diff options
Diffstat (limited to 'drivers/serial/bfin_sport_uart.c')
| -rw-r--r-- | drivers/serial/bfin_sport_uart.c | 614 |
1 files changed, 614 insertions, 0 deletions
diff --git a/drivers/serial/bfin_sport_uart.c b/drivers/serial/bfin_sport_uart.c new file mode 100644 index 000000000000..aca1240ad808 --- /dev/null +++ b/drivers/serial/bfin_sport_uart.c @@ -0,0 +1,614 @@ +/* + * File: linux/drivers/serial/bfin_sport_uart.c + * + * Based on: drivers/serial/bfin_5xx.c by Aubrey Li. + * Author: Roy Huang <roy.huang@analog.com> + * + * Created: Nov 22, 2006 + * Copyright: (c) 2006-2007 Analog Devices Inc. + * Description: this driver enable SPORTs on Blackfin emulate UART. + * + * 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, see the file COPYING, or write + * to the Free Software Foundation, Inc., + * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ + +/* + * This driver and the hardware supported are in term of EE-191 of ADI. + * http://www.analog.com/UploadedFiles/Application_Notes/399447663EE191.pdf + * This application note describe how to implement a UART on a Sharc DSP, + * but this driver is implemented on Blackfin Processor. + */ + +/* After reset, there is a prelude of low level pulse when transmit data first + * time. No addtional pulse in following transmit. + * According to document: + * The SPORTs are ready to start transmitting or receiving data no later than + * three serial clock cycles after they are enabled in the SPORTx_TCR1 or + * SPORTx_RCR1 register. No serial clock cycles are lost from this point on. + * The first internal frame sync will occur one frame sync delay after the + * SPORTs are ready. External frame syncs can occur as soon as the SPORT is + * ready. + */ + +/* Thanks to Axel Alatalo <axel@rubico.se> for fixing sport rx bug. Sometimes + * sport receives data incorrectly. The following is Axel's words. + * As EE-191, sport rx samples 3 times of the UART baudrate and takes the + * middle smaple of every 3 samples as the data bit. For a 8-N-1 UART setting, + * 30 samples will be required for a byte. If transmitter sends a 1/3 bit short + * byte due to buadrate drift, then the 30th sample of a byte, this sample is + * also the third sample of the stop bit, will happens on the immediately + * following start bit which will be thrown away and missed. Thus since parts + * of the startbit will be missed and the receiver will begin to drift, the + * effect accumulates over time until synchronization is lost. + * If only require 2 samples of the stopbit (by sampling in total 29 samples), + * then a to short byte as in the case above will be tolerated. Then the 1/3 + * early startbit will trigger a framesync since the last read is complete + * after only 2/3 stopbit and framesync is active during the last 1/3 looking + * for a possible early startbit. */ + +//#define DEBUG + +#include <linux/module.h> +#include <linux/ioport.h> +#include <linux/init.h> +#include <linux/console.h> +#include <linux/sysrq.h> +#include <linux/platform_device.h> +#include <linux/tty.h> +#include <linux/tty_flip.h> +#include <linux/serial_core.h> + +#include <asm/delay.h> +#include <asm/portmux.h> + +#include "bfin_sport_uart.h" + +unsigned short bfin_uart_pin_req_sport0[] = + {P_SPORT0_TFS, P_SPORT0_DTPRI, P_SPORT0_TSCLK, P_SPORT0_RFS, \ + P_SPORT0_DRPRI, P_SPORT0_RSCLK, P_SPORT0_DRSEC, P_SPORT0_DTSEC, 0}; + +unsigned short bfin_uart_pin_req_sport1[] = + {P_SPORT1_TFS, P_SPORT1_DTPRI, P_SPORT1_TSCLK, P_SPORT1_RFS, \ + P_SPORT1_DRPRI, P_SPORT1_RSCLK, P_SPORT1_DRSEC, P_SPORT1_DTSEC, 0}; + +#define DRV_NAME "bfin-sport-uart" + +struct sport_uart_port { + struct uart_port port; + char *name; + + int tx_irq; + int rx_irq; + int err_irq; +}; + +static void sport_uart_tx_chars(struct sport_uart_port *up); +static void sport_stop_tx(struct uart_port *port); + +static inline void tx_one_byte(struct sport_uart_port *up, unsigned int value) +{ + pr_debug("%s value:%x\n", __FUNCTION__, value); + /* Place a Start and Stop bit */ + __asm__ volatile ( + "R2 = b#01111111100;\n\t" + "R3 = b#10000000001;\n\t" + "%0 <<= 2;\n\t" + "%0 = %0 & R2;\n\t" + "%0 = %0 | R3;\n\t" + :"=r"(value) + :"0"(value) + :"R2", "R3"); + pr_debug("%s value:%x\n", __FUNCTION__, value); + + SPORT_PUT_TX(up, value); +} + +static inline unsigned int rx_one_byte(struct sport_uart_port *up) +{ + unsigned int value, extract; + + value = SPORT_GET_RX32(up); + pr_debug("%s value:%x\n", __FUNCTION__, value); + + /* Extract 8 bits data */ + __asm__ volatile ( + "R5 = 0;\n\t" + "P0 = 8;\n\t" + "R1 = 0x1801(Z);\n\t" + "R3 = 0x0300(Z);\n\t" + "R4 = 0;\n\t" + "LSETUP(loop_s, loop_e) LC0 = P0;\nloop_s:\t" + "R2 = extract(%1, R1.L)(Z);\n\t" + "R2 <<= R4;\n\t" + "R5 = R5 | R2;\n\t" + "R1 = R1 - R3;\nloop_e:\t" + "R4 += 1;\n\t" + "%0 = R5;\n\t" + :"=r"(extract) + :"r"(value) + :"P0", "R1", "R2","R3","R4", "R5"); + + pr_debug(" extract:%x\n", extract); + return extract; +} + +static int sport_uart_setup(struct sport_uart_port *up, int sclk, int baud_rate) +{ + int tclkdiv, tfsdiv, rclkdiv; + + /* Set TCR1 and TCR2 */ + SPORT_PUT_TCR1(up, (LTFS | ITFS | TFSR | TLSBIT | ITCLK)); + SPORT_PUT_TCR2(up, 10); + pr_debug("%s TCR1:%x, TCR2:%x\n", __FUNCTION__, SPORT_GET_TCR1(up), SPORT_GET_TCR2(up)); + + /* Set RCR1 and RCR2 */ + SPORT_PUT_RCR1(up, (RCKFE | LARFS | LRFS | RFSR | IRCLK)); + SPORT_PUT_RCR2(up, 28); + pr_debug("%s RCR1:%x, RCR2:%x\n", __FUNCTION__, SPORT_GET_RCR1(up), SPORT_GET_RCR2(up)); + + tclkdiv = sclk/(2 * baud_rate) - 1; + tfsdiv = 12; + rclkdiv = sclk/(2 * baud_rate * 3) - 1; + SPORT_PUT_TCLKDIV(up, tclkdiv); + SPORT_PUT_TFSDIV(up, tfsdiv); + SPORT_PUT_RCLKDIV(up, rclkdiv); + SSYNC(); + pr_debug("%s sclk:%d, baud_rate:%d, tclkdiv:%d, tfsdiv:%d, rclkdiv:%d\n", + __FUNCTION__, sclk, baud_rate, tclkdiv, tfsdiv, rclkdiv); + + return 0; +} + +static irqreturn_t sport_uart_rx_irq(int irq, void *dev_id) +{ + struct sport_uart_port *up = dev_id; + struct tty_struct *tty = up->port.info->tty; + unsigned int ch; + + do { + ch = rx_one_byte(up); + up->port.icount.rx++; + + if (uart_handle_sysrq_char(&up->port, ch)) + ; + else + tty_insert_flip_char(tty, ch, TTY_NORMAL); + } while (SPORT_GET_STAT(up) & RXNE); + tty_flip_buffer_push(tty); + + return IRQ_HANDLED; +} + +static irqreturn_t sport_uart_tx_irq(int irq, void *dev_id) +{ + sport_uart_tx_chars(dev_id); + + return IRQ_HANDLED; +} + +static irqreturn_t sport_uart_err_irq(int irq, void *dev_id) +{ + struct sport_uart_port *up = dev_id; + struct tty_struct *tty = up->port.info->tty; + unsigned int stat = SPORT_GET_STAT(up); + + /* Overflow in RX FIFO */ + if (stat & ROVF) { + up->port.icount.overrun++; + tty_insert_flip_char(tty, 0, TTY_OVERRUN); + SPORT_PUT_STAT(up, ROVF); /* Clear ROVF bit */ + } + /* These should not happen */ + if (stat & (TOVF | TUVF | RUVF)) { + printk(KERN_ERR "SPORT Error:%s %s %s\n", + (stat & TOVF)?"TX overflow":"", + (stat & TUVF)?"TX underflow":"", + (stat & RUVF)?"RX underflow":""); + SPORT_PUT_TCR1(up, SPORT_GET_TCR1(up) & ~TSPEN); + SPORT_PUT_RCR1(up, SPORT_GET_RCR1(up) & ~RSPEN); + } + SSYNC(); + + return IRQ_HANDLED; +} + +/* Reqeust IRQ, Setup clock */ +static int sport_startup(struct uart_port *port) +{ + struct sport_uart_port *up = (struct sport_uart_port *)port; + char buffer[20]; + int retval; + + pr_debug("%s enter\n", __FUNCTION__); + memset(buffer, 20, '\0'); + snprintf(buffer, 20, "%s rx", up->name); + retval = request_irq(up->rx_irq, sport_uart_rx_irq, IRQF_SAMPLE_RANDOM, buffer, up); + if (retval) { + printk(KERN_ERR "Unable to request interrupt %s\n", buffer); + return retval; + } + + snprintf(buffer, 20, "%s tx", up->name); + retval = request_irq(up->tx_irq, sport_uart_tx_irq, IRQF_SAMPLE_RANDOM, buffer, up); + if (retval) { + printk(KERN_ERR "Unable to request interrupt %s\n", buffer); + goto fail1; + } + + snprintf(buffer, 20, "%s err", up->name); + retval = request_irq(up->err_irq, sport_uart_err_irq, IRQF_SAMPLE_RANDOM, buffer, up); + if (retval) { + printk(KERN_ERR "Unable to request interrupt %s\n", buffer); + goto fail2; + } + + if (port->line) { + if (peripheral_request_list(bfin_uart_pin_req_sport1, DRV_NAME)) + goto fail3; + } else { + if (peripheral_request_list(bfin_uart_pin_req_sport0, DRV_NAME)) + goto fail3; + } + + sport_uart_setup(up, get_sclk(), port->uartclk); + + /* Enable receive interrupt */ + SPORT_PUT_RCR1(up, (SPORT_GET_RCR1(up) | RSPEN)); + SSYNC(); + + return 0; + + +fail3: + printk(KERN_ERR DRV_NAME + ": Requesting Peripherals failed\n"); + + free_irq(up->err_irq, up); +fail2: + free_irq(up->tx_irq, up); +fail1: + free_irq(up->rx_irq, up); + + return retval; + +} + +static void sport_uart_tx_chars(struct sport_uart_port *up) +{ + struct circ_buf *xmit = &up->port.info->xmit; + + if (SPORT_GET_STAT(up) & TXF) + return; + + if (up->port.x_char) { + tx_one_byte(up, up->port.x_char); + up->port.icount.tx++; + up->port.x_char = 0; + return; + } + + if (uart_circ_empty(xmit) || uart_tx_stopped(&up->port)) { + sport_stop_tx(&up->port); + return; + } + + while(!(SPORT_GET_STAT(up) & TXF) && !uart_circ_empty(xmit)) { + tx_one_byte(up, xmit->buf[xmit->tail]); + xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE -1); + up->port.icount.tx++; + } + + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + uart_write_wakeup(&up->port); +} + +static unsigned int sport_tx_empty(struct uart_port *port) +{ + struct sport_uart_port *up = (struct sport_uart_port *)port; + unsigned int stat; + + stat = SPORT_GET_STAT(up); + pr_debug("%s stat:%04x\n", __FUNCTION__, stat); + if (stat & TXHRE) { + return TIOCSER_TEMT; + } else + return 0; +} + +static unsigned int sport_get_mctrl(struct uart_port *port) +{ + pr_debug("%s enter\n", __FUNCTION__); + return (TIOCM_CTS | TIOCM_CD | TIOCM_DSR); +} + +static void sport_set_mctrl(struct uart_port *port, unsigned int mctrl) +{ + pr_debug("%s enter\n", __FUNCTION__); +} + +static void sport_stop_tx(struct uart_port *port) +{ + struct sport_uart_port *up = (struct sport_uart_port *)port; + unsigned int stat; + + pr_debug("%s enter\n", __FUNCTION__); + + stat = SPORT_GET_STAT(up); + while(!(stat & TXHRE)) { + udelay(1); + stat = SPORT_GET_STAT(up); + } + /* Although the hold register is empty, last byte is still in shift + * register and not sent out yet. If baud rate is lower than default, + * delay should be longer. For example, if the baud rate is 9600, + * the delay must be at least 2ms by experience */ + udelay(500); + + SPORT_PUT_TCR1(up, (SPORT_GET_TCR1(up) & ~TSPEN)); + SSYNC(); + + return; +} + +static void sport_start_tx(struct uart_port *port) +{ + struct sport_uart_port *up = (struct sport_uart_port *)port; + + pr_debug("%s enter\n", __FUNCTION__); + /* Write data into SPORT FIFO before enable SPROT to transmit */ + sport_uart_tx_chars(up); + + /* Enable transmit, then an interrupt will generated */ + SPORT_PUT_TCR1(up, (SPORT_GET_TCR1(up) | TSPEN)); + SSYNC(); + pr_debug("%s exit\n", __FUNCTION__); +} + +static void sport_stop_rx(struct uart_port *port) +{ + struct sport_uart_port *up = (struct sport_uart_port *)port; + + pr_debug("%s enter\n", __FUNCTION__); + /* Disable sport to stop rx */ + SPORT_PUT_RCR1(up, (SPORT_GET_RCR1(up) & ~RSPEN)); + SSYNC(); +} + +static void sport_enable_ms(struct uart_port *port) +{ + pr_debug("%s enter\n", __FUNCTION__); +} + +static void sport_break_ctl(struct uart_port *port, int break_state) +{ + pr_debug("%s enter\n", __FUNCTION__); +} + +static void sport_shutdown(struct uart_port *port) +{ + struct sport_uart_port *up = (struct sport_uart_port *)port; + + pr_debug("%s enter\n", __FUNCTION__); + + /* Disable sport */ + SPORT_PUT_TCR1(up, (SPORT_GET_TCR1(up) & ~TSPEN)); + SPORT_PUT_RCR1(up, (SPORT_GET_RCR1(up) & ~RSPEN)); + SSYNC(); + + if (port->line) { + peripheral_free_list(bfin_uart_pin_req_sport1); + } else { + peripheral_free_list(bfin_uart_pin_req_sport0); + } + + free_irq(up->rx_irq, up); + free_irq(up->tx_irq, up); + free_irq(up->err_irq, up); +} + +static void sport_set_termios(struct uart_port *port, + struct termios *termios, struct termios *old) +{ + pr_debug("%s enter, c_cflag:%08x\n", __FUNCTION__, termios->c_cflag); + uart_update_timeout(port, CS8 ,port->uartclk); +} + +static const char *sport_type(struct uart_port *port) +{ + struct sport_uart_port *up = (struct sport_uart_port *)port; + + pr_debug("%s enter\n", __FUNCTION__); + return up->name; +} + +static void sport_release_port(struct uart_port *port) +{ + pr_debug("%s enter\n", __FUNCTION__); +} + +static int sport_request_port(struct uart_port *port) +{ + pr_debug("%s enter\n", __FUNCTION__); + return 0; +} + +static void sport_config_port(struct uart_port *port, int flags) +{ + struct sport_uart_port *up = (struct sport_uart_port *)port; + + pr_debug("%s enter\n", __FUNCTION__); + up->port.type = PORT_BFIN_SPORT; +} + +static int sport_verify_port(struct uart_port *port, struct serial_struct *ser) +{ + pr_debug("%s enter\n", __FUNCTION__); + return 0; +} + +struct uart_ops sport_uart_ops = { + .tx_empty = sport_tx_empty, + .set_mctrl = sport_set_mctrl, + .get_mctrl = sport_get_mctrl, + .stop_tx = sport_stop_tx, + .start_tx = sport_start_tx, + .stop_rx = sport_stop_rx, + .enable_ms = sport_enable_ms, + .break_ctl = sport_break_ctl, + .startup = sport_startup, + .shutdown = sport_shutdown, + .set_termios = sport_set_termios, + .type = sport_type, + .release_port = sport_release_port, + .request_port = sport_request_port, + .config_port = sport_config_port, + .verify_port = sport_verify_port, +}; + +static struct sport_uart_port sport_uart_ports[] = { + { /* SPORT 0 */ + .name = "SPORT0", + .tx_irq = IRQ_SPORT0_TX, + .rx_irq = IRQ_SPORT0_RX, + .err_irq= IRQ_SPORT0_ERROR, + .port = { + .type = PORT_BFIN_SPORT, + .iotype = UPIO_MEM, + .membase = (void __iomem *)SPORT0_TCR1, + .mapbase = SPORT0_TCR1, + .irq = IRQ_SPORT0_RX, + .uartclk = CONFIG_SPORT_BAUD_RATE, + .fifosize = 8, + .ops = &sport_uart_ops, + .line = 0, + }, + }, { /* SPORT 1 */ + .name = "SPORT1", + .tx_irq = IRQ_SPORT1_TX, + .rx_irq = IRQ_SPORT1_RX, + .err_irq= IRQ_SPORT1_ERROR, + .port = { + .type = PORT_BFIN_SPORT, + .iotype = UPIO_MEM, + .membase = (void __iomem *)SPORT1_TCR1, + .mapbase = SPORT1_TCR1, + .irq = IRQ_SPORT1_RX, + .uartclk = CONFIG_SPORT_BAUD_RATE, + .fifosize = 8, + .ops = &sport_uart_ops, + .line = 1, + }, + } +}; + +static struct uart_driver sport_uart_reg = { + .owner = THIS_MODULE, + .driver_name = "SPORT-UART", + .dev_name = "ttySS", + .major = 204, + .minor = 84, + .nr = ARRAY_SIZE(sport_uart_ports), + .cons = NULL, +}; + +static int sport_uart_suspend(struct platform_device *dev, pm_message_t state) +{ + struct sport_uart_port *sport = platform_get_drvdata(dev); + + pr_debug("%s enter\n", __FUNCTION__); + if (sport) + uart_suspend_port(&sport_uart_reg, &sport->port); + + return 0; +} + +static int sport_uart_resume(struct platform_device *dev) +{ + struct sport_uart_port *sport = platform_get_drvdata(dev); + + pr_debug("%s enter\n", __FUNCTION__); + if (sport) + uart_resume_port(&sport_uart_reg, &sport->port); + + return 0; +} + +static int sport_uart_probe(struct platform_device *dev) +{ + pr_debug("%s enter\n", __FUNCTION__); + sport_uart_ports[dev->id].port.dev = &dev->dev; + uart_add_one_port(&sport_uart_reg, &sport_uart_ports[dev->id].port); + platform_set_drvdata(dev, &sport_uart_ports[dev->id]); + + return 0; +} + +static int sport_uart_remove(struct platform_device *dev) +{ + struct sport_uart_port *sport = platform_get_drvdata(dev); + + pr_debug("%s enter\n", __FUNCTION__); + platform_set_drvdata(dev, NULL); + + if (sport) + uart_remove_one_port(&sport_uart_reg, &sport->port); + + return 0; +} + +static struct platform_driver sport_uart_driver = { + .probe = sport_uart_probe, + .remove = sport_uart_remove, + .suspend = sport_uart_suspend, + .resume = sport_uart_resume, + .driver = { + .name = DRV_NAME, + }, +}; + +static int __init sport_uart_init(void) +{ + int ret; + + pr_debug("%s enter\n", __FUNCTION__); + ret = uart_register_driver(&sport_uart_reg); + if (ret != 0) { + printk(KERN_ERR "Failed to register %s:%d\n", + sport_uart_reg.driver_name, ret); + return ret; + } + + ret = platform_driver_register(&sport_uart_driver); + if (ret != 0) { + printk(KERN_ERR "Failed to register sport uart driver:%d\n", ret); + uart_unregister_driver(&sport_uart_reg); + } + + + pr_debug("%s exit\n", __FUNCTION__); + return ret; +} + +static void __exit sport_uart_exit(void) +{ + pr_debug("%s enter\n", __FUNCTION__); + platform_driver_unregister(&sport_uart_driver); + uart_unregister_driver(&sport_uart_reg); +} + +module_init(sport_uart_init); +module_exit(sport_uart_exit); + +MODULE_LICENSE("GPL"); |