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