1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Compaq iPAQ h3xxx Atmel microcontroller companion support
4 *
5 * This is an Atmel AT90LS8535 with a special flashed-in firmware that
6 * implements the special protocol used by this driver.
7 *
8 * based on previous kernel 2.4 version by Andrew Christian
9 * Author : Alessandro Gardich <gremlin@gremlin.it>
10 * Author : Dmitry Artamonow <mad_soft@inbox.ru>
11 * Author : Linus Walleij <linus.walleij@linaro.org>
12 */
13
14#include <linux/module.h>
15#include <linux/init.h>
16#include <linux/interrupt.h>
17#include <linux/pm.h>
18#include <linux/delay.h>
19#include <linux/device.h>
20#include <linux/platform_device.h>
21#include <linux/io.h>
22#include <linux/mfd/core.h>
23#include <linux/mfd/ipaq-micro.h>
24#include <linux/string.h>
25#include <linux/random.h>
26#include <linux/slab.h>
27#include <linux/list.h>
28
29#include <mach/hardware.h>
30
31static void ipaq_micro_trigger_tx(struct ipaq_micro *micro)
32{
33	struct ipaq_micro_txdev *tx = &micro->tx;
34	struct ipaq_micro_msg *msg = micro->msg;
35	int i, bp;
36	u8 checksum;
37	u32 val;
38
39	bp = 0;
40	tx->buf[bp++] = CHAR_SOF;
41
42	checksum = ((msg->id & 0x0f) << 4) | (msg->tx_len & 0x0f);
43	tx->buf[bp++] = checksum;
44
45	for (i = 0; i < msg->tx_len; i++) {
46		tx->buf[bp++] = msg->tx_data[i];
47		checksum += msg->tx_data[i];
48	}
49
50	tx->buf[bp++] = checksum;
51	tx->len = bp;
52	tx->index = 0;
53
54	/* Enable interrupt */
55	val = readl(micro->base + UTCR3);
56	val |= UTCR3_TIE;
57	writel(val, micro->base + UTCR3);
58}
59
60int ipaq_micro_tx_msg(struct ipaq_micro *micro, struct ipaq_micro_msg *msg)
61{
62	unsigned long flags;
63
64	dev_dbg(micro->dev, "TX msg: %02x, %d bytes\n", msg->id, msg->tx_len);
65
66	spin_lock_irqsave(&micro->lock, flags);
67	if (micro->msg) {
68		list_add_tail(&msg->node, &micro->queue);
69		spin_unlock_irqrestore(&micro->lock, flags);
70		return 0;
71	}
72	micro->msg = msg;
73	ipaq_micro_trigger_tx(micro);
74	spin_unlock_irqrestore(&micro->lock, flags);
75	return 0;
76}
77EXPORT_SYMBOL(ipaq_micro_tx_msg);
78
79static void micro_rx_msg(struct ipaq_micro *micro, u8 id, int len, u8 *data)
80{
81	dev_dbg(micro->dev, "RX msg: %02x, %d bytes\n", id, len);
82
83	spin_lock(&micro->lock);
84	switch (id) {
85	case MSG_VERSION:
86	case MSG_EEPROM_READ:
87	case MSG_EEPROM_WRITE:
88	case MSG_BACKLIGHT:
89	case MSG_NOTIFY_LED:
90	case MSG_THERMAL_SENSOR:
91	case MSG_BATTERY:
92		/* Handle synchronous messages */
93		if (micro->msg && micro->msg->id == id) {
94			struct ipaq_micro_msg *msg = micro->msg;
95
96			memcpy(msg->rx_data, data, len);
97			msg->rx_len = len;
98			complete(&micro->msg->ack);
99			if (!list_empty(&micro->queue)) {
100				micro->msg = list_entry(micro->queue.next,
101							struct ipaq_micro_msg,
102							node);
103				list_del_init(&micro->msg->node);
104				ipaq_micro_trigger_tx(micro);
105			} else
106				micro->msg = NULL;
107			dev_dbg(micro->dev, "OK RX message 0x%02x\n", id);
108		} else {
109			dev_err(micro->dev,
110				"out of band RX message 0x%02x\n", id);
111			if (!micro->msg)
112				dev_info(micro->dev, "no message queued\n");
113			else
114				dev_info(micro->dev, "expected message %02x\n",
115					 micro->msg->id);
116		}
117		break;
118	case MSG_KEYBOARD:
119		if (micro->key)
120			micro->key(micro->key_data, len, data);
121		else
122			dev_dbg(micro->dev, "key message ignored, no handle\n");
123		break;
124	case MSG_TOUCHSCREEN:
125		if (micro->ts)
126			micro->ts(micro->ts_data, len, data);
127		else
128			dev_dbg(micro->dev, "touchscreen message ignored, no handle\n");
129		break;
130	default:
131		dev_err(micro->dev,
132			"unknown msg %d [%d] %*ph\n", id, len, len, data);
133	}
134	spin_unlock(&micro->lock);
135}
136
137static void micro_process_char(struct ipaq_micro *micro, u8 ch)
138{
139	struct ipaq_micro_rxdev *rx = &micro->rx;
140
141	switch (rx->state) {
142	case STATE_SOF:	/* Looking for SOF */
143		if (ch == CHAR_SOF)
144			rx->state = STATE_ID; /* Next byte is the id and len */
145		break;
146	case STATE_ID: /* Looking for id and len byte */
147		rx->id = (ch & 0xf0) >> 4;
148		rx->len = (ch & 0x0f);
149		rx->index = 0;
150		rx->chksum = ch;
151		rx->state = (rx->len > 0) ? STATE_DATA : STATE_CHKSUM;
152		break;
153	case STATE_DATA: /* Looking for 'len' data bytes */
154		rx->chksum += ch;
155		rx->buf[rx->index] = ch;
156		if (++rx->index == rx->len)
157			rx->state = STATE_CHKSUM;
158		break;
159	case STATE_CHKSUM: /* Looking for the checksum */
160		if (ch == rx->chksum)
161			micro_rx_msg(micro, rx->id, rx->len, rx->buf);
162		rx->state = STATE_SOF;
163		break;
164	}
165}
166
167static void micro_rx_chars(struct ipaq_micro *micro)
168{
169	u32 status, ch;
170
171	while ((status = readl(micro->base + UTSR1)) & UTSR1_RNE) {
172		ch = readl(micro->base + UTDR);
173		if (status & UTSR1_PRE)
174			dev_err(micro->dev, "rx: parity error\n");
175		else if (status & UTSR1_FRE)
176			dev_err(micro->dev, "rx: framing error\n");
177		else if (status & UTSR1_ROR)
178			dev_err(micro->dev, "rx: overrun error\n");
179		micro_process_char(micro, ch);
180	}
181}
182
183static void ipaq_micro_get_version(struct ipaq_micro *micro)
184{
185	struct ipaq_micro_msg msg = {
186		.id = MSG_VERSION,
187	};
188
189	ipaq_micro_tx_msg_sync(micro, &msg);
190	if (msg.rx_len == 4) {
191		memcpy(micro->version, msg.rx_data, 4);
192		micro->version[4] = '\0';
193	} else if (msg.rx_len == 9) {
194		memcpy(micro->version, msg.rx_data, 4);
195		micro->version[4] = '\0';
196		/* Bytes 4-7 are "pack", byte 8 is "boot type" */
197	} else {
198		dev_err(micro->dev,
199			"illegal version message %d bytes\n", msg.rx_len);
200	}
201}
202
203static void ipaq_micro_eeprom_read(struct ipaq_micro *micro,
204				   u8 address, u8 len, u8 *data)
205{
206	struct ipaq_micro_msg msg = {
207		.id = MSG_EEPROM_READ,
208	};
209	u8 i;
210
211	for (i = 0; i < len; i++) {
212		msg.tx_data[0] = address + i;
213		msg.tx_data[1] = 1;
214		msg.tx_len = 2;
215		ipaq_micro_tx_msg_sync(micro, &msg);
216		memcpy(data + (i * 2), msg.rx_data, 2);
217	}
218}
219
220static char *ipaq_micro_str(u8 *wchar, u8 len)
221{
222	char retstr[256];
223	u8 i;
224
225	for (i = 0; i < len / 2; i++)
226		retstr[i] = wchar[i * 2];
227	return kstrdup(retstr, GFP_KERNEL);
228}
229
230static u16 ipaq_micro_to_u16(u8 *data)
231{
232	return data[1] << 8 | data[0];
233}
234
235static void __init ipaq_micro_eeprom_dump(struct ipaq_micro *micro)
236{
237	u8 dump[256];
238	char *str;
239
240	ipaq_micro_eeprom_read(micro, 0, 128, dump);
241	str = ipaq_micro_str(dump, 10);
242	if (str) {
243		dev_info(micro->dev, "HW version %s\n", str);
244		kfree(str);
245	}
246	str = ipaq_micro_str(dump+10, 40);
247	if (str) {
248		dev_info(micro->dev, "serial number: %s\n", str);
249		/* Feed the random pool with this */
250		add_device_randomness(str, strlen(str));
251		kfree(str);
252	}
253	str = ipaq_micro_str(dump+50, 20);
254	if (str) {
255		dev_info(micro->dev, "module ID: %s\n", str);
256		kfree(str);
257	}
258	str = ipaq_micro_str(dump+70, 10);
259	if (str) {
260		dev_info(micro->dev, "product revision: %s\n", str);
261		kfree(str);
262	}
263	dev_info(micro->dev, "product ID: %u\n", ipaq_micro_to_u16(dump+80));
264	dev_info(micro->dev, "frame rate: %u fps\n",
265		 ipaq_micro_to_u16(dump+82));
266	dev_info(micro->dev, "page mode: %u\n", ipaq_micro_to_u16(dump+84));
267	dev_info(micro->dev, "country ID: %u\n", ipaq_micro_to_u16(dump+86));
268	dev_info(micro->dev, "color display: %s\n",
269		 ipaq_micro_to_u16(dump+88) ? "yes" : "no");
270	dev_info(micro->dev, "ROM size: %u MiB\n", ipaq_micro_to_u16(dump+90));
271	dev_info(micro->dev, "RAM size: %u KiB\n", ipaq_micro_to_u16(dump+92));
272	dev_info(micro->dev, "screen: %u x %u\n",
273		 ipaq_micro_to_u16(dump+94), ipaq_micro_to_u16(dump+96));
274}
275
276static void micro_tx_chars(struct ipaq_micro *micro)
277{
278	struct ipaq_micro_txdev *tx = &micro->tx;
279	u32 val;
280
281	while ((tx->index < tx->len) &&
282	       (readl(micro->base + UTSR1) & UTSR1_TNF)) {
283		writel(tx->buf[tx->index], micro->base + UTDR);
284		tx->index++;
285	}
286
287	/* Stop interrupts */
288	val = readl(micro->base + UTCR3);
289	val &= ~UTCR3_TIE;
290	writel(val, micro->base + UTCR3);
291}
292
293static void micro_reset_comm(struct ipaq_micro *micro)
294{
295	struct ipaq_micro_rxdev *rx = &micro->rx;
296	u32 val;
297
298	if (micro->msg)
299		complete(&micro->msg->ack);
300
301	/* Initialize Serial channel protocol frame */
302	rx->state = STATE_SOF;  /* Reset the state machine */
303
304	/* Set up interrupts */
305	writel(0x01, micro->sdlc + 0x0); /* Select UART mode */
306
307	/* Clean up CR3 */
308	writel(0x0, micro->base + UTCR3);
309
310	/* Format: 8N1 */
311	writel(UTCR0_8BitData | UTCR0_1StpBit, micro->base + UTCR0);
312
313	/* Baud rate: 115200 */
314	writel(0x0, micro->base + UTCR1);
315	writel(0x1, micro->base + UTCR2);
316
317	/* Clear SR0 */
318	writel(0xff, micro->base + UTSR0);
319
320	/* Enable RX int, disable TX int */
321	writel(UTCR3_TXE | UTCR3_RXE | UTCR3_RIE, micro->base + UTCR3);
322	val = readl(micro->base + UTCR3);
323	val &= ~UTCR3_TIE;
324	writel(val, micro->base + UTCR3);
325}
326
327static irqreturn_t micro_serial_isr(int irq, void *dev_id)
328{
329	struct ipaq_micro *micro = dev_id;
330	struct ipaq_micro_txdev *tx = &micro->tx;
331	u32 status;
332
333	status = readl(micro->base + UTSR0);
334	do {
335		if (status & (UTSR0_RID | UTSR0_RFS)) {
336			if (status & UTSR0_RID)
337				/* Clear the Receiver IDLE bit */
338				writel(UTSR0_RID, micro->base + UTSR0);
339			micro_rx_chars(micro);
340		}
341
342		/* Clear break bits */
343		if (status & (UTSR0_RBB | UTSR0_REB))
344			writel(status & (UTSR0_RBB | UTSR0_REB),
345			       micro->base + UTSR0);
346
347		if (status & UTSR0_TFS)
348			micro_tx_chars(micro);
349
350		status = readl(micro->base + UTSR0);
351
352	} while (((tx->index < tx->len) && (status & UTSR0_TFS)) ||
353		 (status & (UTSR0_RFS | UTSR0_RID)));
354
355	return IRQ_HANDLED;
356}
357
358static const struct mfd_cell micro_cells[] = {
359	{ .name = "ipaq-micro-backlight", },
360	{ .name = "ipaq-micro-battery", },
361	{ .name = "ipaq-micro-keys", },
362	{ .name = "ipaq-micro-ts", },
363	{ .name = "ipaq-micro-leds", },
364};
365
366static int __maybe_unused micro_resume(struct device *dev)
367{
368	struct ipaq_micro *micro = dev_get_drvdata(dev);
369
370	micro_reset_comm(micro);
371	mdelay(10);
372
373	return 0;
374}
375
376static int __init micro_probe(struct platform_device *pdev)
377{
378	struct ipaq_micro *micro;
379	int ret;
380	int irq;
381
382	micro = devm_kzalloc(&pdev->dev, sizeof(*micro), GFP_KERNEL);
383	if (!micro)
384		return -ENOMEM;
385
386	micro->dev = &pdev->dev;
387
388	micro->base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
389	if (IS_ERR(micro->base))
390		return PTR_ERR(micro->base);
391
392	micro->sdlc = devm_platform_ioremap_resource(pdev, 1);
393	if (IS_ERR(micro->sdlc))
394		return PTR_ERR(micro->sdlc);
395
396	micro_reset_comm(micro);
397
398	irq = platform_get_irq(pdev, 0);
399	if (irq < 0)
400		return -EINVAL;
401	ret = devm_request_irq(&pdev->dev, irq, micro_serial_isr,
402			       IRQF_SHARED, "ipaq-micro",
403			       micro);
404	if (ret) {
405		dev_err(&pdev->dev, "unable to grab serial port IRQ\n");
406		return ret;
407	} else
408		dev_info(&pdev->dev, "grabbed serial port IRQ\n");
409
410	spin_lock_init(&micro->lock);
411	INIT_LIST_HEAD(&micro->queue);
412	platform_set_drvdata(pdev, micro);
413
414	ret = mfd_add_devices(&pdev->dev, pdev->id, micro_cells,
415			      ARRAY_SIZE(micro_cells), NULL, 0, NULL);
416	if (ret) {
417		dev_err(&pdev->dev, "error adding MFD cells");
418		return ret;
419	}
420
421	/* Check version */
422	ipaq_micro_get_version(micro);
423	dev_info(&pdev->dev, "Atmel micro ASIC version %s\n", micro->version);
424	ipaq_micro_eeprom_dump(micro);
425
426	return 0;
427}
428
429static const struct dev_pm_ops micro_dev_pm_ops = {
430	SET_SYSTEM_SLEEP_PM_OPS(NULL, micro_resume)
431};
432
433static struct platform_driver micro_device_driver = {
434	.driver   = {
435		.name	= "ipaq-h3xxx-micro",
436		.pm	= &micro_dev_pm_ops,
437		.suppress_bind_attrs = true,
438	},
439};
440builtin_platform_driver_probe(micro_device_driver, micro_probe);
441