[PATCH] powerpc: hvc_console updates

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.

Signed-off-by: "Ryan S. Arnold" <rsa@us.ibm.com>
Signed-off-by: Arnd Bergmann <abergman@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 29 insertions, 40 deletions

diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c
index a94c5b0cac52..2b6a56b2bf35 100644
--- a/drivers/char/hvc_console.c
+++ b/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_CONSOLES] =
 
 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 *hp)
 
         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)
                 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(struct hvc_struct *hp,
         }
         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 *hp)
                                 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 *hp)
                         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(uint32_t vtermno, int irq,
          * 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 */