drivers/tty/hvc/hvc_vio.c

   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
  41 static const char hvc_driver_name[] = "hvc_console";
  42
  43 static 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
  51 typedef enum hv_protocol {
  52         HV_PROTOCOL_RAW,
  53         HV_PROTOCOL_HVSI
  54 } hv_protocol_t;
  55
  56 struct 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 };
  65 static struct hvterm_priv *hvterm_privs[MAX_NR_HVC_CONSOLES];
  66 /* For early boot console */
  67 static struct hvterm_priv hvterm_priv0;
  68
  69 static 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  */
 118 static 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
 128 static 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
 136 static 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
 146 static 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
 156 static 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
 170 static 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
 181 static void 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
 192 static 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
 201 static 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
 217 static 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
 227 static 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
 255 static 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
 276 static 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
 296 static 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
 365 static 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
 374 static 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 }
 383 device_initcall(hvc_vio_init); /* after drivers/tty/hvc/hvc_console.c */
 384
 385 void __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
 435 void __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
 456 void __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 */