/*
* Driver for GRLIB serial ports (APBUART)
*
* Based on linux/drivers/serial/amba.c
*
* Copyright (C) 2000 Deep Blue Solutions Ltd.
* Copyright (C) 2003 Konrad Eisele <eiselekd@web.de>
* Copyright (C) 2006 Daniel Hellstrom <daniel@gaisler.com>, Aeroflex Gaisler AB
* Copyright (C) 2008 Gilead Kutnick <kutnickg@zin-tech.com>
* Copyright (C) 2009 Kristoffer Glembo <kristoffer@gaisler.com>, Aeroflex Gaisler AB
*/
#if defined(CONFIG_SERIAL_GRLIB_GAISLER_APBUART_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif
#include <linux/module.h>
#include <linux/tty.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/serial.h>
#include <linux/console.h>
#include <linux/sysrq.h>
#include <linux/kthread.h>
#include <linux/device.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/serial_core.h>
#include <asm/irq.h>
#include "apbuart.h"
#define SERIAL_APBUART_MAJOR TTY_MAJOR
#define SERIAL_APBUART_MINOR 64
#define UART_DUMMY_RSR_RX 0x8000 /* for ignore all read */
static void apbuart_tx_chars(struct uart_port *port);
static void apbuart_stop_tx(struct uart_port *port)
{
unsigned int cr;
cr = UART_GET_CTRL(port);
cr &= ~UART_CTRL_TI;
UART_PUT_CTRL(port, cr);
}
static void apbuart_start_tx(struct uart_port *port)
{
unsigned int cr;
cr = UART_GET_CTRL(port);
cr |= UART_CTRL_TI;
UART_PUT_CTRL(port, cr);
if (UART_GET_STATUS(port) & UART_STATUS_THE)
apbuart_tx_chars(port);
}
static void apbuart_stop_rx(struct uart_port *port)
{
unsigned int cr;
cr = UART_GET_CTRL(port);
cr &= ~(UART_CTRL_RI);
UART_PUT_CTRL(port, cr);
}
static void apbuart_enable_ms(struct uart_port *port)
{
/* No modem status change interrupts for APBUART */
}
static void apbuart_rx_chars(struct uart_port *port)
{
struct tty_struct *tty = port->state->port.tty;
unsigned int status, ch, rsr, flag;
unsigned int max_chars = port->fifosize;
status = UART_GET_STATUS(port);
while (UART_RX_DATA(status) && (max_chars--)) {
ch = UART_GET_CHAR(port);
flag = TTY_NORMAL;
port->icount.rx++;
rsr = UART_GET_STATUS(port) | UART_DUMMY_RSR_RX;
UART_PUT_STATUS(port, 0);
if (rsr & UART_STATUS_ERR) {
if (rsr & UART_STATUS_BR) {
rsr &= ~(UART_STATUS_FE | UART_STATUS_PE);
port->icount.brk++;
if (uart_handle_break(port))
goto ignore_char;
} else if (rsr & UART_STATUS_PE) {
port->icount.parity++;
} else if (rsr & UART_STATUS_FE) {
port->icount.frame++;
}
if (rsr & UART_STATUS_OE)
port->icount.overrun++;
rsr &= port->read_status_mask;
if (rsr & UART_STATUS_PE)
flag = TTY_PARITY;
else if (rsr & UART_STATUS_FE)
flag = TTY_FRAME;
}
if (uart_handle_sysrq_char(port, ch))
goto ignore_char;
uart_insert_char(port, rsr, UART_STATUS_OE, ch, flag);
ignore_char:
status = UART_GET_STATUS(port);
}
tty_flip_buffer_push(tty);
}
static void apbuart_tx_chars(struct uart_port *port)
{
struct circ_buf *xmit = &port->state->xmit;
int count;
if (port->x_char) {
UART_PUT_CHAR(port, port->x_char);
port->icount.tx++;
port->x_char = 0;
return;
}
if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
apbuart_stop_tx(port);
return;
}
/* amba: fill FIFO */
count = port->fifosize >> 1;
do {
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;
} while (--count > 0);
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);
if (uart_circ_empty(xmit))
apbuart_stop_tx(port);
}
static irqreturn_t apbuart_int(int irq, void *dev_id)
{
struct uart_port *port = dev_id;
unsigned int status;
spin_lock(&port->lock);
status = UART_GET_STATUS(port);
if (status & UART_STATUS_DR)
apbuart_rx_chars(port);
if (status & UART_STATUS_THE)
apbuart_tx_chars(port);
spin_unlock(&port->lock);
return IRQ_HANDLED;
}
static unsigned int apbuart_tx_empty(struct uart_port *port)
{
unsigned int status = UART_GET_STATUS(port);
return status & UART_STATUS_THE ? TIOCSER_TEMT : 0;
}
static unsigned int apbuart_get_mctrl(struct uart_port *port)
{
/* The GRLIB APBUART handles flow control in hardware */
return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
}
static void apbuart_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
/* The GRLIB APBUART handles flow control in hardware */
}
static void apbuart_break_ctl(struct uart_port *port, int break_state)
{
/* We don't support sending break */
}
static int apbuart_startup(struct uart_port *port)
{
int retval;
unsigned int cr;
/* Allocate the IRQ */
retval = request_irq(port->irq, apbuart_int, 0, "apbuart", port);
if (retval)
return retval;
/* Finally, enable interrupts */
cr = UART_GET_CTRL(port);
UART_PUT_CTRL(port,
cr | UART_CTRL_RE | UART_CTRL_TE |
UART_CTRL_RI | UART_CTRL_TI);
return 0;
}
static void apbuart_shutdown(struct uart_port *port)
{
unsigned int cr;
/* disable all interrupts, disable the port */
cr = UART_GET_CTRL(port);
UART_PUT_CTRL(port,
cr & ~(UART_CTRL_RE | UART_CTRL_TE |
UART_CTRL_RI | UART_CTRL_TI));
/* Free the interrupt */
free_irq(port->irq, port);
}
static void apbuart_set_termios(struct uart_port *port,
struct ktermios *termios, struct ktermios *old)
{
unsigned int 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, port->uartclk / 16);
if (baud == 0)
panic("invalid baudrate %i\n", port->uartclk / 16);
/* uart_get_divisor calc a *16 uart freq, apbuart is *8 */
quot = (uart_get_divisor(port, baud)) * 2;
cr = UART_GET_CTRL(port);
cr &= ~(UART_CTRL_PE | UART_CTRL_PS);
if (termios->c_cflag & PARENB) {
cr |= UART_CTRL_PE;
if ((termios->c_cflag & PARODD))
cr |= UART_CTRL_PS;
}
/* Enable flow control. */
if (termios->c_cflag & CRTSCTS)
cr |= UART_CTRL_FL;
spin_lock_irqsave(&port->lock, flags);
/* Update the per-port timeout. */
uart_update_timeout(port, termios->c_cflag, baud);
port->read_status_mask = UART_STATUS_OE;
if (termios->c_iflag & INPCK)
port->read_status_mask |= UART_STATUS_FE | UART_STATUS_PE;
/* Characters to ignore */
port->ignore_status_mask = 0;
if (termios->c_iflag & IGNPAR)
port->ignore_status_mask |= UART_STATUS_FE | UART_STATUS_PE;
/* Ignore all characters if CREAD is not set. */
if ((termios->c_cflag & CREAD) == 0)
port->ignore_status_mask |= UART_DUMMY_RSR_RX;
/* Set baud rate */
quot -= 1;
UART_PUT_SCAL(port, quot);
UART_PUT_CTRL(port, cr);
spin_unlock_irqrestore(&port->lock, flags);
}
static const char *apbuart_type(struct uart_port *port)
{
return port->type == PORT_APBUART ? "GRLIB/APBUART" : NULL;
}
static void apbuart_release_port(struct uart_port *port)
{
release_mem_region(port->mapbase, 0x100);
}
static int apbuart_request_port(struct uart_port *port)
{
return request_mem_region(port->mapbase, 0x100, "grlib-apbuart")
!= NULL ? 0 : -EBUSY;
return 0;
}
/* Configure/autoconfigure the port */
static void apbuart_config_port(struct uart_port *port, int flags)
{
if (flags & UART_CONFIG_TYPE) {
port->type = PORT_APBUART;
apbuart_request_port(port);
}
}
/* Verify the new serial_struct (for TIOCSSERIAL) */
static int apbuart_verify_port(struct uart_port *port,
struct serial_struct *ser)
{
int ret = 0;
if (ser->type != PORT_UNKNOWN && ser->type != PORT_APBUART)
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 grlib_apbuart_ops = {
.tx_empty = apbuart_tx_empty,
.set_mctrl = apbuart_set_mctrl,
.get_mctrl = apbuart_get_mctrl,
.stop_tx = apbuart_stop_tx,
.start_tx = apbuart_start_tx,
.stop_rx = apbuart_stop_rx,
.enable_ms = apbuart_enable_ms,
.break_ctl = apbuart_break_ctl,
.startup = apbuart_startup,
.shutdown = apbuart_shutdown,
.set_termios = apbuart_set_termios,
.type = apbuart_type,
.release_port = apbuart_release_port,
.request_port = apbuart_request_port,
.config_port = apbuart_config_port,
.verify_port = apbuart_verify_port,
};
static struct uart_port grlib_apbuart_ports[UART_NR];
static struct device_node *grlib_apbuart_nodes[UART_NR];
static int apbuart_scan_fifo_size(struct uart_port *port, int portnumber)
{
int ctrl, loop = 0;
int status;
int fifosize;
unsigned long flags;
ctrl = UART_GET_CTRL(port);
/*
* Enable the transceiver and wait for it to be ready to send data.
* Clear interrupts so that this process will not be externally
* interrupted in the middle (which can cause the transceiver to
* drain prematurely).
*/
local_irq_save(flags);
UART_PUT_CTRL(port, ctrl | UART_CTRL_TE);
while (!UART_TX_READY(UART_GET_STATUS(port)))
loop++;
/*
* Disable the transceiver so data isn't actually sent during the
* actual test.
*/
UART_PUT_CTRL(port, ctrl & ~(UART_CTRL_TE));
fifosize = 1;
UART_PUT_CHAR(port, 0);
/*
* So long as transmitting a character increments the tranceivier FIFO
* length the FIFO must be at least that big. These bytes will
* automatically drain off of the FIFO.
*/
status = UART_GET_STATUS(port);
while (((status >> 20) & 0x3F) == fifosize) {
fifosize++;
UART_PUT_CHAR(port, 0);
status = UART_GET_STATUS(port);
}
fifosize--;
UART_PUT_CTRL(port, ctrl);
local_irq_restore(flags);
if (fifosize == 0)
fifosize = 1;
return fifosize;
}
static void apbuart_flush_fifo(struct uart_port *port)
{
int i;
for (i = 0; i < port->fifosize; i++)
UART_GET_CHAR(port);
}
/* ======================================================================== */
/* Console driver, if enabled */
/* ======================================================================== */
#ifdef CONFIG_SERIAL_GRLIB_GAISLER_APBUART_CONSOLE
static void apbuart_console_putchar(struct uart_port *port, int ch)
{
unsigned int status;
do {
status = UART_GET_STATUS(port);
} while (!UART_TX_READY(status));
UART_PUT_CHAR(port, ch);
}
static void
apbuart_console_write(struct console *co, const char *s, unsigned int count)
{
struct uart_port *port = &grlib_apbuart_ports[co->index];
unsigned int status, old_cr, new_cr;
/* First save the CR then disable the interrupts */
old_cr = UART_GET_CTRL(port);
new_cr = old_cr & ~(UART_CTRL_RI | UART_CTRL_TI);
UART_PUT_CTRL(port, new_cr);
uart_console_write(port, s, count, apbuart_console_putchar);
/*
* Finally, wait for transmitter to become empty
* and restore the TCR
*/
do {
status = UART_GET_STATUS(port);
} while (!UART_TX_READY(status));
UART_PUT_CTRL(port, old_cr);
}
static void __init
apbuart_console_get_options(struct uart_port *port, int *baud,
int *parity, int *bits)
{
if (UART_GET_CTRL(port) & (UART_CTRL_RE | UART_CTRL_TE)) {
unsigned int quot, status;
status = UART_GET_STATUS(port);
*parity = 'n';
if (status & UART_CTRL_PE) {
if ((status & UART_CTRL_PS) == 0)
*parity = 'e';
else
*parity = 'o';
}
*bits = 8;
quot = UART_GET_SCAL(port) / 8;
*baud = port->uartclk / (16 * (quot + 1));
}
}
static int __init apbuart_console_setup(struct console *co, char *options)
{
struct uart_port *port;
int baud = 38400;
int bits = 8;
int parity = 'n';
int flow = 'n';
pr_debug("apbuart_console_setup co=%p, co->index=%i, options=%s\n",
co, co->index, options);
/*
* 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 >= grlib_apbuart_port_nr)
co->index = 0;
port = &grlib_apbuart_ports[co->index];
spin_lock_init(&port->lock);
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
else
apbuart_console_get_options(port, &baud, &parity, &bits);
return uart_set_options(port, co, baud, parity, bits, flow);
}
static struct uart_driver grlib_apbuart_driver;
static struct console grlib_apbuart_console = {
.name = "ttyS",
.write = apbuart_console_write,
.device = uart_console_device,
.setup = apbuart_console_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &grlib_apbuart_driver,
};
static void grlib_apbuart_configure(void);
static int __init apbuart_console_init(void)
{
grlib_apbuart_configure();
register_console(&grlib_apbuart_console);
return 0;
}
console_initcall(apbuart_console_init);
#define APBUART_CONSOLE (&grlib_apbuart_console)
#else
#define APBUART_CONSOLE NULL
#endif
static struct uart_driver grlib_apbuart_driver = {
.owner = THIS_MODULE,
.driver_name = "serial",
.dev_name = "ttyS",
.major = SERIAL_APBUART_MAJOR,
.minor = SERIAL_APBUART_MINOR,
.nr = UART_NR,
.cons = APBUART_CONSOLE,
};
/* ======================================================================== */
/* OF Platform Driver */
/* ======================================================================== */
static int __devinit apbuart_probe(struct of_device *op,
const struct of_device_id *match)
{
int i = -1;
struct uart_port *port = NULL;
i = 0;
for (i = 0; i < grlib_apbuart_port_nr; i++) {
if (op->dev.of_node == grlib_apbuart_nodes[i])
break;
}
port = &grlib_apbuart_ports[i];
port->dev = &op->dev;
uart_add_one_port(&grlib_apbuart_driver, (struct uart_port *) port);
apbuart_flush_fifo((struct uart_port *) port);
printk(KERN_INFO "grlib-apbuart at 0x%llx, irq %d\n",
(unsigned long long) port->mapbase, port->irq);
return 0;
}
static struct of_device_id __initdata apbuart_match[] = {
{
.name = "GAISLER_APBUART",
},
{},
};
static struct of_platform_driver grlib_apbuart_of_driver = {
.probe = apbuart_probe,
.driver = {
.owner = THIS_MODULE,
.name = "grlib-apbuart",
.of_match_table = apbuart_match,
},
};
static void grlib_apbuart_configure(void)
{
static int enum_done;
struct device_node *np, *rp;
struct uart_port *port = NULL;
const u32 *prop;
int freq_khz;
int v = 0, d = 0;
unsigned int addr;
int irq, line;
struct amba_prom_registers *regs;
if (enum_done)
return;
/* Get bus frequency */
rp = of_find_node_by_path("/");
rp = of_get_next_child(rp, NULL);
prop = of_get_property(rp, "clock-frequency", NULL);
freq_khz = *prop;
line = 0;
for_each_matching_node(np, apbuart_match) {
int *vendor = (int *) of_get_property(np, "vendor", NULL);
int *device = (int *) of_get_property(np, "device", NULL);
int *irqs = (int *) of_get_property(np, "interrupts", NULL);
regs = (struct amba_prom_registers *)
of_get_property(np, "reg", NULL);
if (vendor)
v = *vendor;
if (device)
d = *device;
if (!irqs || !regs)
return;
grlib_apbuart_nodes[line] = np;
addr = regs->phys_addr;
irq = *irqs;
port = &grlib_apbuart_ports[line];
port->mapbase = addr;
port->membase = ioremap(addr, sizeof(struct grlib_apbuart_regs_map));
port->irq = irq;
port->iotype = UPIO_MEM;
port->ops = &grlib_apbuart_ops;
port->flags = UPF_BOOT_AUTOCONF;
port->line = line;
port->uartclk = freq_khz * 1000;
port->fifosize = apbuart_scan_fifo_size((struct uart_port *) port, line);
line++;
/* We support maximum UART_NR uarts ... */
if (line == UART_NR)
break;
}
enum_done = 1;
grlib_apbuart_driver.nr = grlib_apbuart_port_nr = line;
}
static int __init grlib_apbuart_init(void)
{
int ret;
/* Find all APBUARTS in device the tree and initialize their ports */
grlib_apbuart_configure();
printk(KERN_INFO "Serial: GRLIB APBUART driver\n");
ret = uart_register_driver(&grlib_apbuart_driver);
if (ret) {
printk(KERN_ERR "%s: uart_register_driver failed (%i)\n",
__FILE__, ret);
return ret;
}
ret = of_register_platform_driver(&grlib_apbuart_of_driver);
if (ret) {
printk(KERN_ERR
"%s: of_register_platform_driver failed (%i)\n",
__FILE__, ret);
uart_unregister_driver(&grlib_apbuart_driver);
return ret;
}
return ret;
}
static void __exit grlib_apbuart_exit(void)
{
int i;
for (i = 0; i < grlib_apbuart_port_nr; i++)
uart_remove_one_port(&grlib_apbuart_driver,
&grlib_apbuart_ports[i]);
uart_unregister_driver(&grlib_apbuart_driver);
of_unregister_platform_driver(&grlib_apbuart_of_driver);
}
module_init(grlib_apbuart_init);
module_exit(grlib_apbuart_exit);
MODULE_AUTHOR("Aeroflex Gaisler AB");
MODULE_DESCRIPTION("GRLIB APBUART serial driver");
MODULE_VERSION("2.1");
MODULE_LICENSE("GPL");
