->dma_chan_tx) return; sport->tx_bytes = 0; dmaengine_terminate_all(sport->dma_chan_tx); if (sport->dma_is_txing) { dma_unmap_sg(sport->port.dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE); temp = readl(sport->port.membase + UCR1); temp &= ~UCR1_TDMAEN; writel(temp, sport->port.membase + UCR1); sport->dma_is_txing = false; } /* * According to the Reference Manual description of the UART SRST bit: * "Reset the transmit and receive state machines, * all FIFOs and register USR1, USR2, UBIR, UBMR, UBRC, URXD, UTXD * and UTS[6-3]". As we don't need to restore the old values from * USR1, USR2, URXD, UTXD, only save/restore the other four registers */ ubir = readl(sport->port.membase + UBIR); ubmr = readl(sport->port.membase + UBMR); uts = readl(sport->port.membase + IMX21_UTS); temp = readl(sport->port.membase + UCR2); temp &= ~UCR2_SRST; writel(temp, sport->port.membase + UCR2); while (!(readl(sport->port.membase + UCR2) & UCR2_SRST) && (--i > 0)) udelay(1); /* Restore the registers */ writel(ubir, sport->port.membase + UBIR); writel(ubmr, sport->port.membase + UBMR); writel(uts, sport->port.membase + IMX21_UTS); } static void imx_set_termios(struct uart_port *port, struct ktermios *termios, struct ktermios *old) { struct imx_port *sport = (struct imx_port *)port; unsigned long flags; unsigned long ucr2, old_ucr1, old_ucr2; unsigned int baud, quot; unsigned int old_csize = old ? old->c_cflag & CSIZE : CS8; unsigned long div, ufcr; unsigned long num, denom; uint64_t tdiv64; /* * We only support CS7 and CS8. */ while ((termios->c_cflag & CSIZE) != CS7 && (termios->c_cflag & CSIZE) != CS8) { termios->c_cflag &= ~CSIZE; termios->c_cflag |= old_csize; old_csize = CS8; } if ((termios->c_cflag & CSIZE) == CS8) ucr2 = UCR2_WS | UCR2_SRST | UCR2_IRTS; else ucr2 = UCR2_SRST | UCR2_IRTS; if (termios->c_cflag & CRTSCTS) { if (sport->have_rtscts) { ucr2 &= ~UCR2_IRTS; if (port->rs485.flags & SER_RS485_ENABLED) { /* * RTS is mandatory for rs485 operation, so keep * it under manual control and keep transmitter * disabled. */ if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND) imx_port_rts_active(sport, &ucr2); else imx_port_rts_inactive(sport, &ucr2); } else { imx_port_rts_auto(sport, &ucr2); } } else { termios->c_cflag &= ~CRTSCTS; } } else if (port->rs485.flags & SER_RS485_ENABLED) { /* disable transmitter */ if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND) imx_port_rts_active(sport, &ucr2); else imx_port_rts_inactive(sport, &ucr2); } if (termios->c_cflag & CSTOPB) ucr2 |= UCR2_STPB; if (termios->c_cflag & PARENB) { ucr2 |= UCR2_PREN; if (termios->c_cflag & PARODD) ucr2 |= UCR2_PROE; } del_timer_sync(&sport->timer); /* * Ask the core to calculate the divisor for us. */ baud = uart_get_baud_rate(port, termios, old, 50, port->uartclk / 16); quot = uart_get_divisor(port, baud); spin_lock_irqsave(&sport->port.lock, flags); sport->port.read_status_mask = 0; if (termios->c_iflag & INPCK) sport->port.read_status_mask |= (URXD_FRMERR | URXD_PRERR); if (termios->c_iflag & (BRKINT | PARMRK)) sport->port.read_status_mask |= URXD_BRK; /* * Characters to ignore */ sport->port.ignore_status_mask = 0; if (termios->c_iflag & IGNPAR) sport->port.ignore_status_mask |= URXD_PRERR | URXD_FRMERR; if (termios->c_iflag & IGNBRK) { sport->port.ignore_status_mask |= URXD_BRK; /* * If we're ignoring parity and break indicators, * ignore overruns too (for real raw support). */ if (termios->c_iflag & IGNPAR) sport->port.ignore_status_mask |= URXD_OVRRUN; } if ((termios->c_cflag & CREAD) == 0) sport->port.ignore_status_mask |= URXD_DUMMY_READ; /* * Update the per-port timeout. */ uart_update_timeout(port, termios->c_cflag, baud); /* * disable interrupts and drain transmitter */ old_ucr1 = readl(sport->port.membase + UCR1); writel(old_ucr1 & ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN), sport->port.membase + UCR1); while (!(readl(sport->port.membase + USR2) & USR2_TXDC)) barrier(); /* then, disable everything */ old_ucr2 = readl(sport->port.membase + UCR2); writel(old_ucr2 & ~(UCR2_TXEN | UCR2_RXEN), sport->port.membase + UCR2); old_ucr2 &= (UCR2_TXEN | UCR2_RXEN | UCR2_ATEN); /* custom-baudrate handling */ div = sport->port.uartclk / (baud * 16); if (baud == 38400 && quot != div) baud = sport->port.uartclk / (quot * 16); div = sport->port.uartclk / (baud * 16); if (div > 7) div = 7; if (!div) div = 1; rational_best_approximation(16 * div * baud, sport->port.uartclk, 1 << 16, 1 << 16, &num, &denom); tdiv64 = sport->port.uartclk; tdiv64 *= num; do_div(tdiv64, denom * 16 * div); tty_termios_encode_baud_rate(termios, (speed_t)tdiv64, (speed_t)tdiv64); num -= 1; denom -= 1; ufcr = readl(sport->port.membase + UFCR); ufcr = (ufcr & (~UFCR_RFDIV)) | UFCR_RFDIV_REG(div); writel(ufcr, sport->port.membase + UFCR); writel(num, sport->port.membase + UBIR); writel(denom, sport->port.membase + UBMR); if (!is_imx1_uart(sport)) writel(sport->port.uartclk / div / 1000, sport->port.membase + IMX21_ONEMS); writel(old_ucr1, sport->port.membase + UCR1); /* set the parity, stop bits and data size */ writel(ucr2 | old_ucr2, sport->port.membase + UCR2); if (UART_ENABLE_MS(&sport->port, termios->c_cflag)) imx_enable_ms(&sport->port); spin_unlock_irqrestore(&sport->port.lock, flags); } static const char *imx_type(struct uart_port *port) { struct imx_port *sport = (struct imx_port *)port; return sport->port.type == PORT_IMX ? "IMX" : NULL; } /* * Configure/autoconfigure the port. */ static void imx_config_port(struct uart_port *port, int flags) { struct imx_port *sport = (struct imx_port *)port; if (flags & UART_CONFIG_TYPE) sport->port.type = PORT_IMX; } /* * Verify the new serial_struct (for TIOCSSERIAL). * The only change we allow are to the flags and type, and * even then only between PORT_IMX and PORT_UNKNOWN */ static int imx_verify_port(struct uart_port *port, struct serial_struct *ser) { struct imx_port *sport = (struct imx_port *)port; int ret = 0; if (ser->type != PORT_UNKNOWN && ser->type != PORT_IMX) ret = -EINVAL; if (sport->port.irq != ser->irq) ret = -EINVAL; if (ser->io_type != UPIO_MEM) ret = -EINVAL; if (sport->port.uartclk / 16 != ser->baud_base) ret = -EINVAL; if (sport->port.mapbase != (unsigned long)ser->iomem_base) ret = -EINVAL; if (sport->port.iobase != ser->port) ret = -EINVAL; if (ser->hub6 != 0) ret = -EINVAL; return ret; } #if defined(CONFIG_CONSOLE_POLL) static int imx_poll_init(struct uart_port *port) { struct imx_port *sport = (struct imx_port *)port; unsigned long flags; unsigned long temp; int retval; retval = clk_prepare_enable(sport->clk_ipg); if (retval) return retval; retval = clk_prepare_enable(sport->clk_per); if (retval) clk_disable_unprepare(sport->clk_ipg); imx_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT); spin_lock_irqsave(&sport->port.lock, flags); temp = readl(sport->port.membase + UCR1); if (is_imx1_uart(sport)) temp |= IMX1_UCR1_UARTCLKEN; temp |= UCR1_UARTEN | UCR1_RRDYEN; temp &= ~(UCR1_TXMPTYEN | UCR1_RTSDEN); writel(temp, sport->port.membase + UCR1); temp = readl(sport->port.membase + UCR2); temp |= UCR2_RXEN; writel(temp, sport->port.membase + UCR2); spin_unlock_irqrestore(&sport->port.lock, flags); return 0; } static int imx_poll_get_char(struct uart_port *port) { if (!(readl_relaxed(port->membase + USR2) & USR2_RDR)) return NO_POLL_CHAR; return readl_relaxed(port->membase + URXD0) & URXD_RX_DATA; } static void imx_poll_put_char(struct uart_port *port, unsigned char c) { unsigned int status; /* drain */ do { status = readl_relaxed(port->membase + USR1); } while (~status & USR1_TRDY); /* write */ writel_relaxed(c, port->membase + URTX0); /* flush */ do { status = readl_relaxed(port->membase + USR2); } while (~status & USR2_TXDC); } #endif static int imx_rs485_config(struct uart_port *port, struct serial_rs485 *rs485conf) { struct imx_port *sport = (struct imx_port *)port; unsigned long temp; /* unimplemented */ rs485conf->delay_rts_before_send = 0; rs485conf->delay_rts_after_send = 0; /* RTS is required to control the transmitter */ if (!sport->have_rtscts && !sport->have_rtsgpio) rs485conf->flags &= ~SER_RS485_ENABLED; if (rs485conf->flags & SER_RS485_ENABLED) { /* disable transmitter */ temp = readl(sport->port.membase + UCR2); if (rs485conf->flags & SER_RS485_RTS_AFTER_SEND) imx_port_rts_active(sport, &temp); else imx_port_rts_inactive(sport, &temp); writel(temp, sport->port.membase + UCR2); } /* Make sure Rx is enabled in case Tx is active with Rx disabled */ if (!(rs485conf->flags & SER_RS485_ENABLED) || rs485conf->flags & SER_RS485_RX_DURING_TX) { temp = readl(sport->port.membase + UCR2); temp |= UCR2_RXEN; writel(temp, sport->port.membase + UCR2); } port->rs485 = *rs485conf; return 0; } static const struct uart_ops imx_pops = { .tx_empty = imx_tx_empty, .set_mctrl = imx_set_mctrl, .get_mctrl = imx_get_mctrl, .stop_tx = imx_stop_tx, .start_tx = imx_start_tx, .stop_rx = imx_stop_rx, .enable_ms = imx_enable_ms, .break_ctl = imx_break_ctl, .startup = imx_startup, .shutdown = imx_shutdown, .flush_buffer = imx_flush_buffer, .set_termios = imx_set_termios, .type = imx_type, .config_port = imx_config_port, .verify_port = imx_verify_port, #if defined(CONFIG_CONSOLE_POLL) .poll_init = imx_poll_init, .poll_get_char = imx_poll_get_char, .poll_put_char = imx_poll_put_char, #endif }; static struct imx_port *imx_ports[UART_NR]; #ifdef CONFIG_SERIAL_IMX_CONSOLE static void imx_console_putchar(struct uart_port *port, int ch) { struct imx_port *sport = (struct imx_port *)port; while (readl(sport->port.membase + uts_reg(sport)) & UTS_TXFULL) barrier(); writel(ch, sport->port.membase + URTX0); } /* * Interrupts are disabled on entering */ static void imx_console_write(struct console *co, const char *s, unsigned int count) { struct imx_port *sport = imx_ports[co->index]; struct imx_port_ucrs old_ucr; unsigned int ucr1; unsigned long flags = 0; int locked = 1; int retval; retval = clk_enable(sport->clk_per); if (retval) return; retval = clk_enable(sport->clk_ipg); if (retval) { clk_disable(sport->clk_per); return; } if (sport->port.sysrq) locked = 0; else if (oops_in_progress) locked = spin_trylock_irqsave(&sport->port.lock, flags); else spin_lock_irqsave(&sport->port.lock, flags); /* * First, save UCR1/2/3 and then disable interrupts */ imx_port_ucrs_save(&sport->port, &old_ucr); ucr1 = old_ucr.ucr1; if (is_imx1_uart(sport)) ucr1 |= IMX1_UCR1_UARTCLKEN; ucr1 |= UCR1_UARTEN; ucr1 &= ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN); writel(ucr1, sport->port.membase + UCR1); writel(old_ucr.ucr2 | UCR2_TXEN, sport->port.membase + UCR2); uart_console_write(&sport->port, s, count, imx_console_putchar); /* * Finally, wait for transmitter to become empty * and restore UCR1/2/3 */ while (!(readl(sport->port.membase + USR2) & USR2_TXDC)); imx_port_ucrs_restore(&sport->port, &old_ucr); if (locked) spin_unlock_irqrestore(&sport->port.lock, flags); clk_disable(sport->clk_ipg); clk_disable(sport->clk_per); } /* * If the port was already initialised (eg, by a boot loader), * try to determine the current setup. */ static void __init imx_console_get_options(struct imx_port *sport, int *baud, int *parity, int *bits) { if (readl(sport->port.membase + UCR1) & UCR1_UARTEN) { /* ok, the port was enabled */ unsigned int ucr2, ubir, ubmr, uartclk; unsigned int baud_raw; unsigned int ucfr_rfdiv; ucr2 = readl(sport->port.membase + UCR2); *parity = 'n'; if (ucr2 & UCR2_PREN) { if (ucr2 & UCR2_PROE) *parity = 'o'; else *parity = 'e'; } if (ucr2 & UCR2_WS) *bits = 8; else *bits = 7; ubir = readl(sport->port.membase + UBIR) & 0xffff; ubmr = readl(sport->port.membase + UBMR) & 0xffff; ucfr_rfdiv = (readl(sport->port.membase + UFCR) & UFCR_RFDIV) >> 7; if (ucfr_rfdiv == 6) ucfr_rfdiv = 7; else ucfr_rfdiv = 6 - ucfr_rfdiv; uartclk = clk_get_rate(sport->clk_per); uartclk /= ucfr_rfdiv; { /* * The next code provides exact computation of * baud_raw = round(((uartclk/16) * (ubir + 1)) / (ubmr + 1)) * without need of float support or long long division, * which would be required to prevent 32bit arithmetic overflow */ unsigned int mul = ubir + 1; unsigned int div = 16 * (ubmr + 1); unsigned int rem = uartclk % div; baud_raw = (uartclk / div) * mul; baud_raw += (rem * mul + div / 2) / div; *baud = (baud_raw + 50) / 100 * 100; } if (*baud != baud_raw) pr_info("Console IMX rounded baud rate from %d to %d\n", baud_raw, *baud); } } static int __init imx_console_setup(struct console *co, char *options) { struct imx_port *sport; int baud = 9600; int bits = 8; int parity = 'n'; int flow = 'n'; int retval; /* * Check whether an invalid uart number has been specified, and * if so, search for the first available port that does have * console support. */ if (co->index == -1 || co->index >= ARRAY_SIZE(imx_ports)) co->index = 0; sport = imx_ports[co->index]; if (sport == NULL) return -ENODEV; /* For setting the registers, we only need to enable the ipg clock. */ retval = clk_prepare_enable(sport->clk_ipg); if (retval) goto error_console; if (options) uart_parse_options(options, &baud, &parity, &bits, &flow); else imx_console_get_options(sport, &baud, &parity, &bits); imx_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT); retval = uart_set_options(&sport->port, co, baud, parity, bits, flow); clk_disable(sport->clk_ipg); if (retval) { clk_unprepare(sport->clk_ipg); goto error_console; } retval = clk_prepare(sport->clk_per); if (retval) clk_disable_unprepare(sport->clk_ipg); error_console: return retval; } static struct uart_driver imx_reg; static struct console imx_console = { .name = DEV_NAME, .write = imx_console_write, .device = uart_console_device, .setup = imx_console_setup, .flags = CON_PRINTBUFFER, .index = -1, .data = &imx_reg, }; #define IMX_CONSOLE &imx_console #ifdef CONFIG_OF static void imx_console_early_putchar(struct uart_port *port, int ch) { while (readl_relaxed(port->membase + IMX21_UTS) & UTS_TXFULL) cpu_relax(); writel_relaxed(ch, port->membase + URTX0); } static void imx_console_early_write(struct console *con, const char *s, unsigned count) { struct earlycon_device *dev = con->data; uart_console_write(&dev->port, s, count, imx_console_early_putchar); } static int __init imx_console_early_setup(struct earlycon_device *dev, const char *opt) { if (!dev->port.membase) return -ENODEV; dev->con->write = imx_console_early_write; return 0; } OF_EARLYCON_DECLARE(ec_imx6q, "fsl,imx6q-uart", imx_console_early_setup); OF_EARLYCON_DECLARE(ec_imx21, "fsl,imx21-uart", imx_console_early_setup); #endif #else #define IMX_CONSOLE NULL #endif static struct uart_driver imx_reg = { .owner = THIS_MODULE, .driver_name = DRIVER_NAME, .dev_name = DEV_NAME, .major = SERIAL_IMX_MAJOR, .minor = MINOR_START, .nr = ARRAY_SIZE(imx_ports), .cons = IMX_CONSOLE, }; #ifdef CONFIG_OF /* * This function returns 1 iff pdev isn't a device instatiated by dt, 0 iff it * could successfully get all information from dt or a negative errno. */ static int serial_imx_probe_dt(struct imx_port *sport, struct platform_device *pdev) { struct device_node *np = pdev->dev.of_node; int ret; sport->devdata = of_device_get_match_data(&pdev->dev); if (!sport->devdata) /* 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, errno %d\n", ret); return ret; } sport->port.line = ret; if (of_get_property(np, "uart-has-rtscts", NULL) || of_get_property(np, "fsl,uart-has-rtscts", NULL) /* deprecated */) sport->have_rtscts = 1; if (of_get_property(np, "fsl,dte-mode", NULL)) sport->dte_mode = 1; if (of_get_property(np, "rts-gpios", NULL)) sport->have_rtsgpio = 1; return 0; } #else static inline int serial_imx_probe_dt(struct imx_port *sport, struct platform_device *pdev) { return 1; } #endif static void serial_imx_probe_pdata(struct imx_port *sport, struct platform_device *pdev) { struct imxuart_platform_data *pdata = dev_get_platdata(&pdev->dev); sport->port.line = pdev->id; sport->devdata = (struct imx_uart_data *) pdev->id_entry->driver_data; if (!pdata) return; if (pdata->flags & IMXUART_HAVE_RTSCTS) sport->have_rtscts = 1; } static int serial_imx_probe(struct platform_device *pdev) { struct imx_port *sport; void __iomem *base; int ret = 0, reg; struct resource *res; int txirq, rxirq, rtsirq; sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL); if (!sport) return -ENOMEM; ret = serial_imx_probe_dt(sport, pdev); if (ret > 0) serial_imx_probe_pdata(sport, pdev); else if (ret < 0) return ret; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(base)) return PTR_ERR(base); rxirq = platform_get_irq(pdev, 0); txirq = platform_get_irq(pdev, 1); rtsirq = platform_get_irq(pdev, 2); sport->port.dev = &pdev->dev; sport->port.mapbase = res->start; sport->port.membase = base; sport->port.type = PORT_IMX, sport->port.iotype = UPIO_MEM; sport->port.irq = rxirq; sport->port.fifosize = 32; sport->port.ops = &imx_pops; sport->port.rs485_config = imx_rs485_config; sport->port.rs485.flags = SER_RS485_RTS_ON_SEND | SER_RS485_RX_DURING_TX; sport->port.flags = UPF_BOOT_AUTOCONF; init_timer(&sport->timer); sport->timer.function = imx_timeout; sport->timer.data = (unsigned long)sport; sport->gpios = mctrl_gpio_init(&sport->port, 0); if (IS_ERR(sport->gpios)) return PTR_ERR(sport->gpios); sport->clk_ipg = devm_clk_get(&pdev->dev, "ipg"); if (IS_ERR(sport->clk_ipg)) { ret = PTR_ERR(sport->clk_ipg); dev_err(&pdev->dev, "failed to get ipg clk: %d\n", ret); return ret; } sport->clk_per = devm_clk_get(&pdev->dev, "per"); if (IS_ERR(sport->clk_per)) { ret = PTR_ERR(sport->clk_per); dev_err(&pdev->dev, "failed to get per clk: %d\n", ret); return ret; } sport->port.uartclk = clk_get_rate(sport->clk_per); /* For register access, we only need to enable the ipg clock. */ ret = clk_prepare_enable(sport->clk_ipg); if (ret) { dev_err(&pdev->dev, "failed to enable per clk: %d\n", ret); return ret; } /* Disable interrupts before requesting them */ reg = readl_relaxed(sport->port.membase + UCR1); reg &= ~(UCR1_ADEN | UCR1_TRDYEN | UCR1_IDEN | UCR1_RRDYEN | UCR1_TXMPTYEN | UCR1_RTSDEN); writel_relaxed(reg, sport->port.membase + UCR1); if (!is_imx1_uart(sport) && sport->dte_mode) { /* * The DCEDTE bit changes the direction of DSR, DCD, DTR and RI * and influences if UCR3_RI and UCR3_DCD changes the level of RI * and DCD (when they are outputs) or enables the respective * irqs. So set this bit early, i.e. before requesting irqs. */ writel(UFCR_DCEDTE, sport->port.membase + UFCR); /* * Disable UCR3_RI and UCR3_DCD irqs. They are also not * enabled later because they cannot be cleared * (confirmed on i.MX25) which makes them unusable. */ writel(IMX21_UCR3_RXDMUXSEL | UCR3_ADNIMP | UCR3_DSR, sport->port.membase + UCR3); } else { writel(0, sport->port.membase + UFCR); } clk_disable_unprepare(sport->clk_ipg); /* * Allocate the IRQ(s) i.MX1 has three interrupts whereas later * chips only have one interrupt. */ if (txirq > 0) { ret = devm_request_irq(&pdev->dev, rxirq, imx_rxint, 0, dev_name(&pdev->dev), sport); if (ret) { dev_err(&pdev->dev, "failed to request rx irq: %d\n", ret); return ret; } ret = devm_request_irq(&pdev->dev, txirq, imx_txint, 0, dev_name(&pdev->dev), sport); if (ret) { dev_err(&pdev->dev, "failed to request tx irq: %d\n", ret); return ret; } } else { ret = devm_request_irq(&pdev->dev, rxirq, imx_int, 0, dev_name(&pdev->dev), sport); if (ret) { dev_err(&pdev->dev, "failed to request irq: %d\n", ret); return ret; } } imx_ports[sport->port.line] = sport; platform_set_drvdata(pdev, sport); return uart_add_one_port(&imx_reg, &sport->port); } static int serial_imx_remove(struct platform_device *pdev) { struct imx_port *sport = platform_get_drvdata(pdev); return uart_remove_one_port(&imx_reg, &sport->port); } static void serial_imx_restore_context(struct imx_port *sport) { if (!sport->context_saved) return; writel(sport->saved_reg[4], sport->port.membase + UFCR); writel(sport->saved_reg[5], sport->port.membase + UESC); writel(sport->saved_reg[6], sport->port.membase + UTIM); writel(sport->saved_reg[7], sport->port.membase + UBIR); writel(sport->saved_reg[8], sport->port.membase + UBMR); writel(sport->saved_reg[9], sport->port.membase + IMX21_UTS); writel(sport->saved_reg[0], sport->port.membase + UCR1); writel(sport->saved_reg[1] | UCR2_SRST, sport->port.membase + UCR2); writel(sport->saved_reg[2], sport->port.membase + UCR3); writel(sport->saved_reg[3], sport->port.membase + UCR4); sport->context_saved = false; } static void serial_imx_save_context(struct imx_port *sport) { /* Save necessary regs */ sport->saved_reg[0] = readl(sport->port.membase + UCR1); sport->saved_reg[1] = readl(sport->port.membase + UCR2); sport->saved_reg[2] = readl(sport->port.membase + UCR3); sport->saved_reg[3] = readl(sport->port.membase + UCR4); sport->saved_reg[4] = readl(sport->port.membase + UFCR); sport->saved_reg[5] = readl(sport->port.membase + UESC); sport->saved_reg[6] = readl(sport->port.membase + UTIM); sport->saved_reg[7] = readl(sport->port.membase + UBIR); sport->saved_reg[8] = readl(sport->port.membase + UBMR); sport->saved_reg[9] = readl(sport->port.membase + IMX21_UTS); sport->context_saved = true; } static void serial_imx_enable_wakeup(struct imx_port *sport, bool on) { unsigned int val; val = readl(sport->port.membase + UCR3); if (on) val |= UCR3_AWAKEN; else val &= ~UCR3_AWAKEN; writel(val, sport->port.membase + UCR3); val = readl(sport->port.membase + UCR1); if (on) val |= UCR1_RTSDEN; else val &= ~UCR1_RTSDEN; writel(val, sport->port.membase + UCR1); } static int imx_serial_port_suspend_noirq(struct device *dev) { struct platform_device *pdev = to_platform_device(dev); struct imx_port *sport = platform_get_drvdata(pdev); int ret; ret = clk_enable(sport->clk_ipg); if (ret) return ret; serial_imx_save_context(sport); clk_disable(sport->clk_ipg); return 0; } static int imx_serial_port_resume_noirq(struct device *dev) { struct platform_device *pdev = to_platform_device(dev); struct imx_port *sport = platform_get_drvdata(pdev); int ret; ret = clk_enable(sport->clk_ipg); if (ret) return ret; serial_imx_restore_context(sport); clk_disable(sport->clk_ipg); return 0; } static int imx_serial_port_suspend(struct device *dev) { struct platform_device *pdev = to_platform_device(dev); struct imx_port *sport = platform_get_drvdata(pdev); /* enable wakeup from i.MX UART */ serial_imx_enable_wakeup(sport, true); uart_suspend_port(&imx_reg, &sport->port); /* Needed to enable clock in suspend_noirq */ return clk_prepare(sport->clk_ipg); } static int imx_serial_port_resume(struct device *dev) { struct platform_device *pdev = to_platform_device(dev); struct imx_port *sport = platform_get_drvdata(pdev); /* disable wakeup from i.MX UART */ serial_imx_enable_wakeup(sport, false); uart_resume_port(&imx_reg, &sport->port); clk_unprepare(sport->clk_ipg); return 0; } static const struct dev_pm_ops imx_serial_port_pm_ops = { .suspend_noirq = imx_serial_port_suspend_noirq, .resume_noirq = imx_serial_port_resume_noirq, .suspend = imx_serial_port_suspend, .resume = imx_serial_port_resume, }; static struct platform_driver serial_imx_driver = { .probe = serial_imx_probe, .remove = serial_imx_remove, .id_table = imx_uart_devtype, .driver = { .name = "imx-uart", .of_match_table = imx_uart_dt_ids, .pm = &imx_serial_port_pm_ops, }, }; static int __init imx_serial_init(void) { int ret = uart_register_driver(&imx_reg); if (ret) return ret; ret = platform_driver_register(&serial_imx_driver); if (ret != 0) uart_unregister_driver(&imx_reg); return ret; } static void __exit imx_serial_exit(void) { platform_driver_unregister(&serial_imx_driver); uart_unregister_driver(&imx_reg); } module_init(imx_serial_init); module_exit(imx_serial_exit); MODULE_AUTHOR("Sascha Hauer"); MODULE_DESCRIPTION("IMX generic serial port driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:imx-uart");