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Subject[PATCH] HVSI driver
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Hi Andrew, this is a console driver for IBM's p5 servers; please
consider it for inclusion. I've addressed all the comments I've received
so far.

Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>

--
Hollis Blanchard
IBM Linux Technology Center

===== drivers/char/Makefile 1.75 vs edited =====
--- 1.75/drivers/char/Makefile Wed Jul 28 23:58:35 2004
+++ edited/drivers/char/Makefile Fri Aug 6 12:04:45 2004
@@ -39,7 +39,7 @@
obj-$(CONFIG_AMIGA_BUILTIN_SERIAL) += amiserial.o
obj-$(CONFIG_SX) += sx.o generic_serial.o
obj-$(CONFIG_RIO) += rio/ generic_serial.o
-obj-$(CONFIG_HVC_CONSOLE) += hvc_console.o
+obj-$(CONFIG_HVC_CONSOLE) += hvc_console.o hvsi.o
obj-$(CONFIG_RAW_DRIVER) += raw.o
obj-$(CONFIG_VIOCONS) += viocons.o
obj-$(CONFIG_VIOTAPE) += viotape.o
===== arch/ppc64/kernel/setup.c 1.62 vs edited =====
--- 1.62/arch/ppc64/kernel/setup.c Fri Jul 2 00:23:46 2004
+++ edited/arch/ppc64/kernel/setup.c Fri Aug 6 12:09:28 2004
@@ -516,10 +516,29 @@
return -ENODEV;
}
}
- } else if (strcmp(name, "vty") == 0)
- /* pSeries LPAR virtual console */
- return add_preferred_console("hvc", 0, NULL);
- else if (strcmp(name, "ch-a") == 0)
+ } else if (strcmp(name, "vty") == 0) {
+ u32 *reg = (u32 *)get_property(prom_stdout, "reg", NULL);
+ char *compat = (char *)get_property(prom_stdout, "compatible", NULL);
+
+ if (reg && compat && (strcmp(compat, "hvterm-protocol") == 0)) {
+ /* Host Virtual Serial Interface */
+ int offset;
+ switch (reg[0]) {
+ case 0x30000000:
+ offset = 0;
+ break;
+ case 0x30000001:
+ offset = 1;
+ break;
+ default:
+ return -ENODEV;
+ }
+ return add_preferred_console("hvsi", offset, NULL);
+ } else {
+ /* pSeries LPAR virtual console */
+ return add_preferred_console("hvc", 0, NULL);
+ }
+ } else if (strcmp(name, "ch-a") == 0)
offset = 0;
else if (strcmp(name, "ch-b") == 0)
offset = 1;
--- /dev/null 2003-01-30 04:24:37.000000000 -0600
+++ linux/drivers/char/hvsi.c 2004-08-18 12:46:36.000000000 -0500
@@ -0,0 +1,1319 @@
+/*
+ * Copyright (C) 2004 Hollis Blanchard <hollisb@us.ibm.com>, IBM
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+/* Host Virtual Serial Interface (HVSI) is a protocol between the hosted OS
+ * and the service processor on IBM pSeries servers. On these servers, there
+ * are no serial ports under the OS's control, and sometimes there is no other
+ * console available either. However, the service processor has two standard
+ * serial ports, so this over-complicated protocol allows the OS to control
+ * those ports by proxy.
+ *
+ * Besides data, the procotol supports the reading/writing of the serial
+ * port's DTR line, and the reading of the CD line. This is to allow the OS to
+ * control a modem attached to the service processor's serial port. Note that
+ * the OS cannot change the speed of the port through this protocol.
+ */
+
+/* TODO:
+ * test FSP reset
+ * add udbg support for xmon/kdb
+ */
+
+#undef DEBUG
+
+#include <linux/console.h>
+#include <linux/ctype.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/major.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/sysrq.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <asm/hvcall.h>
+#include <asm/hvconsole.h>
+#include <asm/prom.h>
+#include <asm/uaccess.h>
+#include <asm/vio.h>
+
+#define HVSI_MAJOR 229
+#define HVSI_MINOR 128
+#define MAX_NR_HVSI_CONSOLES 4
+
+#define HVSI_TIMEOUT (5*HZ)
+#define HVSI_VERSION 1
+#define HVSI_MAX_PACKET 256
+#define HVSI_MAX_READ 16
+#define HVSI_MAX_OUTGOING_DATA 12
+#define N_OUTBUF 12
+
+/*
+ * we pass data via two 8-byte registers, so we would like our char arrays
+ * properly aligned for those loads.
+ */
+#define __ALIGNED__ __attribute__((__aligned__(sizeof(long))))
+
+struct hvsi_struct {
+ struct work_struct writer;
+ wait_queue_head_t emptyq; /* woken when outbuf is emptied */
+ wait_queue_head_t stateq; /* woken when HVSI state changes */
+ spinlock_t lock;
+ int index;
+ struct tty_struct *tty;
+ unsigned int count;
+ uint8_t throttle_buf[128];
+ uint8_t outbuf[N_OUTBUF]; /* to implement write_room and chars_in_buffer */
+ /* inbuf is for packet reassembly. leave a little room for leftovers. */
+ uint8_t inbuf[HVSI_MAX_PACKET + HVSI_MAX_READ];
+ uint8_t *inbuf_end;
+ int n_throttle;
+ int n_outbuf;
+ uint32_t vtermno;
+ uint32_t virq;
+ atomic_t seqno; /* HVSI packet sequence number */
+ uint16_t mctrl;
+ uint8_t state; /* HVSI protocol state */
+ uint8_t flags;
+#ifdef CONFIG_MAGIC_SYSRQ
+ uint8_t sysrq;
+#endif /* CONFIG_MAGIC_SYSRQ */
+};
+static struct hvsi_struct hvsi_ports[MAX_NR_HVSI_CONSOLES];
+
+static struct tty_driver *hvsi_driver;
+static int hvsi_count;
+static int (*hvsi_wait)(struct hvsi_struct *hp, int state);
+
+enum HVSI_PROTOCOL_STATE {
+ HVSI_CLOSED,
+ HVSI_WAIT_FOR_VER_RESPONSE,
+ HVSI_WAIT_FOR_VER_QUERY,
+ HVSI_OPEN,
+ HVSI_WAIT_FOR_MCTRL_RESPONSE,
+};
+#define HVSI_CONSOLE 0x1
+
+#define VS_DATA_PACKET_HEADER 0xff
+#define VS_CONTROL_PACKET_HEADER 0xfe
+#define VS_QUERY_PACKET_HEADER 0xfd
+#define VS_QUERY_RESPONSE_PACKET_HEADER 0xfc
+
+/* control verbs */
+#define VSV_SET_MODEM_CTL 1 /* to service processor only */
+#define VSV_MODEM_CTL_UPDATE 2 /* from service processor only */
+#define VSV_CLOSE_PROTOCOL 3
+
+/* query verbs */
+#define VSV_SEND_VERSION_NUMBER 1
+#define VSV_SEND_MODEM_CTL_STATUS 2
+
+/* yes, these masks are not consecutive. */
+#define HVSI_TSDTR 0x01
+#define HVSI_TSCD 0x20
+
+struct hvsi_header {
+ uint8_t type;
+ uint8_t len;
+ uint16_t seqno;
+} __attribute__((packed));
+
+struct hvsi_data {
+ uint8_t type;
+ uint8_t len;
+ uint16_t seqno;
+ uint8_t data[HVSI_MAX_OUTGOING_DATA];
+} __attribute__((packed));
+
+struct hvsi_control {
+ uint8_t type;
+ uint8_t len;
+ uint16_t seqno;
+ uint16_t verb;
+ /* optional depending on verb: */
+ uint32_t word;
+ uint32_t mask;
+} __attribute__((packed));
+
+struct hvsi_query {
+ uint8_t type;
+ uint8_t len;
+ uint16_t seqno;
+ uint16_t verb;
+} __attribute__((packed));
+
+struct hvsi_query_response {
+ uint8_t type;
+ uint8_t len;
+ uint16_t seqno;
+ uint16_t verb;
+ uint16_t query_seqno;
+ union {
+ uint8_t version;
+ uint32_t mctrl_word;
+ } u;
+} __attribute__((packed));
+
+static inline int is_open(struct hvsi_struct *hp)
+{
+ /* if we're waiting for an mctrl then we're already open */
+ return (hp->state == HVSI_OPEN)
+ || (hp->state == HVSI_WAIT_FOR_MCTRL_RESPONSE);
+}
+
+static inline void print_state(struct hvsi_struct *hp)
+{
+#ifdef DEBUG
+ static const char *state_names[] = {
+ "HVSI_CLOSED",
+ "HVSI_WAIT_FOR_VER_RESPONSE",
+ "HVSI_WAIT_FOR_VER_QUERY",
+ "HVSI_OPEN",
+ "HVSI_WAIT_FOR_MCTRL_RESPONSE",
+ };
+ const char *name = state_names[hp->state];
+
+ if (hp->state > (sizeof(state_names)/sizeof(char*)))
+ name = "UNKNOWN";
+
+ pr_debug("hvsi%i: state = %s\n", hp->index, name);
+#endif /* DEBUG */
+}
+
+static inline void __set_state(struct hvsi_struct *hp, int state)
+{
+ hp->state = state;
+ print_state(hp);
+ wake_up_all(&hp->stateq);
+}
+
+static inline void set_state(struct hvsi_struct *hp, int state)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&hp->lock, flags);
+ __set_state(hp, state);
+ spin_unlock_irqrestore(&hp->lock, flags);
+}
+
+static inline int len_packet(const uint8_t *packet)
+{
+ return (int)((struct hvsi_header *)packet)->len;
+}
+
+static inline int is_header(const uint8_t *packet)
+{
+ struct hvsi_header *header = (struct hvsi_header *)packet;
+ return header->type >= VS_QUERY_RESPONSE_PACKET_HEADER;
+}
+
+static inline int got_packet(const struct hvsi_struct *hp, uint8_t *packet)
+{
+ if (hp->inbuf_end < packet + sizeof(struct hvsi_header))
+ return 0; /* don't even have the packet header */
+
+ if (hp->inbuf_end < (packet + len_packet(packet)))
+ return 0; /* don't have the rest of the packet */
+
+ return 1;
+}
+
+/* shift remaining bytes in packetbuf down */
+static void compact_inbuf(struct hvsi_struct *hp, uint8_t *read_to)
+{
+ int remaining = (int)(hp->inbuf_end - read_to);
+
+ pr_debug("%s: %i chars remain\n", __FUNCTION__, remaining);
+
+ if (read_to != hp->inbuf)
+ memmove(hp->inbuf, read_to, remaining);
+
+ hp->inbuf_end = hp->inbuf + remaining;
+}
+
+#ifdef DEBUG
+#define dbg_dump_packet(packet) dump_packet(packet)
+#define dbg_dump_hex(data, len) dump_hex(data, len)
+#else
+#define dbg_dump_packet(packet) do { } while (0)
+#define dbg_dump_hex(data, len) do { } while (0)
+#endif
+
+static void dump_hex(const uint8_t *data, int len)
+{
+ int i;
+
+ printk(" ");
+ for (i=0; i < len; i++)
+ printk("%.2x", data[i]);
+
+ printk("\n ");
+ for (i=0; i < len; i++) {
+ if (isprint(data[i]))
+ printk("%c", data[i]);
+ else
+ printk(".");
+ }
+ printk("\n");
+}
+
+static void dump_packet(uint8_t *packet)
+{
+ struct hvsi_header *header = (struct hvsi_header *)packet;
+
+ printk("type 0x%x, len %i, seqno %i:\n", header->type, header->len,
+ header->seqno);
+
+ dump_hex(packet, header->len);
+}
+
+/* can't use hvc_get_chars because that strips CRs */
+static int hvsi_read(struct hvsi_struct *hp, char *buf, int count)
+{
+ unsigned long got;
+
+ if (plpar_hcall(H_GET_TERM_CHAR, hp->vtermno, 0, 0, 0, &got,
+ (unsigned long *)buf, (unsigned long *)buf+1) == H_Success)
+ return got;
+ return 0;
+}
+
+/*
+ * we can't call tty_hangup() directly here because we need to call that
+ * outside of our lock
+ */
+static struct tty_struct *hvsi_recv_control(struct hvsi_struct *hp,
+ uint8_t *packet)
+{
+ struct tty_struct *to_hangup = NULL;
+ struct hvsi_control *header = (struct hvsi_control *)packet;
+
+ switch (header->verb) {
+ case VSV_MODEM_CTL_UPDATE:
+ if ((header->word & HVSI_TSCD) == 0) {
+ /* CD went away; no more connection */
+ pr_debug("hvsi%i: CD dropped\n", hp->index);
+ hp->mctrl &= TIOCM_CD;
+ if (!(hp->tty->flags & CLOCAL))
+ to_hangup = hp->tty;
+ }
+ break;
+ case VSV_CLOSE_PROTOCOL:
+ printk(KERN_DEBUG
+ "hvsi%i: service processor closed connection!\n", hp->index);
+ __set_state(hp, HVSI_CLOSED);
+ to_hangup = hp->tty;
+ hp->tty = NULL;
+ break;
+ default:
+ printk(KERN_WARNING "hvsi%i: unknown HVSI control packet: ",
+ hp->index);
+ dump_packet(packet);
+ break;
+ }
+
+ return to_hangup;
+}
+
+static void hvsi_recv_response(struct hvsi_struct *hp, uint8_t *packet)
+{
+ struct hvsi_query_response *resp = (struct hvsi_query_response *)packet;
+
+ switch (hp->state) {
+ case HVSI_WAIT_FOR_VER_RESPONSE:
+ __set_state(hp, HVSI_WAIT_FOR_VER_QUERY);
+ break;
+ case HVSI_WAIT_FOR_MCTRL_RESPONSE:
+ hp->mctrl = 0;
+ if (resp->u.mctrl_word & HVSI_TSDTR)
+ hp->mctrl |= TIOCM_DTR;
+ if (resp->u.mctrl_word & HVSI_TSCD)
+ hp->mctrl |= TIOCM_CD;
+ __set_state(hp, HVSI_OPEN);
+ break;
+ default:
+ printk(KERN_ERR "hvsi%i: unexpected query response: ", hp->index);
+ dump_packet(packet);
+ break;
+ }
+}
+
+/* respond to service processor's version query */
+static int hvsi_version_respond(struct hvsi_struct *hp, uint16_t query_seqno)
+{
+ struct hvsi_query_response packet __ALIGNED__;
+ int wrote;
+
+ packet.type = VS_QUERY_RESPONSE_PACKET_HEADER;
+ packet.len = sizeof(struct hvsi_query_response);
+ packet.seqno = atomic_inc_return(&hp->seqno);
+ packet.verb = VSV_SEND_VERSION_NUMBER;
+ packet.u.version = HVSI_VERSION;
+ packet.query_seqno = query_seqno+1;
+
+ pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
+ dbg_dump_hex((uint8_t*)&packet, packet.len);
+
+ wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
+ if (wrote != packet.len) {
+ printk(KERN_ERR "hvsi%i: couldn't send query response!\n",
+ hp->index);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static void hvsi_recv_query(struct hvsi_struct *hp, uint8_t *packet)
+{
+ struct hvsi_query *query = (struct hvsi_query *)packet;
+
+ switch (hp->state) {
+ case HVSI_WAIT_FOR_VER_QUERY:
+ __set_state(hp, HVSI_OPEN);
+ hvsi_version_respond(hp, query->seqno);
+ break;
+ default:
+ printk(KERN_ERR "hvsi%i: unexpected query: ", hp->index);
+ dump_packet(packet);
+ break;
+ }
+}
+
+static void hvsi_insert_chars(struct hvsi_struct *hp, const char *buf, int len)
+{
+ int i;
+
+ for (i=0; i < len; i++) {
+ char c = buf[i];
+#ifdef CONFIG_MAGIC_SYSRQ
+ if (c == '\0') {
+ hp->sysrq = 1;
+ continue;
+ } else if (hp->sysrq) {
+ handle_sysrq(c, NULL, hp->tty);
+ hp->sysrq = 0;
+ continue;
+ }
+#endif /* CONFIG_MAGIC_SYSRQ */
+ tty_insert_flip_char(hp->tty, c, 0);
+ }
+}
+
+/*
+ * We could get 252 bytes of data at once here. But the tty layer only
+ * throttles us at TTY_THRESHOLD_THROTTLE (128) bytes, so we could overflow
+ * it. Accordingly we won't send more than 128 bytes at a time to the flip
+ * buffer, which will give the tty buffer a chance to throttle us. Should the
+ * value of TTY_THRESHOLD_THROTTLE change in n_tty.c, this code should be
+ * revisited.
+ */
+#define TTY_THRESHOLD_THROTTLE 128
+static struct tty_struct *hvsi_recv_data(struct hvsi_struct *hp,
+ const uint8_t *packet)
+{
+ const struct hvsi_header *header = (const struct hvsi_header *)packet;
+ const uint8_t *data = packet + sizeof(struct hvsi_header);
+ int datalen = header->len - sizeof(struct hvsi_header);
+ int overflow = datalen - TTY_THRESHOLD_THROTTLE;
+
+ pr_debug("queueing %i chars '%.*s'\n", datalen, datalen, data);
+
+ if (datalen == 0)
+ return NULL;
+
+ if (overflow > 0) {
+ pr_debug("%s: got >TTY_THRESHOLD_THROTTLE bytes\n", __FUNCTION__);
+ datalen = TTY_THRESHOLD_THROTTLE;
+ }
+
+ hvsi_insert_chars(hp, data, datalen);
+
+ if (overflow > 0) {
+ /*
+ * we still have more data to deliver, so we need to save off the
+ * overflow and send it later
+ */
+ pr_debug("%s: deferring overflow\n", __FUNCTION__);
+ memcpy(hp->throttle_buf, data + TTY_THRESHOLD_THROTTLE, overflow);
+ hp->n_throttle = overflow;
+ }
+
+ return hp->tty;
+}
+
+/*
+ * Returns true/false indicating data successfully read from hypervisor.
+ * Used both to get packets for tty connections and to advance the state
+ * machine during console handshaking (in which case tty = NULL and we ignore
+ * incoming data).
+ */
+static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct **flip,
+ struct tty_struct **hangup)
+{
+ uint8_t *packet = hp->inbuf;
+ int chunklen;
+
+ *flip = NULL;
+ *hangup = NULL;
+
+ chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ);
+ if (chunklen == 0)
+ return 0;
+
+ pr_debug("%s: got %i bytes\n", __FUNCTION__, chunklen);
+ dbg_dump_hex(hp->inbuf_end, chunklen);
+
+ hp->inbuf_end += chunklen;
+
+ /* handle all completed packets */
+ while ((packet < hp->inbuf_end) && got_packet(hp, packet)) {
+ struct hvsi_header *header = (struct hvsi_header *)packet;
+
+ if (!is_header(packet)) {
+ printk(KERN_ERR "hvsi%i: got malformed packet\n", hp->index);
+ /* skip bytes until we find a header or run out of data */
+ while ((packet < hp->inbuf_end) && (!is_header(packet)))
+ packet++;
+ continue;
+ }
+
+ pr_debug("%s: handling %i-byte packet\n", __FUNCTION__,
+ len_packet(packet));
+ dbg_dump_packet(packet);
+
+ switch (header->type) {
+ case VS_DATA_PACKET_HEADER:
+ if (!is_open(hp))
+ break;
+ if (hp->tty == NULL)
+ break; /* no tty buffer to put data in */
+ *flip = hvsi_recv_data(hp, packet);
+ break;
+ case VS_CONTROL_PACKET_HEADER:
+ *hangup = hvsi_recv_control(hp, packet);
+ break;
+ case VS_QUERY_RESPONSE_PACKET_HEADER:
+ hvsi_recv_response(hp, packet);
+ break;
+ case VS_QUERY_PACKET_HEADER:
+ hvsi_recv_query(hp, packet);
+ break;
+ default:
+ printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n",
+ hp->index, header->type);
+ dump_packet(packet);
+ break;
+ }
+
+ packet += len_packet(packet);
+
+ if (*hangup) {
+ pr_debug("%s: hangup\n", __FUNCTION__);
+ /*
+ * we need to send the hangup now before receiving any more data.
+ * If we get "data, hangup, data", we can't deliver the second
+ * data before the hangup.
+ */
+ break;
+ }
+ }
+
+ compact_inbuf(hp, packet);
+
+ return 1;
+}
+
+static void hvsi_send_overflow(struct hvsi_struct *hp)
+{
+ pr_debug("%s: delivering %i bytes overflow\n", __FUNCTION__,
+ hp->n_throttle);
+
+ hvsi_insert_chars(hp, hp->throttle_buf, hp->n_throttle);
+ hp->n_throttle = 0;
+}
+
+/*
+ * must get all pending data because we only get an irq on empty->non-empty
+ * transition
+ */
+static irqreturn_t hvsi_interrupt(int irq, void *arg, struct pt_regs *regs)
+{
+ struct hvsi_struct *hp = (struct hvsi_struct *)arg;
+ struct tty_struct *flip;
+ struct tty_struct *hangup;
+ unsigned long flags;
+ irqreturn_t handled = IRQ_NONE;
+ int again = 1;
+
+ pr_debug("%s\n", __FUNCTION__);
+
+ while (again) {
+ spin_lock_irqsave(&hp->lock, flags);
+ again = hvsi_load_chunk(hp, &flip, &hangup);
+ handled = IRQ_HANDLED;
+ spin_unlock_irqrestore(&hp->lock, flags);
+
+ /*
+ * we have to call tty_flip_buffer_push() and tty_hangup() outside our
+ * spinlock. But we also have to keep going until we've read all the
+ * available data.
+ */
+
+ if (flip) {
+ /* there was data put in the tty flip buffer */
+ tty_flip_buffer_push(flip);
+ flip = NULL;
+ }
+
+ if (hangup) {
+ tty_hangup(hangup);
+ }
+ }
+
+ spin_lock_irqsave(&hp->lock, flags);
+ if (hp->tty && hp->n_throttle
+ && (!test_bit(TTY_THROTTLED, &hp->tty->flags))) {
+ /* we weren't hung up and we weren't throttled, so we can deliver the
+ * rest now */
+ flip = hp->tty;
+ hvsi_send_overflow(hp);
+ }
+ spin_unlock_irqrestore(&hp->lock, flags);
+
+ if (flip) {
+ tty_flip_buffer_push(flip);
+ }
+
+ return handled;
+}
+
+/* for boot console, before the irq handler is running */
+static int __init poll_for_state(struct hvsi_struct *hp, int state)
+{
+ unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
+
+ for (;;) {
+ hvsi_interrupt(hp->virq, (void *)hp, NULL); /* get pending data */
+
+ if (hp->state == state)
+ return 0;
+
+ mdelay(5);
+ if (time_after(jiffies, end_jiffies))
+ return -EIO;
+ }
+}
+
+/* wait for irq handler to change our state */
+static int wait_for_state(struct hvsi_struct *hp, int state)
+{
+ unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
+ unsigned long timeout;
+ int ret = 0;
+
+ DECLARE_WAITQUEUE(myself, current);
+ set_current_state(TASK_INTERRUPTIBLE);
+ add_wait_queue(&hp->stateq, &myself);
+
+ for (;;) {
+ set_current_state(TASK_INTERRUPTIBLE);
+ if (hp->state == state)
+ break;
+ timeout = end_jiffies - jiffies;
+ if (time_after(jiffies, end_jiffies)) {
+ ret = -EIO;
+ break;
+ }
+ schedule_timeout(timeout);
+ }
+ remove_wait_queue(&hp->stateq, &myself);
+ set_current_state(TASK_RUNNING);
+
+ return ret;
+}
+
+static int hvsi_query(struct hvsi_struct *hp, uint16_t verb)
+{
+ struct hvsi_query packet __ALIGNED__;
+ int wrote;
+
+ packet.type = VS_QUERY_PACKET_HEADER;
+ packet.len = sizeof(struct hvsi_query);
+ packet.seqno = atomic_inc_return(&hp->seqno);
+ packet.verb = verb;
+
+ pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
+ dbg_dump_hex((uint8_t*)&packet, packet.len);
+
+ wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
+ if (wrote != packet.len) {
+ printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index,
+ wrote);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int hvsi_get_mctrl(struct hvsi_struct *hp)
+{
+ int ret;
+
+ set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE);
+ hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS);
+
+ ret = hvsi_wait(hp, HVSI_OPEN);
+ if (ret < 0) {
+ printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index);
+ set_state(hp, HVSI_OPEN);
+ return ret;
+ }
+
+ pr_debug("%s: mctrl 0x%x\n", __FUNCTION__, hp->mctrl);
+
+ return 0;
+}
+
+/* note that we can only set DTR */
+static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl)
+{
+ struct hvsi_control packet __ALIGNED__;
+ int wrote;
+
+ packet.type = VS_CONTROL_PACKET_HEADER,
+ packet.seqno = atomic_inc_return(&hp->seqno);
+ packet.len = sizeof(struct hvsi_control);
+ packet.verb = VSV_SET_MODEM_CTL;
+ packet.mask = HVSI_TSDTR;
+
+ if (mctrl & TIOCM_DTR)
+ packet.word = HVSI_TSDTR;
+
+ pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
+ dbg_dump_hex((uint8_t*)&packet, packet.len);
+
+ wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
+ if (wrote != packet.len) {
+ printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static void hvsi_drain_input(struct hvsi_struct *hp)
+{
+ uint8_t buf[HVSI_MAX_READ] __ALIGNED__;
+ unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
+
+ while (time_before(end_jiffies, jiffies))
+ if (0 == hvsi_read(hp, buf, HVSI_MAX_READ))
+ break;
+}
+
+static int hvsi_handshake(struct hvsi_struct *hp)
+{
+ int ret;
+
+ /*
+ * We could have a CLOSE or other data waiting for us before we even try
+ * to open; try to throw it all away so we don't get confused. (CLOSE
+ * is the first message sent up the pipe when the FSP comes online. We
+ * need to distinguish between "it came up a while ago and we're the first
+ * user" and "it was just reset before it saw our handshake packet".)
+ */
+ hvsi_drain_input(hp);
+
+ set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE);
+ ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER);
+ if (ret < 0) {
+ printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index);
+ return ret;
+ }
+
+ ret = hvsi_wait(hp, HVSI_OPEN);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+static int hvsi_put_chars(struct hvsi_struct *hp, const char *buf, int count)
+{
+ struct hvsi_data packet __ALIGNED__;
+ int ret;
+
+ BUG_ON(count > HVSI_MAX_OUTGOING_DATA);
+
+ packet.type = VS_DATA_PACKET_HEADER;
+ packet.seqno = atomic_inc_return(&hp->seqno);
+ packet.len = count + sizeof(struct hvsi_header);
+ memcpy(&packet.data, buf, count);
+
+ ret = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
+ if (ret == packet.len) {
+ /* return the number of chars written, not the packet length */
+ return count;
+ }
+ return ret; /* return any errors */
+}
+
+static void hvsi_close_protocol(struct hvsi_struct *hp)
+{
+ struct hvsi_control packet __ALIGNED__;
+
+ packet.type = VS_CONTROL_PACKET_HEADER;
+ packet.seqno = atomic_inc_return(&hp->seqno);
+ packet.len = 6;
+ packet.verb = VSV_CLOSE_PROTOCOL;
+
+ pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
+ dbg_dump_hex((uint8_t*)&packet, packet.len);
+
+ hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
+}
+
+static int hvsi_open(struct tty_struct *tty, struct file *filp)
+{
+ struct hvsi_struct *hp;
+ unsigned long flags;
+ int line = tty->index;
+ int ret;
+
+ pr_debug("%s\n", __FUNCTION__);
+
+ if (line < 0 || line >= hvsi_count)
+ return -ENODEV;
+ hp = &hvsi_ports[line];
+
+ tty->driver_data = hp;
+ tty->low_latency = 1; /* avoid throttle/tty_flip_buffer_push race */
+
+ spin_lock_irqsave(&hp->lock, flags);
+ hp->tty = tty;
+ hp->count++;
+ atomic_set(&hp->seqno, 0);
+ h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
+ spin_unlock_irqrestore(&hp->lock, flags);
+
+ if (hp->flags & HVSI_CONSOLE)
+ return 0; /* this has already been handshaked as the console */
+
+ ret = hvsi_handshake(hp);
+ if (ret < 0) {
+ printk(KERN_ERR "%s: HVSI handshaking failed\n", tty->name);
+ return ret;
+ }
+
+ ret = hvsi_get_mctrl(hp);
+ if (ret < 0) {
+ printk(KERN_ERR "%s: couldn't get initial modem flags\n", tty->name);
+ return ret;
+ }
+
+ ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
+ if (ret < 0) {
+ printk(KERN_ERR "%s: couldn't set DTR\n", tty->name);
+ return ret;
+ }
+
+ return 0;
+}
+
+/* wait for hvsi_write_worker to empty hp->outbuf */
+static void hvsi_flush_output(struct hvsi_struct *hp)
+{
+ unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
+ unsigned long timeout;
+
+ DECLARE_WAITQUEUE(myself, current);
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ add_wait_queue(&hp->emptyq, &myself);
+
+ for (;;) {
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ if (hp->n_outbuf <= 0)
+ break;
+ timeout = end_jiffies - jiffies;
+ if (time_after(jiffies, end_jiffies))
+ break;
+ schedule_timeout(timeout);
+ }
+ remove_wait_queue(&hp->emptyq, &myself);
+ set_current_state(TASK_RUNNING);
+
+ /* 'writer' could still be pending if it didn't see n_outbuf = 0 yet */
+ cancel_delayed_work(&hp->writer);
+ flush_scheduled_work();
+
+ /*
+ * it's also possible that our timeout expired and hvsi_write_worker
+ * didn't manage to push outbuf. poof.
+ */
+ hp->n_outbuf = 0;
+}
+
+static void hvsi_close(struct tty_struct *tty, struct file *filp)
+{
+ struct hvsi_struct *hp = tty->driver_data;
+ unsigned long flags;
+
+ pr_debug("%s\n", __FUNCTION__);
+
+ if (tty_hung_up_p(filp))
+ return;
+
+ spin_lock_irqsave(&hp->lock, flags);
+
+ if (--hp->count == 0) {
+ hp->tty = NULL;
+ hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */
+
+ /* only close down connection if it is not the console */
+ if (!(hp->flags & HVSI_CONSOLE)) {
+ h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE); /* no more irqs */
+ __set_state(hp, HVSI_CLOSED);
+ /*
+ * any data delivered to the tty layer after this will be
+ * discarded (except for XON/XOFF)
+ */
+ tty->closing = 1;
+
+ spin_unlock_irqrestore(&hp->lock, flags);
+
+ /* let any existing irq handlers finish. no more will start. */
+ synchronize_irq(hp->virq);
+
+ /* hvsi_write_worker will re-schedule until outbuf is empty. */
+ hvsi_flush_output(hp);
+
+ /* tell FSP to stop sending data */
+ hvsi_close_protocol(hp);
+
+ /*
+ * drain anything FSP is still in the middle of sending, and let
+ * hvsi_handshake drain the rest on the next open.
+ */
+ hvsi_drain_input(hp);
+
+ spin_lock_irqsave(&hp->lock, flags);
+ }
+ } else if (hp->count < 0)
+ printk(KERN_ERR "hvsi_close %lu: oops, count is %d\n",
+ hp - hvsi_ports, hp->count);
+
+ spin_unlock_irqrestore(&hp->lock, flags);
+}
+
+static void hvsi_hangup(struct tty_struct *tty)
+{
+ struct hvsi_struct *hp = tty->driver_data;
+
+ pr_debug("%s\n", __FUNCTION__);
+
+ hp->count = 0;
+ hp->tty = NULL;
+}
+
+/* called with hp->lock held */
+static void hvsi_push(struct hvsi_struct *hp)
+{
+ int n;
+
+ if (hp->n_outbuf <= 0)
+ return;
+
+ n = hvsi_put_chars(hp, hp->outbuf, hp->n_outbuf);
+ if (n != 0) {
+ /*
+ * either all data was sent or there was an error, and we throw away
+ * data on error.
+ */
+ hp->n_outbuf = 0;
+ }
+}
+
+/* hvsi_write_worker will keep rescheduling itself until outbuf is empty */
+static void hvsi_write_worker(void *arg)
+{
+ struct hvsi_struct *hp = (struct hvsi_struct *)arg;
+ unsigned long flags;
+#ifdef DEBUG
+ static long start_j = 0;
+
+ if (start_j == 0)
+ start_j = jiffies;
+#endif /* DEBUG */
+
+ spin_lock_irqsave(&hp->lock, flags);
+
+ hvsi_push(hp);
+ if (hp->n_outbuf > 0)
+ schedule_delayed_work(&hp->writer, 10);
+ else {
+#ifdef DEBUG
+ pr_debug("%s: outbuf emptied after %li jiffies\n", __FUNCTION__,
+ jiffies - start_j);
+ start_j = 0;
+#endif /* DEBUG */
+ wake_up_all(&hp->emptyq);
+ if (test_bit(TTY_DO_WRITE_WAKEUP, &hp->tty->flags)
+ && hp->tty->ldisc.write_wakeup)
+ hp->tty->ldisc.write_wakeup(hp->tty);
+ wake_up_interruptible(&hp->tty->write_wait);
+ }
+
+ spin_unlock_irqrestore(&hp->lock, flags);
+}
+
+static int hvsi_write_room(struct tty_struct *tty)
+{
+ struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
+
+ return N_OUTBUF - hp->n_outbuf;
+}
+
+static int hvsi_chars_in_buffer(struct tty_struct *tty)
+{
+ struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
+
+ return hp->n_outbuf;
+}
+
+static int hvsi_write(struct tty_struct *tty, int from_user,
+ const unsigned char *buf, int count)
+{
+ struct hvsi_struct *hp = tty->driver_data;
+ const char *source = buf;
+ char *kbuf;
+ unsigned long flags;
+ int total = 0;
+ int origcount = count;
+
+ if (from_user) {
+ kbuf = kmalloc(count, GFP_KERNEL);
+ if (kbuf == NULL)
+ return -ENOMEM;
+ if (copy_from_user(kbuf, buf, count)) {
+ kfree(kbuf);
+ return -EFAULT;
+ }
+ source = kbuf;
+ }
+
+ spin_lock_irqsave(&hp->lock, flags);
+
+ if (!is_open(hp)) {
+ /* we're either closing or not yet open; don't accept data */
+ pr_debug("%s: not open\n", __FUNCTION__);
+ goto out;
+ }
+
+ /*
+ * when the hypervisor buffer (16K) fills, data will stay in hp->outbuf
+ * and hvsi_write_worker will be scheduled. subsequent hvsi_write() calls
+ * will see there is no room in outbuf and return.
+ */
+ while ((count > 0) && (hvsi_write_room(hp->tty) > 0)) {
+ int chunksize = min(count, hvsi_write_room(hp->tty));
+
+ BUG_ON(hp->n_outbuf < 0);
+ memcpy(hp->outbuf + hp->n_outbuf, source, chunksize);
+ hp->n_outbuf += chunksize;
+
+ total += chunksize;
+ source += chunksize;
+ count -= chunksize;
+ hvsi_push(hp);
+ }
+
+ if (hp->n_outbuf > 0) {
+ /*
+ * we weren't able to write it all to the hypervisor.
+ * schedule another push attempt.
+ */
+ schedule_delayed_work(&hp->writer, 10);
+ }
+
+out:
+ spin_unlock_irqrestore(&hp->lock, flags);
+
+ if (from_user)
+ kfree(kbuf);
+
+ if (total != origcount)
+ pr_debug("%s: wanted %i, only wrote %i\n", __FUNCTION__, origcount,
+ total);
+
+ return total;
+}
+
+/*
+ * I have never seen throttle or unthrottle called, so this little throttle
+ * buffering scheme may or may not work.
+ */
+static void hvsi_throttle(struct tty_struct *tty)
+{
+ struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
+
+ pr_debug("%s\n", __FUNCTION__);
+
+ h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE);
+}
+
+static void hvsi_unthrottle(struct tty_struct *tty)
+{
+ struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
+ unsigned long flags;
+ int shouldflip = 0;
+
+ pr_debug("%s\n", __FUNCTION__);
+
+ spin_lock_irqsave(&hp->lock, flags);
+ if (hp->n_throttle) {
+ hvsi_send_overflow(hp);
+ shouldflip = 1;
+ }
+ spin_unlock_irqrestore(&hp->lock, flags);
+
+ if (shouldflip)
+ tty_flip_buffer_push(hp->tty);
+
+ h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
+}
+
+static int hvsi_tiocmget(struct tty_struct *tty, struct file *file)
+{
+ struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
+
+ hvsi_get_mctrl(hp);
+ return hp->mctrl;
+}
+
+static int hvsi_tiocmset(struct tty_struct *tty, struct file *file,
+ unsigned int set, unsigned int clear)
+{
+ struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
+ unsigned long flags;
+ uint16_t new_mctrl;
+
+ /* we can only alter DTR */
+ clear &= TIOCM_DTR;
+ set &= TIOCM_DTR;
+
+ spin_lock_irqsave(&hp->lock, flags);
+
+ new_mctrl = (hp->mctrl & ~clear) | set;
+
+ if (hp->mctrl != new_mctrl) {
+ hvsi_set_mctrl(hp, new_mctrl);
+ hp->mctrl = new_mctrl;
+ }
+ spin_unlock_irqrestore(&hp->lock, flags);
+
+ return 0;
+}
+
+
+static struct tty_operations hvsi_ops = {
+ .open = hvsi_open,
+ .close = hvsi_close,
+ .write = hvsi_write,
+ .hangup = hvsi_hangup,
+ .write_room = hvsi_write_room,
+ .chars_in_buffer = hvsi_chars_in_buffer,
+ .throttle = hvsi_throttle,
+ .unthrottle = hvsi_unthrottle,
+ .tiocmget = hvsi_tiocmget,
+ .tiocmset = hvsi_tiocmset,
+};
+
+static int __init hvsi_init(void)
+{
+ int i;
+
+ hvsi_driver = alloc_tty_driver(hvsi_count);
+ if (!hvsi_driver)
+ return -ENOMEM;
+
+ hvsi_driver->owner = THIS_MODULE;
+ hvsi_driver->devfs_name = "hvsi/";
+ hvsi_driver->driver_name = "hvsi";
+ hvsi_driver->name = "hvsi";
+ hvsi_driver->major = HVSI_MAJOR;
+ hvsi_driver->minor_start = HVSI_MINOR;
+ hvsi_driver->type = TTY_DRIVER_TYPE_SYSTEM;
+ hvsi_driver->init_termios = tty_std_termios;
+ hvsi_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL;
+ hvsi_driver->flags = TTY_DRIVER_REAL_RAW;
+ tty_set_operations(hvsi_driver, &hvsi_ops);
+
+ for (i=0; i < hvsi_count; i++) {
+ struct hvsi_struct *hp = &hvsi_ports[i];
+ int ret = 1;
+
+ ret = request_irq(hp->virq, hvsi_interrupt, SA_INTERRUPT, "hvsi", hp);
+ if (ret)
+ printk(KERN_ERR "HVSI: couldn't reserve irq 0x%x (error %i)\n",
+ hp->virq, ret);
+ }
+ hvsi_wait = wait_for_state; /* irqs active now */
+
+ if (tty_register_driver(hvsi_driver))
+ panic("Couldn't register hvsi console driver\n");
+
+ printk(KERN_INFO "HVSI: registered %i devices\n", hvsi_count);
+
+ return 0;
+}
+device_initcall(hvsi_init);
+
+/***** console (not tty) code: *****/
+
+static void hvsi_console_print(struct console *console, const char *buf,
+ unsigned int count)
+{
+ struct hvsi_struct *hp = &hvsi_ports[console->index];
+ char c[HVSI_MAX_OUTGOING_DATA] __ALIGNED__;
+ unsigned int i = 0, n = 0;
+ int ret, donecr = 0;
+
+ mb();
+ if (!is_open(hp))
+ return;
+
+ /*
+ * ugh, we have to translate LF -> CRLF ourselves, in place.
+ * copied from hvc_console.c:
+ */
+ while (count > 0 || i > 0) {
+ if (count > 0 && i < sizeof(c)) {
+ if (buf[n] == '\n' && !donecr) {
+ c[i++] = '\r';
+ donecr = 1;
+ } else {
+ c[i++] = buf[n++];
+ donecr = 0;
+ --count;
+ }
+ } else {
+ ret = hvsi_put_chars(hp, c, i);
+ if (ret < 0)
+ i = 0;
+ i -= ret;
+ }
+ }
+}
+
+static struct tty_driver *hvsi_console_device(struct console *console,
+ int *index)
+{
+ *index = console->index;
+ return hvsi_driver;
+}
+
+static int __init hvsi_console_setup(struct console *console, char *options)
+{
+ struct hvsi_struct *hp = &hvsi_ports[console->index];
+ int ret;
+
+ if (console->index < 0 || console->index >= hvsi_count)
+ return -1;
+
+ /* give the FSP a chance to change the baud rate when we re-open */
+ hvsi_close_protocol(hp);
+
+ ret = hvsi_handshake(hp);
+ if (ret < 0)
+ return ret;
+
+ ret = hvsi_get_mctrl(hp);
+ if (ret < 0)
+ return ret;
+
+ ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
+ if (ret < 0)
+ return ret;
+
+ hp->flags |= HVSI_CONSOLE;
+
+ return 0;
+}
+
+static struct console hvsi_con_driver = {
+ .name = "hvsi",
+ .write = hvsi_console_print,
+ .device = hvsi_console_device,
+ .setup = hvsi_console_setup,
+ .flags = CON_PRINTBUFFER,
+ .index = -1,
+};
+
+static int __init hvsi_console_init(void)
+{
+ struct device_node *vty;
+
+ hvsi_wait = poll_for_state; /* no irqs yet; must poll */
+
+ /* search device tree for vty nodes */
+ for (vty = of_find_compatible_node(NULL, "serial", "hvterm-protocol");
+ vty != NULL;
+ vty = of_find_compatible_node(vty, "serial", "hvterm-protocol")) {
+ struct hvsi_struct *hp;
+ uint32_t *vtermno;
+ uint32_t *irq;
+
+ vtermno = (uint32_t *)get_property(vty, "reg", NULL);
+ irq = (uint32_t *)get_property(vty, "interrupts", NULL);
+ if (!vtermno || !irq)
+ continue;
+
+ if (hvsi_count >= MAX_NR_HVSI_CONSOLES) {
+ of_node_put(vty);
+ break;
+ }
+
+ hp = &hvsi_ports[hvsi_count];
+ INIT_WORK(&hp->writer, hvsi_write_worker, hp);
+ init_waitqueue_head(&hp->emptyq);
+ init_waitqueue_head(&hp->stateq);
+ hp->lock = SPIN_LOCK_UNLOCKED;
+ hp->index = hvsi_count;
+ hp->inbuf_end = hp->inbuf;
+ hp->state = HVSI_CLOSED;
+ hp->vtermno = *vtermno;
+ hp->virq = virt_irq_create_mapping(irq[0]);
+ if (hp->virq == NO_IRQ) {
+ printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n",
+ __FUNCTION__, hp->virq);
+ continue;
+ } else
+ hp->virq = irq_offset_up(hp->virq);
+
+ hvsi_count++;
+ }
+
+ if (hvsi_count)
+ register_console(&hvsi_con_driver);
+ return 0;
+}
+console_initcall(hvsi_console_init);

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