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Subject[PATCH 48/58] tty: moxa: rework the locking a bit
Date
From: Alan Cox <alan@linux.intel.com>

Introduce a lock for moxafunc() to protect the cases where were get collisions
between two function requests at the same time.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/char/moxa.c | 27 ++++++++++++++++++++++-----
1 files changed, 22 insertions(+), 5 deletions(-)
diff --git a/drivers/char/moxa.c b/drivers/char/moxa.c
index d8bcbed..474d936 100644
--- a/drivers/char/moxa.c
+++ b/drivers/char/moxa.c
@@ -248,9 +248,25 @@ static void moxa_wait_finish(void __iomem *ofsAddr)

static void moxafunc(void __iomem *ofsAddr, u16 cmd, u16 arg)
{
+ unsigned long flags;
+ spin_lock_irqsave(&moxafunc_lock, flags);
writew(arg, ofsAddr + FuncArg);
writew(cmd, ofsAddr + FuncCode);
moxa_wait_finish(ofsAddr);
+ spin_unlock_irqrestore(&moxafunc_lock, flags);
+}
+
+static int moxafuncret(void __iomem *ofsAddr, u16 cmd, u16 arg)
+{
+ unsigned long flags;
+ u16 ret;
+ spin_lock_irqsave(&moxafunc_lock, flags);
+ writew(arg, ofsAddr + FuncArg);
+ writew(cmd, ofsAddr + FuncCode);
+ moxa_wait_finish(ofsAddr);
+ ret = readw(ofsAddr + FuncArg);
+ spin_unlock_irqrestore(&moxafunc_lock, flags);
+ return ret;
}

static void moxa_low_water_check(void __iomem *ofsAddr)
@@ -417,6 +433,7 @@ static const struct tty_port_operations moxa_port_ops = {
static struct tty_driver *moxaDriver;
static DEFINE_TIMER(moxaTimer, moxa_poll, 0, 0);
static DEFINE_SPINLOCK(moxa_lock);
+static DEFINE_SPINLOCK(moxafunc_lock);

/*
* HW init
@@ -1823,10 +1840,12 @@ static int MoxaPortSetTermio(struct moxa_port *port, struct ktermios *termio,
baud = MoxaPortSetBaud(port, baud);

if (termio->c_iflag & (IXON | IXOFF | IXANY)) {
+ spin_lock_irq(&moxafunc_lock);
writeb(termio->c_cc[VSTART], ofsAddr + FuncArg);
writeb(termio->c_cc[VSTOP], ofsAddr + FuncArg1);
writeb(FC_SetXonXoff, ofsAddr + FuncCode);
moxa_wait_finish(ofsAddr);
+ spin_unlock_irqrestore(&moxafunc_lock);

}
return baud;
@@ -1879,12 +1898,10 @@ static int MoxaPortLineStatus(struct moxa_port *port)
int val;

ofsAddr = port->tableAddr;
- if (MOXA_IS_320(port->board)) {
- moxafunc(ofsAddr, FC_LineStatus, 0);
- val = readw(ofsAddr + FuncArg);
- } else {
+ if (MOXA_IS_320(port->board))
+ val = moxafuncret(ofsAddr, FC_LineStatus, 0);
+ else
val = readw(ofsAddr + FlagStat) >> 4;
- }
val &= 0x0B;
if (val & 8)
val |= 4;
--
1.6.5.5


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