[patch 01/13] powerpc: hvc_console updates

Arnd Bergmann
2006-03-23T20:43:16Z

[-- Attachment #1: hvc-console-rework-2.diff --]
[-- Type: text/plain, Size: 11770 bytes --]

These are some updates from both Ryan and Arnd for the hvc_console
driver:

The main point is to enable the inclusion of a console driver
for rtas, which is currrently needed for the cell platform.

Also shuffle around some data-type declarations and moves some
functions out of include/asm-ppc64/hvconsole.h and into a new
drivers/char/hvc_console.h file.

From: "Ryan S. Arnold" <rsa@us.ibm.com>
Signed-off-by: "Ryan S. Arnold" <rsa@us.ibm.com>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>

Index: linux-2.6.16-rc/drivers/char/hvc_console.c
===================================================================
--- linux-2.6.16-rc.orig/drivers/char/hvc_console.c
+++ linux-2.6.16-rc/drivers/char/hvc_console.c
@@ -39,8 +39,10 @@
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/delay.h>
+
#include <asm/uaccess.h>
-#include <asm/hvconsole.h>
+
+#include "hvc_console.h"

#define HVC_MAJOR 229
#define HVC_MINOR 0
@@ -54,17 +56,14 @@
#define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */

/*
- * The Linux TTY code does not support dynamic addition of tty derived devices
- * so we need to know how many tty devices we might need when space is allocated
- * for the tty device. Since this driver supports hotplug of vty adapters we
- * need to make sure we have enough allocated.
+ * These sizes are most efficient for vio, because they are the
+ * native transfer size. We could make them selectable in the
+ * future to better deal with backends that want other buffer sizes.
*/
-#define HVC_ALLOC_TTY_ADAPTERS 8
-
#define N_OUTBUF 16
#define N_INBUF 16

-#define __ALIGNED__ __attribute__((__aligned__(8)))
+#define __ALIGNED__ __attribute__((__aligned__(sizeof(long))))

static struct tty_driver *hvc_driver;
static struct task_struct *hvc_task;
@@ -154,7 +153,7 @@ static uint32_t vtermnos[MAX_NR_HVC_CONS

void hvc_console_print(struct console *co, const char *b, unsigned count)
{
- char c[16] __ALIGNED__;
+ char c[N_OUTBUF] __ALIGNED__;
unsigned i = 0, n = 0;
int r, donecr = 0, index = co->index;

@@ -473,8 +472,10 @@ static void hvc_push(struct hvc_struct *

n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf);
if (n <= 0) {
- if (n == 0)
+ if (n == 0) {
+ hp->do_wakeup = 1;
return;
+ }
/* throw away output on error; this happens when
there is no session connected to the vterm. */
hp->n_outbuf = 0;
@@ -486,12 +487,19 @@ static void hvc_push(struct hvc_struct *
hp->do_wakeup = 1;
}

-static inline int __hvc_write_kernel(struct hvc_struct *hp,
- const unsigned char *buf, int count)
+static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count)
{
+ struct hvc_struct *hp = tty->driver_data;
unsigned long flags;
int rsize, written = 0;

+ /* This write was probably executed during a tty close. */
+ if (!hp)
+ return -EPIPE;
+
+ if (hp->count <= 0)
+ return -EIO;
+
spin_lock_irqsave(&hp->lock, flags);

/* Push pending writes */
@@ -510,26 +518,8 @@ static inline int __hvc_write_kernel(str
}
spin_unlock_irqrestore(&hp->lock, flags);

- return written;
-}
-static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count)
-{
- struct hvc_struct *hp = tty->driver_data;
- int written;
-
- /* This write was probably executed during a tty close. */
- if (!hp)
- return -EPIPE;
-
- if (hp->count <= 0)
- return -EIO;
-
- written = __hvc_write_kernel(hp, buf, count);
-
/*
* Racy, but harmless, kick thread if there is still pending data.
- * There really is nothing wrong with kicking the thread, even if there
- * is no buffered data.
*/
if (hp->n_outbuf)
hvc_kick();
@@ -614,6 +604,13 @@ static int hvc_poll(struct hvc_struct *h
spin_unlock_irqrestore(&hp->lock, flags);
tty_hangup(tty);
spin_lock_irqsave(&hp->lock, flags);
+ } else if ( n == -EAGAIN ) {
+ /*
+ * Some back-ends can only ensure a certain min
+ * num of bytes read, which may be > 'count'.
+ * Let the tty clear the flip buff to make room.
+ */
+ poll_mask |= HVC_POLL_READ;
}
break;
}
@@ -635,16 +632,7 @@ static int hvc_poll(struct hvc_struct *h
tty_insert_flip_char(tty, buf[i], 0);
}

- /*
- * Account for the total amount read in one loop, and if above
- * 64 bytes, we do a quick schedule loop to let the tty grok
- * the data and eventually throttle us.
- */
read_total += n;
- if (read_total >= 64) {
- poll_mask |= HVC_POLL_QUICK;
- break;
- }
}
throttled:
/* Wakeup write queue if necessary */
@@ -767,7 +755,8 @@ struct hvc_struct __devinit *hvc_alloc(u
* see if this vterm id matches one registered for console.
*/
for (i=0; i < MAX_NR_HVC_CONSOLES; i++)
- if (vtermnos[i] == hp->vtermno)
+ if (vtermnos[i] == hp->vtermno &&
+ cons_ops[i] == hp->ops)
break;

/* no matching slot, just use a counter */
Index: linux-2.6.16-rc/drivers/char/hvc_console.h
===================================================================
--- /dev/null
+++ linux-2.6.16-rc/drivers/char/hvc_console.h
@@ -0,0 +1,63 @@
+/*
+ * hvc_console.h
+ * Copyright (C) 2005 IBM Corporation
+ *
+ * Author(s):
+ * Ryan S. Arnold <rsa@us.ibm.com>
+ *
+ * hvc_console header information:
+ * moved here from include/asm-powerpc/hvconsole.h
+ * and drivers/char/hvc_console.c
+ *
+ * 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
+ */
+
+#ifndef HVC_CONSOLE_H
+#define HVC_CONSOLE_H
+
+/*
+ * This is the max number of console adapters that can/will be found as
+ * console devices on first stage console init. Any number beyond this range
+ * can't be used as a console device but is still a valid tty device.
+ */
+#define MAX_NR_HVC_CONSOLES 16
+
+/*
+ * The Linux TTY code does not support dynamic addition of tty derived devices
+ * so we need to know how many tty devices we might need when space is allocated
+ * for the tty device. Since this driver supports hotplug of vty adapters we
+ * need to make sure we have enough allocated.
+ */
+#define HVC_ALLOC_TTY_ADAPTERS 8
+
+
+/* implemented by a low level driver */
+struct hv_ops {
+ int (*get_chars)(uint32_t vtermno, char *buf, int count);
+ int (*put_chars)(uint32_t vtermno, const char *buf, int count);
+};
+
+struct hvc_struct;
+
+/* Register a vterm and a slot index for use as a console (console_init) */
+extern int hvc_instantiate(uint32_t vtermno, int index, struct hv_ops *ops);
+
+/* register a vterm for hvc tty operation (module_init or hotplug add) */
+extern struct hvc_struct * __devinit hvc_alloc(uint32_t vtermno, int irq,
+ struct hv_ops *ops);
+/* remove a vterm from hvc tty operation (modele_exit or hotplug remove) */
+extern int __devexit hvc_remove(struct hvc_struct *hp);
+
+#endif // HVC_CONSOLE_H
Index: linux-2.6.16-rc/include/asm-powerpc/hvconsole.h
===================================================================
--- linux-2.6.16-rc.orig/include/asm-powerpc/hvconsole.h
+++ linux-2.6.16-rc/include/asm-powerpc/hvconsole.h
@@ -24,17 +24,16 @@
#ifdef __KERNEL__

/*
- * This is the max number of console adapters that can/will be found as
- * console devices on first stage console init. Any number beyond this range
- * can't be used as a console device but is still a valid tty device.
+ * PSeries firmware will only send/recv up to 16 bytes of character data per
+ * hcall.
*/
-#define MAX_NR_HVC_CONSOLES 16
+#define MAX_VIO_PUT_CHARS 16
+#define SIZE_VIO_GET_CHARS 16

-/* implemented by a low level driver */
-struct hv_ops {
- int (*get_chars)(uint32_t vtermno, char *buf, int count);
- int (*put_chars)(uint32_t vtermno, const char *buf, int count);
-};
+/*
+ * Vio firmware always attempts to fetch MAX_VIO_GET_CHARS chars. The 'count'
+ * parm is included to conform to put_chars() function pointer template
+ */
extern int hvc_get_chars(uint32_t vtermno, char *buf, int count);
extern int hvc_put_chars(uint32_t vtermno, const char *buf, int count);

Index: linux-2.6.16-rc/drivers/char/Kconfig
===================================================================
--- linux-2.6.16-rc.orig/drivers/char/Kconfig
+++ linux-2.6.16-rc/drivers/char/Kconfig
@@ -560,9 +560,19 @@ config TIPAR

If unsure, say N.

+config HVC_DRIVER
+ bool
+ help
+ Users of pSeries machines that want to utilize the hvc console front-end
+ module for their backend console driver should select this option.
+ It will automatically be selected if one of the back-end console drivers
+ is selected.
+
+
config HVC_CONSOLE
bool "pSeries Hypervisor Virtual Console support"
depends on PPC_PSERIES
+ select HVC_DRIVER
help
pSeries machines when partitioned support a hypervisor virtual
console. This driver allows each pSeries partition to have a console
Index: linux-2.6.16-rc/drivers/char/Makefile
===================================================================
--- linux-2.6.16-rc.orig/drivers/char/Makefile
+++ linux-2.6.16-rc/drivers/char/Makefile
@@ -41,11 +41,12 @@ obj-$(CONFIG_N_HDLC) += n_hdlc.o
obj-$(CONFIG_AMIGA_BUILTIN_SERIAL) += amiserial.o
obj-$(CONFIG_SX) += sx.o generic_serial.o
obj-$(CONFIG_RIO) += rio/ generic_serial.o
-obj-$(CONFIG_HVC_CONSOLE) += hvc_console.o hvc_vio.o hvsi.o
+obj-$(CONFIG_HVC_DRIVER) += hvc_console.o
+obj-$(CONFIG_HVC_CONSOLE) += hvc_vio.o hvsi.o
obj-$(CONFIG_RAW_DRIVER) += raw.o
obj-$(CONFIG_SGI_SNSC) += snsc.o snsc_event.o
obj-$(CONFIG_MMTIMER) += mmtimer.o
-obj-$(CONFIG_VIOCONS) += viocons.o
+obj-$(CONFIG_VIOCONS) += viocons.o
obj-$(CONFIG_VIOTAPE) += viotape.o
obj-$(CONFIG_HVCS) += hvcs.o
obj-$(CONFIG_SGI_MBCS) += mbcs.o
Index: linux-2.6.16-rc/drivers/char/hvc_vio.c
===================================================================
--- linux-2.6.16-rc.orig/drivers/char/hvc_vio.c
+++ linux-2.6.16-rc/drivers/char/hvc_vio.c
@@ -31,10 +31,13 @@

#include <linux/types.h>
#include <linux/init.h>
+
#include <asm/hvconsole.h>
#include <asm/vio.h>
#include <asm/prom.h>

+#include "hvc_console.h"
+
char hvc_driver_name[] = "hvc_console";

static struct vio_device_id hvc_driver_table[] __devinitdata = {
@@ -48,6 +51,14 @@ static int filtered_get_chars(uint32_t v
unsigned long got;
int i;

+ /*
+ * Vio firmware will read up to SIZE_VIO_GET_CHARS at its own discretion
+ * so we play safe and avoid the situation where got > count which could
+ * overload the flip buffer.
+ */
+ if (count < SIZE_VIO_GET_CHARS)
+ return -EAGAIN;
+
got = hvc_get_chars(vtermno, buf, count);

/*
Index: linux-2.6.16-rc/arch/powerpc/platforms/pseries/hvconsole.c
===================================================================
--- linux-2.6.16-rc.orig/arch/powerpc/platforms/pseries/hvconsole.c
+++ linux-2.6.16-rc/arch/powerpc/platforms/pseries/hvconsole.c
@@ -62,6 +62,11 @@ int hvc_put_chars(uint32_t vtermno, cons
unsigned long *lbuf = (unsigned long *) buf;
long ret;

+
+ /* hcall will ret H_PARAMETER if 'count' exceeds firmware max.*/
+ if (count > MAX_VIO_PUT_CHARS)
+ count = MAX_VIO_PUT_CHARS;
+
ret = plpar_hcall_norets(H_PUT_TERM_CHAR, vtermno, count, lbuf[0],
lbuf[1]);
if (ret == H_Success)

--