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_text_default[20];
43static unsigned char lcd_no_led_support; /* KittyHawk doesn't support LED on its LCD */
44
45struct lcd_block {
46 unsigned char command; /* stores the command byte */
47 unsigned char on; /* value for turning LED on */
48 unsigned char off; /* value for turning LED off */
49};
50
51/* Structure returned by PDC_RETURN_CHASSIS_INFO */
52/* NOTE: we use unsigned long:16 two times, since the following member
53 lcd_cmd_reg_addr needs to be 64bit aligned on 64bit PA2.0-machines */
54struct pdc_chassis_lcd_info_ret_block {
55 unsigned long model:16; /* DISPLAY_MODEL_XXXX */
56 unsigned long lcd_width:16; /* width of the LCD in chars (DISPLAY_MODEL_LCD only) */
57 unsigned long lcd_cmd_reg_addr; /* ptr to LCD cmd-register & data ptr for LED */
58 unsigned long lcd_data_reg_addr; /* ptr to LCD data-register (LCD only) */
59 unsigned int min_cmd_delay; /* delay in uS after cmd-write (LCD only) */
60 unsigned char reset_cmd1; /* command #1 for writing LCD string (LCD only) */
61 unsigned char reset_cmd2; /* command #2 for writing LCD string (LCD only) */
62 unsigned char act_enable; /* 0 = no activity (LCD only) */
63 struct lcd_block heartbeat;
64 struct lcd_block disk_io;
65 struct lcd_block lan_rcv;
66 struct lcd_block lan_tx;
67 char _pad;
68};
69
70
71/* LCD_CMD and LCD_DATA for KittyHawk machines */
72#define KITTYHAWK_LCD_CMD F_EXTEND(0xf0190000UL)
73#define KITTYHAWK_LCD_DATA (KITTYHAWK_LCD_CMD + 1)
74
75/* lcd_info is pre-initialized to the values needed to program KittyHawk LCD's
76 * HP seems to have used Sharp/Hitachi HD44780 LCDs most of the time. */
77static struct pdc_chassis_lcd_info_ret_block
78lcd_info __attribute__((aligned(8))) =
79{
80 .model = DISPLAY_MODEL_NONE,
81 .lcd_width = 16,
82 .lcd_cmd_reg_addr = KITTYHAWK_LCD_CMD,
83 .lcd_data_reg_addr = KITTYHAWK_LCD_DATA,
84 .min_cmd_delay = 80,
85 .reset_cmd1 = 0x80,
86 .reset_cmd2 = 0xc0,
87};
88
89/* direct access to some of the lcd_info variables */
90#define LCD_CMD_REG lcd_info.lcd_cmd_reg_addr
91#define LCD_DATA_REG lcd_info.lcd_data_reg_addr
92#define LED_DATA_REG lcd_info.lcd_cmd_reg_addr /* LASI & ASP only */
93
94/* ptr to LCD/LED-specific function */
95static void (*led_func_ptr) (unsigned char);
96
97
98static void lcd_print_now(void)
99{
100 int i;
101 char *str = lcd_text;
102
103 if (lcd_info.model != DISPLAY_MODEL_LCD)
104 return;
105
106 if (!lcd_new_text)
107 return;
108 lcd_new_text = 0;
109
110 /* Set LCD Cursor to 1st character */
111 gsc_writeb(lcd_info.reset_cmd1, LCD_CMD_REG);
112 udelay(lcd_info.min_cmd_delay);
113
114 /* Print the string */
115 for (i = 0; i < lcd_info.lcd_width; i++) {
116 gsc_writeb(*str ? *str++ : ' ', LCD_DATA_REG);
117 udelay(lcd_info.min_cmd_delay);
118 }
119}
120
121/**
122 * lcd_print()
123 *
124 * @str: string to show on the LCD. If NULL, print current string again.
125 *
126 * Displays the given string on the LCD-Display of newer machines.
127 */
128void lcd_print(const char *str)
129{
130 /* copy display string to buffer for procfs */
131 if (str)
132 strscpy(lcd_text, str, sizeof(lcd_text));
133 lcd_new_text = 1;
134
135 /* print now if LCD without any LEDs */
136 if (led_type == LED_HAS_LCD)
137 lcd_print_now();
138}
139
140#define LED_DATA 0x01 /* data to shift (0:on 1:off) */
141#define LED_STROBE 0x02 /* strobe to clock data */
142
143/**
144 * led_ASP_driver() - LED driver for the ASP controller chip
145 *
146 * @leds: bitmap representing the LED status
147 */
148static void led_ASP_driver(unsigned char leds)
149{
150 int i;
151
152 leds = ~leds;
153 for (i = 0; i < 8; i++) {
154 unsigned char value;
155 value = (leds & 0x80) >> 7;
156 gsc_writeb( value, LED_DATA_REG );
157 gsc_writeb( value | LED_STROBE, LED_DATA_REG );
158 leds <<= 1;
159 }
160}
161
162/**
163 * led_LASI_driver() - LED driver for the LASI controller chip
164 *
165 * @leds: bitmap representing the LED status
166 */
167static void led_LASI_driver(unsigned char leds)
168{
169 leds = ~leds;
170 gsc_writeb( leds, LED_DATA_REG );
171}
172
173/**
174 * led_LCD_driver() - LED & LCD driver for LCD chips
175 *
176 * @leds: bitmap representing the LED status
177 */
178static void led_LCD_driver(unsigned char leds)
179{
180 static const unsigned char mask[4] = {
181 LED_HEARTBEAT, LED_DISK_IO,
182 LED_LAN_RCV, LED_LAN_TX };
183
184 static struct lcd_block * const blockp[4] = {
185 &lcd_info.heartbeat,
186 &lcd_info.disk_io,
187 &lcd_info.lan_rcv,
188 &lcd_info.lan_tx
189 };
190 static unsigned char latest_leds;
191 int i;
192
193 for (i = 0; i < 4; ++i) {
194 if ((leds & mask[i]) == (latest_leds & mask[i]))
195 continue;
196
197 gsc_writeb( blockp[i]->command, LCD_CMD_REG );
198 udelay(lcd_info.min_cmd_delay);
199
200 gsc_writeb( leds & mask[i] ? blockp[i]->on :
201 blockp[i]->off, LCD_DATA_REG );
202 udelay(lcd_info.min_cmd_delay);
203 }
204 latest_leds = leds;
205
206 lcd_print_now();
207}
208
209
210/**
211 * lcd_system_halt()
212 *
213 * @nb: pointer to the notifier_block structure
214 * @event: the event (SYS_RESTART, SYS_HALT or SYS_POWER_OFF)
215 * @buf: pointer to a buffer (not used)
216 *
217 * Called by the reboot notifier chain at shutdown. Stops all
218 * LED/LCD activities.
219 */
220static int lcd_system_halt(struct notifier_block *nb, unsigned long event, void *buf)
221{
222 const char *txt;
223
224 switch (event) {
225 case SYS_RESTART: txt = "SYSTEM RESTART";
226 break;
227 case SYS_HALT: txt = "SYSTEM HALT";
228 break;
229 case SYS_POWER_OFF: txt = "SYSTEM POWER OFF";
230 break;
231 default: return NOTIFY_DONE;
232 }
233
234 lcd_print(str: txt);
235
236 return NOTIFY_OK;
237}
238
239static struct notifier_block lcd_system_halt_notifier = {
240 .notifier_call = lcd_system_halt,
241};
242
243static void set_led(struct led_classdev *led_cdev, enum led_brightness brightness);
244
245struct hppa_led {
246 struct led_classdev led_cdev;
247 unsigned char led_bit;
248};
249#define to_hppa_led(d) container_of(d, struct hppa_led, led_cdev)
250
251typedef void (*set_handler)(struct led_classdev *, enum led_brightness);
252struct led_type {
253 const char *name;
254 set_handler handler;
255 const char *default_trigger;
256};
257
258#define NUM_LEDS_PER_BOARD 8
259struct hppa_drvdata {
260 struct hppa_led leds[NUM_LEDS_PER_BOARD];
261};
262
263static void set_led(struct led_classdev *led_cdev, enum led_brightness brightness)
264{
265 struct hppa_led *p = to_hppa_led(led_cdev);
266 unsigned char led_bit = p->led_bit;
267
268 if (brightness == LED_OFF)
269 lastleds &= ~led_bit;
270 else
271 lastleds |= led_bit;
272
273 if (led_func_ptr)
274 led_func_ptr(lastleds);
275}
276
277
278static int hppa_led_generic_probe(struct platform_device *pdev,
279 struct led_type *types)
280{
281 struct hppa_drvdata *p;
282 int i, err;
283
284 p = devm_kzalloc(dev: &pdev->dev, size: sizeof(*p), GFP_KERNEL);
285 if (!p)
286 return -ENOMEM;
287
288 for (i = 0; i < NUM_LEDS_PER_BOARD; i++) {
289 struct led_classdev *lp = &p->leds[i].led_cdev;
290
291 p->leds[i].led_bit = BIT(i);
292 lp->name = types[i].name;
293 lp->brightness = LED_FULL;
294 lp->brightness_set = types[i].handler;
295 lp->default_trigger = types[i].default_trigger;
296 err = led_classdev_register(parent: &pdev->dev, led_cdev: lp);
297 if (err) {
298 dev_err(&pdev->dev, "Could not register %s LED\n",
299 lp->name);
300 for (i--; i >= 0; i--)
301 led_classdev_unregister(led_cdev: &p->leds[i].led_cdev);
302 return err;
303 }
304 }
305
306 platform_set_drvdata(pdev, data: p);
307
308 return 0;
309}
310
311static void platform_led_remove(struct platform_device *pdev)
312{
313 struct hppa_drvdata *p = platform_get_drvdata(pdev);
314 int i;
315
316 for (i = 0; i < NUM_LEDS_PER_BOARD; i++)
317 led_classdev_unregister(led_cdev: &p->leds[i].led_cdev);
318}
319
320static struct led_type mainboard_led_types[NUM_LEDS_PER_BOARD] = {
321 {
322 .name = "platform-lan-tx",
323 .handler = set_led,
324 .default_trigger = "tx",
325 },
326 {
327 .name = "platform-lan-rx",
328 .handler = set_led,
329 .default_trigger = "rx",
330 },
331 {
332 .name = "platform-disk",
333 .handler = set_led,
334 .default_trigger = "disk-activity",
335 },
336 {
337 .name = "platform-heartbeat",
338 .handler = set_led,
339 .default_trigger = "heartbeat",
340 },
341 {
342 .name = "platform-LED4",
343 .handler = set_led,
344 .default_trigger = "panic",
345 },
346 {
347 .name = "platform-LED5",
348 .handler = set_led,
349 .default_trigger = "panic",
350 },
351 {
352 .name = "platform-LED6",
353 .handler = set_led,
354 .default_trigger = "panic",
355 },
356 {
357 .name = "platform-LED7",
358 .handler = set_led,
359 .default_trigger = "panic",
360 },
361};
362
363static int platform_led_probe(struct platform_device *pdev)
364{
365 return hppa_led_generic_probe(pdev, types: mainboard_led_types);
366}
367
368MODULE_ALIAS("platform:platform-leds");
369
370static struct platform_driver hppa_mainboard_led_driver = {
371 .probe = platform_led_probe,
372 .remove_new = platform_led_remove,
373 .driver = {
374 .name = "platform-leds",
375 },
376};
377
378static struct platform_driver * const drivers[] = {
379 &hppa_mainboard_led_driver,
380};
381
382static struct platform_device platform_leds = {
383 .name = "platform-leds",
384};
385
386/**
387 * register_led_driver()
388 *
389 * @model: model type, one of the DISPLAY_MODEL_XXXX values
390 * @cmd_reg: physical address of cmd register for the LED/LCD
391 * @data_reg: physical address of data register for the LED/LCD
392 *
393 * Registers a chassis LED or LCD which should be driven by this driver.
394 * Only PDC-based, LASI- or ASP-style LEDs and LCDs are supported.
395 */
396int __init register_led_driver(int model, unsigned long cmd_reg, unsigned long data_reg)
397{
398 if (led_func_ptr || !data_reg)
399 return 1;
400
401 /* No LEDs when running in QEMU */
402 if (running_on_qemu)
403 return 1;
404
405 lcd_info.model = model; /* store the values */
406 LCD_CMD_REG = (cmd_reg == LED_CMD_REG_NONE) ? 0 : cmd_reg;
407
408 switch (lcd_info.model) {
409 case DISPLAY_MODEL_LCD:
410 LCD_DATA_REG = data_reg;
411 pr_info("led: LCD display at %#lx and %#lx\n",
412 LCD_CMD_REG , LCD_DATA_REG);
413 led_func_ptr = led_LCD_driver;
414 if (lcd_no_led_support)
415 led_type = LED_HAS_LCD;
416 else
417 led_type = LED_HAS_LCD | LED_HAS_LED;
418 break;
419
420 case DISPLAY_MODEL_LASI:
421 LED_DATA_REG = data_reg;
422 led_func_ptr = led_LASI_driver;
423 pr_info("led: LED display at %#lx\n", LED_DATA_REG);
424 led_type = LED_HAS_LED;
425 break;
426
427 case DISPLAY_MODEL_OLD_ASP:
428 LED_DATA_REG = data_reg;
429 led_func_ptr = led_ASP_driver;
430 pr_info("led: LED (ASP-style) display at %#lx\n",
431 LED_DATA_REG);
432 led_type = LED_HAS_LED;
433 break;
434
435 default:
436 pr_err("led: Unknown LCD/LED model type %d\n", lcd_info.model);
437 return 1;
438 }
439
440 platform_register_drivers(drivers, ARRAY_SIZE(drivers));
441
442 return register_reboot_notifier(&lcd_system_halt_notifier);
443}
444
445/**
446 * early_led_init()
447 *
448 * early_led_init() is called early in the bootup-process and asks the
449 * PDC for an usable chassis LCD or LED. If the PDC doesn't return any
450 * info, then a LED might be detected by the LASI or ASP drivers later.
451 * KittyHawk machines have often a buggy PDC, so that we explicitly check
452 * for those machines here.
453 */
454static int __init early_led_init(void)
455{
456 struct pdc_chassis_info chassis_info;
457 int ret;
458
459 snprintf(buf: lcd_text_default, size: sizeof(lcd_text_default),
460 fmt: "Linux %s", init_utsname()->release);
461 strcpy(p: lcd_text, q: lcd_text_default);
462 lcd_new_text = 1;
463
464 /* Work around the buggy PDC of KittyHawk-machines */
465 switch (CPU_HVERSION) {
466 case 0x580: /* KittyHawk DC2-100 (K100) */
467 case 0x581: /* KittyHawk DC3-120 (K210) */
468 case 0x582: /* KittyHawk DC3 100 (K400) */
469 case 0x583: /* KittyHawk DC3 120 (K410) */
470 case 0x58B: /* KittyHawk DC2 100 (K200) */
471 pr_info("LCD on KittyHawk-Machine found.\n");
472 lcd_info.model = DISPLAY_MODEL_LCD;
473 /* KittyHawk has no LED support on its LCD, so skip LED detection */
474 lcd_no_led_support = 1;
475 goto found; /* use the preinitialized values of lcd_info */
476 }
477
478 /* initialize the struct, so that we can check for valid return values */
479 chassis_info.actcnt = chassis_info.maxcnt = 0;
480
481 ret = pdc_chassis_info(&chassis_info, &lcd_info, sizeof(lcd_info));
482 if (ret != PDC_OK) {
483not_found:
484 lcd_info.model = DISPLAY_MODEL_NONE;
485 return 1;
486 }
487
488 /* check the results. Some machines have a buggy PDC */
489 if (chassis_info.actcnt <= 0 || chassis_info.actcnt != chassis_info.maxcnt)
490 goto not_found;
491
492 switch (lcd_info.model) {
493 case DISPLAY_MODEL_LCD: /* LCD display */
494 if (chassis_info.actcnt <
495 offsetof(struct pdc_chassis_lcd_info_ret_block, _pad)-1)
496 goto not_found;
497 if (!lcd_info.act_enable) {
498 /* PDC tells LCD should not be used. */
499 goto not_found;
500 }
501 break;
502
503 case DISPLAY_MODEL_NONE: /* no LED or LCD available */
504 goto not_found;
505
506 case DISPLAY_MODEL_LASI: /* Lasi style 8 bit LED display */
507 if (chassis_info.actcnt != 8 && chassis_info.actcnt != 32)
508 goto not_found;
509 break;
510
511 default:
512 pr_warn("PDC reported unknown LCD/LED model %d\n",
513 lcd_info.model);
514 goto not_found;
515 }
516
517found:
518 /* register the LCD/LED driver */
519 return register_led_driver(model: lcd_info.model, LCD_CMD_REG, LCD_DATA_REG);
520}
521arch_initcall(early_led_init);
522
523/**
524 * register_led_regions()
525 *
526 * Register_led_regions() registers the LCD/LED regions for /procfs.
527 * At bootup - where the initialisation of the LCD/LED often happens
528 * not all internal structures of request_region() are properly set up,
529 * so that we delay the led-registration until after busdevices_init()
530 * has been executed.
531 */
532static void __init register_led_regions(void)
533{
534 switch (lcd_info.model) {
535 case DISPLAY_MODEL_LCD:
536 request_mem_region((unsigned long)LCD_CMD_REG, 1, "lcd_cmd");
537 request_mem_region((unsigned long)LCD_DATA_REG, 1, "lcd_data");
538 break;
539 case DISPLAY_MODEL_LASI:
540 case DISPLAY_MODEL_OLD_ASP:
541 request_mem_region((unsigned long)LED_DATA_REG, 1, "led_data");
542 break;
543 }
544}
545
546static int __init startup_leds(void)
547{
548 if (platform_device_register(&platform_leds))
549 printk(KERN_INFO "LED: failed to register LEDs\n");
550 register_led_regions();
551 return 0;
552}
553device_initcall(startup_leds);
554

source code of linux/drivers/parisc/led.c