/* * Cadence UART driver (found in Xilinx Zynq) * * 2011 - 2014 (C) Xilinx Inc. * * 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 driver has originally been pushed by Xilinx using a Zynq-branding. This * still shows in the naming of this file, the kconfig symbols and some symbols * in the code. */ #if defined(CONFIG_SERIAL_XILINX_PS_UART_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) #define SUPPORT_SYSRQ #endif #include #include #include #include #include #include #include #include #include #include #include #include #define CDNS_UART_TTY_NAME "ttyPS" #define CDNS_UART_NAME "xuartps" #define CDNS_UART_MAJOR 0 /* use dynamic node allocation */ #define CDNS_UART_MINOR 0 /* works best with devtmpfs */ #define CDNS_UART_NR_PORTS 2 #define CDNS_UART_FIFO_SIZE 64 /* FIFO size */ #define CDNS_UART_REGISTER_SPACE 0x1000 /* Rx Trigger level */ static int rx_trigger_level = 56; module_param(rx_trigger_level, uint, S_IRUGO); MODULE_PARM_DESC(rx_trigger_level, "Rx trigger level, 1-63 bytes"); /* Rx Timeout */ static int rx_timeout = 10; module_param(rx_timeout, uint, S_IRUGO); MODULE_PARM_DESC(rx_timeout, "Rx timeout, 1-255"); /* Register offsets for the UART. */ #define CDNS_UART_CR 0x00 /* Control Register */ #define CDNS_UART_MR 0x04 /* Mode Register */ #define CDNS_UART_IER 0x08 /* Interrupt Enable */ #define CDNS_UART_IDR 0x0C /* Interrupt Disable */ #define CDNS_UART_IMR 0x10 /* Interrupt Mask */ #define CDNS_UART_ISR 0x14 /* Interrupt Status */ #define CDNS_UART_BAUDGEN 0x18 /* Baud Rate Generator */ #define CDNS_UART_RXTOUT 0x1C /* RX Timeout */ #define CDNS_UART_RXWM 0x20 /* RX FIFO Trigger Level */ #define CDNS_UART_MODEMCR 0x24 /* Modem Control */ #define CDNS_UART_MODEMSR 0x28 /* Modem Status */ #define CDNS_UART_SR 0x2C /* Channel Status */ #define CDNS_UART_FIFO 0x30 /* FIFO */ #define CDNS_UART_BAUDDIV 0x34 /* Baud Rate Divider */ #define CDNS_UART_FLOWDEL 0x38 /* Flow Delay */ #define CDNS_UART_IRRX_PWIDTH 0x3C /* IR Min Received Pulse Width */ #define CDNS_UART_IRTX_PWIDTH 0x40 /* IR Transmitted pulse Width */ #define CDNS_UART_TXWM 0x44 /* TX FIFO Trigger Level */ /* Control Register Bit Definitions */ #define CDNS_UART_CR_STOPBRK 0x00000100 /* Stop TX break */ #define CDNS_UART_CR_STARTBRK 0x00000080 /* Set TX break */ #define CDNS_UART_CR_TX_DIS 0x00000020 /* TX disabled. */ #define CDNS_UART_CR_TX_EN 0x00000010 /* TX enabled */ #define CDNS_UART_CR_RX_DIS 0x00000008 /* RX disabled. */ #define CDNS_UART_CR_RX_EN 0x00000004 /* RX enabled */ #define CDNS_UART_CR_TXRST 0x00000002 /* TX logic reset */ #define CDNS_UART_CR_RXRST 0x00000001 /* RX logic reset */ #define CDNS_UART_CR_RST_TO 0x00000040 /* Restart Timeout Counter */ /* * Mode Register: * The mode register (MR) defines the mode of transfer as well as the data * format. If this register is modified during transmission or reception, * data validity cannot be guaranteed. */ #define CDNS_UART_MR_CLKSEL 0x00000001 /* Pre-scalar selection */ #define CDNS_UART_MR_CHMODE_L_LOOP 0x00000200 /* Local loop back mode */ #define CDNS_UART_MR_CHMODE_NORM 0x00000000 /* Normal mode */ #define CDNS_UART_MR_STOPMODE_2_BIT 0x00000080 /* 2 stop bits */ #define CDNS_UART_MR_STOPMODE_1_BIT 0x00000000 /* 1 stop bit */ #define CDNS_UART_MR_PARITY_NONE 0x00000020 /* No parity mode */ #define CDNS_UART_MR_PARITY_MARK 0x00000018 /* Mark parity mode */ #define CDNS_UART_MR_PARITY_SPACE 0x00000010 /* Space parity mode */ #define CDNS_UART_MR_PARITY_ODD 0x00000008 /* Odd parity mode */ #define CDNS_UART_MR_PARITY_EVEN 0x00000000 /* Even parity mode */ #define CDNS_UART_MR_CHARLEN_6_BIT 0x00000006 /* 6 bits data */ #define CDNS_UART_MR_CHARLEN_7_BIT 0x00000004 /* 7 bits data */ #define CDNS_UART_MR_CHARLEN_8_BIT 0x00000000 /* 8 bits data */ /* * Interrupt Registers: * Interrupt control logic uses the interrupt enable register (IER) and the * interrupt disable register (IDR) to set the value of the bits in the * interrupt mask register (IMR). The IMR determines whether to pass an * interrupt to the interrupt status register (ISR). * Writing a 1 to IER Enables an interrupt, writing a 1 to IDR disables an * interrupt. IMR and ISR are read only, and IER and IDR are write only. * Reading either IER or IDR returns 0x00. * All four registers have the same bit definitions. */ #define CDNS_UART_IXR_TOUT 0x00000100 /* RX Timeout error interrupt */ #define CDNS_UART_IXR_PARITY 0x00000080 /* Parity error interrupt */ #define CDNS_UART_IXR_FRAMING 0x00000040 /* Framing error interrupt */ #define CDNS_UART_IXR_OVERRUN 0x00000020 /* Overrun error interrupt */ #define CDNS_UART_IXR_TXFULL 0x00000010 /* TX FIFO Full interrupt */ #define CDNS_UART_IXR_TXEMPTY 0x00000008 /* TX FIFO empty interrupt */ #define CDNS_UART_ISR_RXEMPTY 0x00000002 /* RX FIFO empty interrupt */ #define CDNS_UART_IXR_RXTRIG 0x00000001 /* RX FIFO trigger interrupt */ #define CDNS_UART_IXR_RXFULL 0x00000004 /* RX FIFO full interrupt. */ #define CDNS_UART_IXR_RXEMPTY 0x00000002 /* RX FIFO empty interrupt. */ #define CDNS_UART_IXR_MASK 0x00001FFF /* Valid bit mask */ #define CDNS_UART_RX_IRQS (CDNS_UART_IXR_PARITY | CDNS_UART_IXR_FRAMING | \ CDNS_UART_IXR_OVERRUN | CDNS_UART_IXR_RXTRIG | \ CDNS_UART_IXR_TOUT) /* Goes in read_status_mask for break detection as the HW doesn't do it*/ #define CDNS_UART_IXR_BRK 0x80000000 /* * Modem Control register: * The read/write Modem Control register controls the interface with the modem * or data set, or a peripheral device emulating a modem. */ #define CDNS_UART_MODEMCR_FCM 0x00000020 /* Automatic flow control mode */ #define CDNS_UART_MODEMCR_RTS 0x00000002 /* Request to send output control */ #define CDNS_UART_MODEMCR_DTR 0x00000001 /* Data Terminal Ready */ /* * Channel Status Register: * The channel status register (CSR) is provided to enable the control logic * to monitor the status of bits in the channel interrupt status register, * even if these are masked out by the interrupt mask register. */ #define CDNS_UART_SR_RXEMPTY 0x00000002 /* RX FIFO empty */ #define CDNS_UART_SR_TXEMPTY 0x00000008 /* TX FIFO empty */ #define CDNS_UART_SR_TXFULL 0x00000010 /* TX FIFO full */ #define CDNS_UART_SR_RXTRIG 0x00000001 /* Rx Trigger */ /* baud dividers min/max values */ #define CDNS_UART_BDIV_MIN 4 #define CDNS_UART_BDIV_MAX 255 #define CDNS_UART_CD_MAX 65535 /** * struct cdns_uart - device data * @port: Pointer to the UART port * @uartclk: Reference clock * @pclk: APB clock * @baud: Current baud rate * @clk_rate_change_nb: Notifier block for clock changes */ struct cdns_uart { struct uart_port *port; struct clk *uartclk; struct clk *pclk; unsigned int baud; struct notifier_block clk_rate_change_nb; }; #define to_cdns_uart(_nb) container_of(_nb, struct cdns_uart, \ clk_rate_change_nb); static void cdns_uart_handle_rx(struct uart_port *port, unsigned int isrstatus) { /* * There is no hardware break detection, so we interpret framing * error with all-zeros data as a break sequence. Most of the time, * there's another non-zero byte at the end of the sequence. */ if (isrstatus & CDNS_UART_IXR_FRAMING) { while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_RXEMPTY)) { if (!readl(port->membase + CDNS_UART_FIFO)) { port->read_status_mask |= CDNS_UART_IXR_BRK; isrstatus &= ~CDNS_UART_IXR_FRAMING; } } writel(CDNS_UART_IXR_FRAMING, port->membase + CDNS_UART_ISR); } /* drop byte with parity error if IGNPAR specified */ if (isrstatus & port->ignore_status_mask & CDNS_UART_IXR_PARITY) isrstatus &= ~(CDNS_UART_IXR_RXTRIG | CDNS_UART_IXR_TOUT); isrstatus &= port->read_status_mask; isrstatus &= ~port->ignore_status_mask; if (!(isrstatus & (CDNS_UART_IXR_TOUT | CDNS_UART_IXR_RXTRIG))) return; while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_RXEMPTY)) { u32 data; char status = TTY_NORMAL; data = readl(port->membase + CDNS_UART_FIFO); /* Non-NULL byte after BREAK is garbage (99%) */ if (data && (port->read_status_mask & CDNS_UART_IXR_BRK)) { port->read_status_mask &= ~CDNS_UART_IXR_BRK; port->icount.brk++; if (uart_handle_break(port)) continue; } if (uart_handle_sysrq_char(port, data)) continue; port->icount.rx++; if (isrstatus & CDNS_UART_IXR_PARITY) { port->icount.parity++; status = TTY_PARITY; } else if (isrstatus & CDNS_UART_IXR_FRAMING) { port->icount.frame++; status = TTY_FRAME; } else if (isrstatus & CDNS_UART_IXR_OVERRUN) { port->icount.overrun++; } uart_insert_char(port, isrstatus, CDNS_UART_IXR_OVERRUN, data, status); } tty_flip_buffer_push(&port->state->port); } static void cdns_uart_handle_tx(struct uart_port *port) { unsigned int numbytes; if (uart_circ_empty(&port->state->xmit)) { writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_IDR); return; } numbytes = port->fifosize; while (numbytes && !uart_circ_empty(&port->state->xmit) && !(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXFULL)) { /* * Get the data from the UART circular buffer * and write it to the cdns_uart's TX_FIFO * register. */ writel(port->state->xmit.buf[port->state->xmit.tail], port->membase + CDNS_UART_FIFO); port->icount.tx++; /* * Adjust the tail of the UART buffer and wrap * the buffer if it reaches limit. */ port->state->xmit.tail = (port->state->xmit.tail + 1) & (UART_XMIT_SIZE - 1); numbytes--; } if (uart_circ_chars_pending(&port->state->xmit) < WAKEUP_CHARS) uart_write_wakeup(port); } /** * cdns_uart_isr - Interrupt handler * @irq: Irq number * @dev_id: Id of the port * * Return: IRQHANDLED */ static irqreturn_t cdns_uart_isr(int irq, void *dev_id) { struct uart_port *port = (struct uart_port *)dev_id; unsigned long flags; unsigned int isrstatus; spin_lock_irqsave(&port->lock, flags); /* Read the interrupt status register to determine which * interrupt(s) is/are active. */ isrstatus = readl(port->membase + CDNS_UART_ISR); if (isrstatus & CDNS_UART_RX_IRQS) cdns_uart_handle_rx(port, isrstatus); if ((isrstatus & CDNS_UART_IXR_TXEMPTY) == CDNS_UART_IXR_TXEMPTY) cdns_uart_handle_tx(port); writel(isrstatus, port->membase + CDNS_UART_ISR); /* be sure to release the lock and tty before leaving */ spin_unlock_irqrestore(&port->lock, flags); return IRQ_HANDLED; } /** * cdns_uart_calc_baud_divs - Calculate baud rate divisors * @clk: UART module input clock * @baud: Desired baud rate * @rbdiv: BDIV value (return value) * @rcd: CD value (return value) * @div8: Value for clk_sel bit in mod (return value) * Return: baud rate, requested baud when possible, or actual baud when there * was too much error, zero if no valid divisors are found. * * Formula to obtain baud rate is * baud_tx/rx rate = clk/CD * (BDIV + 1) * input_clk = (Uart User Defined Clock or Apb Clock) * depends on UCLKEN in MR Reg * clk = input_clk or input_clk/8; * depends on CLKS in MR reg * CD and BDIV depends on values in * baud rate generate register * baud rate clock divisor register */ static unsigned int cdns_uart_calc_baud_divs(unsigned int clk, unsigned int baud, u32 *rbdiv, u32 *rcd, int *div8) { u32 cd, bdiv; unsigned int calc_baud; unsigned int bestbaud = 0; unsigned int bauderror; unsigned int besterror = ~0; if (baud < clk / ((CDNS_UART_BDIV_MAX + 1) * CDNS_UART_CD_MAX)) { *div8 = 1; clk /= 8; } else { *div8 = 0; } for (bdiv = CDNS_UART_BDIV_MIN; bdiv <= CDNS_UART_BDIV_MAX; bdiv++) { cd = DIV_ROUND_CLOSEST(clk, baud * (bdiv + 1)); if (cd < 1 || cd > CDNS_UART_CD_MAX) continue; calc_baud = clk / (cd * (bdiv + 1)); if (baud > calc_baud) bauderror = baud - calc_baud; else bauderror = calc_baud - baud; if (besterror > bauderror) { *rbdiv = bdiv; *rcd = cd; bestbaud = calc_baud; besterror = bauderror; } } /* use the values when percent error is acceptable */ if (((besterror * 100) / baud) < 3) bestbaud = baud; return bestbaud; } /** * cdns_uart_set_baud_rate - Calculate and set the baud rate * @port: Handle to the uart port structure * @baud: Baud rate to set * Return: baud rate, requested baud when possible, or actual baud when there * was too much error, zero if no valid divisors are found. */ static unsigned int cdns_uart_set_baud_rate(struct uart_port *port, unsigned int baud) { unsigned int calc_baud; u32 cd = 0, bdiv = 0; u32 mreg; int div8; struct cdns_uart *cdns_uart = port->private_data; calc_baud = cdns_uart_calc_baud_divs(port->uartclk, baud, &bdiv, &cd, &div8); /* Write new divisors to hardware */ mreg = readl(port->membase + CDNS_UART_MR); if (div8) mreg |= CDNS_UART_MR_CLKSEL; else mreg &= ~CDNS_UART_MR_CLKSEL; writel(mreg, port->membase + CDNS_UART_MR); writel(cd, port->membase + CDNS_UART_BAUDGEN); writel(bdiv, port->membase + CDNS_UART_BAUDDIV); cdns_uart->baud = baud; return calc_baud; } #ifdef CONFIG_COMMON_CLK /** * cdns_uart_clk_notitifer_cb - Clock notifier callback * @nb: Notifier block * @event: Notify event * @data: Notifier data * Return: NOTIFY_OK or NOTIFY_DONE on success, NOTIFY_BAD on error. */ static int cdns_uart_clk_notifier_cb(struct notifier_block *nb, unsigned long event, void *data) { u32 ctrl_reg; struct uart_port *port; int locked = 0; struct clk_notifier_data *ndata = data; unsigned long flags = 0; struct cdns_uart *cdns_uart = to_cdns_uart(nb); port = cdns_uart->port; if (port->suspended) return NOTIFY_OK; switch (event) { case PRE_RATE_CHANGE: { u32 bdiv, cd; int div8; /* * Find out if current baud-rate can be achieved with new clock * frequency. */ if (!cdns_uart_calc_baud_divs(ndata->new_rate, cdns_uart->baud, &bdiv, &cd, &div8)) { dev_warn(port->dev, "clock rate change rejected\n"); return NOTIFY_BAD; } spin_lock_irqsave(&cdns_uart->port->lock, flags); /* Disable the TX and RX to set baud rate */ ctrl_reg = readl(port->membase + CDNS_UART_CR); ctrl_reg |= CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS; writel(ctrl_reg, port->membase + CDNS_UART_CR); spin_unlock_irqrestore(&cdns_uart->port->lock, flags); return NOTIFY_OK; } case POST_RATE_CHANGE: /* * Set clk dividers to generate correct baud with new clock * frequency. */ spin_lock_irqsave(&cdns_uart->port->lock, flags); locked = 1; port->uartclk = ndata->new_rate; cdns_uart->baud = cdns_uart_set_baud_rate(cdns_uart->port, cdns_uart->baud); /* fall through */ case ABORT_RATE_CHANGE: if (!locked) spin_lock_irqsave(&cdns_uart->port->lock, flags); /* Set TX/RX Reset */ ctrl_reg = readl(port->membase + CDNS_UART_CR); ctrl_reg |= CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST; writel(ctrl_reg, port->membase + CDNS_UART_CR); while (readl(port->membase + CDNS_UART_CR) & (CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST)) cpu_relax(); /* * Clear the RX disable and TX disable bits and then set the TX * enable bit and RX enable bit to enable the transmitter and * receiver. */ writel(rx_timeout, port->membase + CDNS_UART_RXTOUT); ctrl_reg = readl(port->membase + CDNS_UART_CR); ctrl_reg &= ~(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS); ctrl_reg |= CDNS_UART_CR_TX_EN | CDNS_UART_CR_RX_EN; writel(ctrl_reg, port->membase + CDNS_UART_CR); spin_unlock_irqrestore(&cdns_uart->port->lock, flags); return NOTIFY_OK; default: return NOTIFY_DONE; } } #endif /** * cdns_uart_start_tx - Start transmitting bytes * @port: Handle to the uart port structure */ static void cdns_uart_start_tx(struct uart_port *port) { unsigned int status; if (uart_tx_stopped(port)) return; /* * Set the TX enable bit and clear the TX disable bit to enable the * transmitter. */ status = readl(port->membase + CDNS_UART_CR); status &= ~CDNS_UART_CR_TX_DIS; status |= CDNS_UART_CR_TX_EN; writel(status, port->membase + CDNS_UART_CR); if (uart_circ_empty(&port->state->xmit)) return; cdns_uart_handle_tx(port); writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_ISR); /* Enable the TX Empty interrupt */ writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_IER); } /** * cdns_uart_stop_tx - Stop TX * @port: Handle to the uart port structure */ static void cdns_uart_stop_tx(struct uart_port *port) { unsigned int regval; regval = readl(port->membase + CDNS_UART_CR); regval |= CDNS_UART_CR_TX_DIS; /* Disable the transmitter */ writel(regval, port->membase + CDNS_UART_CR); } /** * cdns_uart_stop_rx - Stop RX * @port: Handle to the uart port structure */ static void cdns_uart_stop_rx(struct uart_port *port) { unsigned int regval; /* Disable RX IRQs */ writel(CDNS_UART_RX_IRQS, port->membase + CDNS_UART_IDR); /* Disable the receiver */ regval = readl(port->membase + CDNS_UART_CR); regval |= CDNS_UART_CR_RX_DIS; writel(regval, port->membase + CDNS_UART_CR); } /** * cdns_uart_tx_empty - Check whether TX is empty * @port: Handle to the uart port structure * * Return: TIOCSER_TEMT on success, 0 otherwise */ static unsigned int cdns_uart_tx_empty(struct uart_port *port) { unsigned int status; status = readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXEMPTY; return status ? TIOCSER_TEMT : 0; } /** * cdns_uart_break_ctl - Based on the input ctl we have to start or stop * transmitting char breaks * @port: Handle to the uart port structure * @ctl: Value based on which start or stop decision is taken */ static void cdns_uart_break_ctl(struct uart_port *port, int ctl) { unsigned int status; unsigned long flags; spin_lock_irqsave(&port->lock, flags); status = readl(port->membase + CDNS_UART_CR); if (ctl == -1) writel(CDNS_UART_CR_STARTBRK | status, port->membase + CDNS_UART_CR); else { if ((status & CDNS_UART_CR_STOPBRK) == 0) writel(CDNS_UART_CR_STOPBRK | status, port->membase + CDNS_UART_CR); } spin_unlock_irqrestore(&port->lock, flags); } /** * cdns_uart_set_termios - termios operations, handling data length, parity, * stop bits, flow control, baud rate * @port: Handle to the uart port structure * @termios: Handle to the input termios structure * @old: Values of the previously saved termios structure */ static void cdns_uart_set_termios(struct uart_port *port, struct ktermios *termios, struct ktermios *old) { unsigned int cval = 0; unsigned int baud, minbaud, maxbaud; unsigned long flags; unsigned int ctrl_reg, mode_reg; spin_lock_irqsave(&port->lock, flags); /* Wait for the transmit FIFO to empty before making changes */ if (!(readl(port->membase + CDNS_UART_CR) & CDNS_UART_CR_TX_DIS)) { while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXEMPTY)) { cpu_relax(); } } /* Disable the TX and RX to set baud rate */ ctrl_reg = readl(port->membase + CDNS_UART_CR); ctrl_reg |= CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS; writel(ctrl_reg, port->membase + CDNS_UART_CR); /* * Min baud rate = 6bps and Max Baud Rate is 10Mbps for 100Mhz clk * min and max baud should be calculated here based on port->uartclk. * this way we get a valid baud and can safely call set_baud() */ minbaud = port->uartclk / ((CDNS_UART_BDIV_MAX + 1) * CDNS_UART_CD_MAX * 8); maxbaud = port->uartclk / (CDNS_UART_BDIV_MIN + 1); baud = uart_get_baud_rate(port, termios, old, minbaud, maxbaud); baud = cdns_uart_set_baud_rate(port, baud); if (tty_termios_baud_rate(termios)) tty_termios_encode_baud_rate(termios, baud, baud); /* Update the per-port timeout. */ uart_update_timeout(port, termios->c_cflag, baud); /* Set TX/RX Reset */ ctrl_reg = readl(port->membase + CDNS_UART_CR); ctrl_reg |= CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST; writel(ctrl_reg, port->membase + CDNS_UART_CR); /* * Clear the RX disable and TX disable bits and then set the TX enable * bit and RX enable bit to enable the transmitter and receiver. */ ctrl_reg = readl(port->membase + CDNS_UART_CR); ctrl_reg &= ~(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS); ctrl_reg |= CDNS_UART_CR_TX_EN | CDNS_UART_CR_RX_EN; writel(ctrl_reg, port->membase + CDNS_UART_CR); writel(rx_timeout, port->membase + CDNS_UART_RXTOUT); port->read_status_mask = CDNS_UART_IXR_TXEMPTY | CDNS_UART_IXR_RXTRIG | CDNS_UART_IXR_OVERRUN | CDNS_UART_IXR_TOUT; port->ignore_status_mask = 0; if (termios->c_iflag & INPCK) port->read_status_mask |= CDNS_UART_IXR_PARITY | CDNS_UART_IXR_FRAMING; if (termios->c_iflag & IGNPAR) port->ignore_status_mask |= CDNS_UART_IXR_PARITY | CDNS_UART_IXR_FRAMING | CDNS_UART_IXR_OVERRUN; /* ignore all characters if CREAD is not set */ if ((termios->c_cflag & CREAD) == 0) port->ignore_status_mask |= CDNS_UART_IXR_RXTRIG | CDNS_UART_IXR_TOUT | CDNS_UART_IXR_PARITY | CDNS_UART_IXR_FRAMING | CDNS_UART_IXR_OVERRUN; mode_reg = readl(port->membase + CDNS_UART_MR); /* Handling Data Size */ switch (termios->c_cflag & CSIZE) { case CS6: cval |= CDNS_UART_MR_CHARLEN_6_BIT; break; case CS7: cval |= CDNS_UART_MR_CHARLEN_7_BIT; break; default: case CS8: cval |= CDNS_UART_MR_CHARLEN_8_BIT; termios->c_cflag &= ~CSIZE; termios->c_cflag |= CS8; break; } /* Handling Parity and Stop Bits length */ if (termios->c_cflag & CSTOPB) cval |= CDNS_UART_MR_STOPMODE_2_BIT; /* 2 STOP bits */ else cval |= CDNS_UART_MR_STOPMODE_1_BIT; /* 1 STOP bit */ if (termios->c_cflag & PARENB) { /* Mark or Space parity */ if (termios->c_cflag & CMSPAR) { if (termios->c_cflag & PARODD) cval |= CDNS_UART_MR_PARITY_MARK; else cval |= CDNS_UART_MR_PARITY_SPACE; } else { if (termios->c_cflag & PARODD) cval |= CDNS_UART_MR_PARITY_ODD; else cval |= CDNS_UART_MR_PARITY_EVEN; } } else { cval |= CDNS_UART_MR_PARITY_NONE; } cval |= mode_reg & 1; writel(cval, port->membase + CDNS_UART_MR); spin_unlock_irqrestore(&port->lock, flags); } /** * cdns_uart_startup - Called when an application opens a cdns_uart port * @port: Handle to the uart port structure * * Return: 0 on success, negative errno otherwise */ static int cdns_uart_startup(struct uart_port *port) { int ret; unsigned long flags; unsigned int status = 0; spin_lock_irqsave(&port->lock, flags); /* Disable the TX and RX */ writel(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS, port->membase + CDNS_UART_CR); /* Set the Control Register with TX/RX Enable, TX/RX Reset, * no break chars. */ writel(CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST, port->membase + CDNS_UART_CR); /* * Clear the RX disable bit and then set the RX enable bit to enable * the receiver. */ status = readl(port->membase + CDNS_UART_CR); status &= CDNS_UART_CR_RX_DIS; status |= CDNS_UART_CR_RX_EN; writel(status, port->membase + CDNS_UART_CR); /* Set the Mode Register with normal mode,8 data bits,1 stop bit, * no parity. */ writel(CDNS_UART_MR_CHMODE_NORM | CDNS_UART_MR_STOPMODE_1_BIT | CDNS_UART_MR_PARITY_NONE | CDNS_UART_MR_CHARLEN_8_BIT, port->membase + CDNS_UART_MR); /* * Set the RX FIFO Trigger level to use most of the FIFO, but it * can be tuned with a module parameter */ writel(rx_trigger_level, port->membase + CDNS_UART_RXWM); /* * Receive Timeout register is enabled but it * can be tuned with a module parameter */ writel(rx_timeout, port->membase + CDNS_UART_RXTOUT); /* Clear out any pending interrupts before enabling them */ writel(readl(port->membase + CDNS_UART_ISR), port->membase + CDNS_UART_ISR); spin_unlock_irqrestore(&port->lock, flags); ret = request_irq(port->irq, cdns_uart_isr, 0, CDNS_UART_NAME, port); if (ret) { dev_err(port->dev, "request_irq '%d' failed with %d\n", port->irq, ret); return ret; } /* Set the Interrupt Registers with desired interrupts */ writel(CDNS_UART_RX_IRQS, port->membase + CDNS_UART_IER); return 0; } /** * cdns_uart_shutdown - Called when an application closes a cdns_uart port * @port: Handle to the uart port structure */ static void cdns_uart_shutdown(struct uart_port *port) { int status; unsigned long flags; spin_lock_irqsave(&port->lock, flags); /* Disable interrupts */ status = readl(port->membase + CDNS_UART_IMR); writel(status, port->membase + CDNS_UART_IDR); writel(0xffffffff, port->membase + CDNS_UART_ISR); /* Disable the TX and RX */ writel(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS, port->membase + CDNS_UART_CR); spin_unlock_irqrestore(&port->lock, flags); free_irq(port->irq, port); } /** * cdns_uart_type - Set UART type to cdns_uart port * @port: Handle to the uart port structure * * Return: string on success, NULL otherwise */ static const char *cdns_uart_type(struct uart_port *port) { return port->type == PORT_XUARTPS ? CDNS_UART_NAME : NULL; } /** * cdns_uart_verify_port - Verify the port params * @port: Handle to the uart port structure * @ser: Handle to the structure whose members are compared * * Return: 0 on success, negative errno otherwise. */ static int cdns_uart_verify_port(struct uart_port *port, struct serial_struct *ser) { if (ser->type != PORT_UNKNOWN && ser->type != PORT_XUARTPS) return -EINVAL; if (port->irq != ser->irq) return -EINVAL; if (ser->io_type != UPIO_MEM) return -EINVAL; if (port->iobase != ser->port) return -EINVAL; if (ser->hub6 != 0) return -EINVAL; return 0; } /** * cdns_uart_request_port - Claim the memory region attached to cdns_uart port, * called when the driver adds a cdns_uart port via * uart_add_one_port() * @port: Handle to the uart port structure * * Return: 0 on success, negative errno otherwise. */ static int cdns_uart_request_port(struct uart_port *port) { if (!request_mem_region(port->mapbase, CDNS_UART_REGISTER_SPACE, CDNS_UART_NAME)) { return -ENOMEM; } port->membase = ioremap(port->mapbase, CDNS_UART_REGISTER_SPACE); if (!port->membase) { dev_err(port->dev, "Unable to map registers\n"); release_mem_region(port->mapbase, CDNS_UART_REGISTER_SPACE); return -ENOMEM; } return 0; } /** * cdns_uart_release_port - Release UART port * @port: Handle to the uart port structure * * Release the memory region attached to a cdns_uart port. Called when the * driver removes a cdns_uart port via uart_remove_one_port(). */ static void cdns_uart_release_port(struct uart_port *port) { release_mem_region(port->mapbase, CDNS_UART_REGISTER_SPACE); iounmap(port->membase); port->membase = NULL; } /** * cdns_uart_config_port - Configure UART port * @port: Handle to the uart port structure * @flags: If any */ static void cdns_uart_config_port(struct uart_port *port, int flags) { if (flags & UART_CONFIG_TYPE && cdns_uart_request_port(port) == 0) port->type = PORT_XUARTPS; } /** * cdns_uart_get_mctrl - Get the modem control state * @port: Handle to the uart port structure * * Return: the modem control state */ static unsigned int cdns_uart_get_mctrl(struct uart_port *port) { return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR; } static void cdns_uart_set_mctrl(struct uart_port *port, unsigned int mctrl) { u32 val; val = readl(port->membase + CDNS_UART_MODEMCR); val &= ~(CDNS_UART_MODEMCR_RTS | CDNS_UART_MODEMCR_DTR); if (mctrl & TIOCM_RTS) val |= CDNS_UART_MODEMCR_RTS; if (mctrl & TIOCM_DTR) val |= CDNS_UART_MODEMCR_DTR; writel(val, port->membase + CDNS_UART_MODEMCR); } #ifdef CONFIG_CONSOLE_POLL static int cdns_uart_poll_get_char(struct uart_port *port) { int c; unsigned long flags; spin_lock_irqsave(&port->lock, flags); /* Check if FIFO is empty */ if (readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_RXEMPTY) c = NO_POLL_CHAR; else /* Read a character */ c = (unsigned char) readl(port->membase + CDNS_UART_FIFO); spin_unlock_irqrestore(&port->lock, flags); return c; } static void cdns_uart_poll_put_char(struct uart_port *port, unsigned char c) { unsigned long flags; spin_lock_irqsave(&port->lock, flags); /* Wait until FIFO is empty */ while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXEMPTY)) cpu_relax(); /* Write a character */ writel(c, port->membase + CDNS_UART_FIFO); /* Wait until FIFO is empty */ while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXEMPTY)) cpu_relax(); spin_unlock_irqrestore(&port->lock, flags); return; } #endif static void cdns_uart_pm(struct uart_port *port, unsigned int state, unsigned int oldstate) { struct cdns_uart *cdns_uart = port->private_data; switch (state) { case UART_PM_STATE_OFF: clk_disable(cdns_uart->uartclk); clk_disable(cdns_uart->pclk); break; default: clk_enable(cdns_uart->pclk); clk_enable(cdns_uart->uartclk); break; } } static const struct uart_ops cdns_uart_ops = { .set_mctrl = cdns_uart_set_mctrl, .get_mctrl = cdns_uart_get_mctrl, .start_tx = cdns_uart_start_tx, .stop_tx = cdns_uart_stop_tx, .stop_rx = cdns_uart_stop_rx, .tx_empty = cdns_uart_tx_empty, .break_ctl = cdns_uart_break_ctl, .set_termios = cdns_uart_set_termios, .startup = cdns_uart_startup, .shutdown = cdns_uart_shutdown, .pm = cdns_uart_pm, .type = cdns_uart_type, .verify_port = cdns_uart_verify_port, .request_port = cdns_uart_request_port, .release_port = cdns_uart_release_port, .config_port = cdns_uart_config_port, #ifdef CONFIG_CONSOLE_POLL .poll_get_char = cdns_uart_poll_get_char, .poll_put_char = cdns_uart_poll_put_char, #endif }; static struct uart_port cdns_uart_port[CDNS_UART_NR_PORTS]; /** * cdns_uart_get_port - Configure the port from platform device resource info * @id: Port id * * Return: a pointer to a uart_port or NULL for failure */ static struct uart_port *cdns_uart_get_port(int id) { struct uart_port *port; /* Try the given port id if failed use default method */ if (cdns_uart_port[id].mapbase != 0) { /* Find the next unused port */ for (id = 0; id < CDNS_UART_NR_PORTS; id++) if (cdns_uart_port[id].mapbase == 0) break; } if (id >= CDNS_UART_NR_PORTS) return NULL; port = &cdns_uart_port[id]; /* At this point, we've got an empty uart_port struct, initialize it */ spin_lock_init(&port->lock); port->membase = NULL; port->irq = 0; port->type = PORT_UNKNOWN; port->iotype = UPIO_MEM32; port->flags = UPF_BOOT_AUTOCONF; port->ops = &cdns_uart_ops; port->fifosize = CDNS_UART_FIFO_SIZE; port->line = id; port->dev = NULL; return port; } #ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE /** * cdns_uart_console_wait_tx - Wait for the TX to be full * @port: Handle to the uart port structure */ static void cdns_uart_console_wait_tx(struct uart_port *port) { while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXEMPTY)) barrier(); } /** * cdns_uart_console_putchar - write the character to the FIFO buffer * @port: Handle to the uart port structure * @ch: Character to be written */ static void cdns_uart_console_putchar(struct uart_port *port, int ch) { cdns_uart_console_wait_tx(port); writel(ch, port->membase + CDNS_UART_FIFO); } static void __init cdns_early_write(struct console *con, const char *s, unsigned n) { struct earlycon_device *dev = con->data; uart_console_write(&dev->port, s, n, cdns_uart_console_putchar); } static int __init cdns_early_console_setup(struct earlycon_device *device, const char *opt) { if (!device->port.membase) return -ENODEV; device->con->write = cdns_early_write; return 0; } OF_EARLYCON_DECLARE(cdns, "xlnx,xuartps", cdns_early_console_setup); OF_EARLYCON_DECLARE(cdns, "cdns,uart-r1p8", cdns_early_console_setup); OF_EARLYCON_DECLARE(cdns, "cdns,uart-r1p12", cdns_early_console_setup); /** * cdns_uart_console_write - perform write operation * @co: Console handle * @s: Pointer to character array * @count: No of characters */ static void cdns_uart_console_write(struct console *co, const char *s, unsigned int count) { struct uart_port *port = &cdns_uart_port[co->index]; unsigned long flags; unsigned int imr, ctrl; int locked = 1; if (port->sysrq) locked = 0; else if (oops_in_progress) locked = spin_trylock_irqsave(&port->lock, flags); else spin_lock_irqsave(&port->lock, flags); /* save and disable interrupt */ imr = readl(port->membase + CDNS_UART_IMR); writel(imr, port->membase + CDNS_UART_IDR); /* * Make sure that the tx part is enabled. Set the TX enable bit and * clear the TX disable bit to enable the transmitter. */ ctrl = readl(port->membase + CDNS_UART_CR); ctrl &= ~CDNS_UART_CR_TX_DIS; ctrl |= CDNS_UART_CR_TX_EN; writel(ctrl, port->membase + CDNS_UART_CR); uart_console_write(port, s, count, cdns_uart_console_putchar); cdns_uart_console_wait_tx(port); writel(ctrl, port->membase + CDNS_UART_CR); /* restore interrupt state */ writel(imr, port->membase + CDNS_UART_IER); if (locked) spin_unlock_irqrestore(&port->lock, flags); } /** * cdns_uart_console_setup - Initialize the uart to default config * @co: Console handle * @options: Initial settings of uart * * Return: 0 on success, negative errno otherwise. */ static int __init cdns_uart_console_setup(struct console *co, char *options) { struct uart_port *port = &cdns_uart_port[co->index]; int baud = 9600; int bits = 8; int parity = 'n'; int flow = 'n'; if (co->index < 0 || co->index >= CDNS_UART_NR_PORTS) return -EINVAL; if (!port->membase) { pr_debug("console on " CDNS_UART_TTY_NAME "%i not present\n", co->index); return -ENODEV; } if (options) uart_parse_options(options, &baud, &parity, &bits, &flow); return uart_set_options(port, co, baud, parity, bits, flow); } static struct uart_driver cdns_uart_uart_driver; static struct console cdns_uart_console = { .name = CDNS_UART_TTY_NAME, .write = cdns_uart_console_write, .device = uart_console_device, .setup = cdns_uart_console_setup, .flags = CON_PRINTBUFFER, .index = -1, /* Specified on the cmdline (e.g. console=ttyPS ) */ .data = &cdns_uart_uart_driver, }; /** * cdns_uart_console_init - Initialization call * * Return: 0 on success, negative errno otherwise */ static int __init cdns_uart_console_init(void) { register_console(&cdns_uart_console); return 0; } console_initcall(cdns_uart_console_init); #endif /* CONFIG_SERIAL_XILINX_PS_UART_CONSOLE */ static struct uart_driver cdns_uart_uart_driver = { .owner = THIS_MODULE, .driver_name = CDNS_UART_NAME, .dev_name = CDNS_UART_TTY_NAME, .major = CDNS_UART_MAJOR, .minor = CDNS_UART_MINOR, .nr = CDNS_UART_NR_PORTS, #ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE .cons = &cdns_uart_console, #endif }; #ifdef CONFIG_PM_SLEEP /** * cdns_uart_suspend - suspend event * @device: Pointer to the device structure * * Return: 0 */ static int cdns_uart_suspend(struct device *device) { struct uart_port *port = dev_get_drvdata(device); struct tty_struct *tty; struct device *tty_dev; int may_wake = 0; /* Get the tty which could be NULL so don't assume it's valid */ tty = tty_port_tty_get(&port->state->port); if (tty) { tty_dev = tty->dev; may_wake = device_may_wakeup(tty_dev); tty_kref_put(tty); } /* * Call the API provided in serial_core.c file which handles * the suspend. */ uart_suspend_port(&cdns_uart_uart_driver, port); if (console_suspend_enabled && !may_wake) { struct cdns_uart *cdns_uart = port->private_data; clk_disable(cdns_uart->uartclk); clk_disable(cdns_uart->pclk); } else { unsigned long flags = 0; spin_lock_irqsave(&port->lock, flags); /* Empty the receive FIFO 1st before making changes */ while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_RXEMPTY)) readl(port->membase + CDNS_UART_FIFO); /* set RX trigger level to 1 */ writel(1, port->membase + CDNS_UART_RXWM); /* disable RX timeout interrups */ writel(CDNS_UART_IXR_TOUT, port->membase + CDNS_UART_IDR); spin_unlock_irqrestore(&port->lock, flags); } return 0; } /** * cdns_uart_resume - Resume after a previous suspend * @device: Pointer to the device structure * * Return: 0 */ static int cdns_uart_resume(struct device *device) { struct uart_port *port = dev_get_drvdata(device); unsigned long flags = 0; u32 ctrl_reg; struct tty_struct *tty; struct device *tty_dev; int may_wake = 0; /* Get the tty which could be NULL so don't assume it's valid */ tty = tty_port_tty_get(&port->state->port); if (tty) { tty_dev = tty->dev; may_wake = device_may_wakeup(tty_dev); tty_kref_put(tty); } if (console_suspend_enabled && !may_wake) { struct cdns_uart *cdns_uart = port->private_data; clk_enable(cdns_uart->pclk); clk_enable(cdns_uart->uartclk); spin_lock_irqsave(&port->lock, flags); /* Set TX/RX Reset */ ctrl_reg = readl(port->membase + CDNS_UART_CR); ctrl_reg |= CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST; writel(ctrl_reg, port->membase + CDNS_UART_CR); while (readl(port->membase + CDNS_UART_CR) & (CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST)) cpu_relax(); /* restore rx timeout value */ writel(rx_timeout, port->membase + CDNS_UART_RXTOUT); /* Enable Tx/Rx */ ctrl_reg = readl(port->membase + CDNS_UART_CR); ctrl_reg &= ~(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS); ctrl_reg |= CDNS_UART_CR_TX_EN | CDNS_UART_CR_RX_EN; writel(ctrl_reg, port->membase + CDNS_UART_CR); spin_unlock_irqrestore(&port->lock, flags); } else { spin_lock_irqsave(&port->lock, flags); /* restore original rx trigger level */ writel(rx_trigger_level, port->membase + CDNS_UART_RXWM); /* enable RX timeout interrupt */ writel(CDNS_UART_IXR_TOUT, port->membase + CDNS_UART_IER); spin_unlock_irqrestore(&port->lock, flags); } return uart_resume_port(&cdns_uart_uart_driver, port); } #endif /* ! CONFIG_PM_SLEEP */ static SIMPLE_DEV_PM_OPS(cdns_uart_dev_pm_ops, cdns_uart_suspend, cdns_uart_resume); /** * cdns_uart_probe - Platform driver probe * @pdev: Pointer to the platform device structure * * Return: 0 on success, negative errno otherwise */ static int cdns_uart_probe(struct platform_device *pdev) { int rc, id, irq; struct uart_port *port; struct resource *res; struct cdns_uart *cdns_uart_data; cdns_uart_data = devm_kzalloc(&pdev->dev, sizeof(*cdns_uart_data), GFP_KERNEL); if (!cdns_uart_data) return -ENOMEM; cdns_uart_data->pclk = devm_clk_get(&pdev->dev, "pclk"); if (IS_ERR(cdns_uart_data->pclk)) { cdns_uart_data->pclk = devm_clk_get(&pdev->dev, "aper_clk"); if (!IS_ERR(cdns_uart_data->pclk)) dev_err(&pdev->dev, "clock name 'aper_clk' is deprecated.\n"); } if (IS_ERR(cdns_uart_data->pclk)) { dev_err(&pdev->dev, "pclk clock not found.\n"); return PTR_ERR(cdns_uart_data->pclk); } cdns_uart_data->uartclk = devm_clk_get(&pdev->dev, "uart_clk"); if (IS_ERR(cdns_uart_data->uartclk)) { cdns_uart_data->uartclk = devm_clk_get(&pdev->dev, "ref_clk"); if (!IS_ERR(cdns_uart_data->uartclk)) dev_err(&pdev->dev, "clock name 'ref_clk' is deprecated.\n"); } if (IS_ERR(cdns_uart_data->uartclk)) { dev_err(&pdev->dev, "uart_clk clock not found.\n"); return PTR_ERR(cdns_uart_data->uartclk); } rc = clk_prepare(cdns_uart_data->pclk); if (rc) { dev_err(&pdev->dev, "Unable to enable pclk clock.\n"); return rc; } rc = clk_prepare(cdns_uart_data->uartclk); if (rc) { dev_err(&pdev->dev, "Unable to enable device clock.\n"); goto err_out_clk_dis_pclk; } res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!res) { rc = -ENODEV; goto err_out_clk_disable; } irq = platform_get_irq(pdev, 0); if (irq <= 0) { rc = -ENXIO; goto err_out_clk_disable; } #ifdef CONFIG_COMMON_CLK cdns_uart_data->clk_rate_change_nb.notifier_call = cdns_uart_clk_notifier_cb; if (clk_notifier_register(cdns_uart_data->uartclk, &cdns_uart_data->clk_rate_change_nb)) dev_warn(&pdev->dev, "Unable to register clock notifier.\n"); #endif /* Look for a serialN alias */ id = of_alias_get_id(pdev->dev.of_node, "serial"); if (id < 0) id = 0; /* Initialize the port structure */ port = cdns_uart_get_port(id); if (!port) { dev_err(&pdev->dev, "Cannot get uart_port structure\n"); rc = -ENODEV; goto err_out_notif_unreg; } /* * Register the port. * This function also registers this device with the tty layer * and triggers invocation of the config_port() entry point. */ port->mapbase = res->start; port->irq = irq; port->dev = &pdev->dev; port->uartclk = clk_get_rate(cdns_uart_data->uartclk); port->private_data = cdns_uart_data; cdns_uart_data->port = port; platform_set_drvdata(pdev, port); rc = uart_add_one_port(&cdns_uart_uart_driver, port); if (rc) { dev_err(&pdev->dev, "uart_add_one_port() failed; err=%i\n", rc); goto err_out_notif_unreg; } return 0; err_out_notif_unreg: #ifdef CONFIG_COMMON_CLK clk_notifier_unregister(cdns_uart_data->uartclk, &cdns_uart_data->clk_rate_change_nb); #endif err_out_clk_disable: clk_unprepare(cdns_uart_data->uartclk); err_out_clk_dis_pclk: clk_unprepare(cdns_uart_data->pclk); return rc; } /** * cdns_uart_remove - called when the platform driver is unregistered * @pdev: Pointer to the platform device structure * * Return: 0 on success, negative errno otherwise */ static int cdns_uart_remove(struct platform_device *pdev) { struct uart_port *port = platform_get_drvdata(pdev); struct cdns_uart *cdns_uart_data = port->private_data; int rc; /* Remove the cdns_uart port from the serial core */ #ifdef CONFIG_COMMON_CLK clk_notifier_unregister(cdns_uart_data->uartclk, &cdns_uart_data->clk_rate_change_nb); #endif rc = uart_remove_one_port(&cdns_uart_uart_driver, port); port->mapbase = 0; clk_unprepare(cdns_uart_data->uartclk); clk_unprepare(cdns_uart_data->pclk); return rc; } /* Match table for of_platform binding */ static const struct of_device_id cdns_uart_of_match[] = { { .compatible = "xlnx,xuartps", }, { .compatible = "cdns,uart-r1p8", }, {} }; MODULE_DEVICE_TABLE(of, cdns_uart_of_match); static struct platform_driver cdns_uart_platform_driver = { .probe = cdns_uart_probe, .remove = cdns_uart_remove, .driver = { .name = CDNS_UART_NAME, .of_match_table = cdns_uart_of_match, .pm = &cdns_uart_dev_pm_ops, }, }; static int __init cdns_uart_init(void) { int retval = 0; /* Register the cdns_uart driver with the serial core */ retval = uart_register_driver(&cdns_uart_uart_driver); if (retval) return retval; /* Register the platform driver */ retval = platform_driver_register(&cdns_uart_platform_driver); if (retval) uart_unregister_driver(&cdns_uart_uart_driver); return retval; } static void __exit cdns_uart_exit(void) { /* Unregister the platform driver */ platform_driver_unregister(&cdns_uart_platform_driver); /* Unregister the cdns_uart driver */ uart_unregister_driver(&cdns_uart_uart_driver); } module_init(cdns_uart_init); module_exit(cdns_uart_exit); MODULE_DESCRIPTION("Driver for Cadence UART"); MODULE_AUTHOR("Xilinx Inc."); MODULE_LICENSE("GPL");