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		break;
134	}
135	spin_unlock(&micro->lock);
136}
137
138static void micro_process_char(struct ipaq_micro *micro, u8 ch)
139{
140	struct ipaq_micro_rxdev *rx = &micro->rx;
141
142	switch (rx->state) {
143	case STATE_SOF:	/* Looking for SOF */
144		if (ch == CHAR_SOF)
145			rx->state = STATE_ID; /* Next byte is the id and len */
146		break;
147	case STATE_ID: /* Looking for id and len byte */
148		rx->id = (ch & 0xf0) >> 4;
149		rx->len = (ch & 0x0f);
150		rx->index = 0;
151		rx->chksum = ch;
152		rx->state = (rx->len > 0) ? STATE_DATA : STATE_CHKSUM;
153		break;
154	case STATE_DATA: /* Looking for 'len' data bytes */
155		rx->chksum += ch;
156		rx->buf[rx->index] = ch;
157		if (++rx->index == rx->len)
158			rx->state = STATE_CHKSUM;
159		break;
160	case STATE_CHKSUM: /* Looking for the checksum */
161		if (ch == rx->chksum)
162			micro_rx_msg(micro, rx->id, rx->len, rx->buf);
163		rx->state = STATE_SOF;
164		break;
165	}
166}
167
168static void micro_rx_chars(struct ipaq_micro *micro)
169{
170	u32 status, ch;
171
172	while ((status = readl(micro->base + UTSR1)) & UTSR1_RNE) {
173		ch = readl(micro->base + UTDR);
174		if (status & UTSR1_PRE)
175			dev_err(micro->dev, "rx: parity error\n");
176		else if (status & UTSR1_FRE)
177			dev_err(micro->dev, "rx: framing error\n");
178		else if (status & UTSR1_ROR)
179			dev_err(micro->dev, "rx: overrun error\n");
180		micro_process_char(micro, ch);
181	}
182}
183
184static void ipaq_micro_get_version(struct ipaq_micro *micro)
185{
186	struct ipaq_micro_msg msg = {
187		.id = MSG_VERSION,
188	};
189
190	ipaq_micro_tx_msg_sync(micro, &msg);
191	if (msg.rx_len == 4) {
192		memcpy(micro->version, msg.rx_data, 4);
193		micro->version[4] = '\0';
194	} else if (msg.rx_len == 9) {
195		memcpy(micro->version, msg.rx_data, 4);
196		micro->version[4] = '\0';
197		/* Bytes 4-7 are "pack", byte 8 is "boot type" */
198	} else {
199		dev_err(micro->dev,
200			"illegal version message %d bytes\n", msg.rx_len);
201	}
202}
203
204static void ipaq_micro_eeprom_read(struct ipaq_micro *micro,
205				   u8 address, u8 len, u8 *data)
206{
207	struct ipaq_micro_msg msg = {
208		.id = MSG_EEPROM_READ,
209	};
210	u8 i;
211
212	for (i = 0; i < len; i++) {
213		msg.tx_data[0] = address + i;
214		msg.tx_data[1] = 1;
215		msg.tx_len = 2;
216		ipaq_micro_tx_msg_sync(micro, &msg);
217		memcpy(data + (i * 2), msg.rx_data, 2);
218	}
219}
220
221static char *ipaq_micro_str(u8 *wchar, u8 len)
222{
223	char retstr[256];
224	u8 i;
225
226	for (i = 0; i < len / 2; i++)
227		retstr[i] = wchar[i * 2];
228	return kstrdup(retstr, GFP_KERNEL);
229}
230
231static u16 ipaq_micro_to_u16(u8 *data)
232{
233	return data[1] << 8 | data[0];
234}
235
236static void __init ipaq_micro_eeprom_dump(struct ipaq_micro *micro)
237{
238	u8 dump[256];
239	char *str;
240
241	ipaq_micro_eeprom_read(micro, 0, 128, dump);
242	str = ipaq_micro_str(dump, 10);
243	if (str) {
244		dev_info(micro->dev, "HW version %s\n", str);
245		kfree(str);
246	}
247	str = ipaq_micro_str(dump+10, 40);
248	if (str) {
249		dev_info(micro->dev, "serial number: %s\n", str);
250		/* Feed the random pool with this */
251		add_device_randomness(str, strlen(str));
252		kfree(str);
253	}
254	str = ipaq_micro_str(dump+50, 20);
255	if (str) {
256		dev_info(micro->dev, "module ID: %s\n", str);
257		kfree(str);
258	}
259	str = ipaq_micro_str(dump+70, 10);
260	if (str) {
261		dev_info(micro->dev, "product revision: %s\n", str);
262		kfree(str);
263	}
264	dev_info(micro->dev, "product ID: %u\n", ipaq_micro_to_u16(dump+80));
265	dev_info(micro->dev, "frame rate: %u fps\n",
266		 ipaq_micro_to_u16(dump+82));
267	dev_info(micro->dev, "page mode: %u\n", ipaq_micro_to_u16(dump+84));
268	dev_info(micro->dev, "country ID: %u\n", ipaq_micro_to_u16(dump+86));
269	dev_info(micro->dev, "color display: %s\n",
270		 ipaq_micro_to_u16(dump+88) ? "yes" : "no");
271	dev_info(micro->dev, "ROM size: %u MiB\n", ipaq_micro_to_u16(dump+90));
272	dev_info(micro->dev, "RAM size: %u KiB\n", ipaq_micro_to_u16(dump+92));
273	dev_info(micro->dev, "screen: %u x %u\n",
274		 ipaq_micro_to_u16(dump+94), ipaq_micro_to_u16(dump+96));
275}
276
277static void micro_tx_chars(struct ipaq_micro *micro)
278{
279	struct ipaq_micro_txdev *tx = &micro->tx;
280	u32 val;
281
282	while ((tx->index < tx->len) &&
283	       (readl(micro->base + UTSR1) & UTSR1_TNF)) {
284		writel(tx->buf[tx->index], micro->base + UTDR);
285		tx->index++;
286	}
287
288	/* Stop interrupts */
289	val = readl(micro->base + UTCR3);
290	val &= ~UTCR3_TIE;
291	writel(val, micro->base + UTCR3);
292}
293
294static void micro_reset_comm(struct ipaq_micro *micro)
295{
296	struct ipaq_micro_rxdev *rx = &micro->rx;
297	u32 val;
298
299	if (micro->msg)
300		complete(&micro->msg->ack);
301
302	/* Initialize Serial channel protocol frame */
303	rx->state = STATE_SOF;  /* Reset the state machine */
304
305	/* Set up interrupts */
306	writel(0x01, micro->sdlc + 0x0); /* Select UART mode */
307
308	/* Clean up CR3 */
309	writel(0x0, micro->base + UTCR3);
310
311	/* Format: 8N1 */
312	writel(UTCR0_8BitData | UTCR0_1StpBit, micro->base + UTCR0);
313
314	/* Baud rate: 115200 */
315	writel(0x0, micro->base + UTCR1);
316	writel(0x1, micro->base + UTCR2);
317
318	/* Clear SR0 */
319	writel(0xff, micro->base + UTSR0);
320
321	/* Enable RX int, disable TX int */
322	writel(UTCR3_TXE | UTCR3_RXE | UTCR3_RIE, micro->base + UTCR3);
323	val = readl(micro->base + UTCR3);
324	val &= ~UTCR3_TIE;
325	writel(val, micro->base + UTCR3);
326}
327
328static irqreturn_t micro_serial_isr(int irq, void *dev_id)
329{
330	struct ipaq_micro *micro = dev_id;
331	struct ipaq_micro_txdev *tx = &micro->tx;
332	u32 status;
333
334	status = readl(micro->base + UTSR0);
335	do {
336		if (status & (UTSR0_RID | UTSR0_RFS)) {
337			if (status & UTSR0_RID)
338				/* Clear the Receiver IDLE bit */
339				writel(UTSR0_RID, micro->base + UTSR0);
340			micro_rx_chars(micro);
341		}
342
343		/* Clear break bits */
344		if (status & (UTSR0_RBB | UTSR0_REB))
345			writel(status & (UTSR0_RBB | UTSR0_REB),
346			       micro->base + UTSR0);
347
348		if (status & UTSR0_TFS)
349			micro_tx_chars(micro);
350
351		status = readl(micro->base + UTSR0);
352
353	} while (((tx->index < tx->len) && (status & UTSR0_TFS)) ||
354		 (status & (UTSR0_RFS | UTSR0_RID)));
355
356	return IRQ_HANDLED;
357}
358
359static const struct mfd_cell micro_cells[] = {
360	{ .name = "ipaq-micro-backlight", },
361	{ .name = "ipaq-micro-battery", },
362	{ .name = "ipaq-micro-keys", },
363	{ .name = "ipaq-micro-ts", },
364	{ .name = "ipaq-micro-leds", },
365};
366
367static int __maybe_unused micro_resume(struct device *dev)
368{
369	struct ipaq_micro *micro = dev_get_drvdata(dev);
370
371	micro_reset_comm(micro);
372	mdelay(10);
373
374	return 0;
375}
376
377static int __init micro_probe(struct platform_device *pdev)
378{
379	struct ipaq_micro *micro;
380	int ret;
381	int irq;
382
383	micro = devm_kzalloc(&pdev->dev, sizeof(*micro), GFP_KERNEL);
384	if (!micro)
385		return -ENOMEM;
386
387	micro->dev = &pdev->dev;
388
389	micro->base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
390	if (IS_ERR(micro->base))
391		return PTR_ERR(micro->base);
392
393	micro->sdlc = devm_platform_ioremap_resource(pdev, 1);
394	if (IS_ERR(micro->sdlc))
395		return PTR_ERR(micro->sdlc);
396
397	micro_reset_comm(micro);
398
399	irq = platform_get_irq(pdev, 0);
400	if (irq < 0)
401		return -EINVAL;
402	ret = devm_request_irq(&pdev->dev, irq, micro_serial_isr,
403			       IRQF_SHARED, "ipaq-micro",
404			       micro);
405	if (ret) {
406		dev_err(&pdev->dev, "unable to grab serial port IRQ\n");
407		return ret;
408	} else
409		dev_info(&pdev->dev, "grabbed serial port IRQ\n");
410
411	spin_lock_init(&micro->lock);
412	INIT_LIST_HEAD(&micro->queue);
413	platform_set_drvdata(pdev, micro);
414
415	ret = mfd_add_devices(&pdev->dev, pdev->id, micro_cells,
416			      ARRAY_SIZE(micro_cells), NULL, 0, NULL);
417	if (ret) {
418		dev_err(&pdev->dev, "error adding MFD cells");
419		return ret;
420	}
421
422	/* Check version */
423	ipaq_micro_get_version(micro);
424	dev_info(&pdev->dev, "Atmel micro ASIC version %s\n", micro->version);
425	ipaq_micro_eeprom_dump(micro);
426
427	return 0;
428}
429
430static const struct dev_pm_ops micro_dev_pm_ops = {
431	SET_SYSTEM_SLEEP_PM_OPS(NULL, micro_resume)
432};
433
434static struct platform_driver micro_device_driver = {
435	.driver   = {
436		.name	= "ipaq-h3xxx-micro",
437		.pm	= &micro_dev_pm_ops,
438		.suppress_bind_attrs = true,
439	},
440};
441builtin_platform_driver_probe(micro_device_driver, micro_probe);