tty/hvc/hvc_vio.c

0001 // SPDX-License-Identifier: GPL-2.0+
0002 /*
0003  * vio driver interface to hvc_console.c
0004  *
0005  * This code was moved here to allow the remaining code to be reused as a
0006  * generic polling mode with semi-reliable transport driver core to the
0007  * console and tty subsystems.
0008  *
0009  *
0010  * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
0011  * Copyright (C) 2001 Paul Mackerras <paulus@au.ibm.com>, IBM
0012  * Copyright (C) 2004 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp.
0013  * Copyright (C) 2004 IBM Corporation
0014  *
0015  * Additional Author(s):
0016  *  Ryan S. Arnold <rsa@us.ibm.com>
0017  *
0018  * TODO:
0019  *
0020  *   - handle error in sending hvsi protocol packets
0021  *   - retry nego on subsequent sends ?
0022  */
0023
0024 #undef DEBUG
0025
0026 #include <linux/types.h>
0027 #include <linux/init.h>
0028 #include <linux/delay.h>
0029 #include <linux/slab.h>
0030 #include <linux/console.h>
0031 #include <linux/of.h>
0032
0033 #include <asm/hvconsole.h>
0034 #include <asm/vio.h>
0035 #include <asm/hvsi.h>
0036 #include <asm/udbg.h>
0037 #include <asm/machdep.h>
0038
0039 #include "hvc_console.h"
0040
0041 static const char hvc_driver_name[] = "hvc_console";
0042
0043 static const struct vio_device_id hvc_driver_table[] = {
0044     {"serial", "hvterm1"},
0045 #ifndef HVC_OLD_HVSI
0046     {"serial", "hvterm-protocol"},
0047 #endif
0048     { "", "" }
0049 };
0050
0051 typedef enum hv_protocol {
0052     HV_PROTOCOL_RAW,
0053     HV_PROTOCOL_HVSI
0054 } hv_protocol_t;
0055
0056 struct hvterm_priv {
0057     u32         termno; /* HV term number */
0058     hv_protocol_t       proto;  /* Raw data or HVSI packets */
0059     struct hvsi_priv    hvsi;   /* HVSI specific data */
0060     spinlock_t      buf_lock;
0061     char            buf[SIZE_VIO_GET_CHARS];
0062     int         left;
0063     int         offset;
0064 };
0065 static struct hvterm_priv *hvterm_privs[MAX_NR_HVC_CONSOLES];
0066 /* For early boot console */
0067 static struct hvterm_priv hvterm_priv0;
0068
0069 static int hvterm_raw_get_chars(uint32_t vtermno, char *buf, int count)
0070 {
0071     struct hvterm_priv *pv = hvterm_privs[vtermno];
0072     unsigned long i;
0073     unsigned long flags;
0074     int got;
0075
0076     if (WARN_ON(!pv))
0077         return 0;
0078
0079     spin_lock_irqsave(&pv->buf_lock, flags);
0080
0081     if (pv->left == 0) {
0082         pv->offset = 0;
0083         pv->left = hvc_get_chars(pv->termno, pv->buf, count);
0084
0085         /*
0086          * Work around a HV bug where it gives us a null
0087          * after every \r.  -- paulus
0088          */
0089         for (i = 1; i < pv->left; ++i) {
0090             if (pv->buf[i] == 0 && pv->buf[i-1] == '\r') {
0091                 --pv->left;
0092                 if (i < pv->left) {
0093                     memmove(&pv->buf[i], &pv->buf[i+1],
0094                         pv->left - i);
0095                 }
0096             }
0097         }
0098     }
0099
0100     got = min(count, pv->left);
0101     memcpy(buf, &pv->buf[pv->offset], got);
0102     pv->offset += got;
0103     pv->left -= got;
0104
0105     spin_unlock_irqrestore(&pv->buf_lock, flags);
0106
0107     return got;
0108 }
0109
0110 /**
0111  * hvterm_raw_put_chars: send characters to firmware for given vterm adapter
0112  * @vtermno: The virtual terminal number.
0113  * @buf: The characters to send. Because of the underlying hypercall in
0114  *       hvc_put_chars(), this buffer must be at least 16 bytes long, even if
0115  *       you are sending fewer chars.
0116  * @count: number of chars to send.
0117  */
0118 static int hvterm_raw_put_chars(uint32_t vtermno, const char *buf, int count)
0119 {
0120     struct hvterm_priv *pv = hvterm_privs[vtermno];
0121
0122     if (WARN_ON(!pv))
0123         return 0;
0124
0125     return hvc_put_chars(pv->termno, buf, count);
0126 }
0127
0128 static const struct hv_ops hvterm_raw_ops = {
0129     .get_chars = hvterm_raw_get_chars,
0130     .put_chars = hvterm_raw_put_chars,
0131     .notifier_add = notifier_add_irq,
0132     .notifier_del = notifier_del_irq,
0133     .notifier_hangup = notifier_hangup_irq,
0134 };
0135
0136 static int hvterm_hvsi_get_chars(uint32_t vtermno, char *buf, int count)
0137 {
0138     struct hvterm_priv *pv = hvterm_privs[vtermno];
0139
0140     if (WARN_ON(!pv))
0141         return 0;
0142
0143     return hvsilib_get_chars(&pv->hvsi, buf, count);
0144 }
0145
0146 static int hvterm_hvsi_put_chars(uint32_t vtermno, const char *buf, int count)
0147 {
0148     struct hvterm_priv *pv = hvterm_privs[vtermno];
0149
0150     if (WARN_ON(!pv))
0151         return 0;
0152
0153     return hvsilib_put_chars(&pv->hvsi, buf, count);
0154 }
0155
0156 static int hvterm_hvsi_open(struct hvc_struct *hp, int data)
0157 {
0158     struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
0159     int rc;
0160
0161     pr_devel("HVSI@%x: open !\n", pv->termno);
0162
0163     rc = notifier_add_irq(hp, data);
0164     if (rc)
0165         return rc;
0166
0167     return hvsilib_open(&pv->hvsi, hp);
0168 }
0169
0170 static void hvterm_hvsi_close(struct hvc_struct *hp, int data)
0171 {
0172     struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
0173
0174     pr_devel("HVSI@%x: do close !\n", pv->termno);
0175
0176     hvsilib_close(&pv->hvsi, hp);
0177
0178     notifier_del_irq(hp, data);
0179 }
0180
0181 static void hvterm_hvsi_hangup(struct hvc_struct *hp, int data)
0182 {
0183     struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
0184
0185     pr_devel("HVSI@%x: do hangup !\n", pv->termno);
0186
0187     hvsilib_close(&pv->hvsi, hp);
0188
0189     notifier_hangup_irq(hp, data);
0190 }
0191
0192 static int hvterm_hvsi_tiocmget(struct hvc_struct *hp)
0193 {
0194     struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
0195
0196     if (!pv)
0197         return -EINVAL;
0198     return pv->hvsi.mctrl;
0199 }
0200
0201 static int hvterm_hvsi_tiocmset(struct hvc_struct *hp, unsigned int set,
0202                 unsigned int clear)
0203 {
0204     struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
0205
0206     pr_devel("HVSI@%x: Set modem control, set=%x,clr=%x\n",
0207          pv->termno, set, clear);
0208
0209     if (set & TIOCM_DTR)
0210         hvsilib_write_mctrl(&pv->hvsi, 1);
0211     else if (clear & TIOCM_DTR)
0212         hvsilib_write_mctrl(&pv->hvsi, 0);
0213
0214     return 0;
0215 }
0216
0217 static const struct hv_ops hvterm_hvsi_ops = {
0218     .get_chars = hvterm_hvsi_get_chars,
0219     .put_chars = hvterm_hvsi_put_chars,
0220     .notifier_add = hvterm_hvsi_open,
0221     .notifier_del = hvterm_hvsi_close,
0222     .notifier_hangup = hvterm_hvsi_hangup,
0223     .tiocmget = hvterm_hvsi_tiocmget,
0224     .tiocmset = hvterm_hvsi_tiocmset,
0225 };
0226
0227 static void udbg_hvc_putc(char c)
0228 {
0229     int count = -1;
0230     unsigned char bounce_buffer[16];
0231
0232     if (!hvterm_privs[0])
0233         return;
0234
0235     if (c == '\n')
0236         udbg_hvc_putc('\r');
0237
0238     do {
0239         switch(hvterm_privs[0]->proto) {
0240         case HV_PROTOCOL_RAW:
0241             /*
0242              * hvterm_raw_put_chars requires at least a 16-byte
0243              * buffer, so go via the bounce buffer
0244              */
0245             bounce_buffer[0] = c;
0246             count = hvterm_raw_put_chars(0, bounce_buffer, 1);
0247             break;
0248         case HV_PROTOCOL_HVSI:
0249             count = hvterm_hvsi_put_chars(0, &c, 1);
0250             break;
0251         }
0252     } while (count == 0 || count == -EAGAIN);
0253 }
0254
0255 static int udbg_hvc_getc_poll(void)
0256 {
0257     int rc = 0;
0258     char c;
0259
0260     if (!hvterm_privs[0])
0261         return -1;
0262
0263     switch(hvterm_privs[0]->proto) {
0264     case HV_PROTOCOL_RAW:
0265         rc = hvterm_raw_get_chars(0, &c, 1);
0266         break;
0267     case HV_PROTOCOL_HVSI:
0268         rc = hvterm_hvsi_get_chars(0, &c, 1);
0269         break;
0270     }
0271     if (!rc)
0272         return -1;
0273     return c;
0274 }
0275
0276 static int udbg_hvc_getc(void)
0277 {
0278     int ch;
0279
0280     if (!hvterm_privs[0])
0281         return -1;
0282
0283     for (;;) {
0284         ch = udbg_hvc_getc_poll();
0285         if (ch == -1) {
0286             /* This shouldn't be needed...but... */
0287             volatile unsigned long delay;
0288             for (delay=0; delay < 2000000; delay++)
0289                 ;
0290         } else {
0291             return ch;
0292         }
0293     }
0294 }
0295
0296 static int hvc_vio_probe(struct vio_dev *vdev,
0297                    const struct vio_device_id *id)
0298 {
0299     const struct hv_ops *ops;
0300     struct hvc_struct *hp;
0301     struct hvterm_priv *pv;
0302     hv_protocol_t proto;
0303     int i, termno = -1;
0304
0305     /* probed with invalid parameters. */
0306     if (!vdev || !id)
0307         return -EPERM;
0308
0309     if (of_device_is_compatible(vdev->dev.of_node, "hvterm1")) {
0310         proto = HV_PROTOCOL_RAW;
0311         ops = &hvterm_raw_ops;
0312     } else if (of_device_is_compatible(vdev->dev.of_node, "hvterm-protocol")) {
0313         proto = HV_PROTOCOL_HVSI;
0314         ops = &hvterm_hvsi_ops;
0315     } else {
0316         pr_err("hvc_vio: Unknown protocol for %pOF\n", vdev->dev.of_node);
0317         return -ENXIO;
0318     }
0319
0320     pr_devel("hvc_vio_probe() device %pOF, using %s protocol\n",
0321          vdev->dev.of_node,
0322          proto == HV_PROTOCOL_RAW ? "raw" : "hvsi");
0323
0324     /* Is it our boot one ? */
0325     if (hvterm_privs[0] == &hvterm_priv0 &&
0326         vdev->unit_address == hvterm_priv0.termno) {
0327         pv = hvterm_privs[0];
0328         termno = 0;
0329         pr_devel("->boot console, using termno 0\n");
0330     }
0331     /* nope, allocate a new one */
0332     else {
0333         for (i = 0; i < MAX_NR_HVC_CONSOLES && termno < 0; i++)
0334             if (!hvterm_privs[i])
0335                 termno = i;
0336         pr_devel("->non-boot console, using termno %d\n", termno);
0337         if (termno < 0)
0338             return -ENODEV;
0339         pv = kzalloc(sizeof(struct hvterm_priv), GFP_KERNEL);
0340         if (!pv)
0341             return -ENOMEM;
0342         pv->termno = vdev->unit_address;
0343         pv->proto = proto;
0344         spin_lock_init(&pv->buf_lock);
0345         hvterm_privs[termno] = pv;
0346         hvsilib_init(&pv->hvsi, hvc_get_chars, hvc_put_chars,
0347                  pv->termno, 0);
0348     }
0349
0350     hp = hvc_alloc(termno, vdev->irq, ops, MAX_VIO_PUT_CHARS);
0351     if (IS_ERR(hp))
0352         return PTR_ERR(hp);
0353     dev_set_drvdata(&vdev->dev, hp);
0354
0355     /* register udbg if it's not there already for console 0 */
0356     if (hp->index == 0 && !udbg_putc) {
0357         udbg_putc = udbg_hvc_putc;
0358         udbg_getc = udbg_hvc_getc;
0359         udbg_getc_poll = udbg_hvc_getc_poll;
0360     }
0361
0362     return 0;
0363 }
0364
0365 static struct vio_driver hvc_vio_driver = {
0366     .id_table   = hvc_driver_table,
0367     .probe      = hvc_vio_probe,
0368     .name       = hvc_driver_name,
0369     .driver = {
0370         .suppress_bind_attrs    = true,
0371     },
0372 };
0373
0374 static int __init hvc_vio_init(void)
0375 {
0376     int rc;
0377
0378     /* Register as a vio device to receive callbacks */
0379     rc = vio_register_driver(&hvc_vio_driver);
0380
0381     return rc;
0382 }
0383 device_initcall(hvc_vio_init); /* after drivers/tty/hvc/hvc_console.c */
0384
0385 void __init hvc_vio_init_early(void)
0386 {
0387     const __be32 *termno;
0388     const struct hv_ops *ops;
0389
0390     /* find the boot console from /chosen/stdout */
0391     /* Check if it's a virtual terminal */
0392     if (!of_node_name_prefix(of_stdout, "vty"))
0393         return;
0394     termno = of_get_property(of_stdout, "reg", NULL);
0395     if (termno == NULL)
0396         return;
0397     hvterm_priv0.termno = of_read_number(termno, 1);
0398     spin_lock_init(&hvterm_priv0.buf_lock);
0399     hvterm_privs[0] = &hvterm_priv0;
0400
0401     /* Check the protocol */
0402     if (of_device_is_compatible(of_stdout, "hvterm1")) {
0403         hvterm_priv0.proto = HV_PROTOCOL_RAW;
0404         ops = &hvterm_raw_ops;
0405     }
0406     else if (of_device_is_compatible(of_stdout, "hvterm-protocol")) {
0407         hvterm_priv0.proto = HV_PROTOCOL_HVSI;
0408         ops = &hvterm_hvsi_ops;
0409         hvsilib_init(&hvterm_priv0.hvsi, hvc_get_chars, hvc_put_chars,
0410                  hvterm_priv0.termno, 1);
0411         /* HVSI, perform the handshake now */
0412         hvsilib_establish(&hvterm_priv0.hvsi);
0413     } else
0414         return;
0415     udbg_putc = udbg_hvc_putc;
0416     udbg_getc = udbg_hvc_getc;
0417     udbg_getc_poll = udbg_hvc_getc_poll;
0418 #ifdef HVC_OLD_HVSI
0419     /* When using the old HVSI driver don't register the HVC
0420      * backend for HVSI, only do udbg
0421      */
0422     if (hvterm_priv0.proto == HV_PROTOCOL_HVSI)
0423         return;
0424 #endif
0425     /* Check whether the user has requested a different console. */
0426     if (!strstr(boot_command_line, "console="))
0427         add_preferred_console("hvc", 0, NULL);
0428     hvc_instantiate(0, 0, ops);
0429 }
0430
0431 /* call this from early_init() for a working debug console on
0432  * vterm capable LPAR machines
0433  */
0434 #ifdef CONFIG_PPC_EARLY_DEBUG_LPAR
0435 void __init udbg_init_debug_lpar(void)
0436 {
0437     /*
0438      * If we're running as a hypervisor then we definitely can't call the
0439      * hypervisor to print debug output (we *are* the hypervisor), so don't
0440      * register if we detect that MSR_HV=1.
0441      */
0442     if (mfmsr() & MSR_HV)
0443         return;
0444
0445     hvterm_privs[0] = &hvterm_priv0;
0446     hvterm_priv0.termno = 0;
0447     hvterm_priv0.proto = HV_PROTOCOL_RAW;
0448     spin_lock_init(&hvterm_priv0.buf_lock);
0449     udbg_putc = udbg_hvc_putc;
0450     udbg_getc = udbg_hvc_getc;
0451     udbg_getc_poll = udbg_hvc_getc_poll;
0452 }
0453 #endif /* CONFIG_PPC_EARLY_DEBUG_LPAR */
0454
0455 #ifdef CONFIG_PPC_EARLY_DEBUG_LPAR_HVSI
0456 void __init udbg_init_debug_lpar_hvsi(void)
0457 {
0458     /* See comment above in udbg_init_debug_lpar() */
0459     if (mfmsr() & MSR_HV)
0460         return;
0461
0462     hvterm_privs[0] = &hvterm_priv0;
0463     hvterm_priv0.termno = CONFIG_PPC_EARLY_DEBUG_HVSI_VTERMNO;
0464     hvterm_priv0.proto = HV_PROTOCOL_HVSI;
0465     spin_lock_init(&hvterm_priv0.buf_lock);
0466     udbg_putc = udbg_hvc_putc;
0467     udbg_getc = udbg_hvc_getc;
0468     udbg_getc_poll = udbg_hvc_getc_poll;
0469     hvsilib_init(&hvterm_priv0.hvsi, hvc_get_chars, hvc_put_chars,
0470              hvterm_priv0.termno, 1);
0471     hvsilib_establish(&hvterm_priv0.hvsi);
0472 }
0473 #endif /* CONFIG_PPC_EARLY_DEBUG_LPAR_HVSI */