/*
* 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");
