aboutsummaryrefslogtreecommitdiff
path: root/arch/arm/mach-ebsa110/core.c
blob: 804c9122b7b3626e76eadcd3c950429612e87969 (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
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
/*
 *  linux/arch/arm/mach-ebsa110/core.c
 *
 *  Copyright (C) 1998-2001 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 *  Extra MM routines for the EBSA-110 architecture
 */
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/serial_8250.h>
#include <linux/init.h>
#include <linux/io.h>

#include <mach/hardware.h>
#include <asm/irq.h>
#include <asm/setup.h>
#include <asm/mach-types.h>
#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/system.h>

#include <asm/mach/arch.h>
#include <asm/mach/irq.h>
#include <asm/mach/map.h>

#include <asm/mach/time.h>

#define IRQ_MASK		0xfe000000	/* read */
#define IRQ_MSET		0xfe000000	/* write */
#define IRQ_STAT		0xff000000	/* read */
#define IRQ_MCLR		0xff000000	/* write */

static void ebsa110_mask_irq(struct irq_data *d)
{
	__raw_writeb(1 << d->irq, IRQ_MCLR);
}

static void ebsa110_unmask_irq(struct irq_data *d)
{
	__raw_writeb(1 << d->irq, IRQ_MSET);
}

static struct irq_chip ebsa110_irq_chip = {
	.irq_ack	= ebsa110_mask_irq,
	.irq_mask	= ebsa110_mask_irq,
	.irq_unmask	= ebsa110_unmask_irq,
};
 
static void __init ebsa110_init_irq(void)
{
	unsigned long flags;
	unsigned int irq;

	local_irq_save(flags);
	__raw_writeb(0xff, IRQ_MCLR);
	__raw_writeb(0x55, IRQ_MSET);
	__raw_writeb(0x00, IRQ_MSET);
	if (__raw_readb(IRQ_MASK) != 0x55)
		while (1);
	__raw_writeb(0xff, IRQ_MCLR);	/* clear all interrupt enables */
	local_irq_restore(flags);

	for (irq = 0; irq < NR_IRQS; irq++) {
		irq_set_chip_and_handler(irq, &ebsa110_irq_chip,
					 handle_level_irq);
		set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
	}
}

static struct map_desc ebsa110_io_desc[] __initdata = {
	/*
	 * sparse external-decode ISAIO space
	 */
	{	/* IRQ_STAT/IRQ_MCLR */
		.virtual	= IRQ_STAT,
		.pfn		= __phys_to_pfn(TRICK4_PHYS),
		.length		= PGDIR_SIZE,
		.type		= MT_DEVICE
	}, {	/* IRQ_MASK/IRQ_MSET */
		.virtual	= IRQ_MASK,
		.pfn		= __phys_to_pfn(TRICK3_PHYS),
		.length		= PGDIR_SIZE,
		.type		= MT_DEVICE
	}, {	/* SOFT_BASE */
		.virtual	= SOFT_BASE,
		.pfn		= __phys_to_pfn(TRICK1_PHYS),
		.length		= PGDIR_SIZE,
		.type		= MT_DEVICE
	}, {	/* PIT_BASE */
		.virtual	= PIT_BASE,
		.pfn		= __phys_to_pfn(TRICK0_PHYS),
		.length		= PGDIR_SIZE,
		.type		= MT_DEVICE
	},

	/*
	 * self-decode ISAIO space
	 */
	{
		.virtual	= ISAIO_BASE,
		.pfn		= __phys_to_pfn(ISAIO_PHYS),
		.length		= ISAIO_SIZE,
		.type		= MT_DEVICE
	}, {
		.virtual	= ISAMEM_BASE,
		.pfn		= __phys_to_pfn(ISAMEM_PHYS),
		.length		= ISAMEM_SIZE,
		.type		= MT_DEVICE
	}
};

static void __init ebsa110_map_io(void)
{
	iotable_init(ebsa110_io_desc, ARRAY_SIZE(ebsa110_io_desc));
}


#define PIT_CTRL		(PIT_BASE + 0x0d)
#define PIT_T2			(PIT_BASE + 0x09)
#define PIT_T1			(PIT_BASE + 0x05)
#define PIT_T0			(PIT_BASE + 0x01)

/*
 * This is the rate at which your MCLK signal toggles (in Hz)
 * This was measured on a 10 digit frequency counter sampling
 * over 1 second.
 */
#define MCLK	47894000

/*
 * This is the rate at which the PIT timers get clocked
 */
#define CLKBY7	(MCLK / 7)

/*
 * This is the counter value.  We tick at 200Hz on this platform.
 */
#define COUNT	((CLKBY7 + (HZ / 2)) / HZ)

/*
 * Get the time offset from the system PIT.  Note that if we have missed an
 * interrupt, then the PIT counter will roll over (ie, be negative).
 * This actually works out to be convenient.
 */
static unsigned long ebsa110_gettimeoffset(void)
{
	unsigned long offset, count;

	__raw_writeb(0x40, PIT_CTRL);
	count = __raw_readb(PIT_T1);
	count |= __raw_readb(PIT_T1) << 8;

	/*
	 * If count > COUNT, make the number negative.
	 */
	if (count > COUNT)
		count |= 0xffff0000;

	offset = COUNT;
	offset -= count;

	/*
	 * `offset' is in units of timer counts.  Convert
	 * offset to units of microseconds.
	 */
	offset = offset * (1000000 / HZ) / COUNT;

	return offset;
}

static irqreturn_t
ebsa110_timer_interrupt(int irq, void *dev_id)
{
	u32 count;

	/* latch and read timer 1 */
	__raw_writeb(0x40, PIT_CTRL);
	count = __raw_readb(PIT_T1);
	count |= __raw_readb(PIT_T1) << 8;

	count += COUNT;

	__raw_writeb(count & 0xff, PIT_T1);
	__raw_writeb(count >> 8, PIT_T1);

	timer_tick();

	return IRQ_HANDLED;
}

static struct irqaction ebsa110_timer_irq = {
	.name		= "EBSA110 Timer Tick",
	.flags		= IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
	.handler	= ebsa110_timer_interrupt,
};

/*
 * Set up timer interrupt.
 */
static void __init ebsa110_timer_init(void)
{
	/*
	 * Timer 1, mode 2, LSB/MSB
	 */
	__raw_writeb(0x70, PIT_CTRL);
	__raw_writeb(COUNT & 0xff, PIT_T1);
	__raw_writeb(COUNT >> 8, PIT_T1);

	setup_irq(IRQ_EBSA110_TIMER0, &ebsa110_timer_irq);
}

static struct sys_timer ebsa110_timer = {
	.init		= ebsa110_timer_init,
	.offset		= ebsa110_gettimeoffset,
};

static struct plat_serial8250_port serial_platform_data[] = {
	{
		.iobase		= 0x3f8,
		.irq		= 1,
		.uartclk	= 1843200,
		.regshift	= 0,
		.iotype		= UPIO_PORT,
		.flags		= UPF_BOOT_AUTOCONF | UPF_SKIP_TEST,
	},
	{
		.iobase		= 0x2f8,
		.irq		= 2,
		.uartclk	= 1843200,
		.regshift	= 0,
		.iotype		= UPIO_PORT,
		.flags		= UPF_BOOT_AUTOCONF | UPF_SKIP_TEST,
	},
	{ },
};

static struct platform_device serial_device = {
	.name			= "serial8250",
	.id			= PLAT8250_DEV_PLATFORM,
	.dev			= {
		.platform_data	= serial_platform_data,
	},
};

static struct resource am79c961_resources[] = {
	{
		.start		= 0x220,
		.end		= 0x238,
		.flags		= IORESOURCE_IO,
	}, {
		.start		= IRQ_EBSA110_ETHERNET,
		.end		= IRQ_EBSA110_ETHERNET,
		.flags		= IORESOURCE_IRQ,
	},
};

static struct platform_device am79c961_device = {
	.name			= "am79c961",
	.id			= -1,
	.num_resources		= ARRAY_SIZE(am79c961_resources),
	.resource		= am79c961_resources,
};

static struct platform_device *ebsa110_devices[] = {
	&serial_device,
	&am79c961_device,
};

/*
 * EBSA110 idling methodology:
 *
 * We can not execute the "wait for interrupt" instruction since that
 * will stop our MCLK signal (which provides the clock for the glue
 * logic, and therefore the timer interrupt).
 *
 * Instead, we spin, polling the IRQ_STAT register for the occurrence
 * of any interrupt with core clock down to the memory clock.
 */
static void ebsa110_idle(void)
{
	const char *irq_stat = (char *)0xff000000;

	/* disable clock switching */
	asm volatile ("mcr p15, 0, ip, c15, c2, 2" : : : "cc");

	/* wait for an interrupt to occur */
	while (!*irq_stat);

	/* enable clock switching */
	asm volatile ("mcr p15, 0, ip, c15, c1, 2" : : : "cc");
}

static int __init ebsa110_init(void)
{
	arm_pm_idle = ebsa110_idle;
	return platform_add_devices(ebsa110_devices, ARRAY_SIZE(ebsa110_devices));
}

arch_initcall(ebsa110_init);

static void ebsa110_restart(char mode, const char *cmd)
{
	soft_restart(0x80000000);
}

MACHINE_START(EBSA110, "EBSA110")
	/* Maintainer: Russell King */
	.atag_offset	= 0x400,
	.reserve_lp0	= 1,
	.reserve_lp2	= 1,
	.restart_mode	= 's',
	.map_io		= ebsa110_map_io,
	.init_irq	= ebsa110_init_irq,
	.timer		= &ebsa110_timer,
	.restart	= ebsa110_restart,
MACHINE_END