core.c revision 6df29debb7fc04ac3f92038c57437f40bab4e72d 
1/*
2 *  linux/arch/arm/mach-ebsa110/core.c
3 *
4 *  Copyright (C) 1998-2001 Russell King
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 *  Extra MM routines for the EBSA-110 architecture
11 */
12#include <linux/kernel.h>
13#include <linux/mm.h>
14#include <linux/interrupt.h>
15#include <linux/serial_8250.h>
16#include <linux/init.h>
17
18#include <asm/hardware.h>
19#include <asm/irq.h>
20#include <asm/io.h>
21#include <asm/setup.h>
22#include <asm/mach-types.h>
23#include <asm/pgtable.h>
24#include <asm/page.h>
25#include <asm/system.h>
26
27#include <asm/mach/arch.h>
28#include <asm/mach/irq.h>
29#include <asm/mach/map.h>
30
31#include <asm/mach/time.h>
32
33#define IRQ_MASK		0xfe000000	/* read */
34#define IRQ_MSET		0xfe000000	/* write */
35#define IRQ_STAT		0xff000000	/* read */
36#define IRQ_MCLR		0xff000000	/* write */
37
38static void ebsa110_mask_irq(unsigned int irq)
39{
40	__raw_writeb(1 << irq, IRQ_MCLR);
41}
42
43static void ebsa110_unmask_irq(unsigned int irq)
44{
45	__raw_writeb(1 << irq, IRQ_MSET);
46}
47
48static struct irqchip ebsa110_irq_chip = {
49	.ack	= ebsa110_mask_irq,
50	.mask	= ebsa110_mask_irq,
51	.unmask = ebsa110_unmask_irq,
52};
53
54static void __init ebsa110_init_irq(void)
55{
56	unsigned long flags;
57	unsigned int irq;
58
59	local_irq_save(flags);
60	__raw_writeb(0xff, IRQ_MCLR);
61	__raw_writeb(0x55, IRQ_MSET);
62	__raw_writeb(0x00, IRQ_MSET);
63	if (__raw_readb(IRQ_MASK) != 0x55)
64		while (1);
65	__raw_writeb(0xff, IRQ_MCLR);	/* clear all interrupt enables */
66	local_irq_restore(flags);
67
68	for (irq = 0; irq < NR_IRQS; irq++) {
69		set_irq_chip(irq, &ebsa110_irq_chip);
70		set_irq_handler(irq, do_level_IRQ);
71		set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
72	}
73}
74
75static struct map_desc ebsa110_io_desc[] __initdata = {
76	/*
77	 * sparse external-decode ISAIO space
78	 */
79	{ IRQ_STAT,    TRICK4_PHYS, PGDIR_SIZE,  MT_DEVICE }, /* IRQ_STAT/IRQ_MCLR */
80	{ IRQ_MASK,    TRICK3_PHYS, PGDIR_SIZE,  MT_DEVICE }, /* IRQ_MASK/IRQ_MSET */
81	{ SOFT_BASE,   TRICK1_PHYS, PGDIR_SIZE,  MT_DEVICE }, /* SOFT_BASE */
82	{ PIT_BASE,    TRICK0_PHYS, PGDIR_SIZE,  MT_DEVICE }, /* PIT_BASE */
83
84	/*
85	 * self-decode ISAIO space
86	 */
87	{ ISAIO_BASE,  ISAIO_PHYS,  ISAIO_SIZE,  MT_DEVICE },
88	{ ISAMEM_BASE, ISAMEM_PHYS, ISAMEM_SIZE, MT_DEVICE }
89};
90
91static void __init ebsa110_map_io(void)
92{
93	iotable_init(ebsa110_io_desc, ARRAY_SIZE(ebsa110_io_desc));
94}
95
96
97#define PIT_CTRL		(PIT_BASE + 0x0d)
98#define PIT_T2			(PIT_BASE + 0x09)
99#define PIT_T1			(PIT_BASE + 0x05)
100#define PIT_T0			(PIT_BASE + 0x01)
101
102/*
103 * This is the rate at which your MCLK signal toggles (in Hz)
104 * This was measured on a 10 digit frequency counter sampling
105 * over 1 second.
106 */
107#define MCLK	47894000
108
109/*
110 * This is the rate at which the PIT timers get clocked
111 */
112#define CLKBY7	(MCLK / 7)
113
114/*
115 * This is the counter value.  We tick at 200Hz on this platform.
116 */
117#define COUNT	((CLKBY7 + (HZ / 2)) / HZ)
118
119/*
120 * Get the time offset from the system PIT.  Note that if we have missed an
121 * interrupt, then the PIT counter will roll over (ie, be negative).
122 * This actually works out to be convenient.
123 */
124static unsigned long ebsa110_gettimeoffset(void)
125{
126	unsigned long offset, count;
127
128	__raw_writeb(0x40, PIT_CTRL);
129	count = __raw_readb(PIT_T1);
130	count |= __raw_readb(PIT_T1) << 8;
131
132	/*
133	 * If count > COUNT, make the number negative.
134	 */
135	if (count > COUNT)
136		count |= 0xffff0000;
137
138	offset = COUNT;
139	offset -= count;
140
141	/*
142	 * `offset' is in units of timer counts.  Convert
143	 * offset to units of microseconds.
144	 */
145	offset = offset * (1000000 / HZ) / COUNT;
146
147	return offset;
148}
149
150static irqreturn_t
151ebsa110_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
152{
153	u32 count;
154
155	write_seqlock(&xtime_lock);
156
157	/* latch and read timer 1 */
158	__raw_writeb(0x40, PIT_CTRL);
159	count = __raw_readb(PIT_T1);
160	count |= __raw_readb(PIT_T1) << 8;
161
162	count += COUNT;
163
164	__raw_writeb(count & 0xff, PIT_T1);
165	__raw_writeb(count >> 8, PIT_T1);
166
167	timer_tick(regs);
168
169	write_sequnlock(&xtime_lock);
170
171	return IRQ_HANDLED;
172}
173
174static struct irqaction ebsa110_timer_irq = {
175	.name		= "EBSA110 Timer Tick",
176	.flags		= SA_INTERRUPT | SA_TIMER,
177	.handler	= ebsa110_timer_interrupt,
178};
179
180/*
181 * Set up timer interrupt.
182 */
183static void __init ebsa110_timer_init(void)
184{
185	/*
186	 * Timer 1, mode 2, LSB/MSB
187	 */
188	__raw_writeb(0x70, PIT_CTRL);
189	__raw_writeb(COUNT & 0xff, PIT_T1);
190	__raw_writeb(COUNT >> 8, PIT_T1);
191
192	setup_irq(IRQ_EBSA110_TIMER0, &ebsa110_timer_irq);
193}
194
195static struct sys_timer ebsa110_timer = {
196	.init		= ebsa110_timer_init,
197	.offset		= ebsa110_gettimeoffset,
198};
199
200static struct plat_serial8250_port serial_platform_data[] = {
201	{
202		.iobase		= 0x3f8,
203		.irq		= 1,
204		.uartclk	= 1843200,
205		.regshift	= 0,
206		.iotype		= UPIO_PORT,
207		.flags		= UPF_BOOT_AUTOCONF | UPF_SKIP_TEST,
208	},
209	{
210		.iobase		= 0x2f8,
211		.irq		= 2,
212		.uartclk	= 1843200,
213		.regshift	= 0,
214		.iotype		= UPIO_PORT,
215		.flags		= UPF_BOOT_AUTOCONF | UPF_SKIP_TEST,
216	},
217	{ },
218};
219
220static struct platform_device serial_device = {
221	.name			= "serial8250",
222	.id			= PLAT8250_DEV_PLATFORM,
223	.dev			= {
224		.platform_data	= serial_platform_data,
225	},
226};
227
228static int __init ebsa110_init(void)
229{
230	return platform_device_register(&serial_device);
231}
232
233arch_initcall(ebsa110_init);
234
235MACHINE_START(EBSA110, "EBSA110")
236	/* Maintainer: Russell King */
237	.phys_ram	= 0x00000000,
238	.phys_io	= 0xe0000000,
239	.io_pg_offst	= ((0xe0000000) >> 18) & 0xfffc,
240	.boot_params	= 0x00000400,
241	.reserve_lp0	= 1,
242	.reserve_lp2	= 1,
243	.soft_reboot	= 1,
244	.map_io		= ebsa110_map_io,
245	.init_irq	= ebsa110_init_irq,
246	.timer		= &ebsa110_timer,
247MACHINE_END
248