// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *      Chassis LCD/LED driver for HP-PARISC workstations
 *
 *      (c) Copyright 2000 Red Hat Software
 *      (c) Copyright 2000 Helge Deller <hdeller@redhat.com>
 *      (c) Copyright 2001 Randolph Chung <tausq@debian.org>
 *      (c) Copyright 2000-2023 Helge Deller <deller@gmx.de>
 *
 *      The control of the LEDs and LCDs on PARISC machines has to be done
 *      completely in software.
 *
 *      The LEDs can be configured at runtime in /sys/class/leds/
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/ioport.h>
#include <linux/utsname.h>
#include <linux/capability.h>
#include <linux/delay.h>
#include <linux/reboot.h>
#include <linux/uaccess.h>
#include <linux/leds.h>
#include <linux/platform_device.h>

#include <asm/io.h>
#include <asm/processor.h>
#include <asm/hardware.h>
#include <asm/param.h>          /* HZ */
#include <asm/led.h>
#include <asm/pdc.h>

#define LED_HAS_LCD 1
#define LED_HAS_LED 2

static unsigned char led_type;          /* bitmask of LED_HAS_XXX */
static unsigned char lastleds;          /* LED state from most recent update */
static unsigned char lcd_new_text;
static unsigned char lcd_text[20];
static unsigned char lcd_no_led_support; /* KittyHawk doesn't support LED on its LCD */

struct lcd_block {
        unsigned char command;  /* stores the command byte      */
        unsigned char on;       /* value for turning LED on     */
        unsigned char off;      /* value for turning LED off    */
};

/* Structure returned by PDC_RETURN_CHASSIS_INFO */
/* NOTE: we use unsigned long:16 two times, since the following member
   lcd_cmd_reg_addr needs to be 64bit aligned on 64bit PA2.0-machines */
struct pdc_chassis_lcd_info_ret_block {
        unsigned long model:16;         /* DISPLAY_MODEL_XXXX */
        unsigned long lcd_width:16;     /* width of the LCD in chars (DISPLAY_MODEL_LCD only) */
        unsigned long lcd_cmd_reg_addr; /* ptr to LCD cmd-register & data ptr for LED */
        unsigned long lcd_data_reg_addr; /* ptr to LCD data-register (LCD only) */
        unsigned int min_cmd_delay;     /* delay in uS after cmd-write (LCD only) */
        unsigned char reset_cmd1;       /* command #1 for writing LCD string (LCD only) */
        unsigned char reset_cmd2;       /* command #2 for writing LCD string (LCD only) */
        unsigned char act_enable;       /* 0 = no activity (LCD only) */
        struct lcd_block heartbeat;
        struct lcd_block disk_io;
        struct lcd_block lan_rcv;
        struct lcd_block lan_tx;
        char _pad;
};


/* LCD_CMD and LCD_DATA for KittyHawk machines */
#define KITTYHAWK_LCD_CMD  F_EXTEND(0xf0190000UL)
#define KITTYHAWK_LCD_DATA (KITTYHAWK_LCD_CMD + 1)

/* lcd_info is pre-initialized to the values needed to program KittyHawk LCD's
 * HP seems to have used Sharp/Hitachi HD44780 LCDs most of the time. */
static struct pdc_chassis_lcd_info_ret_block
lcd_info __attribute__((aligned(8)))  =
{
        .model =                DISPLAY_MODEL_NONE,
        .lcd_width =            16,
        .lcd_cmd_reg_addr =     KITTYHAWK_LCD_CMD,
        .lcd_data_reg_addr =    KITTYHAWK_LCD_DATA,
        .min_cmd_delay =        80,
        .reset_cmd1 =           0x80,
        .reset_cmd2 =           0xc0,
};

/* direct access to some of the lcd_info variables */
#define LCD_CMD_REG     lcd_info.lcd_cmd_reg_addr
#define LCD_DATA_REG    lcd_info.lcd_data_reg_addr
#define LED_DATA_REG    lcd_info.lcd_cmd_reg_addr       /* LASI & ASP only */

/* ptr to LCD/LED-specific function */
static void (*led_func_ptr) (unsigned char);


static void lcd_print_now(void)
{
        int i;
        char *str = lcd_text;

        if (lcd_info.model != DISPLAY_MODEL_LCD)
                return;

        if (!lcd_new_text)
                return;
        lcd_new_text = 0;

        /* Set LCD Cursor to 1st character */
        gsc_writeb(lcd_info.reset_cmd1, LCD_CMD_REG);
        udelay(lcd_info.min_cmd_delay);

        /* Print the string */
        for (i = 0; i < lcd_info.lcd_width; i++) {
                gsc_writeb(*str ? *str++ : ' ', LCD_DATA_REG);
                udelay(lcd_info.min_cmd_delay);
        }
}

/**
 *      lcd_print()
 *
 *      @str: string to show on the LCD. If NULL, print current string again.
 *
 *      Displays the given string on the LCD-Display of newer machines.
 */
void lcd_print(const char *str)
{
        /* copy display string to buffer for procfs */
        if (str)
                strscpy(lcd_text, str, sizeof(lcd_text));
        lcd_new_text = 1;

        /* print now if LCD without any LEDs */
        if (led_type == LED_HAS_LCD)
                lcd_print_now();
}

#define LED_DATA        0x01    /* data to shift (0:on 1:off) */
#define LED_STROBE      0x02    /* strobe to clock data */

/**
 *      led_ASP_driver() - LED driver for the ASP controller chip
 *
 *      @leds: bitmap representing the LED status
 */
static void led_ASP_driver(unsigned char leds)
{
        int i;

        leds = ~leds;
        for (i = 0; i < 8; i++) {
                unsigned char value;
                value = (leds & 0x80) >> 7;
                gsc_writeb( value,               LED_DATA_REG );
                gsc_writeb( value | LED_STROBE,  LED_DATA_REG );
                leds <<= 1;
        }
}

/**
 *      led_LASI_driver() - LED driver for the LASI controller chip
 *
 *      @leds: bitmap representing the LED status
 */
static void led_LASI_driver(unsigned char leds)
{
        leds = ~leds;
        gsc_writeb( leds, LED_DATA_REG );
}

/**
 *      led_LCD_driver() - LED & LCD driver for LCD chips
 *
 *      @leds: bitmap representing the LED status
 */
static void led_LCD_driver(unsigned char leds)
{
        static const unsigned char mask[4] = {
                LED_HEARTBEAT, LED_DISK_IO,
                LED_LAN_RCV, LED_LAN_TX };

        static struct lcd_block * const blockp[4] = {
                &lcd_info.heartbeat,
                &lcd_info.disk_io,
                &lcd_info.lan_rcv,
                &lcd_info.lan_tx
        };
        static unsigned char latest_leds;
        int i;

        for (i = 0; i < 4; ++i) {
                if ((leds & mask[i]) == (latest_leds & mask[i]))
                        continue;

                gsc_writeb( blockp[i]->command, LCD_CMD_REG );
                udelay(lcd_info.min_cmd_delay);

                gsc_writeb( leds & mask[i] ? blockp[i]->on :
                                blockp[i]->off, LCD_DATA_REG );
                udelay(lcd_info.min_cmd_delay);
        }
        latest_leds = leds;

        lcd_print_now();
}


/**
 *      lcd_system_halt()
 *
 *      @nb: pointer to the notifier_block structure
 *      @event: the event (SYS_RESTART, SYS_HALT or SYS_POWER_OFF)
 *      @buf: pointer to a buffer (not used)
 *
 *      Called by the reboot notifier chain at shutdown. Stops all
 *      LED/LCD activities.
 */
static int lcd_system_halt(struct notifier_block *nb, unsigned long event, void *buf)
{
        const char *txt;

        switch (event) {
        case SYS_RESTART:       txt = "SYSTEM RESTART";
                                break;
        case SYS_HALT:          txt = "SYSTEM HALT";
                                break;
        case SYS_POWER_OFF:     txt = "SYSTEM POWER OFF";
                                break;
        default:                return NOTIFY_DONE;
        }

        lcd_print(txt);

        return NOTIFY_OK;
}

static struct notifier_block lcd_system_halt_notifier = {
        .notifier_call = lcd_system_halt,
};

static void set_led(struct led_classdev *led_cdev, enum led_brightness brightness);

struct hppa_led {
        struct led_classdev     led_cdev;
        unsigned char           led_bit;
};
#define to_hppa_led(d) container_of(d, struct hppa_led, led_cdev)

typedef void (*set_handler)(struct led_classdev *, enum led_brightness);
struct led_type {
        const char      *name;
        set_handler     handler;
        const char      *default_trigger;
};

#define NUM_LEDS_PER_BOARD      8
struct hppa_drvdata {
        struct hppa_led leds[NUM_LEDS_PER_BOARD];
};

static void set_led(struct led_classdev *led_cdev, enum led_brightness brightness)
{
        struct hppa_led *p = to_hppa_led(led_cdev);
        unsigned char led_bit = p->led_bit;

        if (brightness == LED_OFF)
                lastleds &= ~led_bit;
        else
                lastleds |= led_bit;

        if (led_func_ptr)
                led_func_ptr(lastleds);
}


static int hppa_led_generic_probe(struct platform_device *pdev,
                                  struct led_type *types)
{
        struct hppa_drvdata *p;
        int i, err;

        p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);
        if (!p)
                return -ENOMEM;

        for (i = 0; i < NUM_LEDS_PER_BOARD; i++) {
                struct led_classdev *lp = &p->leds[i].led_cdev;

                p->leds[i].led_bit = BIT(i);
                lp->name = types[i].name;
                lp->brightness = LED_FULL;
                lp->brightness_set = types[i].handler;
                lp->default_trigger = types[i].default_trigger;
                err = led_classdev_register(&pdev->dev, lp);
                if (err) {
                        dev_err(&pdev->dev, "Could not register %s LED\n",
                               lp->name);
                        for (i--; i >= 0; i--)
                                led_classdev_unregister(&p->leds[i].led_cdev);
                        return err;
                }
        }

        platform_set_drvdata(pdev, p);

        return 0;
}

static void platform_led_remove(struct platform_device *pdev)
{
        struct hppa_drvdata *p = platform_get_drvdata(pdev);
        int i;

        for (i = 0; i < NUM_LEDS_PER_BOARD; i++)
                led_classdev_unregister(&p->leds[i].led_cdev);
}

static struct led_type mainboard_led_types[NUM_LEDS_PER_BOARD] = {
        {
                .name           = "platform-lan-tx",
                .handler        = set_led,
                .default_trigger = "tx",
        },
        {
                .name           = "platform-lan-rx",
                .handler        = set_led,
                .default_trigger = "rx",
        },
        {
                .name           = "platform-disk",
                .handler        = set_led,
                .default_trigger = "disk-activity",
        },
        {
                .name           = "platform-heartbeat",
                .handler        = set_led,
                .default_trigger = "heartbeat",
        },
        {
                .name           = "platform-LED4",
                .handler        = set_led,
                .default_trigger = "panic",
        },
        {
                .name           = "platform-LED5",
                .handler        = set_led,
                .default_trigger = "panic",
        },
        {
                .name           = "platform-LED6",
                .handler        = set_led,
                .default_trigger = "panic",
        },
        {
                .name           = "platform-LED7",
                .handler        = set_led,
                .default_trigger = "panic",
        },
};

static int platform_led_probe(struct platform_device *pdev)
{
        return hppa_led_generic_probe(pdev, mainboard_led_types);
}

MODULE_ALIAS("platform:platform-leds");

static struct platform_driver hppa_mainboard_led_driver = {
        .probe          = platform_led_probe,
        .remove         = platform_led_remove,
        .driver         = {
                .name   = "platform-leds",
        },
};

static struct platform_driver * const drivers[] = {
        &hppa_mainboard_led_driver,
};

static struct platform_device platform_leds = {
        .name = "platform-leds",
};

/**
 *      register_led_driver()
 *
 *      @model: model type, one of the DISPLAY_MODEL_XXXX values
 *      @cmd_reg: physical address of cmd register for the LED/LCD
 *      @data_reg: physical address of data register for the LED/LCD
 *
 *      Registers a chassis LED or LCD which should be driven by this driver.
 *      Only PDC-based, LASI- or ASP-style LEDs and LCDs are supported.
 */
int __init register_led_driver(int model, unsigned long cmd_reg, unsigned long data_reg)
{
        if (led_func_ptr || !data_reg)
                return 1;

        /* No LEDs when running in QEMU */
        if (running_on_qemu)
                return 1;

        lcd_info.model = model;         /* store the values */
        LCD_CMD_REG = (cmd_reg == LED_CMD_REG_NONE) ? 0 : cmd_reg;

        switch (lcd_info.model) {
        case DISPLAY_MODEL_LCD:
                LCD_DATA_REG = data_reg;
                pr_info("led: LCD display at %#lx and %#lx\n",
                        LCD_CMD_REG , LCD_DATA_REG);
                led_func_ptr = led_LCD_driver;
                if (lcd_no_led_support)
                        led_type = LED_HAS_LCD;
                else
                        led_type = LED_HAS_LCD | LED_HAS_LED;
                break;

        case DISPLAY_MODEL_LASI:
                LED_DATA_REG = data_reg;
                led_func_ptr = led_LASI_driver;
                pr_info("led: LED display at %#lx\n", LED_DATA_REG);
                led_type = LED_HAS_LED;
                break;

        case DISPLAY_MODEL_OLD_ASP:
                LED_DATA_REG = data_reg;
                led_func_ptr = led_ASP_driver;
                pr_info("led: LED (ASP-style) display at %#lx\n",
                    LED_DATA_REG);
                led_type = LED_HAS_LED;
                break;

        default:
                pr_err("led: Unknown LCD/LED model type %d\n", lcd_info.model);
                return 1;
        }

        platform_register_drivers(drivers, ARRAY_SIZE(drivers));

        return register_reboot_notifier(&lcd_system_halt_notifier);
}

/**
 *      early_led_init()
 *
 *      early_led_init() is called early in the bootup-process and asks the
 *      PDC for an usable chassis LCD or LED. If the PDC doesn't return any
 *      info, then a LED might be detected by the LASI or ASP drivers later.
 *      KittyHawk machines have often a buggy PDC, so that we explicitly check
 *      for those machines here.
 */
static int __init early_led_init(void)
{
        struct pdc_chassis_info chassis_info;
        int ret;

        scnprintf(lcd_text, sizeof(lcd_text),
                "Linux %s", init_utsname()->release);
        lcd_new_text = 1;

        /* Work around the buggy PDC of KittyHawk-machines */
        switch (CPU_HVERSION) {
        case 0x580:             /* KittyHawk DC2-100 (K100) */
        case 0x581:             /* KittyHawk DC3-120 (K210) */
        case 0x582:             /* KittyHawk DC3 100 (K400) */
        case 0x583:             /* KittyHawk DC3 120 (K410) */
        case 0x58B:             /* KittyHawk DC2 100 (K200) */
                pr_info("LCD on KittyHawk-Machine found.\n");
                lcd_info.model = DISPLAY_MODEL_LCD;
                /* KittyHawk has no LED support on its LCD, so skip LED detection */
                lcd_no_led_support = 1;
                goto found;     /* use the preinitialized values of lcd_info */
        }

        /* initialize the struct, so that we can check for valid return values */
        chassis_info.actcnt = chassis_info.maxcnt = 0;

        ret = pdc_chassis_info(&chassis_info, &lcd_info, sizeof(lcd_info));
        if (ret != PDC_OK) {
not_found:
                lcd_info.model = DISPLAY_MODEL_NONE;
                return 1;
        }

        /* check the results. Some machines have a buggy PDC */
        if (chassis_info.actcnt <= 0 || chassis_info.actcnt != chassis_info.maxcnt)
                goto not_found;

        switch (lcd_info.model) {
        case DISPLAY_MODEL_LCD:         /* LCD display */
                if (chassis_info.actcnt <
                        offsetof(struct pdc_chassis_lcd_info_ret_block, _pad)-1)
                        goto not_found;
                if (!lcd_info.act_enable) {
                        /* PDC tells LCD should not be used. */
                        goto not_found;
                }
                break;

        case DISPLAY_MODEL_NONE:        /* no LED or LCD available */
                goto not_found;

        case DISPLAY_MODEL_LASI:        /* Lasi style 8 bit LED display */
                if (chassis_info.actcnt != 8 && chassis_info.actcnt != 32)
                        goto not_found;
                break;

        default:
                pr_warn("PDC reported unknown LCD/LED model %d\n",
                       lcd_info.model);
                goto not_found;
        }

found:
        /* register the LCD/LED driver */
        return register_led_driver(lcd_info.model, LCD_CMD_REG, LCD_DATA_REG);
}
arch_initcall(early_led_init);

/**
 *      register_led_regions()
 *
 *      Register_led_regions() registers the LCD/LED regions for /procfs.
 *      At bootup - where the initialisation of the LCD/LED often happens
 *      not all internal structures of request_region() are properly set up,
 *      so that we delay the led-registration until after busdevices_init()
 *      has been executed.
 */
static void __init register_led_regions(void)
{
        switch (lcd_info.model) {
        case DISPLAY_MODEL_LCD:
                request_mem_region((unsigned long)LCD_CMD_REG,  1, "lcd_cmd");
                request_mem_region((unsigned long)LCD_DATA_REG, 1, "lcd_data");
                break;
        case DISPLAY_MODEL_LASI:
        case DISPLAY_MODEL_OLD_ASP:
                request_mem_region((unsigned long)LED_DATA_REG, 1, "led_data");
                break;
        }
}

static int __init startup_leds(void)
{
        if (platform_device_register(&platform_leds))
                printk(KERN_INFO "LED: failed to register LEDs\n");
        register_led_regions();
        return 0;
}
device_initcall(startup_leds);