Merge tag '4.8-doc-fixes' of git://git.lwn.net/linux
[deliverable/linux.git] / arch / mips / ath79 / early_printk.c
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d4a67d9d 1/*
0bd3acdf 2 * Atheros AR7XXX/AR9XXX SoC early printk support
d4a67d9d 3 *
0bd3acdf 4 * Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
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5 * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 as published
9 * by the Free Software Foundation.
10 */
11
12#include <linux/io.h>
0bd3acdf 13#include <linux/errno.h>
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14#include <linux/serial_reg.h>
15#include <asm/addrspace.h>
16
0bd3acdf 17#include <asm/mach-ath79/ath79.h>
d4a67d9d 18#include <asm/mach-ath79/ar71xx_regs.h>
0bd3acdf 19#include <asm/mach-ath79/ar933x_uart.h>
d4a67d9d 20
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21static void (*_prom_putchar) (unsigned char);
22
23static inline void prom_putchar_wait(void __iomem *reg, u32 mask, u32 val)
d4a67d9d 24{
0bd3acdf 25 u32 t;
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26
27 do {
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28 t = __raw_readl(reg);
29 if ((t & mask) == val)
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30 break;
31 } while (1);
32}
33
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34#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
35
0bd3acdf 36static void prom_putchar_ar71xx(unsigned char ch)
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37{
38 void __iomem *base = (void __iomem *)(KSEG1ADDR(AR71XX_UART_BASE));
39
f5b556c9 40 prom_putchar_wait(base + UART_LSR * 4, BOTH_EMPTY, BOTH_EMPTY);
d4a67d9d 41 __raw_writel(ch, base + UART_TX * 4);
f5b556c9 42 prom_putchar_wait(base + UART_LSR * 4, BOTH_EMPTY, BOTH_EMPTY);
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43}
44
45static void prom_putchar_ar933x(unsigned char ch)
46{
47 void __iomem *base = (void __iomem *)(KSEG1ADDR(AR933X_UART_BASE));
48
49 prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR,
50 AR933X_UART_DATA_TX_CSR);
51 __raw_writel(AR933X_UART_DATA_TX_CSR | ch, base + AR933X_UART_DATA_REG);
52 prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR,
53 AR933X_UART_DATA_TX_CSR);
54}
55
56static void prom_putchar_dummy(unsigned char ch)
57{
58 /* nothing to do */
59}
60
61static void prom_putchar_init(void)
62{
63 void __iomem *base;
64 u32 id;
65
66 base = (void __iomem *)(KSEG1ADDR(AR71XX_RESET_BASE));
67 id = __raw_readl(base + AR71XX_RESET_REG_REV_ID);
68 id &= REV_ID_MAJOR_MASK;
69
70 switch (id) {
71 case REV_ID_MAJOR_AR71XX:
72 case REV_ID_MAJOR_AR7240:
73 case REV_ID_MAJOR_AR7241:
74 case REV_ID_MAJOR_AR7242:
75 case REV_ID_MAJOR_AR913X:
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76 case REV_ID_MAJOR_AR9341:
77 case REV_ID_MAJOR_AR9342:
78 case REV_ID_MAJOR_AR9344:
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79 case REV_ID_MAJOR_QCA9556:
80 case REV_ID_MAJOR_QCA9558:
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81 _prom_putchar = prom_putchar_ar71xx;
82 break;
83
84 case REV_ID_MAJOR_AR9330:
85 case REV_ID_MAJOR_AR9331:
86 _prom_putchar = prom_putchar_ar933x;
87 break;
88
89 default:
90 _prom_putchar = prom_putchar_dummy;
91 break;
92 }
93}
94
95void prom_putchar(unsigned char ch)
96{
97 if (!_prom_putchar)
98 prom_putchar_init();
99
100 _prom_putchar(ch);
d4a67d9d 101}
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