led.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 *	Chassis LCD/LED driver for HP-PARISC workstations
  4 *
  5 *	(c) Copyright 2000 Red Hat Software
  6 *	(c) Copyright 2000 Helge Deller <hdeller@redhat.com>
  7 *	(c) Copyright 2001 Randolph Chung <tausq@debian.org>
  8 *	(c) Copyright 2000-2023 Helge Deller <deller@gmx.de>
  9 *
 10 *	The control of the LEDs and LCDs on PARISC machines has to be done
 11 *	completely in software.
 12 *
 13 *	The LEDs can be configured at runtime in /sys/class/leds/
 14 */
 15
 16#include <linux/module.h>
 17#include <linux/init.h>
 18#include <linux/types.h>
 19#include <linux/ioport.h>
 20#include <linux/utsname.h>
 21#include <linux/capability.h>
 22#include <linux/delay.h>
 23#include <linux/reboot.h>
 24#include <linux/uaccess.h>
 25#include <linux/leds.h>
 26#include <linux/platform_device.h>
 27
 28#include <asm/io.h>
 29#include <asm/processor.h>
 30#include <asm/hardware.h>
 31#include <asm/param.h>		/* HZ */
 32#include <asm/led.h>
 33#include <asm/pdc.h>
 34
 35#define LED_HAS_LCD 1
 36#define LED_HAS_LED 2
 37
 38static unsigned char led_type;		/* bitmask of LED_HAS_XXX */
 39static unsigned char lastleds;		/* LED state from most recent update */
 40static unsigned char lcd_new_text;
 41static unsigned char lcd_text[20];
 42static unsigned char lcd_no_led_support; /* KittyHawk doesn't support LED on its LCD */
 43
 44struct lcd_block {
 45	unsigned char command;	/* stores the command byte      */
 46	unsigned char on;	/* value for turning LED on     */
 47	unsigned char off;	/* value for turning LED off    */
 48};
 49
 50/* Structure returned by PDC_RETURN_CHASSIS_INFO */
 51/* NOTE: we use unsigned long:16 two times, since the following member
 52   lcd_cmd_reg_addr needs to be 64bit aligned on 64bit PA2.0-machines */
 53struct pdc_chassis_lcd_info_ret_block {
 54	unsigned long model:16;		/* DISPLAY_MODEL_XXXX */
 55	unsigned long lcd_width:16;	/* width of the LCD in chars (DISPLAY_MODEL_LCD only) */
 56	unsigned long lcd_cmd_reg_addr;	/* ptr to LCD cmd-register & data ptr for LED */
 57	unsigned long lcd_data_reg_addr; /* ptr to LCD data-register (LCD only) */
 58	unsigned int min_cmd_delay;	/* delay in uS after cmd-write (LCD only) */
 59	unsigned char reset_cmd1;	/* command #1 for writing LCD string (LCD only) */
 60	unsigned char reset_cmd2;	/* command #2 for writing LCD string (LCD only) */
 61	unsigned char act_enable;	/* 0 = no activity (LCD only) */
 62	struct lcd_block heartbeat;
 63	struct lcd_block disk_io;
 64	struct lcd_block lan_rcv;
 65	struct lcd_block lan_tx;
 66	char _pad;
 67};
 68
 69
 70/* LCD_CMD and LCD_DATA for KittyHawk machines */
 71#define KITTYHAWK_LCD_CMD  F_EXTEND(0xf0190000UL)
 72#define KITTYHAWK_LCD_DATA (KITTYHAWK_LCD_CMD + 1)
 73
 74/* lcd_info is pre-initialized to the values needed to program KittyHawk LCD's
 75 * HP seems to have used Sharp/Hitachi HD44780 LCDs most of the time. */
 76static struct pdc_chassis_lcd_info_ret_block
 77lcd_info __attribute__((aligned(8)))  =
 78{
 79	.model =		DISPLAY_MODEL_NONE,
 80	.lcd_width =		16,
 81	.lcd_cmd_reg_addr =	KITTYHAWK_LCD_CMD,
 82	.lcd_data_reg_addr =	KITTYHAWK_LCD_DATA,
 83	.min_cmd_delay =	80,
 84	.reset_cmd1 =		0x80,
 85	.reset_cmd2 =		0xc0,
 86};
 87
 88/* direct access to some of the lcd_info variables */
 89#define LCD_CMD_REG	lcd_info.lcd_cmd_reg_addr
 90#define LCD_DATA_REG	lcd_info.lcd_data_reg_addr
 91#define LED_DATA_REG	lcd_info.lcd_cmd_reg_addr	/* LASI & ASP only */
 92
 93/* ptr to LCD/LED-specific function */
 94static void (*led_func_ptr) (unsigned char);
 95
 96
 97static void lcd_print_now(void)
 98{
 99	int i;
100	char *str = lcd_text;
101
102	if (lcd_info.model != DISPLAY_MODEL_LCD)
103		return;
104
105	if (!lcd_new_text)
106		return;
107	lcd_new_text = 0;
108
109	/* Set LCD Cursor to 1st character */
110	gsc_writeb(lcd_info.reset_cmd1, LCD_CMD_REG);
111	udelay(lcd_info.min_cmd_delay);
112
113	/* Print the string */
114	for (i = 0; i < lcd_info.lcd_width; i++) {
115		gsc_writeb(*str ? *str++ : ' ', LCD_DATA_REG);
116		udelay(lcd_info.min_cmd_delay);
117	}
118}
119
120/**
121 *	lcd_print()
122 *
123 *	@str: string to show on the LCD. If NULL, print current string again.
124 *
125 *	Displays the given string on the LCD-Display of newer machines.
126 */
127void lcd_print(const char *str)
128{
129	/* copy display string to buffer for procfs */
130	if (str)
131		strscpy(lcd_text, str, sizeof(lcd_text));
132	lcd_new_text = 1;
133
134	/* print now if LCD without any LEDs */
135	if (led_type == LED_HAS_LCD)
136		lcd_print_now();
137}
138
139#define	LED_DATA	0x01	/* data to shift (0:on 1:off) */
140#define	LED_STROBE	0x02	/* strobe to clock data */
141
142/**
143 *	led_ASP_driver() - LED driver for the ASP controller chip
144 *
145 *	@leds: bitmap representing the LED status
146 */
147static void led_ASP_driver(unsigned char leds)
148{
149	int i;
150
151	leds = ~leds;
152	for (i = 0; i < 8; i++) {
153		unsigned char value;
154		value = (leds & 0x80) >> 7;
155		gsc_writeb( value,		 LED_DATA_REG );
156		gsc_writeb( value | LED_STROBE,	 LED_DATA_REG );
157		leds <<= 1;
158	}
159}
160
161/**
162 *	led_LASI_driver() - LED driver for the LASI controller chip
163 *
164 *	@leds: bitmap representing the LED status
165 */
166static void led_LASI_driver(unsigned char leds)
167{
168	leds = ~leds;
169	gsc_writeb( leds, LED_DATA_REG );
170}
171
172/**
173 *	led_LCD_driver() - LED & LCD driver for LCD chips
174 *
175 *	@leds: bitmap representing the LED status
176 */
177static void led_LCD_driver(unsigned char leds)
178{
179	static const unsigned char mask[4] = {
180		LED_HEARTBEAT, LED_DISK_IO,
181		LED_LAN_RCV, LED_LAN_TX };
182
183	static struct lcd_block * const blockp[4] = {
184		&lcd_info.heartbeat,
185		&lcd_info.disk_io,
186		&lcd_info.lan_rcv,
187		&lcd_info.lan_tx
188	};
189	static unsigned char latest_leds;
190	int i;
191
192	for (i = 0; i < 4; ++i) {
193		if ((leds & mask[i]) == (latest_leds & mask[i]))
194			continue;
195
196		gsc_writeb( blockp[i]->command, LCD_CMD_REG );
197		udelay(lcd_info.min_cmd_delay);
198
199		gsc_writeb( leds & mask[i] ? blockp[i]->on :
200				blockp[i]->off, LCD_DATA_REG );
201		udelay(lcd_info.min_cmd_delay);
202	}
203	latest_leds = leds;
204
205	lcd_print_now();
206}
207
208
209/**
210 *	lcd_system_halt()
211 *
212 *	@nb: pointer to the notifier_block structure
213 *	@event: the event (SYS_RESTART, SYS_HALT or SYS_POWER_OFF)
214 *	@buf: pointer to a buffer (not used)
215 *
216 *	Called by the reboot notifier chain at shutdown. Stops all
217 *	LED/LCD activities.
218 */
219static int lcd_system_halt(struct notifier_block *nb, unsigned long event, void *buf)
220{
221	const char *txt;
222
223	switch (event) {
224	case SYS_RESTART:	txt = "SYSTEM RESTART";
225				break;
226	case SYS_HALT:		txt = "SYSTEM HALT";
227				break;
228	case SYS_POWER_OFF:	txt = "SYSTEM POWER OFF";
229				break;
230	default:		return NOTIFY_DONE;
231	}
232
233	lcd_print(txt);
234
235	return NOTIFY_OK;
236}
237
238static struct notifier_block lcd_system_halt_notifier = {
239	.notifier_call = lcd_system_halt,
240};
241
242static void set_led(struct led_classdev *led_cdev, enum led_brightness brightness);
243
244struct hppa_led {
245	struct led_classdev	led_cdev;
246	unsigned char		led_bit;
247};
248#define to_hppa_led(d) container_of(d, struct hppa_led, led_cdev)
249
250typedef void (*set_handler)(struct led_classdev *, enum led_brightness);
251struct led_type {
252	const char	*name;
253	set_handler	handler;
254	const char	*default_trigger;
255};
256
257#define NUM_LEDS_PER_BOARD	8
258struct hppa_drvdata {
259	struct hppa_led	leds[NUM_LEDS_PER_BOARD];
260};
261
262static void set_led(struct led_classdev *led_cdev, enum led_brightness brightness)
263{
264	struct hppa_led *p = to_hppa_led(led_cdev);
265	unsigned char led_bit = p->led_bit;
266
267	if (brightness == LED_OFF)
268		lastleds &= ~led_bit;
269	else
270		lastleds |= led_bit;
271
272	if (led_func_ptr)
273		led_func_ptr(lastleds);
274}
275
276
277static int hppa_led_generic_probe(struct platform_device *pdev,
278				  struct led_type *types)
279{
280	struct hppa_drvdata *p;
281	int i, err;
282
283	p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);
284	if (!p)
285		return -ENOMEM;
286
287	for (i = 0; i < NUM_LEDS_PER_BOARD; i++) {
288		struct led_classdev *lp = &p->leds[i].led_cdev;
289
290		p->leds[i].led_bit = BIT(i);
291		lp->name = types[i].name;
292		lp->brightness = LED_FULL;
293		lp->brightness_set = types[i].handler;
294		lp->default_trigger = types[i].default_trigger;
295		err = led_classdev_register(&pdev->dev, lp);
296		if (err) {
297			dev_err(&pdev->dev, "Could not register %s LED\n",
298			       lp->name);
299			for (i--; i >= 0; i--)
300				led_classdev_unregister(&p->leds[i].led_cdev);
301			return err;
302		}
303	}
304
305	platform_set_drvdata(pdev, p);
306
307	return 0;
308}
309
310static void platform_led_remove(struct platform_device *pdev)
311{
312	struct hppa_drvdata *p = platform_get_drvdata(pdev);
313	int i;
314
315	for (i = 0; i < NUM_LEDS_PER_BOARD; i++)
316		led_classdev_unregister(&p->leds[i].led_cdev);
317}
318
319static struct led_type mainboard_led_types[NUM_LEDS_PER_BOARD] = {
320	{
321		.name		= "platform-lan-tx",
322		.handler	= set_led,
323		.default_trigger = "tx",
324	},
325	{
326		.name		= "platform-lan-rx",
327		.handler	= set_led,
328		.default_trigger = "rx",
329	},
330	{
331		.name		= "platform-disk",
332		.handler	= set_led,
333		.default_trigger = "disk-activity",
334	},
335	{
336		.name		= "platform-heartbeat",
337		.handler	= set_led,
338		.default_trigger = "heartbeat",
339	},
340	{
341		.name		= "platform-LED4",
342		.handler	= set_led,
343		.default_trigger = "panic",
344	},
345	{
346		.name		= "platform-LED5",
347		.handler	= set_led,
348		.default_trigger = "panic",
349	},
350	{
351		.name		= "platform-LED6",
352		.handler	= set_led,
353		.default_trigger = "panic",
354	},
355	{
356		.name		= "platform-LED7",
357		.handler	= set_led,
358		.default_trigger = "panic",
359	},
360};
361
362static int platform_led_probe(struct platform_device *pdev)
363{
364	return hppa_led_generic_probe(pdev, mainboard_led_types);
365}
366
367MODULE_ALIAS("platform:platform-leds");
368
369static struct platform_driver hppa_mainboard_led_driver = {
370	.probe		= platform_led_probe,
371	.remove		= platform_led_remove,
372	.driver		= {
373		.name	= "platform-leds",
374	},
375};
376
377static struct platform_driver * const drivers[] = {
378	&hppa_mainboard_led_driver,
379};
380
381static struct platform_device platform_leds = {
382	.name = "platform-leds",
383};
384
385/**
386 *	register_led_driver()
387 *
388 *	@model: model type, one of the DISPLAY_MODEL_XXXX values
389 *	@cmd_reg: physical address of cmd register for the LED/LCD
390 *	@data_reg: physical address of data register for the LED/LCD
391 *
392 *	Registers a chassis LED or LCD which should be driven by this driver.
393 *	Only PDC-based, LASI- or ASP-style LEDs and LCDs are supported.
394 */
395int __init register_led_driver(int model, unsigned long cmd_reg, unsigned long data_reg)
396{
397	if (led_func_ptr || !data_reg)
398		return 1;
399
400	/* No LEDs when running in QEMU */
401	if (running_on_qemu)
402		return 1;
403
404	lcd_info.model = model;		/* store the values */
405	LCD_CMD_REG = (cmd_reg == LED_CMD_REG_NONE) ? 0 : cmd_reg;
406
407	switch (lcd_info.model) {
408	case DISPLAY_MODEL_LCD:
409		LCD_DATA_REG = data_reg;
410		pr_info("led: LCD display at %#lx and %#lx\n",
411			LCD_CMD_REG , LCD_DATA_REG);
412		led_func_ptr = led_LCD_driver;
413		if (lcd_no_led_support)
414			led_type = LED_HAS_LCD;
415		else
416			led_type = LED_HAS_LCD | LED_HAS_LED;
417		break;
418
419	case DISPLAY_MODEL_LASI:
420		LED_DATA_REG = data_reg;
421		led_func_ptr = led_LASI_driver;
422		pr_info("led: LED display at %#lx\n", LED_DATA_REG);
423		led_type = LED_HAS_LED;
424		break;
425
426	case DISPLAY_MODEL_OLD_ASP:
427		LED_DATA_REG = data_reg;
428		led_func_ptr = led_ASP_driver;
429		pr_info("led: LED (ASP-style) display at %#lx\n",
430		    LED_DATA_REG);
431		led_type = LED_HAS_LED;
432		break;
433
434	default:
435		pr_err("led: Unknown LCD/LED model type %d\n", lcd_info.model);
436		return 1;
437	}
438
439	platform_register_drivers(drivers, ARRAY_SIZE(drivers));
440
441	return register_reboot_notifier(&lcd_system_halt_notifier);
442}
443
444/**
445 *	early_led_init()
446 *
447 *	early_led_init() is called early in the bootup-process and asks the
448 *	PDC for an usable chassis LCD or LED. If the PDC doesn't return any
449 *	info, then a LED might be detected by the LASI or ASP drivers later.
450 *	KittyHawk machines have often a buggy PDC, so that we explicitly check
451 *	for those machines here.
452 */
453static int __init early_led_init(void)
454{
455	struct pdc_chassis_info chassis_info;
456	int ret;
457
458	scnprintf(lcd_text, sizeof(lcd_text),
459		"Linux %s", init_utsname()->release);
460	lcd_new_text = 1;
461
462	/* Work around the buggy PDC of KittyHawk-machines */
463	switch (CPU_HVERSION) {
464	case 0x580:		/* KittyHawk DC2-100 (K100) */
465	case 0x581:		/* KittyHawk DC3-120 (K210) */
466	case 0x582:		/* KittyHawk DC3 100 (K400) */
467	case 0x583:		/* KittyHawk DC3 120 (K410) */
468	case 0x58B:		/* KittyHawk DC2 100 (K200) */
469		pr_info("LCD on KittyHawk-Machine found.\n");
470		lcd_info.model = DISPLAY_MODEL_LCD;
471		/* KittyHawk has no LED support on its LCD, so skip LED detection */
472		lcd_no_led_support = 1;
473		goto found;	/* use the preinitialized values of lcd_info */
474	}
475
476	/* initialize the struct, so that we can check for valid return values */
477	chassis_info.actcnt = chassis_info.maxcnt = 0;
478
479	ret = pdc_chassis_info(&chassis_info, &lcd_info, sizeof(lcd_info));
480	if (ret != PDC_OK) {
481not_found:
482		lcd_info.model = DISPLAY_MODEL_NONE;
483		return 1;
484	}
485
486	/* check the results. Some machines have a buggy PDC */
487	if (chassis_info.actcnt <= 0 || chassis_info.actcnt != chassis_info.maxcnt)
488		goto not_found;
489
490	switch (lcd_info.model) {
491	case DISPLAY_MODEL_LCD:		/* LCD display */
492		if (chassis_info.actcnt <
493			offsetof(struct pdc_chassis_lcd_info_ret_block, _pad)-1)
494			goto not_found;
495		if (!lcd_info.act_enable) {
496			/* PDC tells LCD should not be used. */
497			goto not_found;
498		}
499		break;
500
501	case DISPLAY_MODEL_NONE:	/* no LED or LCD available */
502		goto not_found;
503
504	case DISPLAY_MODEL_LASI:	/* Lasi style 8 bit LED display */
505		if (chassis_info.actcnt != 8 && chassis_info.actcnt != 32)
506			goto not_found;
507		break;
508
509	default:
510		pr_warn("PDC reported unknown LCD/LED model %d\n",
511		       lcd_info.model);
512		goto not_found;
513	}
514
515found:
516	/* register the LCD/LED driver */
517	return register_led_driver(lcd_info.model, LCD_CMD_REG, LCD_DATA_REG);
518}
519arch_initcall(early_led_init);
520
521/**
522 *	register_led_regions()
523 *
524 *	Register_led_regions() registers the LCD/LED regions for /procfs.
525 *	At bootup - where the initialisation of the LCD/LED often happens
526 *	not all internal structures of request_region() are properly set up,
527 *	so that we delay the led-registration until after busdevices_init()
528 *	has been executed.
529 */
530static void __init register_led_regions(void)
531{
532	switch (lcd_info.model) {
533	case DISPLAY_MODEL_LCD:
534		request_mem_region((unsigned long)LCD_CMD_REG,  1, "lcd_cmd");
535		request_mem_region((unsigned long)LCD_DATA_REG, 1, "lcd_data");
536		break;
537	case DISPLAY_MODEL_LASI:
538	case DISPLAY_MODEL_OLD_ASP:
539		request_mem_region((unsigned long)LED_DATA_REG, 1, "led_data");
540		break;
541	}
542}
543
544static int __init startup_leds(void)
545{
546	if (platform_device_register(&platform_leds))
547                printk(KERN_INFO "LED: failed to register LEDs\n");
548	register_led_regions();
549	return 0;
550}
551device_initcall(startup_leds);