Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / tty / serial / amba-pl010.c
diff --git a/kernel/drivers/tty/serial/amba-pl010.c b/kernel/drivers/tty/serial/amba-pl010.c
new file mode 100644 (file)
index 0000000..5d41d5b
--- /dev/null
@@ -0,0 +1,843 @@
+/*
+ *  Driver for AMBA serial ports
+ *
+ *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
+ *
+ *  Copyright 1999 ARM Limited
+ *  Copyright (C) 2000 Deep Blue Solutions Ltd.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * This is a generic driver for ARM AMBA-type serial ports.  They
+ * have a lot of 16550-like features, but are not register compatible.
+ * Note that although they do have CTS, DCD and DSR inputs, they do
+ * not have an RI input, nor do they have DTR or RTS outputs.  If
+ * required, these have to be supplied via some other means (eg, GPIO)
+ * and hooked into this driver.
+ */
+
+#if defined(CONFIG_SERIAL_AMBA_PL010_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
+#include <linux/module.h>
+#include <linux/ioport.h>
+#include <linux/init.h>
+#include <linux/console.h>
+#include <linux/sysrq.h>
+#include <linux/device.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/serial_core.h>
+#include <linux/serial.h>
+#include <linux/amba/bus.h>
+#include <linux/amba/serial.h>
+#include <linux/clk.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+
+#define UART_NR                8
+
+#define SERIAL_AMBA_MAJOR      204
+#define SERIAL_AMBA_MINOR      16
+#define SERIAL_AMBA_NR         UART_NR
+
+#define AMBA_ISR_PASS_LIMIT    256
+
+#define UART_RX_DATA(s)                (((s) & UART01x_FR_RXFE) == 0)
+#define UART_TX_READY(s)       (((s) & UART01x_FR_TXFF) == 0)
+
+#define UART_DUMMY_RSR_RX      256
+#define UART_PORT_SIZE         64
+
+/*
+ * We wrap our port structure around the generic uart_port.
+ */
+struct uart_amba_port {
+       struct uart_port        port;
+       struct clk              *clk;
+       struct amba_device      *dev;
+       struct amba_pl010_data  *data;
+       unsigned int            old_status;
+};
+
+static void pl010_stop_tx(struct uart_port *port)
+{
+       struct uart_amba_port *uap =
+               container_of(port, struct uart_amba_port, port);
+       unsigned int cr;
+
+       cr = readb(uap->port.membase + UART010_CR);
+       cr &= ~UART010_CR_TIE;
+       writel(cr, uap->port.membase + UART010_CR);
+}
+
+static void pl010_start_tx(struct uart_port *port)
+{
+       struct uart_amba_port *uap =
+               container_of(port, struct uart_amba_port, port);
+       unsigned int cr;
+
+       cr = readb(uap->port.membase + UART010_CR);
+       cr |= UART010_CR_TIE;
+       writel(cr, uap->port.membase + UART010_CR);
+}
+
+static void pl010_stop_rx(struct uart_port *port)
+{
+       struct uart_amba_port *uap =
+               container_of(port, struct uart_amba_port, port);
+       unsigned int cr;
+
+       cr = readb(uap->port.membase + UART010_CR);
+       cr &= ~(UART010_CR_RIE | UART010_CR_RTIE);
+       writel(cr, uap->port.membase + UART010_CR);
+}
+
+static void pl010_disable_ms(struct uart_port *port)
+{
+       struct uart_amba_port *uap = (struct uart_amba_port *)port;
+       unsigned int cr;
+
+       cr = readb(uap->port.membase + UART010_CR);
+       cr &= ~UART010_CR_MSIE;
+       writel(cr, uap->port.membase + UART010_CR);
+}
+
+static void pl010_enable_ms(struct uart_port *port)
+{
+       struct uart_amba_port *uap =
+               container_of(port, struct uart_amba_port, port);
+       unsigned int cr;
+
+       cr = readb(uap->port.membase + UART010_CR);
+       cr |= UART010_CR_MSIE;
+       writel(cr, uap->port.membase + UART010_CR);
+}
+
+static void pl010_rx_chars(struct uart_amba_port *uap)
+{
+       unsigned int status, ch, flag, rsr, max_count = 256;
+
+       status = readb(uap->port.membase + UART01x_FR);
+       while (UART_RX_DATA(status) && max_count--) {
+               ch = readb(uap->port.membase + UART01x_DR);
+               flag = TTY_NORMAL;
+
+               uap->port.icount.rx++;
+
+               /*
+                * Note that the error handling code is
+                * out of the main execution path
+                */
+               rsr = readb(uap->port.membase + UART01x_RSR) | UART_DUMMY_RSR_RX;
+               if (unlikely(rsr & UART01x_RSR_ANY)) {
+                       writel(0, uap->port.membase + UART01x_ECR);
+
+                       if (rsr & UART01x_RSR_BE) {
+                               rsr &= ~(UART01x_RSR_FE | UART01x_RSR_PE);
+                               uap->port.icount.brk++;
+                               if (uart_handle_break(&uap->port))
+                                       goto ignore_char;
+                       } else if (rsr & UART01x_RSR_PE)
+                               uap->port.icount.parity++;
+                       else if (rsr & UART01x_RSR_FE)
+                               uap->port.icount.frame++;
+                       if (rsr & UART01x_RSR_OE)
+                               uap->port.icount.overrun++;
+
+                       rsr &= uap->port.read_status_mask;
+
+                       if (rsr & UART01x_RSR_BE)
+                               flag = TTY_BREAK;
+                       else if (rsr & UART01x_RSR_PE)
+                               flag = TTY_PARITY;
+                       else if (rsr & UART01x_RSR_FE)
+                               flag = TTY_FRAME;
+               }
+
+               if (uart_handle_sysrq_char(&uap->port, ch))
+                       goto ignore_char;
+
+               uart_insert_char(&uap->port, rsr, UART01x_RSR_OE, ch, flag);
+
+       ignore_char:
+               status = readb(uap->port.membase + UART01x_FR);
+       }
+       spin_unlock(&uap->port.lock);
+       tty_flip_buffer_push(&uap->port.state->port);
+       spin_lock(&uap->port.lock);
+}
+
+static void pl010_tx_chars(struct uart_amba_port *uap)
+{
+       struct circ_buf *xmit = &uap->port.state->xmit;
+       int count;
+
+       if (uap->port.x_char) {
+               writel(uap->port.x_char, uap->port.membase + UART01x_DR);
+               uap->port.icount.tx++;
+               uap->port.x_char = 0;
+               return;
+       }
+       if (uart_circ_empty(xmit) || uart_tx_stopped(&uap->port)) {
+               pl010_stop_tx(&uap->port);
+               return;
+       }
+
+       count = uap->port.fifosize >> 1;
+       do {
+               writel(xmit->buf[xmit->tail], uap->port.membase + UART01x_DR);
+               xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+               uap->port.icount.tx++;
+               if (uart_circ_empty(xmit))
+                       break;
+       } while (--count > 0);
+
+       if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+               uart_write_wakeup(&uap->port);
+
+       if (uart_circ_empty(xmit))
+               pl010_stop_tx(&uap->port);
+}
+
+static void pl010_modem_status(struct uart_amba_port *uap)
+{
+       unsigned int status, delta;
+
+       writel(0, uap->port.membase + UART010_ICR);
+
+       status = readb(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
+
+       delta = status ^ uap->old_status;
+       uap->old_status = status;
+
+       if (!delta)
+               return;
+
+       if (delta & UART01x_FR_DCD)
+               uart_handle_dcd_change(&uap->port, status & UART01x_FR_DCD);
+
+       if (delta & UART01x_FR_DSR)
+               uap->port.icount.dsr++;
+
+       if (delta & UART01x_FR_CTS)
+               uart_handle_cts_change(&uap->port, status & UART01x_FR_CTS);
+
+       wake_up_interruptible(&uap->port.state->port.delta_msr_wait);
+}
+
+static irqreturn_t pl010_int(int irq, void *dev_id)
+{
+       struct uart_amba_port *uap = dev_id;
+       unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
+       int handled = 0;
+
+       spin_lock(&uap->port.lock);
+
+       status = readb(uap->port.membase + UART010_IIR);
+       if (status) {
+               do {
+                       if (status & (UART010_IIR_RTIS | UART010_IIR_RIS))
+                               pl010_rx_chars(uap);
+                       if (status & UART010_IIR_MIS)
+                               pl010_modem_status(uap);
+                       if (status & UART010_IIR_TIS)
+                               pl010_tx_chars(uap);
+
+                       if (pass_counter-- == 0)
+                               break;
+
+                       status = readb(uap->port.membase + UART010_IIR);
+               } while (status & (UART010_IIR_RTIS | UART010_IIR_RIS |
+                                  UART010_IIR_TIS));
+               handled = 1;
+       }
+
+       spin_unlock(&uap->port.lock);
+
+       return IRQ_RETVAL(handled);
+}
+
+static unsigned int pl010_tx_empty(struct uart_port *port)
+{
+       struct uart_amba_port *uap =
+               container_of(port, struct uart_amba_port, port);
+       unsigned int status = readb(uap->port.membase + UART01x_FR);
+       return status & UART01x_FR_BUSY ? 0 : TIOCSER_TEMT;
+}
+
+static unsigned int pl010_get_mctrl(struct uart_port *port)
+{
+       struct uart_amba_port *uap =
+               container_of(port, struct uart_amba_port, port);
+       unsigned int result = 0;
+       unsigned int status;
+
+       status = readb(uap->port.membase + UART01x_FR);
+       if (status & UART01x_FR_DCD)
+               result |= TIOCM_CAR;
+       if (status & UART01x_FR_DSR)
+               result |= TIOCM_DSR;
+       if (status & UART01x_FR_CTS)
+               result |= TIOCM_CTS;
+
+       return result;
+}
+
+static void pl010_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+       struct uart_amba_port *uap =
+               container_of(port, struct uart_amba_port, port);
+
+       if (uap->data)
+               uap->data->set_mctrl(uap->dev, uap->port.membase, mctrl);
+}
+
+static void pl010_break_ctl(struct uart_port *port, int break_state)
+{
+       struct uart_amba_port *uap =
+               container_of(port, struct uart_amba_port, port);
+       unsigned long flags;
+       unsigned int lcr_h;
+
+       spin_lock_irqsave(&uap->port.lock, flags);
+       lcr_h = readb(uap->port.membase + UART010_LCRH);
+       if (break_state == -1)
+               lcr_h |= UART01x_LCRH_BRK;
+       else
+               lcr_h &= ~UART01x_LCRH_BRK;
+       writel(lcr_h, uap->port.membase + UART010_LCRH);
+       spin_unlock_irqrestore(&uap->port.lock, flags);
+}
+
+static int pl010_startup(struct uart_port *port)
+{
+       struct uart_amba_port *uap =
+               container_of(port, struct uart_amba_port, port);
+       int retval;
+
+       /*
+        * Try to enable the clock producer.
+        */
+       retval = clk_prepare_enable(uap->clk);
+       if (retval)
+               goto out;
+
+       uap->port.uartclk = clk_get_rate(uap->clk);
+
+       /*
+        * Allocate the IRQ
+        */
+       retval = request_irq(uap->port.irq, pl010_int, 0, "uart-pl010", uap);
+       if (retval)
+               goto clk_dis;
+
+       /*
+        * initialise the old status of the modem signals
+        */
+       uap->old_status = readb(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
+
+       /*
+        * Finally, enable interrupts
+        */
+       writel(UART01x_CR_UARTEN | UART010_CR_RIE | UART010_CR_RTIE,
+              uap->port.membase + UART010_CR);
+
+       return 0;
+
+ clk_dis:
+       clk_disable_unprepare(uap->clk);
+ out:
+       return retval;
+}
+
+static void pl010_shutdown(struct uart_port *port)
+{
+       struct uart_amba_port *uap =
+               container_of(port, struct uart_amba_port, port);
+
+       /*
+        * Free the interrupt
+        */
+       free_irq(uap->port.irq, uap);
+
+       /*
+        * disable all interrupts, disable the port
+        */
+       writel(0, uap->port.membase + UART010_CR);
+
+       /* disable break condition and fifos */
+       writel(readb(uap->port.membase + UART010_LCRH) &
+               ~(UART01x_LCRH_BRK | UART01x_LCRH_FEN),
+              uap->port.membase + UART010_LCRH);
+
+       /*
+        * Shut down the clock producer
+        */
+       clk_disable_unprepare(uap->clk);
+}
+
+static void
+pl010_set_termios(struct uart_port *port, struct ktermios *termios,
+                    struct ktermios *old)
+{
+       struct uart_amba_port *uap =
+               container_of(port, struct uart_amba_port, port);
+       unsigned int lcr_h, old_cr;
+       unsigned long flags;
+       unsigned int baud, quot;
+
+       /*
+        * Ask the core to calculate the divisor for us.
+        */
+       baud = uart_get_baud_rate(port, termios, old, 0, uap->port.uartclk/16); 
+       quot = uart_get_divisor(port, baud);
+
+       switch (termios->c_cflag & CSIZE) {
+       case CS5:
+               lcr_h = UART01x_LCRH_WLEN_5;
+               break;
+       case CS6:
+               lcr_h = UART01x_LCRH_WLEN_6;
+               break;
+       case CS7:
+               lcr_h = UART01x_LCRH_WLEN_7;
+               break;
+       default: // CS8
+               lcr_h = UART01x_LCRH_WLEN_8;
+               break;
+       }
+       if (termios->c_cflag & CSTOPB)
+               lcr_h |= UART01x_LCRH_STP2;
+       if (termios->c_cflag & PARENB) {
+               lcr_h |= UART01x_LCRH_PEN;
+               if (!(termios->c_cflag & PARODD))
+                       lcr_h |= UART01x_LCRH_EPS;
+       }
+       if (uap->port.fifosize > 1)
+               lcr_h |= UART01x_LCRH_FEN;
+
+       spin_lock_irqsave(&uap->port.lock, flags);
+
+       /*
+        * Update the per-port timeout.
+        */
+       uart_update_timeout(port, termios->c_cflag, baud);
+
+       uap->port.read_status_mask = UART01x_RSR_OE;
+       if (termios->c_iflag & INPCK)
+               uap->port.read_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE;
+       if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
+               uap->port.read_status_mask |= UART01x_RSR_BE;
+
+       /*
+        * Characters to ignore
+        */
+       uap->port.ignore_status_mask = 0;
+       if (termios->c_iflag & IGNPAR)
+               uap->port.ignore_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE;
+       if (termios->c_iflag & IGNBRK) {
+               uap->port.ignore_status_mask |= UART01x_RSR_BE;
+               /*
+                * If we're ignoring parity and break indicators,
+                * ignore overruns too (for real raw support).
+                */
+               if (termios->c_iflag & IGNPAR)
+                       uap->port.ignore_status_mask |= UART01x_RSR_OE;
+       }
+
+       /*
+        * Ignore all characters if CREAD is not set.
+        */
+       if ((termios->c_cflag & CREAD) == 0)
+               uap->port.ignore_status_mask |= UART_DUMMY_RSR_RX;
+
+       /* first, disable everything */
+       old_cr = readb(uap->port.membase + UART010_CR) & ~UART010_CR_MSIE;
+
+       if (UART_ENABLE_MS(port, termios->c_cflag))
+               old_cr |= UART010_CR_MSIE;
+
+       writel(0, uap->port.membase + UART010_CR);
+
+       /* Set baud rate */
+       quot -= 1;
+       writel((quot & 0xf00) >> 8, uap->port.membase + UART010_LCRM);
+       writel(quot & 0xff, uap->port.membase + UART010_LCRL);
+
+       /*
+        * ----------v----------v----------v----------v-----
+        * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L
+        * ----------^----------^----------^----------^-----
+        */
+       writel(lcr_h, uap->port.membase + UART010_LCRH);
+       writel(old_cr, uap->port.membase + UART010_CR);
+
+       spin_unlock_irqrestore(&uap->port.lock, flags);
+}
+
+static void pl010_set_ldisc(struct uart_port *port, struct ktermios *termios)
+{
+       if (termios->c_line == N_PPS) {
+               port->flags |= UPF_HARDPPS_CD;
+               spin_lock_irq(&port->lock);
+               pl010_enable_ms(port);
+               spin_unlock_irq(&port->lock);
+       } else {
+               port->flags &= ~UPF_HARDPPS_CD;
+               if (!UART_ENABLE_MS(port, termios->c_cflag)) {
+                       spin_lock_irq(&port->lock);
+                       pl010_disable_ms(port);
+                       spin_unlock_irq(&port->lock);
+               }
+       }
+}
+
+static const char *pl010_type(struct uart_port *port)
+{
+       return port->type == PORT_AMBA ? "AMBA" : NULL;
+}
+
+/*
+ * Release the memory region(s) being used by 'port'
+ */
+static void pl010_release_port(struct uart_port *port)
+{
+       release_mem_region(port->mapbase, UART_PORT_SIZE);
+}
+
+/*
+ * Request the memory region(s) being used by 'port'
+ */
+static int pl010_request_port(struct uart_port *port)
+{
+       return request_mem_region(port->mapbase, UART_PORT_SIZE, "uart-pl010")
+                       != NULL ? 0 : -EBUSY;
+}
+
+/*
+ * Configure/autoconfigure the port.
+ */
+static void pl010_config_port(struct uart_port *port, int flags)
+{
+       if (flags & UART_CONFIG_TYPE) {
+               port->type = PORT_AMBA;
+               pl010_request_port(port);
+       }
+}
+
+/*
+ * verify the new serial_struct (for TIOCSSERIAL).
+ */
+static int pl010_verify_port(struct uart_port *port, struct serial_struct *ser)
+{
+       int ret = 0;
+       if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA)
+               ret = -EINVAL;
+       if (ser->irq < 0 || ser->irq >= nr_irqs)
+               ret = -EINVAL;
+       if (ser->baud_base < 9600)
+               ret = -EINVAL;
+       return ret;
+}
+
+static struct uart_ops amba_pl010_pops = {
+       .tx_empty       = pl010_tx_empty,
+       .set_mctrl      = pl010_set_mctrl,
+       .get_mctrl      = pl010_get_mctrl,
+       .stop_tx        = pl010_stop_tx,
+       .start_tx       = pl010_start_tx,
+       .stop_rx        = pl010_stop_rx,
+       .enable_ms      = pl010_enable_ms,
+       .break_ctl      = pl010_break_ctl,
+       .startup        = pl010_startup,
+       .shutdown       = pl010_shutdown,
+       .set_termios    = pl010_set_termios,
+       .set_ldisc      = pl010_set_ldisc,
+       .type           = pl010_type,
+       .release_port   = pl010_release_port,
+       .request_port   = pl010_request_port,
+       .config_port    = pl010_config_port,
+       .verify_port    = pl010_verify_port,
+};
+
+static struct uart_amba_port *amba_ports[UART_NR];
+
+#ifdef CONFIG_SERIAL_AMBA_PL010_CONSOLE
+
+static void pl010_console_putchar(struct uart_port *port, int ch)
+{
+       struct uart_amba_port *uap =
+               container_of(port, struct uart_amba_port, port);
+       unsigned int status;
+
+       do {
+               status = readb(uap->port.membase + UART01x_FR);
+               barrier();
+       } while (!UART_TX_READY(status));
+       writel(ch, uap->port.membase + UART01x_DR);
+}
+
+static void
+pl010_console_write(struct console *co, const char *s, unsigned int count)
+{
+       struct uart_amba_port *uap = amba_ports[co->index];
+       unsigned int status, old_cr;
+
+       clk_enable(uap->clk);
+
+       /*
+        *      First save the CR then disable the interrupts
+        */
+       old_cr = readb(uap->port.membase + UART010_CR);
+       writel(UART01x_CR_UARTEN, uap->port.membase + UART010_CR);
+
+       uart_console_write(&uap->port, s, count, pl010_console_putchar);
+
+       /*
+        *      Finally, wait for transmitter to become empty
+        *      and restore the TCR
+        */
+       do {
+               status = readb(uap->port.membase + UART01x_FR);
+               barrier();
+       } while (status & UART01x_FR_BUSY);
+       writel(old_cr, uap->port.membase + UART010_CR);
+
+       clk_disable(uap->clk);
+}
+
+static void __init
+pl010_console_get_options(struct uart_amba_port *uap, int *baud,
+                            int *parity, int *bits)
+{
+       if (readb(uap->port.membase + UART010_CR) & UART01x_CR_UARTEN) {
+               unsigned int lcr_h, quot;
+               lcr_h = readb(uap->port.membase + UART010_LCRH);
+
+               *parity = 'n';
+               if (lcr_h & UART01x_LCRH_PEN) {
+                       if (lcr_h & UART01x_LCRH_EPS)
+                               *parity = 'e';
+                       else
+                               *parity = 'o';
+               }
+
+               if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7)
+                       *bits = 7;
+               else
+                       *bits = 8;
+
+               quot = readb(uap->port.membase + UART010_LCRL) |
+                      readb(uap->port.membase + UART010_LCRM) << 8;
+               *baud = uap->port.uartclk / (16 * (quot + 1));
+       }
+}
+
+static int __init pl010_console_setup(struct console *co, char *options)
+{
+       struct uart_amba_port *uap;
+       int baud = 38400;
+       int bits = 8;
+       int parity = 'n';
+       int flow = 'n';
+       int ret;
+
+       /*
+        * 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 >= UART_NR)
+               co->index = 0;
+       uap = amba_ports[co->index];
+       if (!uap)
+               return -ENODEV;
+
+       ret = clk_prepare(uap->clk);
+       if (ret)
+               return ret;
+
+       uap->port.uartclk = clk_get_rate(uap->clk);
+
+       if (options)
+               uart_parse_options(options, &baud, &parity, &bits, &flow);
+       else
+               pl010_console_get_options(uap, &baud, &parity, &bits);
+
+       return uart_set_options(&uap->port, co, baud, parity, bits, flow);
+}
+
+static struct uart_driver amba_reg;
+static struct console amba_console = {
+       .name           = "ttyAM",
+       .write          = pl010_console_write,
+       .device         = uart_console_device,
+       .setup          = pl010_console_setup,
+       .flags          = CON_PRINTBUFFER,
+       .index          = -1,
+       .data           = &amba_reg,
+};
+
+#define AMBA_CONSOLE   &amba_console
+#else
+#define AMBA_CONSOLE   NULL
+#endif
+
+static struct uart_driver amba_reg = {
+       .owner                  = THIS_MODULE,
+       .driver_name            = "ttyAM",
+       .dev_name               = "ttyAM",
+       .major                  = SERIAL_AMBA_MAJOR,
+       .minor                  = SERIAL_AMBA_MINOR,
+       .nr                     = UART_NR,
+       .cons                   = AMBA_CONSOLE,
+};
+
+static int pl010_probe(struct amba_device *dev, const struct amba_id *id)
+{
+       struct uart_amba_port *uap;
+       void __iomem *base;
+       int i, ret;
+
+       for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
+               if (amba_ports[i] == NULL)
+                       break;
+
+       if (i == ARRAY_SIZE(amba_ports))
+               return -EBUSY;
+
+       uap = devm_kzalloc(&dev->dev, sizeof(struct uart_amba_port),
+                          GFP_KERNEL);
+       if (!uap)
+               return -ENOMEM;
+
+       base = devm_ioremap(&dev->dev, dev->res.start,
+                           resource_size(&dev->res));
+       if (!base)
+               return -ENOMEM;
+
+       uap->clk = devm_clk_get(&dev->dev, NULL);
+       if (IS_ERR(uap->clk))
+               return PTR_ERR(uap->clk);
+
+       uap->port.dev = &dev->dev;
+       uap->port.mapbase = dev->res.start;
+       uap->port.membase = base;
+       uap->port.iotype = UPIO_MEM;
+       uap->port.irq = dev->irq[0];
+       uap->port.fifosize = 16;
+       uap->port.ops = &amba_pl010_pops;
+       uap->port.flags = UPF_BOOT_AUTOCONF;
+       uap->port.line = i;
+       uap->dev = dev;
+       uap->data = dev_get_platdata(&dev->dev);
+
+       amba_ports[i] = uap;
+
+       amba_set_drvdata(dev, uap);
+       ret = uart_add_one_port(&amba_reg, &uap->port);
+       if (ret)
+               amba_ports[i] = NULL;
+
+       return ret;
+}
+
+static int pl010_remove(struct amba_device *dev)
+{
+       struct uart_amba_port *uap = amba_get_drvdata(dev);
+       int i;
+
+       uart_remove_one_port(&amba_reg, &uap->port);
+
+       for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
+               if (amba_ports[i] == uap)
+                       amba_ports[i] = NULL;
+
+       return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int pl010_suspend(struct device *dev)
+{
+       struct uart_amba_port *uap = dev_get_drvdata(dev);
+
+       if (uap)
+               uart_suspend_port(&amba_reg, &uap->port);
+
+       return 0;
+}
+
+static int pl010_resume(struct device *dev)
+{
+       struct uart_amba_port *uap = dev_get_drvdata(dev);
+
+       if (uap)
+               uart_resume_port(&amba_reg, &uap->port);
+
+       return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(pl010_dev_pm_ops, pl010_suspend, pl010_resume);
+
+static struct amba_id pl010_ids[] = {
+       {
+               .id     = 0x00041010,
+               .mask   = 0x000fffff,
+       },
+       { 0, 0 },
+};
+
+MODULE_DEVICE_TABLE(amba, pl010_ids);
+
+static struct amba_driver pl010_driver = {
+       .drv = {
+               .name   = "uart-pl010",
+               .pm     = &pl010_dev_pm_ops,
+       },
+       .id_table       = pl010_ids,
+       .probe          = pl010_probe,
+       .remove         = pl010_remove,
+};
+
+static int __init pl010_init(void)
+{
+       int ret;
+
+       printk(KERN_INFO "Serial: AMBA driver\n");
+
+       ret = uart_register_driver(&amba_reg);
+       if (ret == 0) {
+               ret = amba_driver_register(&pl010_driver);
+               if (ret)
+                       uart_unregister_driver(&amba_reg);
+       }
+       return ret;
+}
+
+static void __exit pl010_exit(void)
+{
+       amba_driver_unregister(&pl010_driver);
+       uart_unregister_driver(&amba_reg);
+}
+
+module_init(pl010_init);
+module_exit(pl010_exit);
+
+MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd");
+MODULE_DESCRIPTION("ARM AMBA serial port driver");
+MODULE_LICENSE("GPL");