1 /*
2 * Atheros AR7XXX/AR9XXX SoC early printk support
3 *
4 * Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
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>
13 #include <linux/errno.h>
14 #include <linux/serial_reg.h>
15 #include <asm/addrspace.h>
16
17 #include <asm/mach-ath79/ath79.h>
18 #include <asm/mach-ath79/ar71xx_regs.h>
19 #include <asm/mach-ath79/ar933x_uart.h>
20
21 static void (*_prom_putchar) (unsigned char);
22
prom_putchar_wait(void __iomem * reg,u32 mask,u32 val)23 static inline void prom_putchar_wait(void __iomem *reg, u32 mask, u32 val)
24 {
25 u32 t;
26
27 do {
28 t = __raw_readl(reg);
29 if ((t & mask) == val)
30 break;
31 } while (1);
32 }
33
34 #define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
35
prom_putchar_ar71xx(unsigned char ch)36 static void prom_putchar_ar71xx(unsigned char ch)
37 {
38 void __iomem *base = (void __iomem *)(KSEG1ADDR(AR71XX_UART_BASE));
39
40 prom_putchar_wait(base + UART_LSR * 4, BOTH_EMPTY, BOTH_EMPTY);
41 __raw_writel(ch, base + UART_TX * 4);
42 prom_putchar_wait(base + UART_LSR * 4, BOTH_EMPTY, BOTH_EMPTY);
43 }
44
prom_putchar_ar933x(unsigned char ch)45 static 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
prom_putchar_dummy(unsigned char ch)56 static void prom_putchar_dummy(unsigned char ch)
57 {
58 /* nothing to do */
59 }
60
prom_putchar_init(void)61 static 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:
76 case REV_ID_MAJOR_AR9341:
77 case REV_ID_MAJOR_AR9342:
78 case REV_ID_MAJOR_AR9344:
79 case REV_ID_MAJOR_QCA9556:
80 case REV_ID_MAJOR_QCA9558:
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
prom_putchar(unsigned char ch)95 void prom_putchar(unsigned char ch)
96 {
97 if (!_prom_putchar)
98 prom_putchar_init();
99
100 _prom_putchar(ch);
101 }
102