Driver for Atmel AT91 / AT32 Serial ports

/* *  linux/drivers/char/atmel_serial.c * *  Driver for Atmel AT91 / AT32 Serial ports *  Copyright (C) 2003 Rick Bronson * *  Based on drivers/char/serial_sa1100.c, by Deep Blue Solutions Ltd. *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o. * *  DMA support added by Chip Coldwell. * * 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 * */#include <linux/module.h>#include <linux/tty.h>#include <linux/ioport.h>#include <linux/slab.h>#include <linux/init.h>#include <linux/serial.h>#include <linux/clk.h>#include <linux/console.h>#include <linux/sysrq.h>#include <linux/tty_flip.h>#include <linux/platform_device.h>#include <linux/dma-mapping.h>#include <linux/atmel_pdc.h>#include <linux/atmel_serial.h>#include <asm/io.h>#include <asm/mach/serial_at91.h>#include <mach/board.h>#ifdef CONFIG_ARM#include <mach/cpu.h>#include <mach/gpio.h>#endif#define PDC_BUFFER_SIZE512/* Revisit: We should calculate this based on the actual port settings */#define PDC_RX_TIMEOUT(3 * 10)/* 3 bytes */#if defined(CONFIG_SERIAL_ATMEL_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)#define SUPPORT_SYSRQ#endif#include <linux/serial_core.h>#ifdef CONFIG_SERIAL_ATMEL_TTYAT/* Use device name ttyAT, major 204 and minor 154-169.  This is necessary if we * should coexist with the 8250 driver, such as if we have an external 16C550 * UART. */#define SERIAL_ATMEL_MAJOR204#define MINOR_START154#define ATMEL_DEVICENAME"ttyAT"#else/* Use device name ttyS, major 4, minor 64-68.  This is the usual serial port * name, but it is legally reserved for the 8250 driver. */#define SERIAL_ATMEL_MAJORTTY_MAJOR#define MINOR_START64#define ATMEL_DEVICENAME"ttyS"#endif#define ATMEL_ISR_PASS_LIMIT256/* UART registers. CR is write-only, hence no GET macro */#define UART_PUT_CR(port,v)__raw_writel(v, (port)->membase + ATMEL_US_CR)#define UART_GET_MR(port)__raw_readl((port)->membase + ATMEL_US_MR)#define UART_PUT_MR(port,v)__raw_writel(v, (port)->membase + ATMEL_US_MR)#define UART_PUT_IER(port,v)__raw_writel(v, (port)->membase + ATMEL_US_IER)#define UART_PUT_IDR(port,v)__raw_writel(v, (port)->membase + ATMEL_US_IDR)#define UART_GET_IMR(port)__raw_readl((port)->membase + ATMEL_US_IMR)#define UART_GET_CSR(port)__raw_readl((port)->membase + ATMEL_US_CSR)#define UART_GET_CHAR(port)__raw_readl((port)->membase + ATMEL_US_RHR)#define UART_PUT_CHAR(port,v)__raw_writel(v, (port)->membase + ATMEL_US_THR)#define UART_GET_BRGR(port)__raw_readl((port)->membase + ATMEL_US_BRGR)#define UART_PUT_BRGR(port,v)__raw_writel(v, (port)->membase + ATMEL_US_BRGR)#define UART_PUT_RTOR(port,v)__raw_writel(v, (port)->membase + ATMEL_US_RTOR) /* PDC registers */#define UART_PUT_PTCR(port,v)__raw_writel(v, (port)->membase + ATMEL_PDC_PTCR)#define UART_GET_PTSR(port)__raw_readl((port)->membase + ATMEL_PDC_PTSR)#define UART_PUT_RPR(port,v)__raw_writel(v, (port)->membase + ATMEL_PDC_RPR)#define UART_GET_RPR(port)__raw_readl((port)->membase + ATMEL_PDC_RPR)#define UART_PUT_RCR(port,v)__raw_writel(v, (port)->membase + ATMEL_PDC_RCR)#define UART_PUT_RNPR(port,v)__raw_writel(v, (port)->membase + ATMEL_PDC_RNPR)#define UART_PUT_RNCR(port,v)__raw_writel(v, (port)->membase + ATMEL_PDC_RNCR)#define UART_PUT_TPR(port,v)__raw_writel(v, (port)->membase + ATMEL_PDC_TPR)#define UART_PUT_TCR(port,v)__raw_writel(v, (port)->membase + ATMEL_PDC_TCR)#define UART_GET_TCR(port)__raw_readl((port)->membase + ATMEL_PDC_TCR)static int (*atmel_open_hook)(struct uart_port *);static void (*atmel_close_hook)(struct uart_port *);struct atmel_dma_buffer {unsigned char*buf;dma_addr_tdma_addr;unsigned intdma_size;unsigned intofs;};struct atmel_uart_char {u16status;u16ch;};#define ATMEL_SERIAL_RINGSIZE 1024/* * We wrap our port structure around the generic uart_port. */struct atmel_uart_port {struct uart_portuart;/* uart */struct clk*clk;/* uart clock */intmay_wakeup;/* cached value of device_may_wakeup for times we need to disable it */u32backup_imr;/* IMR saved during suspend */intbreak_active;/* break being received */shortuse_dma_rx;/* enable PDC receiver */shortpdc_rx_idx;/* current PDC RX buffer */struct atmel_dma_bufferpdc_rx[2];/* PDC receier */shortuse_dma_tx;/* enable PDC transmitter */struct atmel_dma_bufferpdc_tx;/* PDC transmitter */struct tasklet_structtasklet;unsigned intirq_status;unsigned intirq_status_prev;struct circ_bufrx_ring;};static struct atmel_uart_port atmel_ports[ATMEL_MAX_UART];#ifdef SUPPORT_SYSRQstatic struct console atmel_console;#endifstatic inline struct atmel_uart_port *to_atmel_uart_port(struct uart_port *uart){return container_of(uart, struct atmel_uart_port, uart);}#ifdef CONFIG_SERIAL_ATMEL_PDCstatic bool atmel_use_dma_rx(struct uart_port *port){struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);return atmel_port->use_dma_rx;}static bool atmel_use_dma_tx(struct uart_port *port){struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);return atmel_port->use_dma_tx;}#elsestatic bool atmel_use_dma_rx(struct uart_port *port){return false;}static bool atmel_use_dma_tx(struct uart_port *port){return false;}#endif/* * Return TIOCSER_TEMT when transmitter FIFO and Shift register is empty. */static u_int atmel_tx_empty(struct uart_port *port){return (UART_GET_CSR(port) & ATMEL_US_TXEMPTY) ? TIOCSER_TEMT : 0;}/* * Set state of the modem control output lines */static void atmel_set_mctrl(struct uart_port *port, u_int mctrl){unsigned int control = 0;unsigned int mode;#ifdef CONFIG_ARCH_AT91RM9200if (cpu_is_at91rm9200()) {/* * AT91RM9200 Errata #39: RTS0 is not internally connected * to PA21. We need to drive the pin manually. */if (port->mapbase == AT91RM9200_BASE_US0) {if (mctrl & TIOCM_RTS)at91_set_gpio_value(AT91_PIN_PA21, 0);elseat91_set_gpio_value(AT91_PIN_PA21, 1);}}#endifif (mctrl & TIOCM_RTS)control |= ATMEL_US_RTSEN;elsecontrol |= ATMEL_US_RTSDIS;if (mctrl & TIOCM_DTR)control |= ATMEL_US_DTREN;elsecontrol |= ATMEL_US_DTRDIS;UART_PUT_CR(port, control);/* Local loopback mode? */mode = UART_GET_MR(port) & ~ATMEL_US_CHMODE;if (mctrl & TIOCM_LOOP)mode |= ATMEL_US_CHMODE_LOC_LOOP;elsemode |= ATMEL_US_CHMODE_NORMAL;UART_PUT_MR(port, mode);}/* * Get state of the modem control input lines */static u_int atmel_get_mctrl(struct uart_port *port){unsigned int status, ret = 0;status = UART_GET_CSR(port);/* * The control signals are active low. */if (!(status & ATMEL_US_DCD))ret |= TIOCM_CD;if (!(status & ATMEL_US_CTS))ret |= TIOCM_CTS;if (!(status & ATMEL_US_DSR))ret |= TIOCM_DSR;if (!(status & ATMEL_US_RI))ret |= TIOCM_RI;return ret;}/* * Stop transmitting. */static void atmel_stop_tx(struct uart_port *port){if (atmel_use_dma_tx(port)) {/* disable PDC transmit */UART_PUT_PTCR(port, ATMEL_PDC_TXTDIS);UART_PUT_IDR(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE);} elseUART_PUT_IDR(port, ATMEL_US_TXRDY);}/* * Start transmitting. */static void atmel_start_tx(struct uart_port *port){if (atmel_use_dma_tx(port)) {if (UART_GET_PTSR(port) & ATMEL_PDC_TXTEN)/* The transmitter is already running.  Yes, we   really need this.*/return;UART_PUT_IER(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE);/* re-enable PDC transmit */UART_PUT_PTCR(port, ATMEL_PDC_TXTEN);} elseUART_PUT_IER(port, ATMEL_US_TXRDY);}/* * Stop receiving - port is in process of being closed. */static void atmel_stop_rx(struct uart_port *port){if (atmel_use_dma_rx(port)) {/* disable PDC receive */UART_PUT_PTCR(port, ATMEL_PDC_RXTDIS);UART_PUT_IDR(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);} elseUART_PUT_IDR(port, ATMEL_US_RXRDY);}/* * Enable modem status interrupts */static void atmel_enable_ms(struct uart_port *port){UART_PUT_IER(port, ATMEL_US_RIIC | ATMEL_US_DSRIC| ATMEL_US_DCDIC | ATMEL_US_CTSIC);}/* * Control the transmission of a break signal */static void atmel_break_ctl(struct uart_port *port, int break_state){if (break_state != 0)UART_PUT_CR(port, ATMEL_US_STTBRK);/* start break */elseUART_PUT_CR(port, ATMEL_US_STPBRK);/* stop break */}/* * Stores the incoming character in the ring buffer */static voidatmel_buffer_rx_char(struct uart_port *port, unsigned int status,     unsigned int ch){struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);struct circ_buf *ring = &atmel_port->rx_ring;struct atmel_uart_char *c;if (!CIRC_SPACE(ring->head, ring->tail, ATMEL_SERIAL_RINGSIZE))/* Buffer overflow, ignore char */return;c = &((struct atmel_uart_char *)ring->buf)[ring->head];c->status= status;c->ch= ch;/* Make sure the character is stored before we update head. */smp_wmb();ring->head = (ring->head + 1) & (ATMEL_SERIAL_RINGSIZE - 1);}/* * Deal with parity, framing and overrun errors. */static void atmel_pdc_rxerr(struct uart_port *port, unsigned int status){/* clear error */UART_PUT_CR(port, ATMEL_US_RSTSTA);if (status & ATMEL_US_RXBRK) {/* ignore side-effect */status &= ~(ATMEL_US_PARE | ATMEL_US_FRAME);port->icount.brk++;}if (status & ATMEL_US_PARE)port->icount.parity++;if (status & ATMEL_US_FRAME)port->icount.frame++;if (status & ATMEL_US_OVRE)port->icount.overrun++;}/* * Characters received (called from interrupt handler) */static void atmel_rx_chars(struct uart_port *port){struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);unsigned int status, ch;status = UART_GET_CSR(port);while (status & ATMEL_US_RXRDY) {ch = UART_GET_CHAR(port);/* * note that the error handling code is * out of the main execution path */if (unlikely(status & (ATMEL_US_PARE | ATMEL_US_FRAME       | ATMEL_US_OVRE | ATMEL_US_RXBRK)     || atmel_port->break_active)) {/* clear error */UART_PUT_CR(port, ATMEL_US_RSTSTA);if (status & ATMEL_US_RXBRK    && !atmel_port->break_active) {atmel_port->break_active = 1;UART_PUT_IER(port, ATMEL_US_RXBRK);} else {/* * This is either the end-of-break * condition or we've received at * least one character without RXBRK * being set. In both cases, the next * RXBRK will indicate start-of-break. */UART_PUT_IDR(port, ATMEL_US_RXBRK);status &= ~ATMEL_US_RXBRK;atmel_port->break_active = 0;}}atmel_buffer_rx_char(port, status, ch);status = UART_GET_CSR(port);}tasklet_schedule(&atmel_port->tasklet);}/* * Transmit characters (called from tasklet with TXRDY interrupt * disabled) */static void atmel_tx_chars(struct uart_port *port){struct circ_buf *xmit = &port->info->xmit;if (port->x_char && UART_GET_CSR(port) & ATMEL_US_TXRDY) {UART_PUT_CHAR(port, port->x_char);port->icount.tx++;port->x_char = 0;}if (uart_circ_empty(xmit) || uart_tx_stopped(port))return;while (UART_GET_CSR(port) & ATMEL_US_TXRDY) {UART_PUT_CHAR(port, xmit->buf[xmit->tail]);xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);port->icount.tx++;if (uart_circ_empty(xmit))break;}if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)uart_write_wakeup(port);if (!uart_circ_empty(xmit))UART_PUT_IER(port, ATMEL_US_TXRDY);}/* * receive interrupt handler. */static voidatmel_handle_receive(struct uart_port *port, unsigned int pending){struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);if (atmel_use_dma_rx(port)) {/* * PDC receive. Just schedule the tasklet and let it * figure out the details. * * TODO: We're not handling error flags correctly at * the moment. */if (pending & (ATMEL_US_ENDRX | ATMEL_US_TIMEOUT)) {UART_PUT_IDR(port, (ATMEL_US_ENDRX| ATMEL_US_TIMEOUT));tasklet_schedule(&atmel_port->tasklet);}if (pending & (ATMEL_US_RXBRK | ATMEL_US_OVRE |ATMEL_US_FRAME | ATMEL_US_PARE))atmel_pdc_rxerr(port, pending);}/* Interrupt receive */if (pending & ATMEL_US_RXRDY)atmel_rx_chars(port);else if (pending & ATMEL_US_RXBRK) {/* * End of break detected. If it came along with a * character, atmel_rx_chars will handle it. */UART_PUT_CR(port, ATMEL_US_RSTSTA);UART_PUT_IDR(port, ATMEL_US_RXBRK);atmel_port->break_active = 0;}}/* * transmit interrupt handler. (Transmit is IRQF_NODELAY safe) */static voidatmel_handle_transmit(struct uart_port *port, unsigned int pending){struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);if (atmel_use_dma_tx(port)) {/* PDC transmit */if (pending & (ATMEL_US_ENDTX | ATMEL_US_TXBUFE)) {UART_PUT_IDR(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE);tasklet_schedule(&atmel_port->tasklet);}} else {/* Interrupt transmit */if (pending & ATMEL_US_TXRDY) {UART_PUT_IDR(port, ATMEL_US_TXRDY);tasklet_schedule(&atmel_port->tasklet);}}}/* * status flags interrupt handler. */static voidatmel_handle_status(struct uart_port *port, unsigned int pending,    unsigned int status){struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);if (pending & (ATMEL_US_RIIC | ATMEL_US_DSRIC | ATMEL_US_DCDIC| ATMEL_US_CTSIC)) {atmel_port->irq_status = status;tasklet_schedule(&atmel_port->tasklet);}}/* * Interrupt handler */static irqreturn_t atmel_interrupt(int irq, void *dev_id){struct uart_port *port = dev_id;unsigned int status, pending, pass_counter = 0;do {status = UART_GET_CSR(port);pending = status & UART_GET_IMR(port);if (!pending)break;atmel_handle_receive(port, pending);atmel_handle_status(port, pending, status);atmel_handle_transmit(port, pending);} while (pass_counter++ < ATMEL_ISR_PASS_LIMIT);return pass_counter ? IRQ_HANDLED : IRQ_NONE;}/* * Called from tasklet with ENDTX and TXBUFE interrupts disabled. */static void atmel_tx_dma(struct uart_port *port){struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);struct circ_buf *xmit = &port->info->xmit;struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx;int count;/* nothing left to transmit? */if (UART_GET_TCR(port))return;xmit->tail += pdc->ofs;xmit->tail &= UART_XMIT_SIZE - 1;port->icount.tx += pdc->ofs;pdc->ofs = 0;/* more to transmit - setup next transfer *//* disable PDC transmit */UART_PUT_PTCR(port, ATMEL_PDC_TXTDIS);if (!uart_circ_empty(xmit) && !uart_tx_stopped(port)) {dma_sync_single_for_device(port->dev,   pdc->dma_addr,   pdc->dma_size,   DMA_TO_DEVICE);count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);pdc->ofs = count;UART_PUT_TPR(port, pdc->dma_addr + xmit->tail);UART_PUT_TCR(port, count);/* re-enable PDC transmit and interrupts */UART_PUT_PTCR(port, ATMEL_PDC_TXTEN);UART_PUT_IER(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE);}if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)uart_write_wakeup(port);}static void atmel_rx_from_ring(struct uart_port *port){struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);struct circ_buf *ring = &atmel_port->rx_ring;unsigned int flg;unsigned int status;while (ring->head != ring->tail) {struct atmel_uart_char c;/* Make sure c is loaded after head. */smp_rmb();c = ((struct atmel_uart_char *)ring->buf)[ring->tail];ring->tail = (ring->tail + 1) & (ATMEL_SERIAL_RINGSIZE - 1);port->icount.rx++;status = c.status;flg = TTY_NORMAL;/* * note that the error handling code is * out of the main execution path */if (unlikely(status & (ATMEL_US_PARE | ATMEL_US_FRAME       | ATMEL_US_OVRE | ATMEL_US_RXBRK))) {if (status & ATMEL_US_RXBRK) {/* ignore side-effect */status &= ~(ATMEL_US_PARE | ATMEL_US_FRAME);port->icount.brk++;if (uart_handle_break(port))continue;}if (status & ATMEL_US_PARE)port->icount.parity++;if (status & ATMEL_US_FRAME)port->icount.frame++;if (status & ATMEL_US_OVRE)port->icount.overrun++;status &= port->read_status_mask;if (status & ATMEL_US_RXBRK)flg = TTY_BREAK;else if (status & ATMEL_US_PARE)flg = TTY_PARITY;else if (status & ATMEL_US_FRAME)flg = TTY_FRAME;}if (uart_handle_sysrq_char(port, c.ch))continue;uart_insert_char(port, status, ATMEL_US_OVRE, c.ch, flg);}/* * Drop the lock here since it might end up calling * uart_start(), which takes the lock. */spin_unlock(&port->lock);tty_flip_buffer_push(port->info->port.tty);spin_lock(&port->lock);}static void atmel_rx_from_dma(struct uart_port *port){struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);struct tty_struct *tty = port->info->port.tty;struct atmel_dma_buffer *pdc;int rx_idx = atmel_port->pdc_rx_idx;unsigned int head;unsigned int tail;unsigned int count;do {/* Reset the UART timeout early so that we don't miss one */UART_PUT_CR(port, ATMEL_US_STTTO);pdc = &atmel_port->pdc_rx[rx_idx];head = UART_GET_RPR(port) - pdc->dma_addr;tail = pdc->ofs;/* If the PDC has switched buffers, RPR won't contain * any address within the current buffer. Since head * is unsigned, we just need a one-way comparison to * find out. * * In this case, we just need to consume the entire * buffer and resubmit it for DMA. This will clear the * ENDRX bit as well, so that we can safely re-enable * all interrupts below. */head = min(head, pdc->dma_size);if (likely(head != tail)) {dma_sync_single_for_cpu(port->dev, pdc->dma_addr,pdc->dma_size, DMA_FROM_DEVICE);/* * head will only wrap around when we recycle * the DMA buffer, and when that happens, we * explicitly set tail to 0. So head will * always be greater than tail. */count = head - tail;tty_insert_flip_string(tty, pdc->buf + pdc->ofs, count);dma_sync_single_for_device(port->dev, pdc->dma_addr,pdc->dma_size, DMA_FROM_DEVICE);port->icount.rx += count;pdc->ofs = head;}/* * If the current buffer is full, we need to check if * the next one contains any additional data. */if (head >= pdc->dma_size) {pdc->ofs = 0;UART_PUT_RNPR(port, pdc->dma_addr);UART_PUT_RNCR(port, pdc->dma_size);rx_idx = !rx_idx;atmel_port->pdc_rx_idx = rx_idx;}} while (head >= pdc->dma_size);/* * Drop the lock here since it might end up calling * uart_start(), which takes the lock. */spin_unlock(&port->lock);tty_flip_buffer_push(tty);spin_lock(&port->lock);UART_PUT_IER(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);}/* * tasklet handling tty stuff outside the interrupt handler. */static void atmel_tasklet_func(unsigned long data){struct uart_port *port = (struct uart_port *)data;struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);unsigned int status;unsigned int status_change;/* The interrupt handler does not take the lock */spin_lock(&port->lock);if (atmel_use_dma_tx(port))atmel_tx_dma(port);elseatmel_tx_chars(port);status = atmel_port->irq_status;status_change = status ^ atmel_port->irq_status_prev;if (status_change & (ATMEL_US_RI | ATMEL_US_DSR| ATMEL_US_DCD | ATMEL_US_CTS)) {/* TODO: All reads to CSR will clear these interrupts! */if (status_change & ATMEL_US_RI)port->icount.rng++;if (status_change & ATMEL_US_DSR)port->icount.dsr++;if (status_change & ATMEL_US_DCD)uart_handle_dcd_change(port, !(status & ATMEL_US_DCD));if (status_change & ATMEL_US_CTS)uart_handle_cts_change(port, !(status & ATMEL_US_CTS));wake_up_interruptible(&port->info->delta_msr_wait);atmel_port->irq_status_prev = status;}if (atmel_use_dma_rx(port))atmel_rx_from_dma(port);elseatmel_rx_from_ring(port);spin_unlock(&port->lock);}/* * Perform initialization and enable port for reception */static int atmel_startup(struct uart_port *port){struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);struct tty_struct *tty = port->info->port.tty;int retval;/* * Ensure that no interrupts are enabled otherwise when * request_irq() is called we could get stuck trying to * handle an unexpected interrupt */UART_PUT_IDR(port, -1);/* * Allocate the IRQ */retval = request_irq(port->irq, atmel_interrupt, IRQF_SHARED,tty ? tty->name : "atmel_serial", port);if (retval) {printk("atmel_serial: atmel_startup - Can't get irq\n");return retval;}/* * Initialize DMA (if necessary) */if (atmel_use_dma_rx(port)) {int i;for (i = 0; i < 2; i++) {struct atmel_dma_buffer *pdc = &atmel_port->pdc_rx[i];pdc->buf = kmalloc(PDC_BUFFER_SIZE, GFP_KERNEL);if (pdc->buf == NULL) {if (i != 0) {dma_unmap_single(port->dev,atmel_port->pdc_rx[0].dma_addr,PDC_BUFFER_SIZE,DMA_FROM_DEVICE);kfree(atmel_port->pdc_rx[0].buf);}free_irq(port->irq, port);return -ENOMEM;}pdc->dma_addr = dma_map_single(port->dev,       pdc->buf,       PDC_BUFFER_SIZE,       DMA_FROM_DEVICE);pdc->dma_size = PDC_BUFFER_SIZE;pdc->ofs = 0;}atmel_port->pdc_rx_idx = 0;UART_PUT_RPR(port, atmel_port->pdc_rx[0].dma_addr);UART_PUT_RCR(port, PDC_BUFFER_SIZE);UART_PUT_RNPR(port, atmel_port->pdc_rx[1].dma_addr);UART_PUT_RNCR(port, PDC_BUFFER_SIZE);}if (atmel_use_dma_tx(port)) {struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx;struct circ_buf *xmit = &port->info->xmit;pdc->buf = xmit->buf;pdc->dma_addr = dma_map_single(port->dev,       pdc->buf,       UART_XMIT_SIZE,       DMA_TO_DEVICE);pdc->dma_size = UART_XMIT_SIZE;pdc->ofs = 0;}/* * If there is a specific "open" function (to register * control line interrupts) */if (atmel_open_hook) {retval = atmel_open_hook(port);if (retval) {free_irq(port->irq, port);return retval;}}/* Save current CSR for comparison in atmel_tasklet_func() */atmel_port->irq_status_prev = UART_GET_CSR(port);atmel_port->irq_status = atmel_port->irq_status_prev;/* * Finally, enable the serial port */UART_PUT_CR(port, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);/* enable xmit & rcvr */UART_PUT_CR(port, ATMEL_US_TXEN | ATMEL_US_RXEN);if (atmel_use_dma_rx(port)) {/* set UART timeout */UART_PUT_RTOR(port, PDC_RX_TIMEOUT);UART_PUT_CR(port, ATMEL_US_STTTO);UART_PUT_IER(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);/* enable PDC controller */UART_PUT_PTCR(port, ATMEL_PDC_RXTEN);} else {/* enable receive only */UART_PUT_IER(port, ATMEL_US_RXRDY);}return 0;}/* * Disable the port */static void atmel_shutdown(struct uart_port *port){struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);/* * Ensure everything is stopped. */atmel_stop_rx(port);atmel_stop_tx(port);/* * Shut-down the DMA. */if (atmel_use_dma_rx(port)) {int i;for (i = 0; i < 2; i++) {struct atmel_dma_buffer *pdc = &atmel_port->pdc_rx[i];dma_unmap_single(port->dev, pdc->dma_addr, pdc->dma_size, DMA_FROM_DEVICE);kfree(pdc->buf);}}if (atmel_use_dma_tx(port)) {struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx;dma_unmap_single(port->dev, pdc->dma_addr, pdc->dma_size, DMA_TO_DEVICE);}/* * Disable all interrupts, port and break condition. */UART_PUT_CR(port, ATMEL_US_RSTSTA);UART_PUT_IDR(port, -1);/* * Free the interrupt */free_irq(port->irq, port);/* * If there is a specific "close" function (to unregister * control line interrupts) */if (atmel_close_hook)atmel_close_hook(port);}/* * Flush any TX data submitted for DMA. Called when the TX circular * buffer is reset. */static void atmel_flush_buffer(struct uart_port *port){struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);if (atmel_use_dma_tx(port)) {UART_PUT_TCR(port, 0);atmel_port->pdc_tx.ofs = 0;}}/* * Power / Clock management. */static void atmel_serial_pm(struct uart_port *port, unsigned int state,    unsigned int oldstate){struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);switch (state) {case 0:/* * Enable the peripheral clock for this serial port. * This is called on uart_open() or a resume event. */clk_enable(atmel_port->clk);/* re-enable interrupts if we disabled some on suspend */UART_PUT_IER(port, atmel_port->backup_imr);break;case 3:/* Back up the interrupt mask and disable all interrupts */atmel_port->backup_imr = UART_GET_IMR(port);UART_PUT_IDR(port, -1);/* * Disable the peripheral clock for this serial port. * This is called on uart_close() or a suspend event. */clk_disable(atmel_port->clk);break;default:printk(KERN_ERR "atmel_serial: unknown pm %d\n", state);}}/* * Change the port parameters */static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,      struct ktermios *old){unsigned long flags;unsigned int mode, imr, quot, baud;/* Get current mode register */mode = UART_GET_MR(port) & ~(ATMEL_US_USCLKS | ATMEL_US_CHRL| ATMEL_US_NBSTOP | ATMEL_US_PAR| ATMEL_US_USMODE);baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);quot = uart_get_divisor(port, baud);if (quot > 65535) {/* BRGR is 16-bit, so switch to slower clock */quot /= 8;mode |= ATMEL_US_USCLKS_MCK_DIV8;}/* byte size */switch (termios->c_cflag & CSIZE) {case CS5:mode |= ATMEL_US_CHRL_5;break;case CS6:mode |= ATMEL_US_CHRL_6;break;case CS7:mode |= ATMEL_US_CHRL_7;break;default:mode |= ATMEL_US_CHRL_8;break;}/* stop bits */if (termios->c_cflag & CSTOPB)mode |= ATMEL_US_NBSTOP_2;/* parity */if (termios->c_cflag & PARENB) {/* Mark or Space parity */if (termios->c_cflag & CMSPAR) {if (termios->c_cflag & PARODD)mode |= ATMEL_US_PAR_MARK;elsemode |= ATMEL_US_PAR_SPACE;} else if (termios->c_cflag & PARODD)mode |= ATMEL_US_PAR_ODD;elsemode |= ATMEL_US_PAR_EVEN;} elsemode |= ATMEL_US_PAR_NONE;/* hardware handshake (RTS/CTS) */if (termios->c_cflag & CRTSCTS)mode |= ATMEL_US_USMODE_HWHS;elsemode |= ATMEL_US_USMODE_NORMAL;spin_lock_irqsave(&port->lock, flags);port->read_status_mask = ATMEL_US_OVRE;if (termios->c_iflag & INPCK)port->read_status_mask |= (ATMEL_US_FRAME | ATMEL_US_PARE);if (termios->c_iflag & (BRKINT | PARMRK))port->read_status_mask |= ATMEL_US_RXBRK;if (atmel_use_dma_rx(port))/* need to enable error interrupts */UART_PUT_IER(port, port->read_status_mask);/* * Characters to ignore */port->ignore_status_mask = 0;if (termios->c_iflag & IGNPAR)port->ignore_status_mask |= (ATMEL_US_FRAME | ATMEL_US_PARE);if (termios->c_iflag & IGNBRK) {port->ignore_status_mask |= ATMEL_US_RXBRK;/* * If we're ignoring parity and break indicators, * ignore overruns too (for real raw support). */if (termios->c_iflag & IGNPAR)port->ignore_status_mask |= ATMEL_US_OVRE;}/* TODO: Ignore all characters if CREAD is set.*//* update the per-port timeout */uart_update_timeout(port, termios->c_cflag, baud);/* save/disable interrupts and drain transmitter */imr = UART_GET_IMR(port);UART_PUT_IDR(port, -1);while (!(UART_GET_CSR(port) & ATMEL_US_TXEMPTY))cpu_relax();/* disable receiver and transmitter */UART_PUT_CR(port, ATMEL_US_TXDIS | ATMEL_US_RXDIS);                //Add by zhangwei for 485        if (port->irq == AT91SAM9260_ID_US0)                mode |= ATMEL_US_USMODE_RS485;        if (port->irq == AT91SAM9260_ID_US1)                mode |= ATMEL_US_USMODE_RS485;        if (port->irq == AT91SAM9260_ID_US2)                mode |= ATMEL_US_USMODE_RS485;        if (port->irq == AT91SAM9260_ID_US3)                mode |= ATMEL_US_USMODE_RS485;        UART_PUT_MR(port, mode);/* set the baud rate */UART_PUT_BRGR(port, quot);UART_PUT_CR(port, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);UART_PUT_CR(port, ATMEL_US_TXEN | ATMEL_US_RXEN);/* restore interrupts */UART_PUT_IER(port, imr);/* CTS flow-control and modem-status interrupts */if (UART_ENABLE_MS(port, termios->c_cflag))port->ops->enable_ms(port);spin_unlock_irqrestore(&port->lock, flags);}/* * Return string describing the specified port */static const char *atmel_type(struct uart_port *port){return (port->type == PORT_ATMEL) ? "ATMEL_SERIAL" : NULL;}/* * Release the memory region(s) being used by 'port'. */static void atmel_release_port(struct uart_port *port){struct platform_device *pdev = to_platform_device(port->dev);int size = pdev->resource[0].end - pdev->resource[0].start + 1;release_mem_region(port->mapbase, size);if (port->flags & UPF_IOREMAP) {iounmap(port->membase);port->membase = NULL;}}/* * Request the memory region(s) being used by 'port'. */static int atmel_request_port(struct uart_port *port){struct platform_device *pdev = to_platform_device(port->dev);int size = pdev->resource[0].end - pdev->resource[0].start + 1;if (!request_mem_region(port->mapbase, size, "atmel_serial"))return -EBUSY;if (port->flags & UPF_IOREMAP) {port->membase = ioremap(port->mapbase, size);if (port->membase == NULL) {release_mem_region(port->mapbase, size);return -ENOMEM;}}return 0;}/* * Configure/autoconfigure the port. */static void atmel_config_port(struct uart_port *port, int flags){if (flags & UART_CONFIG_TYPE) {port->type = PORT_ATMEL;atmel_request_port(port);}}/* * Verify the new serial_struct (for TIOCSSERIAL). */static int atmel_verify_port(struct uart_port *port, struct serial_struct *ser){int ret = 0;if (ser->type != PORT_UNKNOWN && ser->type != PORT_ATMEL)ret = -EINVAL;if (port->irq != ser->irq)ret = -EINVAL;if (ser->io_type != SERIAL_IO_MEM)ret = -EINVAL;if (port->uartclk / 16 != ser->baud_base)ret = -EINVAL;if ((void *)port->mapbase != ser->iomem_base)ret = -EINVAL;if (port->iobase != ser->port)ret = -EINVAL;if (ser->hub6 != 0)ret = -EINVAL;return ret;}static struct uart_ops atmel_pops = {.tx_empty= atmel_tx_empty,.set_mctrl= atmel_set_mctrl,.get_mctrl= atmel_get_mctrl,.stop_tx= atmel_stop_tx,.start_tx= atmel_start_tx,.stop_rx= atmel_stop_rx,.enable_ms= atmel_enable_ms,.break_ctl= atmel_break_ctl,.startup= atmel_startup,.shutdown= atmel_shutdown,.flush_buffer= atmel_flush_buffer,.set_termios= atmel_set_termios,.type= atmel_type,.release_port= atmel_release_port,.request_port= atmel_request_port,.config_port= atmel_config_port,.verify_port= atmel_verify_port,.pm= atmel_serial_pm,};/* * Configure the port from the platform device resource info. */static void __devinit atmel_init_port(struct atmel_uart_port *atmel_port,      struct platform_device *pdev){struct uart_port *port = &atmel_port->uart;struct atmel_uart_data *data = pdev->dev.platform_data;port->iotype= UPIO_MEM;port->flags= UPF_BOOT_AUTOCONF;port->ops= &atmel_pops;port->fifosize= 1;port->line= pdev->id;port->dev= &pdev->dev;port->mapbase= pdev->resource[0].start;port->irq= pdev->resource[1].start;tasklet_init(&atmel_port->tasklet, atmel_tasklet_func,(unsigned long)port);memset(&atmel_port->rx_ring, 0, sizeof(atmel_port->rx_ring));if (data->regs)/* Already mapped by setup code */port->membase = data->regs;else {port->flags|= UPF_IOREMAP;port->membase= NULL;}/* for console, the clock could already be configured */if (!atmel_port->clk) {atmel_port->clk = clk_get(&pdev->dev, "usart");clk_enable(atmel_port->clk);port->uartclk = clk_get_rate(atmel_port->clk);clk_disable(atmel_port->clk);/* only enable clock when USART is in use */}atmel_port->use_dma_rx = data->use_dma_rx;atmel_port->use_dma_tx = data->use_dma_tx;if (atmel_use_dma_tx(port))port->fifosize = PDC_BUFFER_SIZE;}/* * Register board-specific modem-control line handlers. */void __init atmel_register_uart_fns(struct atmel_port_fns *fns){if (fns->enable_ms)atmel_pops.enable_ms = fns->enable_ms;if (fns->get_mctrl)atmel_pops.get_mctrl = fns->get_mctrl;if (fns->set_mctrl)atmel_pops.set_mctrl = fns->set_mctrl;atmel_open_hook= fns->open;atmel_close_hook= fns->close;atmel_pops.pm= fns->pm;atmel_pops.set_wake= fns->set_wake;}#ifdef CONFIG_SERIAL_ATMEL_CONSOLEstatic void atmel_console_putchar(struct uart_port *port, int ch){while (!(UART_GET_CSR(port) & ATMEL_US_TXRDY))cpu_relax();UART_PUT_CHAR(port, ch);}/* * Interrupts are disabled on entering */static void atmel_console_write(struct console *co, const char *s, u_int count){struct uart_port *port = &atmel_ports[co->index].uart;unsigned int status, imr;unsigned int pdc_tx;/* * First, save IMR and then disable interrupts */imr = UART_GET_IMR(port);UART_PUT_IDR(port, ATMEL_US_RXRDY | ATMEL_US_TXRDY);/* Store PDC transmit status and disable it */pdc_tx = UART_GET_PTSR(port) & ATMEL_PDC_TXTEN;UART_PUT_PTCR(port, ATMEL_PDC_TXTDIS);uart_console_write(port, s, count, atmel_console_putchar);/* * Finally, wait for transmitter to become empty * and restore IMR */do {status = UART_GET_CSR(port);} while (!(status & ATMEL_US_TXRDY));/* Restore PDC transmit status */if (pdc_tx)UART_PUT_PTCR(port, ATMEL_PDC_TXTEN);/* set interrupts back the way they were */UART_PUT_IER(port, imr);}/* * If the port was already initialised (eg, by a boot loader), * try to determine the current setup. */static void __init atmel_console_get_options(struct uart_port *port, int *baud,     int *parity, int *bits){unsigned int mr, quot;/* * If the baud rate generator isn't running, the port wasn't * initialized by the boot loader. */quot = UART_GET_BRGR(port) & ATMEL_US_CD;if (!quot)return;mr = UART_GET_MR(port) & ATMEL_US_CHRL;if (mr == ATMEL_US_CHRL_8)*bits = 8;else*bits = 7;mr = UART_GET_MR(port) & ATMEL_US_PAR;if (mr == ATMEL_US_PAR_EVEN)*parity = 'e';else if (mr == ATMEL_US_PAR_ODD)*parity = 'o';/* * The serial core only rounds down when matching this to a * supported baud rate. Make sure we don't end up slightly * lower than one of those, as it would make us fall through * to a much lower baud rate than we really want. */*baud = port->uartclk / (16 * (quot - 1));}static int __init atmel_console_setup(struct console *co, char *options){struct uart_port *port = &atmel_ports[co->index].uart;int baud = 115200;int bits = 8;int parity = 'n';int flow = 'n';if (port->membase == NULL) {/* Port not initialized yet - delay setup */return -ENODEV;}clk_enable(atmel_ports[co->index].clk);UART_PUT_IDR(port, -1);UART_PUT_CR(port, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);UART_PUT_CR(port, ATMEL_US_TXEN | ATMEL_US_RXEN);if (options)uart_parse_options(options, &baud, &parity, &bits, &flow);elseatmel_console_get_options(port, &baud, &parity, &bits);return uart_set_options(port, co, baud, parity, bits, flow);}static struct uart_driver atmel_uart;static struct console atmel_console = {.name= ATMEL_DEVICENAME,.write= atmel_console_write,.device= uart_console_device,.setup= atmel_console_setup,.flags= CON_PRINTBUFFER,.index= -1,.data= &atmel_uart,};#define ATMEL_CONSOLE_DEVICE(&atmel_console)/* * Early console initialization (before VM subsystem initialized). */static int __init atmel_console_init(void){if (atmel_default_console_device) {add_preferred_console(ATMEL_DEVICENAME,      atmel_default_console_device->id, NULL);atmel_init_port(&atmel_ports[atmel_default_console_device->id],atmel_default_console_device);register_console(&atmel_console);}return 0;}console_initcall(atmel_console_init);/* * Late console initialization. */static int __init atmel_late_console_init(void){if (atmel_default_console_device    && !(atmel_console.flags & CON_ENABLED))register_console(&atmel_console);return 0;}core_initcall(atmel_late_console_init);static inline bool atmel_is_console_port(struct uart_port *port){return port->cons && port->cons->index == port->line;}#else#define ATMEL_CONSOLE_DEVICENULLstatic inline bool atmel_is_console_port(struct uart_port *port){return false;}#endifstatic struct uart_driver atmel_uart = {.owner= THIS_MODULE,.driver_name= "atmel_serial",.dev_name= ATMEL_DEVICENAME,.major= SERIAL_ATMEL_MAJOR,.minor= MINOR_START,.nr= ATMEL_MAX_UART,.cons= ATMEL_CONSOLE_DEVICE,};#ifdef CONFIG_PMstatic bool atmel_serial_clk_will_stop(void){#ifdef CONFIG_ARCH_AT91return at91_suspend_entering_slow_clock();#elsereturn false;#endif}static int atmel_serial_suspend(struct platform_device *pdev,pm_message_t state){struct uart_port *port = platform_get_drvdata(pdev);struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);if (atmel_is_console_port(port) && console_suspend_enabled) {/* Drain the TX shifter */while (!(UART_GET_CSR(port) & ATMEL_US_TXEMPTY))cpu_relax();}/* we can not wake up if we're running on slow clock */atmel_port->may_wakeup = device_may_wakeup(&pdev->dev);if (atmel_serial_clk_will_stop())device_set_wakeup_enable(&pdev->dev, 0);uart_suspend_port(&atmel_uart, port);return 0;}static int atmel_serial_resume(struct platform_device *pdev){struct uart_port *port = platform_get_drvdata(pdev);struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);uart_resume_port(&atmel_uart, port);device_set_wakeup_enable(&pdev->dev, atmel_port->may_wakeup);return 0;}#else#define atmel_serial_suspend NULL#define atmel_serial_resume NULL#endifstatic int __devinit atmel_serial_probe(struct platform_device *pdev){struct atmel_uart_port *port;void *data;int ret;BUILD_BUG_ON(!is_power_of_2(ATMEL_SERIAL_RINGSIZE));port = &atmel_ports[pdev->id];port->backup_imr = 0;atmel_init_port(port, pdev);if (!atmel_use_dma_rx(&port->uart)) {ret = -ENOMEM;data = kmalloc(sizeof(struct atmel_uart_char)* ATMEL_SERIAL_RINGSIZE, GFP_KERNEL);if (!data)goto err_alloc_ring;port->rx_ring.buf = data;}ret = uart_add_one_port(&atmel_uart, &port->uart);if (ret)goto err_add_port;if (atmel_is_console_port(&port->uart)&& ATMEL_CONSOLE_DEVICE->flags & CON_ENABLED) {/* * The serial core enabled the clock for us, so undo * the clk_enable() in atmel_console_setup() */clk_disable(port->clk);}device_init_wakeup(&pdev->dev, 1);platform_set_drvdata(pdev, port);return 0;err_add_port:kfree(port->rx_ring.buf);port->rx_ring.buf = NULL;err_alloc_ring:if (!atmel_is_console_port(&port->uart)) {clk_put(port->clk);port->clk = NULL;}return ret;}static int __devexit atmel_serial_remove(struct platform_device *pdev){struct uart_port *port = platform_get_drvdata(pdev);struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);int ret = 0;device_init_wakeup(&pdev->dev, 0);platform_set_drvdata(pdev, NULL);ret = uart_remove_one_port(&atmel_uart, port);tasklet_kill(&atmel_port->tasklet);kfree(atmel_port->rx_ring.buf);/* "port" is allocated statically, so we shouldn't free it */clk_put(atmel_port->clk);return ret;}static struct platform_driver atmel_serial_driver = {.probe= atmel_serial_probe,.remove= __devexit_p(atmel_serial_remove),.suspend= atmel_serial_suspend,.resume= atmel_serial_resume,.driver= {.name= "atmel_usart",.owner= THIS_MODULE,},};static int __init atmel_serial_init(void){int ret;ret = uart_register_driver(&atmel_uart);if (ret)return ret;ret = platform_driver_register(&atmel_serial_driver);if (ret)uart_unregister_driver(&atmel_uart);return ret;}static void __exit atmel_serial_exit(void){platform_driver_unregister(&atmel_serial_driver);uart_unregister_driver(&atmel_uart);}module_init(atmel_serial_init);module_exit(atmel_serial_exit);MODULE_AUTHOR("Rick Bronson");MODULE_DESCRIPTION("Atmel AT91 / AT32 serial port driver");MODULE_LICENSE("GPL");MODULE_ALIAS("platform:atmel_usart");