core.c revision 58591942789abe1ea18e3fb1e8d8502c70060c29 
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#include <linux/io.h>
18
19#include <mach/hardware.h>
20#include <asm/irq.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_misc.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#include "core.h"
34
35static void ebsa110_mask_irq(struct irq_data *d)
36{
37	__raw_writeb(1 << d->irq, IRQ_MCLR);
38}
39
40static void ebsa110_unmask_irq(struct irq_data *d)
41{
42	__raw_writeb(1 << d->irq, IRQ_MSET);
43}
44
45static struct irq_chip ebsa110_irq_chip = {
46	.irq_ack	= ebsa110_mask_irq,
47	.irq_mask	= ebsa110_mask_irq,
48	.irq_unmask	= ebsa110_unmask_irq,
49};
50
51static void __init ebsa110_init_irq(void)
52{
53	unsigned long flags;
54	unsigned int irq;
55
56	local_irq_save(flags);
57	__raw_writeb(0xff, IRQ_MCLR);
58	__raw_writeb(0x55, IRQ_MSET);
59	__raw_writeb(0x00, IRQ_MSET);
60	if (__raw_readb(IRQ_MASK) != 0x55)
61		while (1);
62	__raw_writeb(0xff, IRQ_MCLR);	/* clear all interrupt enables */
63	local_irq_restore(flags);
64
65	for (irq = 0; irq < NR_IRQS; irq++) {
66		irq_set_chip_and_handler(irq, &ebsa110_irq_chip,
67					 handle_level_irq);
68		set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
69	}
70}
71
72static struct map_desc ebsa110_io_desc[] __initdata = {
73	/*
74	 * sparse external-decode ISAIO space
75	 */
76	{	/* IRQ_STAT/IRQ_MCLR */
77		.virtual	= (unsigned long)IRQ_STAT,
78		.pfn		= __phys_to_pfn(TRICK4_PHYS),
79		.length		= TRICK4_SIZE,
80		.type		= MT_DEVICE
81	}, {	/* IRQ_MASK/IRQ_MSET */
82		.virtual	= (unsigned long)IRQ_MASK,
83		.pfn		= __phys_to_pfn(TRICK3_PHYS),
84		.length		= TRICK3_SIZE,
85		.type		= MT_DEVICE
86	}, {	/* SOFT_BASE */
87		.virtual	= (unsigned long)SOFT_BASE,
88		.pfn		= __phys_to_pfn(TRICK1_PHYS),
89		.length		= TRICK1_SIZE,
90		.type		= MT_DEVICE
91	}, {	/* PIT_BASE */
92		.virtual	= (unsigned long)PIT_BASE,
93		.pfn		= __phys_to_pfn(TRICK0_PHYS),
94		.length		= TRICK0_SIZE,
95		.type		= MT_DEVICE
96	},
97
98	/*
99	 * self-decode ISAIO space
100	 */
101	{
102		.virtual	= ISAIO_BASE,
103		.pfn		= __phys_to_pfn(ISAIO_PHYS),
104		.length		= ISAIO_SIZE,
105		.type		= MT_DEVICE
106	}, {
107		.virtual	= ISAMEM_BASE,
108		.pfn		= __phys_to_pfn(ISAMEM_PHYS),
109		.length		= ISAMEM_SIZE,
110		.type		= MT_DEVICE
111	}
112};
113
114static void __init ebsa110_map_io(void)
115{
116	iotable_init(ebsa110_io_desc, ARRAY_SIZE(ebsa110_io_desc));
117}
118
119static void __iomem *ebsa110_ioremap_caller(phys_addr_t cookie, size_t size,
120					    unsigned int flags, void *caller)
121{
122	return (void __iomem *)cookie;
123}
124
125static void ebsa110_iounmap(volatile void __iomem *io_addr)
126{}
127
128static void __init ebsa110_init_early(void)
129{
130	arch_ioremap_caller = ebsa110_ioremap_caller;
131	arch_iounmap = ebsa110_iounmap;
132}
133
134#define PIT_CTRL		(PIT_BASE + 0x0d)
135#define PIT_T2			(PIT_BASE + 0x09)
136#define PIT_T1			(PIT_BASE + 0x05)
137#define PIT_T0			(PIT_BASE + 0x01)
138
139/*
140 * This is the rate at which your MCLK signal toggles (in Hz)
141 * This was measured on a 10 digit frequency counter sampling
142 * over 1 second.
143 */
144#define MCLK	47894000
145
146/*
147 * This is the rate at which the PIT timers get clocked
148 */
149#define CLKBY7	(MCLK / 7)
150
151/*
152 * This is the counter value.  We tick at 200Hz on this platform.
153 */
154#define COUNT	((CLKBY7 + (HZ / 2)) / HZ)
155
156/*
157 * Get the time offset from the system PIT.  Note that if we have missed an
158 * interrupt, then the PIT counter will roll over (ie, be negative).
159 * This actually works out to be convenient.
160 */
161static u32 ebsa110_gettimeoffset(void)
162{
163	unsigned long offset, count;
164
165	__raw_writeb(0x40, PIT_CTRL);
166	count = __raw_readb(PIT_T1);
167	count |= __raw_readb(PIT_T1) << 8;
168
169	/*
170	 * If count > COUNT, make the number negative.
171	 */
172	if (count > COUNT)
173		count |= 0xffff0000;
174
175	offset = COUNT;
176	offset -= count;
177
178	/*
179	 * `offset' is in units of timer counts.  Convert
180	 * offset to units of microseconds.
181	 */
182	offset = offset * (1000000 / HZ) / COUNT;
183
184	return offset * 1000;
185}
186
187static irqreturn_t
188ebsa110_timer_interrupt(int irq, void *dev_id)
189{
190	u32 count;
191
192	/* latch and read timer 1 */
193	__raw_writeb(0x40, PIT_CTRL);
194	count = __raw_readb(PIT_T1);
195	count |= __raw_readb(PIT_T1) << 8;
196
197	count += COUNT;
198
199	__raw_writeb(count & 0xff, PIT_T1);
200	__raw_writeb(count >> 8, PIT_T1);
201
202	timer_tick();
203
204	return IRQ_HANDLED;
205}
206
207static struct irqaction ebsa110_timer_irq = {
208	.name		= "EBSA110 Timer Tick",
209	.flags		= IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
210	.handler	= ebsa110_timer_interrupt,
211};
212
213/*
214 * Set up timer interrupt.
215 */
216void __init ebsa110_timer_init(void)
217{
218	arch_gettimeoffset = ebsa110_gettimeoffset;
219
220	/*
221	 * Timer 1, mode 2, LSB/MSB
222	 */
223	__raw_writeb(0x70, PIT_CTRL);
224	__raw_writeb(COUNT & 0xff, PIT_T1);
225	__raw_writeb(COUNT >> 8, PIT_T1);
226
227	setup_irq(IRQ_EBSA110_TIMER0, &ebsa110_timer_irq);
228}
229
230static struct plat_serial8250_port serial_platform_data[] = {
231	{
232		.iobase		= 0x3f8,
233		.irq		= 1,
234		.uartclk	= 1843200,
235		.regshift	= 0,
236		.iotype		= UPIO_PORT,
237		.flags		= UPF_BOOT_AUTOCONF | UPF_SKIP_TEST,
238	},
239	{
240		.iobase		= 0x2f8,
241		.irq		= 2,
242		.uartclk	= 1843200,
243		.regshift	= 0,
244		.iotype		= UPIO_PORT,
245		.flags		= UPF_BOOT_AUTOCONF | UPF_SKIP_TEST,
246	},
247	{ },
248};
249
250static struct platform_device serial_device = {
251	.name			= "serial8250",
252	.id			= PLAT8250_DEV_PLATFORM,
253	.dev			= {
254		.platform_data	= serial_platform_data,
255	},
256};
257
258static struct resource am79c961_resources[] = {
259	{
260		.start		= 0x220,
261		.end		= 0x238,
262		.flags		= IORESOURCE_IO,
263	}, {
264		.start		= IRQ_EBSA110_ETHERNET,
265		.end		= IRQ_EBSA110_ETHERNET,
266		.flags		= IORESOURCE_IRQ,
267	},
268};
269
270static struct platform_device am79c961_device = {
271	.name			= "am79c961",
272	.id			= -1,
273	.num_resources		= ARRAY_SIZE(am79c961_resources),
274	.resource		= am79c961_resources,
275};
276
277static struct platform_device *ebsa110_devices[] = {
278	&serial_device,
279	&am79c961_device,
280};
281
282/*
283 * EBSA110 idling methodology:
284 *
285 * We can not execute the "wait for interrupt" instruction since that
286 * will stop our MCLK signal (which provides the clock for the glue
287 * logic, and therefore the timer interrupt).
288 *
289 * Instead, we spin, polling the IRQ_STAT register for the occurrence
290 * of any interrupt with core clock down to the memory clock.
291 */
292static void ebsa110_idle(void)
293{
294	const char *irq_stat = (char *)0xff000000;
295
296	/* disable clock switching */
297	asm volatile ("mcr p15, 0, ip, c15, c2, 2" : : : "cc");
298
299	/* wait for an interrupt to occur */
300	while (!*irq_stat);
301
302	/* enable clock switching */
303	asm volatile ("mcr p15, 0, ip, c15, c1, 2" : : : "cc");
304}
305
306static int __init ebsa110_init(void)
307{
308	arm_pm_idle = ebsa110_idle;
309	return platform_add_devices(ebsa110_devices, ARRAY_SIZE(ebsa110_devices));
310}
311
312arch_initcall(ebsa110_init);
313
314static void ebsa110_restart(char mode, const char *cmd)
315{
316	soft_restart(0x80000000);
317}
318
319MACHINE_START(EBSA110, "EBSA110")
320	/* Maintainer: Russell King */
321	.atag_offset	= 0x400,
322	.reserve_lp0	= 1,
323	.reserve_lp2	= 1,
324	.map_io		= ebsa110_map_io,
325	.init_early	= ebsa110_init_early,
326	.init_irq	= ebsa110_init_irq,
327	.init_time	= ebsa110_timer_init,
328	.restart	= ebsa110_restart,
329MACHINE_END
330