summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/platforms/embedded6xx/ls_uart.c
blob: 0d9f1500a67185f23f78a9cfa02833f9a796d1b6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
#include <linux/workqueue.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/serial_reg.h>
#include <linux/serial_8250.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/termbits.h>

#include "mpc10x.h"

static void __iomem *avr_addr;
static unsigned long avr_clock;

static struct work_struct wd_work;

static void wd_stop(struct work_struct *unused)
{
	const char string[] = "AAAAFFFFJJJJ>>>>VVVV>>>>ZZZZVVVVKKKK";
	int i = 0, rescue = 8;
	int len = strlen(string);

	while (rescue--) {
		int j;
		char lsr = in_8(avr_addr + UART_LSR);

		if (lsr & (UART_LSR_THRE | UART_LSR_TEMT)) {
			for (j = 0; j < 16 && i < len; j++, i++)
				out_8(avr_addr + UART_TX, string[i]);
			if (i == len) {
				/* Read "OK" back: 4ms for the last "KKKK"
				   plus a couple bytes back */
				msleep(7);
				printk("linkstation: disarming the AVR watchdog: ");
				while (in_8(avr_addr + UART_LSR) & UART_LSR_DR)
					printk("%c", in_8(avr_addr + UART_RX));
				break;
			}
		}
		msleep(17);
	}
	printk("\n");
}

#define AVR_QUOT(clock) ((clock) + 8 * 9600) / (16 * 9600)

void avr_uart_configure(void)
{
	unsigned char cval = UART_LCR_WLEN8;
	unsigned int quot = AVR_QUOT(avr_clock);

	if (!avr_addr || !avr_clock)
		return;

	out_8(avr_addr + UART_LCR, cval);			/* initialise UART */
	out_8(avr_addr + UART_MCR, 0);
	out_8(avr_addr + UART_IER, 0);

	cval |= UART_LCR_STOP | UART_LCR_PARITY | UART_LCR_EPAR;

	out_8(avr_addr + UART_LCR, cval);			/* Set character format */

	out_8(avr_addr + UART_LCR, cval | UART_LCR_DLAB);	/* set DLAB */
	out_8(avr_addr + UART_DLL, quot & 0xff);		/* LS of divisor */
	out_8(avr_addr + UART_DLM, quot >> 8);			/* MS of divisor */
	out_8(avr_addr + UART_LCR, cval);			/* reset DLAB */
	out_8(avr_addr + UART_FCR, UART_FCR_ENABLE_FIFO);	/* enable FIFO */
}

void avr_uart_send(const char c)
{
	if (!avr_addr || !avr_clock)
		return;

	out_8(avr_addr + UART_TX, c);
	out_8(avr_addr + UART_TX, c);
	out_8(avr_addr + UART_TX, c);
	out_8(avr_addr + UART_TX, c);
}

static void __init ls_uart_init(void)
{
	local_irq_disable();

#ifndef CONFIG_SERIAL_8250
	out_8(avr_addr + UART_FCR, UART_FCR_ENABLE_FIFO);	/* enable FIFO */
	out_8(avr_addr + UART_FCR, UART_FCR_ENABLE_FIFO |
	      UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);	/* clear FIFOs */
	out_8(avr_addr + UART_FCR, 0);
	out_8(avr_addr + UART_IER, 0);

	/* Clear up interrupts */
	(void) in_8(avr_addr + UART_LSR);
	(void) in_8(avr_addr + UART_RX);
	(void) in_8(avr_addr + UART_IIR);
	(void) in_8(avr_addr + UART_MSR);
#endif
	avr_uart_configure();

	local_irq_enable();
}

static int __init ls_uarts_init(void)
{
	struct device_node *avr;
	phys_addr_t phys_addr;
	int len;

	avr = of_find_node_by_path("/soc10x/serial@80004500");
	if (!avr)
		return -EINVAL;

	avr_clock = *(u32*)of_get_property(avr, "clock-frequency", &len);
	phys_addr = ((u32*)of_get_property(avr, "reg", &len))[0];

	if (!avr_clock || !phys_addr)
		return -EINVAL;

	avr_addr = ioremap(phys_addr, 32);
	if (!avr_addr)
		return -EFAULT;

	ls_uart_init();

	INIT_WORK(&wd_work, wd_stop);
	schedule_work(&wd_work);

	return 0;
}

late_initcall(ls_uarts_init);