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authorAnton Blanchard <anton@samba.org>2011-07-12 23:19:57 +0400
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2011-07-19 09:13:07 +0400
commit19df9abdd30a0448e5940c6aa3527096bb69aca7 (patch)
tree207168aac6dc399419eb0048c4ba47e69628a7cf /drivers/tty
parent88962934226c570717c346684ab5ed2f09c2b359 (diff)
downloadlinux-19df9abdd30a0448e5940c6aa3527096bb69aca7.tar.xz
powerpc/pseries: Fix hvterm_raw_get_chars to accept < 16 chars, fixing xmon
commit 4d2bb3f50036 (powerpc/pseries: Re-implement HVSI as part of hvc_vio) changed udbg_getc to be based on hvterm_raw_get_chars. Unfortunately hvterm_raw_get_chars returns -EAGAIN if you ask for anything less than 16 characters. As a result xmon no longer accepts input and prints a stream of junk to the screen. The recent change highlights a problem that xmon on pseries VIO has had all along, that it can drop input characters. The issue is the hypervisor call does not take a count argument and can return up to 16 characters. This patch adds a per vterm buffer that we copy input data into and give it out as requested. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/hvc/hvc_vio.c58
1 files changed, 37 insertions, 21 deletions
diff --git a/drivers/tty/hvc/hvc_vio.c b/drivers/tty/hvc/hvc_vio.c
index 710c06ca70f4..ae659a4596b0 100644
--- a/drivers/tty/hvc/hvc_vio.c
+++ b/drivers/tty/hvc/hvc_vio.c
@@ -71,41 +71,53 @@ struct hvterm_priv {
u32 termno; /* HV term number */
hv_protocol_t proto; /* Raw data or HVSI packets */
struct hvsi_priv hvsi; /* HVSI specific data */
+ spinlock_t buf_lock;
+ char buf[SIZE_VIO_GET_CHARS];
+ int left;
+ int offset;
};
static struct hvterm_priv *hvterm_privs[MAX_NR_HVC_CONSOLES];
-
/* For early boot console */
static struct hvterm_priv hvterm_priv0;
static int hvterm_raw_get_chars(uint32_t vtermno, char *buf, int count)
{
struct hvterm_priv *pv = hvterm_privs[vtermno];
- unsigned long got, i;
+ unsigned long i;
+ unsigned long flags;
+ int got;
if (WARN_ON(!pv))
return 0;
- /*
- * 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(pv->termno, buf, count);
-
- /*
- * Work around a HV bug where it gives us a null
- * after every \r. -- paulus
- */
- for (i = 1; i < got; ++i) {
- if (buf[i] == 0 && buf[i-1] == '\r') {
- --got;
- if (i < got)
- memmove(&buf[i], &buf[i+1], got - i);
+ spin_lock_irqsave(&pv->buf_lock, flags);
+
+ if (pv->left == 0) {
+ pv->offset = 0;
+ pv->left = hvc_get_chars(pv->termno, pv->buf, count);
+
+ /*
+ * Work around a HV bug where it gives us a null
+ * after every \r. -- paulus
+ */
+ for (i = 1; i < pv->left; ++i) {
+ if (pv->buf[i] == 0 && pv->buf[i-1] == '\r') {
+ --pv->left;
+ if (i < pv->left) {
+ memmove(&pv->buf[i], &pv->buf[i+1],
+ pv->left - i);
+ }
+ }
}
}
+
+ got = min(count, pv->left);
+ memcpy(buf, &pv->buf[pv->offset], got);
+ pv->offset += got;
+ pv->left -= got;
+
+ spin_unlock_irqrestore(&pv->buf_lock, flags);
+
return got;
}
@@ -266,6 +278,7 @@ static int __devinit hvc_vio_probe(struct vio_dev *vdev,
return -ENOMEM;
pv->termno = vdev->unit_address;
pv->proto = proto;
+ spin_lock_init(&pv->buf_lock);
hvterm_privs[termno] = pv;
hvsilib_init(&pv->hvsi, hvc_get_chars, hvc_put_chars,
pv->termno, 0);
@@ -406,6 +419,7 @@ void __init hvc_vio_init_early(void)
if (termno == NULL)
goto out;
hvterm_priv0.termno = *termno;
+ spin_lock_init(&hvterm_priv0.buf_lock);
hvterm_privs[0] = &hvterm_priv0;
/* Check the protocol */
@@ -447,6 +461,7 @@ void __init udbg_init_debug_lpar(void)
hvterm_privs[0] = &hvterm_priv0;
hvterm_priv0.termno = 0;
hvterm_priv0.proto = HV_PROTOCOL_RAW;
+ spin_lock_init(&hvterm_priv0.buf_lock)
udbg_putc = udbg_hvc_putc;
udbg_getc = udbg_hvc_getc;
udbg_getc_poll = udbg_hvc_getc_poll;
@@ -459,6 +474,7 @@ void __init udbg_init_debug_lpar_hvsi(void)
hvterm_privs[0] = &hvterm_priv0;
hvterm_priv0.termno = CONFIG_PPC_EARLY_DEBUG_HVSI_VTERMNO;
hvterm_priv0.proto = HV_PROTOCOL_HVSI;
+ spin_lock_init(&hvterm_priv0.buf_lock)
udbg_putc = udbg_hvc_putc;
udbg_getc = udbg_hvc_getc;
udbg_getc_poll = udbg_hvc_getc_poll;