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/*
* Copyright 2008-2011, IBM Corporation
*
* 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.
*/
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/io.h>
#include <linux/of_address.h>
#include "wsp.h"
/*
* The UART connection to the H8 is over ttyS1 which is just a 16550.
* We assume that FW has it setup right and no one messes with it.
*/
static u8 __iomem *h8;
#define RBR 0 /* Receiver Buffer Register */
#define THR 0 /* Transmitter Holding Register */
#define LSR 5 /* Line Status Register */
#define LSR_DR 0x01 /* LSR value for Data-Ready */
#define LSR_THRE 0x20 /* LSR value for Transmitter-Holding-Register-Empty */
static void wsp_h8_putc(int c)
{
u8 lsr;
do {
lsr = readb(h8 + LSR);
} while ((lsr & LSR_THRE) != LSR_THRE);
writeb(c, h8 + THR);
}
static int wsp_h8_getc(void)
{
u8 lsr;
do {
lsr = readb(h8 + LSR);
} while ((lsr & LSR_DR) != LSR_DR);
return readb(h8 + RBR);
}
static void wsp_h8_puts(const char *s, int sz)
{
int i;
for (i = 0; i < sz; i++) {
wsp_h8_putc(s[i]);
/* no flow control so wait for echo */
wsp_h8_getc();
}
wsp_h8_putc('\r');
wsp_h8_putc('\n');
}
static void wsp_h8_terminal_cmd(const char *cmd, int sz)
{
hard_irq_disable();
wsp_h8_puts(cmd, sz);
/* should never return, but just in case */
for (;;)
continue;
}
void wsp_h8_restart(char *cmd)
{
static const char restart[] = "warm-reset";
(void)cmd;
wsp_h8_terminal_cmd(restart, sizeof(restart) - 1);
}
void wsp_h8_power_off(void)
{
static const char off[] = "power-off";
wsp_h8_terminal_cmd(off, sizeof(off) - 1);
}
static void __iomem *wsp_h8_getaddr(void)
{
struct device_node *aliases;
struct device_node *uart;
struct property *path;
void __iomem *va = NULL;
/*
* there is nothing in the devtree to tell us which is mapped
* to the H8, but se know it is the second serial port.
*/
aliases = of_find_node_by_path("/aliases");
if (aliases == NULL)
return NULL;
path = of_find_property(aliases, "serial1", NULL);
if (path == NULL)
goto out;
uart = of_find_node_by_path(path->value);
if (uart == NULL)
goto out;
va = of_iomap(uart, 0);
/* remove it so no one messes with it */
of_detach_node(uart);
of_node_put(uart);
out:
of_node_put(aliases);
return va;
}
void __init wsp_setup_h8(void)
{
h8 = wsp_h8_getaddr();
/* Devtree change? lets hard map it anyway */
if (h8 == NULL) {
pr_warn("UART to H8 could not be found");
h8 = ioremap(0xffc0008000ULL, 0x100);
}
}
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