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drivers/tty/serial/pch_uart.c: add console support

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Add console support to pch_uart.  To enable append e.g.
console=ttyPCH0,115200 to your kernel command line.

This is not expected work on CM-iTC boards due to their having a different
clock.

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alexander Stein 2011-11-15 15:04:07 -08:00 committed by Greg Kroah-Hartman
parent b82e324b3c
commit e30f867d40
2 changed files with 168 additions and 1 deletions
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9
drivers/tty/serial/Kconfig
View File

@ -1575,6 +1575,15 @@ config SERIAL_PCH_UART
ML7213/ML7223 is companion chip for Intel Atom E6xx series.
ML7213/ML7223 is completely compatible for Intel EG20T PCH.
config SERIAL_PCH_UART_CONSOLE
bool "Support for console on Intel EG20T PCH UART/OKI SEMICONDUCTOR ML7213 IOH"
depends on SERIAL_PCH_UART=y
select SERIAL_CORE_CONSOLE
help
Say Y here if you wish to use the PCH UART as the system console
(the system console is the device which receives all kernel messages and
warnings and which allows logins in single user mode).
config SERIAL_MSM_SMD
bool "Enable tty device interface for some SMD ports"
default n

160
drivers/tty/serial/pch_uart.c
View File

@ -25,6 +25,9 @@
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/dmi.h>
#include <linux/console.h>
#include <linux/nmi.h>
#include <linux/delay.h>
#include <linux/dmaengine.h>
#include <linux/pch_dma.h>
@ -198,6 +201,10 @@ enum {
#define PCI_VENDOR_ID_ROHM 0x10DB
#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
#define DEFAULT_BAUD_RATE 1843200 /* 1.8432MHz */
struct pch_uart_buffer {
unsigned char *buf;
int size;
@ -272,6 +279,9 @@ static struct pch_uart_driver_data drv_dat[] = {
[pch_ml7223_uart1] = {PCH_UART_2LINE, 1},
};
#ifdef CONFIG_SERIAL_PCH_UART_CONSOLE
static struct eg20t_port *pch_uart_ports[PCH_UART_NR];
#endif
static unsigned int default_baud = 9600;
static const int trigger_level_256[4] = { 1, 64, 128, 224 };
static const int trigger_level_64[4] = { 1, 16, 32, 56 };
@ -1380,6 +1390,143 @@ static struct uart_ops pch_uart_ops = {
.verify_port = pch_uart_verify_port
};
#ifdef CONFIG_SERIAL_PCH_UART_CONSOLE
/*
* Wait for transmitter & holding register to empty
*/
static void wait_for_xmitr(struct eg20t_port *up, int bits)
{
unsigned int status, tmout = 10000;
/* Wait up to 10ms for the character(s) to be sent. */
for (;;) {
status = ioread8(up->membase + UART_LSR);
if ((status & bits) == bits)
break;
if (--tmout == 0)
break;
udelay(1);
}
/* Wait up to 1s for flow control if necessary */
if (up->port.flags & UPF_CONS_FLOW) {
unsigned int tmout;
for (tmout = 1000000; tmout; tmout--) {
unsigned int msr = ioread8(up->membase + UART_MSR);
if (msr & UART_MSR_CTS)
break;
udelay(1);
touch_nmi_watchdog();
}
}
}
static void pch_console_putchar(struct uart_port *port, int ch)
{
struct eg20t_port *priv =
container_of(port, struct eg20t_port, port);
wait_for_xmitr(priv, UART_LSR_THRE);
iowrite8(ch, priv->membase + PCH_UART_THR);
}
/*
* Print a string to the serial port trying not to disturb
* any possible real use of the port...
*
* The console_lock must be held when we get here.
*/
static void
pch_console_write(struct console *co, const char *s, unsigned int count)
{
struct eg20t_port *priv;
unsigned long flags;
u8 ier;
int locked = 1;
priv = pch_uart_ports[co->index];
touch_nmi_watchdog();
local_irq_save(flags);
if (priv->port.sysrq) {
/* serial8250_handle_port() already took the lock */
locked = 0;
} else if (oops_in_progress) {
locked = spin_trylock(&priv->port.lock);
} else
spin_lock(&priv->port.lock);
/*
* First save the IER then disable the interrupts
*/
ier = ioread8(priv->membase + UART_IER);
pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_ALL_INT);
uart_console_write(&priv->port, s, count, pch_console_putchar);
/*
* Finally, wait for transmitter to become empty
* and restore the IER
*/
wait_for_xmitr(priv, BOTH_EMPTY);
iowrite8(ier, priv->membase + UART_IER);
if (locked)
spin_unlock(&priv->port.lock);
local_irq_restore(flags);
}
static int __init pch_console_setup(struct console *co, char *options)
{
struct uart_port *port;
int baud = 9600;
int bits = 8;
int parity = 'n';
int flow = 'n';
/*
* 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 >= PCH_UART_NR)
co->index = 0;
port = &pch_uart_ports[co->index]->port;
if (!port || (!port->iobase && !port->membase))
return -ENODEV;
/* setup uartclock */
port->uartclk = DEFAULT_BAUD_RATE;
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
return uart_set_options(port, co, baud, parity, bits, flow);
}
static struct uart_driver pch_uart_driver;
static struct console pch_console = {
.name = PCH_UART_DRIVER_DEVICE,
.write = pch_console_write,
.device = uart_console_device,
.setup = pch_console_setup,
.flags = CON_PRINTBUFFER | CON_ANYTIME,
.index = -1,
.data = &pch_uart_driver,
};
#define PCH_CONSOLE (&pch_console)
#else
#define PCH_CONSOLE NULL
#endif
static struct uart_driver pch_uart_driver = {
.owner = THIS_MODULE,
.driver_name = KBUILD_MODNAME,
@ -1387,6 +1534,7 @@ static struct uart_driver pch_uart_driver = {
.major = 0,
.minor = 0,
.nr = PCH_UART_NR,
.cons = PCH_CONSOLE,
};
static struct eg20t_port *pch_uart_init_port(struct pci_dev *pdev,
@ -1413,7 +1561,7 @@ static struct eg20t_port *pch_uart_init_port(struct pci_dev *pdev,
if (!rxbuf)
goto init_port_free_txbuf;
base_baud = 1843200; /* 1.8432MHz */
base_baud = DEFAULT_BAUD_RATE;
/* quirk for CM-iTC board */
board_name = dmi_get_system_info(DMI_BOARD_NAME);
@ -1463,6 +1611,9 @@ static struct eg20t_port *pch_uart_init_port(struct pci_dev *pdev,
pci_set_drvdata(pdev, priv);
pch_uart_hal_request(pdev, fifosize, base_baud);
#ifdef CONFIG_SERIAL_PCH_UART_CONSOLE
pch_uart_ports[board->line_no] = priv;
#endif
ret = uart_add_one_port(&pch_uart_driver, &priv->port);
if (ret < 0)
goto init_port_hal_free;
@ -1470,6 +1621,9 @@ static struct eg20t_port *pch_uart_init_port(struct pci_dev *pdev,
return priv;
init_port_hal_free:
#ifdef CONFIG_SERIAL_PCH_UART_CONSOLE
pch_uart_ports[board->line_no] = NULL;
#endif
free_page((unsigned long)rxbuf);
init_port_free_txbuf:
kfree(priv);
@ -1492,6 +1646,10 @@ static void pch_uart_pci_remove(struct pci_dev *pdev)
priv = (struct eg20t_port *)pci_get_drvdata(pdev);
pci_disable_msi(pdev);
#ifdef CONFIG_SERIAL_PCH_UART_CONSOLE
pch_uart_ports[priv->port.line] = NULL;
#endif
pch_uart_exit_port(priv);
pci_disable_device(pdev);
kfree(priv);