linux/drivers/serial/uartlite.c

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/*
* uartlite.c: Serial driver for Xilinx uartlite serial controller
*
* Copyright (C) 2006 Peter Korsgaard <jacmet@sunsite.dk>
* Copyright (C) 2007 Secret Lab Technologies Ltd.
*
* This file is licensed under the terms of the GNU General Public License
* version 2. This program is licensed "as is" without any warranty of any
* kind, whether express or implied.
*/
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/console.h>
#include <linux/serial.h>
#include <linux/serial_core.h>
#include <linux/tty.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <asm/io.h>
#if defined(CONFIG_OF) && (defined(CONFIG_PPC32) || defined(CONFIG_MICROBLAZE))
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>
/* Match table for of_platform binding */
static struct of_device_id ulite_of_match[] __devinitdata = {
{ .compatible = "xlnx,opb-uartlite-1.00.b", },
{ .compatible = "xlnx,xps-uartlite-1.00.a", },
{}
};
MODULE_DEVICE_TABLE(of, ulite_of_match);
#endif
#define ULITE_NAME "ttyUL"
#define ULITE_MAJOR 204
#define ULITE_MINOR 187
#define ULITE_NR_UARTS 4
/* ---------------------------------------------------------------------
* Register definitions
*
* For register details see datasheet:
* http://www.xilinx.com/bvdocs/ipcenter/data_sheet/opb_uartlite.pdf
*/
#define ULITE_RX 0x00
#define ULITE_TX 0x04
#define ULITE_STATUS 0x08
#define ULITE_CONTROL 0x0c
#define ULITE_REGION 16
#define ULITE_STATUS_RXVALID 0x01
#define ULITE_STATUS_RXFULL 0x02
#define ULITE_STATUS_TXEMPTY 0x04
#define ULITE_STATUS_TXFULL 0x08
#define ULITE_STATUS_IE 0x10
#define ULITE_STATUS_OVERRUN 0x20
#define ULITE_STATUS_FRAME 0x40
#define ULITE_STATUS_PARITY 0x80
#define ULITE_CONTROL_RST_TX 0x01
#define ULITE_CONTROL_RST_RX 0x02
#define ULITE_CONTROL_IE 0x10
static struct uart_port ulite_ports[ULITE_NR_UARTS];
/* ---------------------------------------------------------------------
* Core UART driver operations
*/
static int ulite_receive(struct uart_port *port, int stat)
{
struct tty_struct *tty = port->state->port.tty;
unsigned char ch = 0;
char flag = TTY_NORMAL;
if ((stat & (ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN
| ULITE_STATUS_FRAME)) == 0)
return 0;
/* stats */
if (stat & ULITE_STATUS_RXVALID) {
port->icount.rx++;
ch = readb(port->membase + ULITE_RX);
if (stat & ULITE_STATUS_PARITY)
port->icount.parity++;
}
if (stat & ULITE_STATUS_OVERRUN)
port->icount.overrun++;
if (stat & ULITE_STATUS_FRAME)
port->icount.frame++;
/* drop byte with parity error if IGNPAR specificed */
if (stat & port->ignore_status_mask & ULITE_STATUS_PARITY)
stat &= ~ULITE_STATUS_RXVALID;
stat &= port->read_status_mask;
if (stat & ULITE_STATUS_PARITY)
flag = TTY_PARITY;
stat &= ~port->ignore_status_mask;
if (stat & ULITE_STATUS_RXVALID)
tty_insert_flip_char(tty, ch, flag);
if (stat & ULITE_STATUS_FRAME)
tty_insert_flip_char(tty, 0, TTY_FRAME);
if (stat & ULITE_STATUS_OVERRUN)
tty_insert_flip_char(tty, 0, TTY_OVERRUN);
return 1;
}
static int ulite_transmit(struct uart_port *port, int stat)
{
struct circ_buf *xmit = &port->state->xmit;
if (stat & ULITE_STATUS_TXFULL)
return 0;
if (port->x_char) {
writeb(port->x_char, port->membase + ULITE_TX);
port->x_char = 0;
port->icount.tx++;
return 1;
}
if (uart_circ_empty(xmit) || uart_tx_stopped(port))
return 0;
writeb(xmit->buf[xmit->tail], port->membase + ULITE_TX);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE-1);
port->icount.tx++;
/* wake up */
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);
return 1;
}
static irqreturn_t ulite_isr(int irq, void *dev_id)
{
struct uart_port *port = dev_id;
int busy, n = 0;
do {
int stat = readb(port->membase + ULITE_STATUS);
busy = ulite_receive(port, stat);
busy |= ulite_transmit(port, stat);
n++;
} while (busy);
/* work done? */
if (n > 1) {
tty_flip_buffer_push(port->state->port.tty);
return IRQ_HANDLED;
} else {
return IRQ_NONE;
}
}
static unsigned int ulite_tx_empty(struct uart_port *port)
{
unsigned long flags;
unsigned int ret;
spin_lock_irqsave(&port->lock, flags);
ret = readb(port->membase + ULITE_STATUS);
spin_unlock_irqrestore(&port->lock, flags);
return ret & ULITE_STATUS_TXEMPTY ? TIOCSER_TEMT : 0;
}
static unsigned int ulite_get_mctrl(struct uart_port *port)
{
return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
}
static void ulite_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
/* N/A */
}
static void ulite_stop_tx(struct uart_port *port)
{
/* N/A */
}
static void ulite_start_tx(struct uart_port *port)
{
ulite_transmit(port, readb(port->membase + ULITE_STATUS));
}
static void ulite_stop_rx(struct uart_port *port)
{
/* don't forward any more data (like !CREAD) */
port->ignore_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY
| ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
}
static void ulite_enable_ms(struct uart_port *port)
{
/* N/A */
}
static void ulite_break_ctl(struct uart_port *port, int ctl)
{
/* N/A */
}
static int ulite_startup(struct uart_port *port)
{
int ret;
ret = request_irq(port->irq, ulite_isr,
IRQF_SHARED | IRQF_SAMPLE_RANDOM, "uartlite", port);
if (ret)
return ret;
writeb(ULITE_CONTROL_RST_RX | ULITE_CONTROL_RST_TX,
port->membase + ULITE_CONTROL);
writeb(ULITE_CONTROL_IE, port->membase + ULITE_CONTROL);
return 0;
}
static void ulite_shutdown(struct uart_port *port)
{
writeb(0, port->membase + ULITE_CONTROL);
readb(port->membase + ULITE_CONTROL); /* dummy */
free_irq(port->irq, port);
}
static void ulite_set_termios(struct uart_port *port, struct ktermios *termios,
struct ktermios *old)
{
unsigned long flags;
unsigned int baud;
spin_lock_irqsave(&port->lock, flags);
port->read_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN
| ULITE_STATUS_TXFULL;
if (termios->c_iflag & INPCK)
port->read_status_mask |=
ULITE_STATUS_PARITY | ULITE_STATUS_FRAME;
port->ignore_status_mask = 0;
if (termios->c_iflag & IGNPAR)
port->ignore_status_mask |= ULITE_STATUS_PARITY
| ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
/* ignore all characters if CREAD is not set */
if ((termios->c_cflag & CREAD) == 0)
port->ignore_status_mask |=
ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY
| ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
/* update timeout */
baud = uart_get_baud_rate(port, termios, old, 0, 460800);
uart_update_timeout(port, termios->c_cflag, baud);
spin_unlock_irqrestore(&port->lock, flags);
}
static const char *ulite_type(struct uart_port *port)
{
return port->type == PORT_UARTLITE ? "uartlite" : NULL;
}
static void ulite_release_port(struct uart_port *port)
{
release_mem_region(port->mapbase, ULITE_REGION);
iounmap(port->membase);
port->membase = NULL;
}
static int ulite_request_port(struct uart_port *port)
{
pr_debug("ulite console: port=%p; port->mapbase=%llx\n",
port, (unsigned long long) port->mapbase);
if (!request_mem_region(port->mapbase, ULITE_REGION, "uartlite")) {
dev_err(port->dev, "Memory region busy\n");
return -EBUSY;
}
port->membase = ioremap(port->mapbase, ULITE_REGION);
if (!port->membase) {
dev_err(port->dev, "Unable to map registers\n");
release_mem_region(port->mapbase, ULITE_REGION);
return -EBUSY;
}
return 0;
}
static void ulite_config_port(struct uart_port *port, int flags)
{
if (!ulite_request_port(port))
port->type = PORT_UARTLITE;
}
static int ulite_verify_port(struct uart_port *port, struct serial_struct *ser)
{
/* we don't want the core code to modify any port params */
return -EINVAL;
}
static struct uart_ops ulite_ops = {
.tx_empty = ulite_tx_empty,
.set_mctrl = ulite_set_mctrl,
.get_mctrl = ulite_get_mctrl,
.stop_tx = ulite_stop_tx,
.start_tx = ulite_start_tx,
.stop_rx = ulite_stop_rx,
.enable_ms = ulite_enable_ms,
.break_ctl = ulite_break_ctl,
.startup = ulite_startup,
.shutdown = ulite_shutdown,
.set_termios = ulite_set_termios,
.type = ulite_type,
.release_port = ulite_release_port,
.request_port = ulite_request_port,
.config_port = ulite_config_port,
.verify_port = ulite_verify_port
};
/* ---------------------------------------------------------------------
* Console driver operations
*/
#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
static void ulite_console_wait_tx(struct uart_port *port)
{
int i;
u8 val;
/* Spin waiting for TX fifo to have space available */
for (i = 0; i < 100000; i++) {
val = readb(port->membase + ULITE_STATUS);
if ((val & ULITE_STATUS_TXFULL) == 0)
break;
cpu_relax();
}
}
static void ulite_console_putchar(struct uart_port *port, int ch)
{
ulite_console_wait_tx(port);
writeb(ch, port->membase + ULITE_TX);
}
static void ulite_console_write(struct console *co, const char *s,
unsigned int count)
{
struct uart_port *port = &ulite_ports[co->index];
unsigned long flags;
unsigned int ier;
int locked = 1;
if (oops_in_progress) {
locked = spin_trylock_irqsave(&port->lock, flags);
} else
spin_lock_irqsave(&port->lock, flags);
/* save and disable interrupt */
ier = readb(port->membase + ULITE_STATUS) & ULITE_STATUS_IE;
writeb(0, port->membase + ULITE_CONTROL);
uart_console_write(port, s, count, ulite_console_putchar);
ulite_console_wait_tx(port);
/* restore interrupt state */
if (ier)
writeb(ULITE_CONTROL_IE, port->membase + ULITE_CONTROL);
if (locked)
spin_unlock_irqrestore(&port->lock, flags);
}
uartlite: fix crash when using as console Move the ulite_console_setup to the .devinit section since it might be called on probe, which is in devinit. Fixes the crash below where the uartlite hw is probed after the .init section is freed from the kernel. uartlite: ttyUL0 at MMIO 0xc8000100 (irq = 30) is a uartlite BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<c176720e>] ulite_console_setup+0x6f/0xa8 *pdpt = 0000000036fb0001 *pde = 0000000000000000 Oops: 0000 [#1] PREEMPT SMP last sysfs file: /sys/devices/pci0000:00/0000:00:1f.1/host0/uevent Modules linked in: puffin(+) serio_raw Pid: 151, comm: modprobe Not tainted (2.6.31.5-1.0.b1-b1 #1) POULSBO EIP: 0060:[<c176720e>] EFLAGS: 00010246 CPU: 0 EIP is at ulite_console_setup+0x6f/0xa8 EAX: c16ec824 EBX: c16ec824 ECX: c176719f EDX: 00000000 ESI: 00000000 EDI: c17b42c4 EBP: f6fd1cf0 ESP: f6fd1cd8 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 Process modprobe (pid: 151, ti=f6fd0000 task=f6fa1020 task.ti=f6fd0000) Stack: c1031f51 00000000 00000000 00000246 c182237c f7742000 f6fd1d5c c11fd316 <0> c16ec85c f77420d4 0000001e 00000000 00000000 c1633e78 4f494d4d 63783020 <0> 30303038 00303031 f6fd1d3c c10e0786 f6fd1d48 00000000 f6fd1d48 00000000 Call Trace: [<c1031f51>] ? register_console+0xf6/0x1fc [<c11fd316>] ? uart_add_one_port+0x237/0x2bb [<c10e0786>] ? sysfs_add_one+0x13/0xd3 [<c10e142f>] ? sysfs_do_create_link+0xba/0xfc [<c146f200>] ? ulite_probe+0x198/0x1eb [<c12064ee>] ? platform_drv_probe+0xc/0xe [<c120597b>] ? driver_probe_device+0x79/0x105 [<c1205a8e>] ? __device_attach+0x28/0x30 [<c120511f>] ? bus_for_each_drv+0x3d/0x67 [<c1205af9>] ? device_attach+0x44/0x58 [<c1205a66>] ? __device_attach+0x0/0x30 [<c1204fb8>] ? bus_probe_device+0x1f/0x34 [<c1203e68>] ? device_add+0x385/0x4c0 [<c148491f>] ? _write_unlock+0x8/0x1f [<c1206aac>] ? platform_device_add+0xd9/0x11c [<c120c685>] ? mfd_add_devices+0x165/0x1bc [<f831b378>] ? puffin_probe+0x2d0/0x390 [puffin] [<c11a08ef>] ? pci_match_device+0xa0/0xa7 [<c11a07bc>] ? local_pci_probe+0xe/0x10 [<c11a11db>] ? pci_device_probe+0x43/0x66 [<c120597b>] ? driver_probe_device+0x79/0x105 [<c1205a4a>] ? __driver_attach+0x43/0x5f [<c120535d>] ? bus_for_each_dev+0x3d/0x67 [<c1205852>] ? driver_attach+0x14/0x16 [<c1205a07>] ? __driver_attach+0x0/0x5f [<c1204dea>] ? bus_add_driver+0xf9/0x220 [<c1205c8f>] ? driver_register+0x8b/0xeb [<c11a1518>] ? __pci_register_driver+0x43/0x9f [<c10477ef>] ? __blocking_notifier_call_chain+0x40/0x4c [<f831f000>] ? puffin_init+0x0/0x48 [puffin] [<f831f017>] ? puffin_init+0x17/0x48 [puffin] [<c1001139>] ? do_one_initcall+0x4c/0x131 [<c105607b>] ? sys_init_module+0xa7/0x1b7 [<c1002a61>] ? syscall_call+0x7/0xb Code: 6e 74 00 00 00 92 33 00 00 18 00 0e 01 73 79 6e 63 65 2d 72 65 67 69 73 74 72 79 0c 00 49 32 00 00 14 00 09 01 61 6c 73 61 2d 69 <6e> 66 6f 00 00 00 42 37 00 00 10 00 07 01 6b 69 6c 6c 61 6c 6c EIP: [<c176720e>] ulite_console_setup+0x6f/0xa8 SS:ESP 0068:f6fd1cd8 CR2: 0000000000000000 Signed-off-by: Richard Röjfors <richard.rojfors@pelagicore.com> Acked-by: Peter Korsgaard <jacmet@sunsite.dk> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-02-02 21:44:12 +00:00
static int __devinit ulite_console_setup(struct console *co, char *options)
{
struct uart_port *port;
int baud = 9600;
int bits = 8;
int parity = 'n';
int flow = 'n';
if (co->index < 0 || co->index >= ULITE_NR_UARTS)
return -EINVAL;
port = &ulite_ports[co->index];
/* Has the device been initialized yet? */
if (!port->mapbase) {
pr_debug("console on ttyUL%i not present\n", co->index);
return -ENODEV;
}
/* not initialized yet? */
if (!port->membase) {
if (ulite_request_port(port))
return -ENODEV;
}
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
return uart_set_options(port, co, baud, parity, bits, flow);
}
static struct uart_driver ulite_uart_driver;
static struct console ulite_console = {
.name = ULITE_NAME,
.write = ulite_console_write,
.device = uart_console_device,
.setup = ulite_console_setup,
.flags = CON_PRINTBUFFER,
.index = -1, /* Specified on the cmdline (e.g. console=ttyUL0 ) */
.data = &ulite_uart_driver,
};
static int __init ulite_console_init(void)
{
register_console(&ulite_console);
return 0;
}
console_initcall(ulite_console_init);
#endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */
static struct uart_driver ulite_uart_driver = {
.owner = THIS_MODULE,
.driver_name = "uartlite",
.dev_name = ULITE_NAME,
.major = ULITE_MAJOR,
.minor = ULITE_MINOR,
.nr = ULITE_NR_UARTS,
#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
.cons = &ulite_console,
#endif
};
/* ---------------------------------------------------------------------
* Port assignment functions (mapping devices to uart_port structures)
*/
/** ulite_assign: register a uartlite device with the driver
*
* @dev: pointer to device structure
* @id: requested id number. Pass -1 for automatic port assignment
* @base: base address of uartlite registers
* @irq: irq number for uartlite
*
* Returns: 0 on success, <0 otherwise
*/
static int __devinit ulite_assign(struct device *dev, int id, u32 base, int irq)
{
struct uart_port *port;
int rc;
/* if id = -1; then scan for a free id and use that */
if (id < 0) {
for (id = 0; id < ULITE_NR_UARTS; id++)
if (ulite_ports[id].mapbase == 0)
break;
}
if (id < 0 || id >= ULITE_NR_UARTS) {
dev_err(dev, "%s%i too large\n", ULITE_NAME, id);
return -EINVAL;
}
if ((ulite_ports[id].mapbase) && (ulite_ports[id].mapbase != base)) {
dev_err(dev, "cannot assign to %s%i; it is already in use\n",
ULITE_NAME, id);
return -EBUSY;
}
port = &ulite_ports[id];
spin_lock_init(&port->lock);
port->fifosize = 16;
port->regshift = 2;
port->iotype = UPIO_MEM;
port->iobase = 1; /* mark port in use */
port->mapbase = base;
port->membase = NULL;
port->ops = &ulite_ops;
port->irq = irq;
port->flags = UPF_BOOT_AUTOCONF;
port->dev = dev;
port->type = PORT_UNKNOWN;
port->line = id;
dev_set_drvdata(dev, port);
/* Register the port */
rc = uart_add_one_port(&ulite_uart_driver, port);
if (rc) {
dev_err(dev, "uart_add_one_port() failed; err=%i\n", rc);
port->mapbase = 0;
dev_set_drvdata(dev, NULL);
return rc;
}
return 0;
}
/** ulite_release: register a uartlite device with the driver
*
* @dev: pointer to device structure
*/
static int __devexit ulite_release(struct device *dev)
{
struct uart_port *port = dev_get_drvdata(dev);
int rc = 0;
if (port) {
rc = uart_remove_one_port(&ulite_uart_driver, port);
dev_set_drvdata(dev, NULL);
port->mapbase = 0;
}
return rc;
}
/* ---------------------------------------------------------------------
* Platform bus binding
*/
static int __devinit ulite_probe(struct platform_device *pdev)
{
struct resource *res, *res2;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -ENODEV;
res2 = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
if (!res2)
return -ENODEV;
return ulite_assign(&pdev->dev, pdev->id, res->start, res2->start);
}
static int __devexit ulite_remove(struct platform_device *pdev)
{
return ulite_release(&pdev->dev);
}
/* work with hotplug and coldplug */
MODULE_ALIAS("platform:uartlite");
static struct platform_driver ulite_platform_driver = {
.probe = ulite_probe,
.remove = __devexit_p(ulite_remove),
.driver = {
.owner = THIS_MODULE,
.name = "uartlite",
},
};
/* ---------------------------------------------------------------------
* OF bus bindings
*/
#if defined(CONFIG_OF) && (defined(CONFIG_PPC32) || defined(CONFIG_MICROBLAZE))
static int __devinit
ulite_of_probe(struct of_device *op, const struct of_device_id *match)
{
struct resource res;
const unsigned int *id;
int irq, rc;
dev_dbg(&op->dev, "%s(%p, %p)\n", __func__, op, match);
rc = of_address_to_resource(op->node, 0, &res);
if (rc) {
dev_err(&op->dev, "invalid address\n");
return rc;
}
irq = irq_of_parse_and_map(op->node, 0);
id = of_get_property(op->node, "port-number", NULL);
return ulite_assign(&op->dev, id ? *id : -1, res.start+3, irq);
}
static int __devexit ulite_of_remove(struct of_device *op)
{
return ulite_release(&op->dev);
}
static struct of_platform_driver ulite_of_driver = {
.owner = THIS_MODULE,
.name = "uartlite",
.match_table = ulite_of_match,
.probe = ulite_of_probe,
.remove = __devexit_p(ulite_of_remove),
.driver = {
.name = "uartlite",
},
};
/* Registration helpers to keep the number of #ifdefs to a minimum */
static inline int __init ulite_of_register(void)
{
pr_debug("uartlite: calling of_register_platform_driver()\n");
return of_register_platform_driver(&ulite_of_driver);
}
static inline void __exit ulite_of_unregister(void)
{
of_unregister_platform_driver(&ulite_of_driver);
}
#else /* CONFIG_OF && (CONFIG_PPC32 || CONFIG_MICROBLAZE) */
/* Appropriate config not enabled; do nothing helpers */
static inline int __init ulite_of_register(void) { return 0; }
static inline void __exit ulite_of_unregister(void) { }
#endif /* CONFIG_OF && (CONFIG_PPC32 || CONFIG_MICROBLAZE) */
/* ---------------------------------------------------------------------
* Module setup/teardown
*/
int __init ulite_init(void)
{
int ret;
pr_debug("uartlite: calling uart_register_driver()\n");
ret = uart_register_driver(&ulite_uart_driver);
if (ret)
goto err_uart;
ret = ulite_of_register();
if (ret)
goto err_of;
pr_debug("uartlite: calling platform_driver_register()\n");
ret = platform_driver_register(&ulite_platform_driver);
if (ret)
goto err_plat;
return 0;
err_plat:
ulite_of_unregister();
err_of:
uart_unregister_driver(&ulite_uart_driver);
err_uart:
printk(KERN_ERR "registering uartlite driver failed: err=%i", ret);
return ret;
}
void __exit ulite_exit(void)
{
platform_driver_unregister(&ulite_platform_driver);
ulite_of_unregister();
uart_unregister_driver(&ulite_uart_driver);
}
module_init(ulite_init);
module_exit(ulite_exit);
MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
MODULE_DESCRIPTION("Xilinx uartlite serial driver");
MODULE_LICENSE("GPL");