linux/drivers/tty/hvc/hvc_vio.c
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   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * vio driver interface to hvc_console.c
   4 *
   5 * This code was moved here to allow the remaining code to be reused as a
   6 * generic polling mode with semi-reliable transport driver core to the
   7 * console and tty subsystems.
   8 *
   9 *
  10 * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
  11 * Copyright (C) 2001 Paul Mackerras <paulus@au.ibm.com>, IBM
  12 * Copyright (C) 2004 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp.
  13 * Copyright (C) 2004 IBM Corporation
  14 *
  15 * Additional Author(s):
  16 *  Ryan S. Arnold <rsa@us.ibm.com>
  17 *
  18 * TODO:
  19 *
  20 *   - handle error in sending hvsi protocol packets
  21 *   - retry nego on subsequent sends ?
  22 */
  23
  24#undef DEBUG
  25
  26#include <linux/types.h>
  27#include <linux/init.h>
  28#include <linux/delay.h>
  29#include <linux/slab.h>
  30#include <linux/console.h>
  31
  32#include <asm/hvconsole.h>
  33#include <asm/vio.h>
  34#include <asm/prom.h>
  35#include <asm/hvsi.h>
  36#include <asm/udbg.h>
  37#include <asm/machdep.h>
  38
  39#include "hvc_console.h"
  40
  41static const char hvc_driver_name[] = "hvc_console";
  42
  43static const struct vio_device_id hvc_driver_table[] = {
  44        {"serial", "hvterm1"},
  45#ifndef HVC_OLD_HVSI
  46        {"serial", "hvterm-protocol"},
  47#endif
  48        { "", "" }
  49};
  50
  51typedef enum hv_protocol {
  52        HV_PROTOCOL_RAW,
  53        HV_PROTOCOL_HVSI
  54} hv_protocol_t;
  55
  56struct hvterm_priv {
  57        u32                     termno; /* HV term number */
  58        hv_protocol_t           proto;  /* Raw data or HVSI packets */
  59        struct hvsi_priv        hvsi;   /* HVSI specific data */
  60        spinlock_t              buf_lock;
  61        char                    buf[SIZE_VIO_GET_CHARS];
  62        int                     left;
  63        int                     offset;
  64};
  65static struct hvterm_priv *hvterm_privs[MAX_NR_HVC_CONSOLES];
  66/* For early boot console */
  67static struct hvterm_priv hvterm_priv0;
  68
  69static int hvterm_raw_get_chars(uint32_t vtermno, char *buf, int count)
  70{
  71        struct hvterm_priv *pv = hvterm_privs[vtermno];
  72        unsigned long i;
  73        unsigned long flags;
  74        int got;
  75
  76        if (WARN_ON(!pv))
  77                return 0;
  78
  79        spin_lock_irqsave(&pv->buf_lock, flags);
  80
  81        if (pv->left == 0) {
  82                pv->offset = 0;
  83                pv->left = hvc_get_chars(pv->termno, pv->buf, count);
  84
  85                /*
  86                 * Work around a HV bug where it gives us a null
  87                 * after every \r.  -- paulus
  88                 */
  89                for (i = 1; i < pv->left; ++i) {
  90                        if (pv->buf[i] == 0 && pv->buf[i-1] == '\r') {
  91                                --pv->left;
  92                                if (i < pv->left) {
  93                                        memmove(&pv->buf[i], &pv->buf[i+1],
  94                                                pv->left - i);
  95                                }
  96                        }
  97                }
  98        }
  99
 100        got = min(count, pv->left);
 101        memcpy(buf, &pv->buf[pv->offset], got);
 102        pv->offset += got;
 103        pv->left -= got;
 104
 105        spin_unlock_irqrestore(&pv->buf_lock, flags);
 106
 107        return got;
 108}
 109
 110/**
 111 * hvterm_raw_put_chars: send characters to firmware for given vterm adapter
 112 * @vtermno: The virtual terminal number.
 113 * @buf: The characters to send. Because of the underlying hypercall in
 114 *       hvc_put_chars(), this buffer must be at least 16 bytes long, even if
 115 *       you are sending fewer chars.
 116 * @count: number of chars to send.
 117 */
 118static int hvterm_raw_put_chars(uint32_t vtermno, const char *buf, int count)
 119{
 120        struct hvterm_priv *pv = hvterm_privs[vtermno];
 121
 122        if (WARN_ON(!pv))
 123                return 0;
 124
 125        return hvc_put_chars(pv->termno, buf, count);
 126}
 127
 128static const struct hv_ops hvterm_raw_ops = {
 129        .get_chars = hvterm_raw_get_chars,
 130        .put_chars = hvterm_raw_put_chars,
 131        .notifier_add = notifier_add_irq,
 132        .notifier_del = notifier_del_irq,
 133        .notifier_hangup = notifier_hangup_irq,
 134};
 135
 136static int hvterm_hvsi_get_chars(uint32_t vtermno, char *buf, int count)
 137{
 138        struct hvterm_priv *pv = hvterm_privs[vtermno];
 139
 140        if (WARN_ON(!pv))
 141                return 0;
 142
 143        return hvsilib_get_chars(&pv->hvsi, buf, count);
 144}
 145
 146static int hvterm_hvsi_put_chars(uint32_t vtermno, const char *buf, int count)
 147{
 148        struct hvterm_priv *pv = hvterm_privs[vtermno];
 149
 150        if (WARN_ON(!pv))
 151                return 0;
 152
 153        return hvsilib_put_chars(&pv->hvsi, buf, count);
 154}
 155
 156static int hvterm_hvsi_open(struct hvc_struct *hp, int data)
 157{
 158        struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
 159        int rc;
 160
 161        pr_devel("HVSI@%x: open !\n", pv->termno);
 162
 163        rc = notifier_add_irq(hp, data);
 164        if (rc)
 165                return rc;
 166
 167        return hvsilib_open(&pv->hvsi, hp);
 168}
 169
 170static void hvterm_hvsi_close(struct hvc_struct *hp, int data)
 171{
 172        struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
 173
 174        pr_devel("HVSI@%x: do close !\n", pv->termno);
 175
 176        hvsilib_close(&pv->hvsi, hp);
 177
 178        notifier_del_irq(hp, data);
 179}
 180
 181void hvterm_hvsi_hangup(struct hvc_struct *hp, int data)
 182{
 183        struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
 184
 185        pr_devel("HVSI@%x: do hangup !\n", pv->termno);
 186
 187        hvsilib_close(&pv->hvsi, hp);
 188
 189        notifier_hangup_irq(hp, data);
 190}
 191
 192static int hvterm_hvsi_tiocmget(struct hvc_struct *hp)
 193{
 194        struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
 195
 196        if (!pv)
 197                return -EINVAL;
 198        return pv->hvsi.mctrl;
 199}
 200
 201static int hvterm_hvsi_tiocmset(struct hvc_struct *hp, unsigned int set,
 202                                unsigned int clear)
 203{
 204        struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
 205
 206        pr_devel("HVSI@%x: Set modem control, set=%x,clr=%x\n",
 207                 pv->termno, set, clear);
 208
 209        if (set & TIOCM_DTR)
 210                hvsilib_write_mctrl(&pv->hvsi, 1);
 211        else if (clear & TIOCM_DTR)
 212                hvsilib_write_mctrl(&pv->hvsi, 0);
 213
 214        return 0;
 215}
 216
 217static const struct hv_ops hvterm_hvsi_ops = {
 218        .get_chars = hvterm_hvsi_get_chars,
 219        .put_chars = hvterm_hvsi_put_chars,
 220        .notifier_add = hvterm_hvsi_open,
 221        .notifier_del = hvterm_hvsi_close,
 222        .notifier_hangup = hvterm_hvsi_hangup,
 223        .tiocmget = hvterm_hvsi_tiocmget,
 224        .tiocmset = hvterm_hvsi_tiocmset,
 225};
 226
 227static void udbg_hvc_putc(char c)
 228{
 229        int count = -1;
 230        unsigned char bounce_buffer[16];
 231
 232        if (!hvterm_privs[0])
 233                return;
 234
 235        if (c == '\n')
 236                udbg_hvc_putc('\r');
 237
 238        do {
 239                switch(hvterm_privs[0]->proto) {
 240                case HV_PROTOCOL_RAW:
 241                        /*
 242                         * hvterm_raw_put_chars requires at least a 16-byte
 243                         * buffer, so go via the bounce buffer
 244                         */
 245                        bounce_buffer[0] = c;
 246                        count = hvterm_raw_put_chars(0, bounce_buffer, 1);
 247                        break;
 248                case HV_PROTOCOL_HVSI:
 249                        count = hvterm_hvsi_put_chars(0, &c, 1);
 250                        break;
 251                }
 252        } while(count == 0);
 253}
 254
 255static int udbg_hvc_getc_poll(void)
 256{
 257        int rc = 0;
 258        char c;
 259
 260        if (!hvterm_privs[0])
 261                return -1;
 262
 263        switch(hvterm_privs[0]->proto) {
 264        case HV_PROTOCOL_RAW:
 265                rc = hvterm_raw_get_chars(0, &c, 1);
 266                break;
 267        case HV_PROTOCOL_HVSI:
 268                rc = hvterm_hvsi_get_chars(0, &c, 1);
 269                break;
 270        }
 271        if (!rc)
 272                return -1;
 273        return c;
 274}
 275
 276static int udbg_hvc_getc(void)
 277{
 278        int ch;
 279
 280        if (!hvterm_privs[0])
 281                return -1;
 282
 283        for (;;) {
 284                ch = udbg_hvc_getc_poll();
 285                if (ch == -1) {
 286                        /* This shouldn't be needed...but... */
 287                        volatile unsigned long delay;
 288                        for (delay=0; delay < 2000000; delay++)
 289                                ;
 290                } else {
 291                        return ch;
 292                }
 293        }
 294}
 295
 296static int hvc_vio_probe(struct vio_dev *vdev,
 297                                   const struct vio_device_id *id)
 298{
 299        const struct hv_ops *ops;
 300        struct hvc_struct *hp;
 301        struct hvterm_priv *pv;
 302        hv_protocol_t proto;
 303        int i, termno = -1;
 304
 305        /* probed with invalid parameters. */
 306        if (!vdev || !id)
 307                return -EPERM;
 308
 309        if (of_device_is_compatible(vdev->dev.of_node, "hvterm1")) {
 310                proto = HV_PROTOCOL_RAW;
 311                ops = &hvterm_raw_ops;
 312        } else if (of_device_is_compatible(vdev->dev.of_node, "hvterm-protocol")) {
 313                proto = HV_PROTOCOL_HVSI;
 314                ops = &hvterm_hvsi_ops;
 315        } else {
 316                pr_err("hvc_vio: Unknown protocol for %pOF\n", vdev->dev.of_node);
 317                return -ENXIO;
 318        }
 319
 320        pr_devel("hvc_vio_probe() device %pOF, using %s protocol\n",
 321                 vdev->dev.of_node,
 322                 proto == HV_PROTOCOL_RAW ? "raw" : "hvsi");
 323
 324        /* Is it our boot one ? */
 325        if (hvterm_privs[0] == &hvterm_priv0 &&
 326            vdev->unit_address == hvterm_priv0.termno) {
 327                pv = hvterm_privs[0];
 328                termno = 0;
 329                pr_devel("->boot console, using termno 0\n");
 330        }
 331        /* nope, allocate a new one */
 332        else {
 333                for (i = 0; i < MAX_NR_HVC_CONSOLES && termno < 0; i++)
 334                        if (!hvterm_privs[i])
 335                                termno = i;
 336                pr_devel("->non-boot console, using termno %d\n", termno);
 337                if (termno < 0)
 338                        return -ENODEV;
 339                pv = kzalloc(sizeof(struct hvterm_priv), GFP_KERNEL);
 340                if (!pv)
 341                        return -ENOMEM;
 342                pv->termno = vdev->unit_address;
 343                pv->proto = proto;
 344                spin_lock_init(&pv->buf_lock);
 345                hvterm_privs[termno] = pv;
 346                hvsilib_init(&pv->hvsi, hvc_get_chars, hvc_put_chars,
 347                             pv->termno, 0);
 348        }
 349
 350        hp = hvc_alloc(termno, vdev->irq, ops, MAX_VIO_PUT_CHARS);
 351        if (IS_ERR(hp))
 352                return PTR_ERR(hp);
 353        dev_set_drvdata(&vdev->dev, hp);
 354
 355        /* register udbg if it's not there already for console 0 */
 356        if (hp->index == 0 && !udbg_putc) {
 357                udbg_putc = udbg_hvc_putc;
 358                udbg_getc = udbg_hvc_getc;
 359                udbg_getc_poll = udbg_hvc_getc_poll;
 360        }
 361
 362        return 0;
 363}
 364
 365static struct vio_driver hvc_vio_driver = {
 366        .id_table       = hvc_driver_table,
 367        .probe          = hvc_vio_probe,
 368        .name           = hvc_driver_name,
 369        .driver = {
 370                .suppress_bind_attrs    = true,
 371        },
 372};
 373
 374static int __init hvc_vio_init(void)
 375{
 376        int rc;
 377
 378        /* Register as a vio device to receive callbacks */
 379        rc = vio_register_driver(&hvc_vio_driver);
 380
 381        return rc;
 382}
 383device_initcall(hvc_vio_init); /* after drivers/tty/hvc/hvc_console.c */
 384
 385void __init hvc_vio_init_early(void)
 386{
 387        const __be32 *termno;
 388        const struct hv_ops *ops;
 389
 390        /* find the boot console from /chosen/stdout */
 391        /* Check if it's a virtual terminal */
 392        if (!of_node_name_prefix(of_stdout, "vty"))
 393                return;
 394        termno = of_get_property(of_stdout, "reg", NULL);
 395        if (termno == NULL)
 396                return;
 397        hvterm_priv0.termno = of_read_number(termno, 1);
 398        spin_lock_init(&hvterm_priv0.buf_lock);
 399        hvterm_privs[0] = &hvterm_priv0;
 400
 401        /* Check the protocol */
 402        if (of_device_is_compatible(of_stdout, "hvterm1")) {
 403                hvterm_priv0.proto = HV_PROTOCOL_RAW;
 404                ops = &hvterm_raw_ops;
 405        }
 406        else if (of_device_is_compatible(of_stdout, "hvterm-protocol")) {
 407                hvterm_priv0.proto = HV_PROTOCOL_HVSI;
 408                ops = &hvterm_hvsi_ops;
 409                hvsilib_init(&hvterm_priv0.hvsi, hvc_get_chars, hvc_put_chars,
 410                             hvterm_priv0.termno, 1);
 411                /* HVSI, perform the handshake now */
 412                hvsilib_establish(&hvterm_priv0.hvsi);
 413        } else
 414                return;
 415        udbg_putc = udbg_hvc_putc;
 416        udbg_getc = udbg_hvc_getc;
 417        udbg_getc_poll = udbg_hvc_getc_poll;
 418#ifdef HVC_OLD_HVSI
 419        /* When using the old HVSI driver don't register the HVC
 420         * backend for HVSI, only do udbg
 421         */
 422        if (hvterm_priv0.proto == HV_PROTOCOL_HVSI)
 423                return;
 424#endif
 425        /* Check whether the user has requested a different console. */
 426        if (!strstr(boot_command_line, "console="))
 427                add_preferred_console("hvc", 0, NULL);
 428        hvc_instantiate(0, 0, ops);
 429}
 430
 431/* call this from early_init() for a working debug console on
 432 * vterm capable LPAR machines
 433 */
 434#ifdef CONFIG_PPC_EARLY_DEBUG_LPAR
 435void __init udbg_init_debug_lpar(void)
 436{
 437        /*
 438         * If we're running as a hypervisor then we definitely can't call the
 439         * hypervisor to print debug output (we *are* the hypervisor), so don't
 440         * register if we detect that MSR_HV=1.
 441         */
 442        if (mfmsr() & MSR_HV)
 443                return;
 444
 445        hvterm_privs[0] = &hvterm_priv0;
 446        hvterm_priv0.termno = 0;
 447        hvterm_priv0.proto = HV_PROTOCOL_RAW;
 448        spin_lock_init(&hvterm_priv0.buf_lock);
 449        udbg_putc = udbg_hvc_putc;
 450        udbg_getc = udbg_hvc_getc;
 451        udbg_getc_poll = udbg_hvc_getc_poll;
 452}
 453#endif /* CONFIG_PPC_EARLY_DEBUG_LPAR */
 454
 455#ifdef CONFIG_PPC_EARLY_DEBUG_LPAR_HVSI
 456void __init udbg_init_debug_lpar_hvsi(void)
 457{
 458        /* See comment above in udbg_init_debug_lpar() */
 459        if (mfmsr() & MSR_HV)
 460                return;
 461
 462        hvterm_privs[0] = &hvterm_priv0;
 463        hvterm_priv0.termno = CONFIG_PPC_EARLY_DEBUG_HVSI_VTERMNO;
 464        hvterm_priv0.proto = HV_PROTOCOL_HVSI;
 465        spin_lock_init(&hvterm_priv0.buf_lock);
 466        udbg_putc = udbg_hvc_putc;
 467        udbg_getc = udbg_hvc_getc;
 468        udbg_getc_poll = udbg_hvc_getc_poll;
 469        hvsilib_init(&hvterm_priv0.hvsi, hvc_get_chars, hvc_put_chars,
 470                     hvterm_priv0.termno, 1);
 471        hvsilib_establish(&hvterm_priv0.hvsi);
 472}
 473#endif /* CONFIG_PPC_EARLY_DEBUG_LPAR_HVSI */
 474