// SPDX-License-Identifier: GPL-2.0+
/*
 * opal driver interface to hvc_console.c
 *
 * Copyright 2011 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp.
 */

#undef DEBUG

#include <linux/types.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/console.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/export.h>
#include <linux/interrupt.h>

#include <asm/hvconsole.h>
#include <asm/firmware.h>
#include <asm/hvsi.h>
#include <asm/udbg.h>
#include <asm/opal.h>

#include "hvc_console.h"

static const char hvc_opal_name[] = "hvc_opal";

static const struct of_device_id hvc_opal_match[] = {
        { .name = "serial", .compatible = "ibm,opal-console-raw" },
        { .name = "serial", .compatible = "ibm,opal-console-hvsi" },
        { },
};

typedef enum hv_protocol {
        HV_PROTOCOL_RAW,
        HV_PROTOCOL_HVSI
} hv_protocol_t;

struct hvc_opal_priv {
        hv_protocol_t           proto;  /* Raw data or HVSI packets */
        struct hvsi_priv        hvsi;   /* HVSI specific data */
};
static struct hvc_opal_priv *hvc_opal_privs[MAX_NR_HVC_CONSOLES];

/* For early boot console */
static struct hvc_opal_priv hvc_opal_boot_priv;
static u32 hvc_opal_boot_termno;

static const struct hv_ops hvc_opal_raw_ops = {
        .get_chars = opal_get_chars,
        .put_chars = opal_put_chars,
        .flush = opal_flush_chars,
        .notifier_add = notifier_add_irq,
        .notifier_del = notifier_del_irq,
        .notifier_hangup = notifier_hangup_irq,
};

static ssize_t hvc_opal_hvsi_get_chars(uint32_t vtermno, u8 *buf, size_t count)
{
        struct hvc_opal_priv *pv = hvc_opal_privs[vtermno];

        if (WARN_ON(!pv))
                return -ENODEV;

        return hvsilib_get_chars(&pv->hvsi, buf, count);
}

static ssize_t hvc_opal_hvsi_put_chars(uint32_t vtermno, const u8 *buf,
                                       size_t count)
{
        struct hvc_opal_priv *pv = hvc_opal_privs[vtermno];

        if (WARN_ON(!pv))
                return -ENODEV;

        return hvsilib_put_chars(&pv->hvsi, buf, count);
}

static int hvc_opal_hvsi_open(struct hvc_struct *hp, int data)
{
        struct hvc_opal_priv *pv = hvc_opal_privs[hp->vtermno];
        int rc;

        pr_devel("HVSI@%x: do open !\n", hp->vtermno);

        rc = notifier_add_irq(hp, data);
        if (rc)
                return rc;

        return hvsilib_open(&pv->hvsi, hp);
}

static void hvc_opal_hvsi_close(struct hvc_struct *hp, int data)
{
        struct hvc_opal_priv *pv = hvc_opal_privs[hp->vtermno];

        pr_devel("HVSI@%x: do close !\n", hp->vtermno);

        hvsilib_close(&pv->hvsi, hp);

        notifier_del_irq(hp, data);
}

static void hvc_opal_hvsi_hangup(struct hvc_struct *hp, int data)
{
        struct hvc_opal_priv *pv = hvc_opal_privs[hp->vtermno];

        pr_devel("HVSI@%x: do hangup !\n", hp->vtermno);

        hvsilib_close(&pv->hvsi, hp);

        notifier_hangup_irq(hp, data);
}

static int hvc_opal_hvsi_tiocmget(struct hvc_struct *hp)
{
        struct hvc_opal_priv *pv = hvc_opal_privs[hp->vtermno];

        if (!pv)
                return -EINVAL;
        return pv->hvsi.mctrl;
}

static int hvc_opal_hvsi_tiocmset(struct hvc_struct *hp, unsigned int set,
                                unsigned int clear)
{
        struct hvc_opal_priv *pv = hvc_opal_privs[hp->vtermno];

        pr_devel("HVSI@%x: Set modem control, set=%x,clr=%x\n",
                 hp->vtermno, set, clear);

        if (set & TIOCM_DTR)
                hvsilib_write_mctrl(&pv->hvsi, 1);
        else if (clear & TIOCM_DTR)
                hvsilib_write_mctrl(&pv->hvsi, 0);

        return 0;
}

static const struct hv_ops hvc_opal_hvsi_ops = {
        .get_chars = hvc_opal_hvsi_get_chars,
        .put_chars = hvc_opal_hvsi_put_chars,
        .flush = opal_flush_chars,
        .notifier_add = hvc_opal_hvsi_open,
        .notifier_del = hvc_opal_hvsi_close,
        .notifier_hangup = hvc_opal_hvsi_hangup,
        .tiocmget = hvc_opal_hvsi_tiocmget,
        .tiocmset = hvc_opal_hvsi_tiocmset,
};

static int hvc_opal_probe(struct platform_device *dev)
{
        const struct hv_ops *ops;
        struct hvc_struct *hp;
        struct hvc_opal_priv *pv;
        hv_protocol_t proto;
        unsigned int termno, irq, boot = 0;
        const __be32 *reg;

        if (of_device_is_compatible(dev->dev.of_node, "ibm,opal-console-raw")) {
                proto = HV_PROTOCOL_RAW;
                ops = &hvc_opal_raw_ops;
        } else if (of_device_is_compatible(dev->dev.of_node,
                                           "ibm,opal-console-hvsi")) {
                proto = HV_PROTOCOL_HVSI;
                ops = &hvc_opal_hvsi_ops;
        } else {
                pr_err("hvc_opal: Unknown protocol for %pOF\n",
                       dev->dev.of_node);
                return -ENXIO;
        }

        reg = of_get_property(dev->dev.of_node, "reg", NULL);
        termno = reg ? be32_to_cpup(reg) : 0;

        /* Is it our boot one ? */
        if (hvc_opal_privs[termno] == &hvc_opal_boot_priv) {
                pv = hvc_opal_privs[termno];
                boot = 1;
        } else if (hvc_opal_privs[termno] == NULL) {
                pv = kzalloc_obj(struct hvc_opal_priv);
                if (!pv)
                        return -ENOMEM;
                pv->proto = proto;
                hvc_opal_privs[termno] = pv;
                if (proto == HV_PROTOCOL_HVSI) {
                        /*
                         * We want put_chars to be atomic to avoid mangling of
                         * hvsi packets.
                         */
                        hvsilib_init(&pv->hvsi,
                                     opal_get_chars, opal_put_chars_atomic,
                                     termno, 0);
                }

                /* Instanciate now to establish a mapping index==vtermno */
                hvc_instantiate(termno, termno, ops);
        } else {
                pr_err("hvc_opal: Device %pOF has duplicate terminal number #%d\n",
                       dev->dev.of_node, termno);
                return -ENXIO;
        }

        pr_info("hvc%d: %s protocol on %pOF%s\n", termno,
                proto == HV_PROTOCOL_RAW ? "raw" : "hvsi",
                dev->dev.of_node,
                boot ? " (boot console)" : "");

        irq = irq_of_parse_and_map(dev->dev.of_node, 0);
        if (!irq) {
                pr_info("hvc%d: No interrupts property, using OPAL event\n",
                                termno);
                irq = opal_event_request(ilog2(OPAL_EVENT_CONSOLE_INPUT));
        }

        if (!irq) {
                pr_err("hvc_opal: Unable to map interrupt for device %pOF\n",
                        dev->dev.of_node);
                return irq;
        }

        hp = hvc_alloc(termno, irq, ops, MAX_VIO_PUT_CHARS);
        if (IS_ERR(hp))
                return PTR_ERR(hp);

        /* hvc consoles on powernv may need to share a single irq */
        hp->flags = IRQF_SHARED;
        dev_set_drvdata(&dev->dev, hp);

        return 0;
}

static void hvc_opal_remove(struct platform_device *dev)
{
        struct hvc_struct *hp = dev_get_drvdata(&dev->dev);
        int termno;

        termno = hp->vtermno;
        hvc_remove(hp);
        if (hvc_opal_privs[termno] != &hvc_opal_boot_priv)
                kfree(hvc_opal_privs[termno]);
        hvc_opal_privs[termno] = NULL;
}

static struct platform_driver hvc_opal_driver = {
        .probe          = hvc_opal_probe,
        .remove         = hvc_opal_remove,
        .driver         = {
                .name   = hvc_opal_name,
                .of_match_table = hvc_opal_match,
        }
};

static int __init hvc_opal_init(void)
{
        if (!firmware_has_feature(FW_FEATURE_OPAL))
                return -ENODEV;

        /* Register as a vio device to receive callbacks */
        return platform_driver_register(&hvc_opal_driver);
}
device_initcall(hvc_opal_init);

static void udbg_opal_putc(char c)
{
        unsigned int termno = hvc_opal_boot_termno;
        int count = -1;

        if (c == '\n')
                udbg_opal_putc('\r');

        do {
                switch(hvc_opal_boot_priv.proto) {
                case HV_PROTOCOL_RAW:
                        count = opal_put_chars(termno, &c, 1);
                        break;
                case HV_PROTOCOL_HVSI:
                        count = hvc_opal_hvsi_put_chars(termno, &c, 1);
                        break;
                }

                /* This is needed for the cosole to flush
                 * when there aren't any interrupts.
                 */
                opal_flush_console(termno);
        } while(count == 0 || count == -EAGAIN);
}

static int udbg_opal_getc_poll(void)
{
        unsigned int termno = hvc_opal_boot_termno;
        int rc = 0;
        char c;

        switch(hvc_opal_boot_priv.proto) {
        case HV_PROTOCOL_RAW:
                rc = opal_get_chars(termno, &c, 1);
                break;
        case HV_PROTOCOL_HVSI:
                rc = hvc_opal_hvsi_get_chars(termno, &c, 1);
                break;
        }
        if (!rc)
                return -1;
        return c;
}

static int udbg_opal_getc(void)
{
        int ch;
        for (;;) {
                ch = udbg_opal_getc_poll();
                if (ch != -1)
                        return ch;
        }
}

static void udbg_init_opal_common(void)
{
        udbg_putc = udbg_opal_putc;
        udbg_getc = udbg_opal_getc;
        udbg_getc_poll = udbg_opal_getc_poll;
}

void __init hvc_opal_init_early(void)
{
        struct device_node *stdout_node = of_node_get(of_stdout);
        const __be32 *termno;
        const struct hv_ops *ops;
        u32 index;

        /* If the console wasn't in /chosen, try /ibm,opal */
        if (!stdout_node) {
                struct device_node *opal, *np;

                /* Current OPAL takeover doesn't provide the stdout
                 * path, so we hard wire it
                 */
                opal = of_find_node_by_path("/ibm,opal/consoles");
                if (opal) {
                        pr_devel("hvc_opal: Found consoles in new location\n");
                } else {
                        opal = of_find_node_by_path("/ibm,opal");
                        if (opal)
                                pr_devel("hvc_opal: "
                                         "Found consoles in old location\n");
                }
                if (!opal)
                        return;
                for_each_child_of_node(opal, np) {
                        if (of_node_name_eq(np, "serial")) {
                                stdout_node = np;
                                break;
                        }
                }
                of_node_put(opal);
        }
        if (!stdout_node)
                return;
        termno = of_get_property(stdout_node, "reg", NULL);
        index = termno ? be32_to_cpup(termno) : 0;
        if (index >= MAX_NR_HVC_CONSOLES)
                return;
        hvc_opal_privs[index] = &hvc_opal_boot_priv;

        /* Check the protocol */
        if (of_device_is_compatible(stdout_node, "ibm,opal-console-raw")) {
                hvc_opal_boot_priv.proto = HV_PROTOCOL_RAW;
                ops = &hvc_opal_raw_ops;
                pr_devel("hvc_opal: Found RAW console\n");
        }
        else if (of_device_is_compatible(stdout_node,"ibm,opal-console-hvsi")) {
                hvc_opal_boot_priv.proto = HV_PROTOCOL_HVSI;
                ops = &hvc_opal_hvsi_ops;
                hvsilib_init(&hvc_opal_boot_priv.hvsi,
                             opal_get_chars, opal_put_chars_atomic,
                             index, 1);
                /* HVSI, perform the handshake now */
                hvsilib_establish(&hvc_opal_boot_priv.hvsi);
                pr_devel("hvc_opal: Found HVSI console\n");
        } else
                goto out;
        hvc_opal_boot_termno = index;
        udbg_init_opal_common();
        add_preferred_console("hvc", index, NULL);
        hvc_instantiate(index, index, ops);
out:
        of_node_put(stdout_node);
}

#ifdef CONFIG_PPC_EARLY_DEBUG_OPAL_RAW
void __init udbg_init_debug_opal_raw(void)
{
        u32 index = CONFIG_PPC_EARLY_DEBUG_OPAL_VTERMNO;
        hvc_opal_privs[index] = &hvc_opal_boot_priv;
        hvc_opal_boot_priv.proto = HV_PROTOCOL_RAW;
        hvc_opal_boot_termno = index;
        udbg_init_opal_common();
}
#endif /* CONFIG_PPC_EARLY_DEBUG_OPAL_RAW */

#ifdef CONFIG_PPC_EARLY_DEBUG_OPAL_HVSI
void __init udbg_init_debug_opal_hvsi(void)
{
        u32 index = CONFIG_PPC_EARLY_DEBUG_OPAL_VTERMNO;
        hvc_opal_privs[index] = &hvc_opal_boot_priv;
        hvc_opal_boot_termno = index;
        udbg_init_opal_common();
        hvsilib_init(&hvc_opal_boot_priv.hvsi,
                     opal_get_chars, opal_put_chars_atomic,
                     index, 1);
        hvsilib_establish(&hvc_opal_boot_priv.hvsi);
}
#endif /* CONFIG_PPC_EARLY_DEBUG_OPAL_HVSI */