1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * linux/arch/arm/mach-ebsa110/core.c
4 *
5 * Copyright (C) 1998-2001 Russell King
6 *
7 * Extra MM routines for the EBSA-110 architecture
8 */
9 #include <linux/kernel.h>
10 #include <linux/mm.h>
11 #include <linux/interrupt.h>
12 #include <linux/serial_8250.h>
13 #include <linux/init.h>
14 #include <linux/io.h>
15
16 #include <mach/hardware.h>
17 #include <asm/irq.h>
18 #include <asm/setup.h>
19 #include <asm/mach-types.h>
20 #include <asm/page.h>
21 #include <asm/system_misc.h>
22
23 #include <asm/mach/arch.h>
24 #include <asm/mach/irq.h>
25 #include <asm/mach/map.h>
26
27 #include <asm/mach/time.h>
28
29 #include "core.h"
30
ebsa110_mask_irq(struct irq_data * d)31 static void ebsa110_mask_irq(struct irq_data *d)
32 {
33 __raw_writeb(1 << d->irq, IRQ_MCLR);
34 }
35
ebsa110_unmask_irq(struct irq_data * d)36 static void ebsa110_unmask_irq(struct irq_data *d)
37 {
38 __raw_writeb(1 << d->irq, IRQ_MSET);
39 }
40
41 static struct irq_chip ebsa110_irq_chip = {
42 .irq_ack = ebsa110_mask_irq,
43 .irq_mask = ebsa110_mask_irq,
44 .irq_unmask = ebsa110_unmask_irq,
45 };
46
ebsa110_init_irq(void)47 static void __init ebsa110_init_irq(void)
48 {
49 unsigned long flags;
50 unsigned int irq;
51
52 local_irq_save(flags);
53 __raw_writeb(0xff, IRQ_MCLR);
54 __raw_writeb(0x55, IRQ_MSET);
55 __raw_writeb(0x00, IRQ_MSET);
56 if (__raw_readb(IRQ_MASK) != 0x55)
57 while (1);
58 __raw_writeb(0xff, IRQ_MCLR); /* clear all interrupt enables */
59 local_irq_restore(flags);
60
61 for (irq = 0; irq < NR_IRQS; irq++) {
62 irq_set_chip_and_handler(irq, &ebsa110_irq_chip,
63 handle_level_irq);
64 irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
65 }
66 }
67
68 static struct map_desc ebsa110_io_desc[] __initdata = {
69 /*
70 * sparse external-decode ISAIO space
71 */
72 { /* IRQ_STAT/IRQ_MCLR */
73 .virtual = (unsigned long)IRQ_STAT,
74 .pfn = __phys_to_pfn(TRICK4_PHYS),
75 .length = TRICK4_SIZE,
76 .type = MT_DEVICE
77 }, { /* IRQ_MASK/IRQ_MSET */
78 .virtual = (unsigned long)IRQ_MASK,
79 .pfn = __phys_to_pfn(TRICK3_PHYS),
80 .length = TRICK3_SIZE,
81 .type = MT_DEVICE
82 }, { /* SOFT_BASE */
83 .virtual = (unsigned long)SOFT_BASE,
84 .pfn = __phys_to_pfn(TRICK1_PHYS),
85 .length = TRICK1_SIZE,
86 .type = MT_DEVICE
87 }, { /* PIT_BASE */
88 .virtual = (unsigned long)PIT_BASE,
89 .pfn = __phys_to_pfn(TRICK0_PHYS),
90 .length = TRICK0_SIZE,
91 .type = MT_DEVICE
92 },
93
94 /*
95 * self-decode ISAIO space
96 */
97 {
98 .virtual = ISAIO_BASE,
99 .pfn = __phys_to_pfn(ISAIO_PHYS),
100 .length = ISAIO_SIZE,
101 .type = MT_DEVICE
102 }, {
103 .virtual = ISAMEM_BASE,
104 .pfn = __phys_to_pfn(ISAMEM_PHYS),
105 .length = ISAMEM_SIZE,
106 .type = MT_DEVICE
107 }
108 };
109
ebsa110_map_io(void)110 static void __init ebsa110_map_io(void)
111 {
112 iotable_init(ebsa110_io_desc, ARRAY_SIZE(ebsa110_io_desc));
113 }
114
ebsa110_ioremap_caller(phys_addr_t cookie,size_t size,unsigned int flags,void * caller)115 static void __iomem *ebsa110_ioremap_caller(phys_addr_t cookie, size_t size,
116 unsigned int flags, void *caller)
117 {
118 return (void __iomem *)cookie;
119 }
120
ebsa110_iounmap(volatile void __iomem * io_addr)121 static void ebsa110_iounmap(volatile void __iomem *io_addr)
122 {}
123
ebsa110_init_early(void)124 static void __init ebsa110_init_early(void)
125 {
126 arch_ioremap_caller = ebsa110_ioremap_caller;
127 arch_iounmap = ebsa110_iounmap;
128 }
129
130 #define PIT_CTRL (PIT_BASE + 0x0d)
131 #define PIT_T2 (PIT_BASE + 0x09)
132 #define PIT_T1 (PIT_BASE + 0x05)
133 #define PIT_T0 (PIT_BASE + 0x01)
134
135 /*
136 * This is the rate at which your MCLK signal toggles (in Hz)
137 * This was measured on a 10 digit frequency counter sampling
138 * over 1 second.
139 */
140 #define MCLK 47894000
141
142 /*
143 * This is the rate at which the PIT timers get clocked
144 */
145 #define CLKBY7 (MCLK / 7)
146
147 /*
148 * This is the counter value. We tick at 200Hz on this platform.
149 */
150 #define COUNT ((CLKBY7 + (HZ / 2)) / HZ)
151
152 /*
153 * Get the time offset from the system PIT. Note that if we have missed an
154 * interrupt, then the PIT counter will roll over (ie, be negative).
155 * This actually works out to be convenient.
156 */
ebsa110_gettimeoffset(void)157 static u32 ebsa110_gettimeoffset(void)
158 {
159 unsigned long offset, count;
160
161 __raw_writeb(0x40, PIT_CTRL);
162 count = __raw_readb(PIT_T1);
163 count |= __raw_readb(PIT_T1) << 8;
164
165 /*
166 * If count > COUNT, make the number negative.
167 */
168 if (count > COUNT)
169 count |= 0xffff0000;
170
171 offset = COUNT;
172 offset -= count;
173
174 /*
175 * `offset' is in units of timer counts. Convert
176 * offset to units of microseconds.
177 */
178 offset = offset * (1000000 / HZ) / COUNT;
179
180 return offset * 1000;
181 }
182
183 static irqreturn_t
ebsa110_timer_interrupt(int irq,void * dev_id)184 ebsa110_timer_interrupt(int irq, void *dev_id)
185 {
186 u32 count;
187
188 /* latch and read timer 1 */
189 __raw_writeb(0x40, PIT_CTRL);
190 count = __raw_readb(PIT_T1);
191 count |= __raw_readb(PIT_T1) << 8;
192
193 count += COUNT;
194
195 __raw_writeb(count & 0xff, PIT_T1);
196 __raw_writeb(count >> 8, PIT_T1);
197
198 timer_tick();
199
200 return IRQ_HANDLED;
201 }
202
203 /*
204 * Set up timer interrupt.
205 */
ebsa110_timer_init(void)206 void __init ebsa110_timer_init(void)
207 {
208 int irq = IRQ_EBSA110_TIMER0;
209
210 arch_gettimeoffset = ebsa110_gettimeoffset;
211
212 /*
213 * Timer 1, mode 2, LSB/MSB
214 */
215 __raw_writeb(0x70, PIT_CTRL);
216 __raw_writeb(COUNT & 0xff, PIT_T1);
217 __raw_writeb(COUNT >> 8, PIT_T1);
218
219 if (request_irq(irq, ebsa110_timer_interrupt, IRQF_TIMER | IRQF_IRQPOLL,
220 "EBSA110 Timer Tick", NULL))
221 pr_err("Failed to request irq %d (EBSA110 Timer Tick)\n", irq);
222 }
223
224 static struct plat_serial8250_port serial_platform_data[] = {
225 {
226 .iobase = 0x3f8,
227 .irq = 1,
228 .uartclk = 1843200,
229 .regshift = 0,
230 .iotype = UPIO_PORT,
231 .flags = UPF_BOOT_AUTOCONF | UPF_SKIP_TEST,
232 },
233 {
234 .iobase = 0x2f8,
235 .irq = 2,
236 .uartclk = 1843200,
237 .regshift = 0,
238 .iotype = UPIO_PORT,
239 .flags = UPF_BOOT_AUTOCONF | UPF_SKIP_TEST,
240 },
241 { },
242 };
243
244 static struct platform_device serial_device = {
245 .name = "serial8250",
246 .id = PLAT8250_DEV_PLATFORM,
247 .dev = {
248 .platform_data = serial_platform_data,
249 },
250 };
251
252 static struct resource am79c961_resources[] = {
253 {
254 .start = 0x220,
255 .end = 0x238,
256 .flags = IORESOURCE_IO,
257 }, {
258 .start = IRQ_EBSA110_ETHERNET,
259 .end = IRQ_EBSA110_ETHERNET,
260 .flags = IORESOURCE_IRQ,
261 },
262 };
263
264 static struct platform_device am79c961_device = {
265 .name = "am79c961",
266 .id = -1,
267 .num_resources = ARRAY_SIZE(am79c961_resources),
268 .resource = am79c961_resources,
269 };
270
271 static struct platform_device *ebsa110_devices[] = {
272 &serial_device,
273 &am79c961_device,
274 };
275
276 /*
277 * EBSA110 idling methodology:
278 *
279 * We can not execute the "wait for interrupt" instruction since that
280 * will stop our MCLK signal (which provides the clock for the glue
281 * logic, and therefore the timer interrupt).
282 *
283 * Instead, we spin, polling the IRQ_STAT register for the occurrence
284 * of any interrupt with core clock down to the memory clock.
285 */
ebsa110_idle(void)286 static void ebsa110_idle(void)
287 {
288 const char *irq_stat = (char *)0xff000000;
289
290 /* disable clock switching */
291 asm volatile ("mcr p15, 0, ip, c15, c2, 2" : : : "cc");
292
293 /* wait for an interrupt to occur */
294 while (!*irq_stat);
295
296 /* enable clock switching */
297 asm volatile ("mcr p15, 0, ip, c15, c1, 2" : : : "cc");
298 }
299
ebsa110_init(void)300 static int __init ebsa110_init(void)
301 {
302 arm_pm_idle = ebsa110_idle;
303 return platform_add_devices(ebsa110_devices, ARRAY_SIZE(ebsa110_devices));
304 }
305
306 arch_initcall(ebsa110_init);
307
ebsa110_restart(enum reboot_mode mode,const char * cmd)308 static void ebsa110_restart(enum reboot_mode mode, const char *cmd)
309 {
310 soft_restart(0x80000000);
311 }
312
313 MACHINE_START(EBSA110, "EBSA110")
314 /* Maintainer: Russell King */
315 .atag_offset = 0x400,
316 .reserve_lp0 = 1,
317 .reserve_lp2 = 1,
318 .map_io = ebsa110_map_io,
319 .init_early = ebsa110_init_early,
320 .init_irq = ebsa110_init_irq,
321 .init_time = ebsa110_timer_init,
322 .restart = ebsa110_restart,
323 MACHINE_END
324