lkml.org 
[lkml]   [2020]   [May]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 1/4] m68k/mac: Don't send IOP message until channel is idle
Date
In the following sequence of calls, iop_do_send() gets called when the
"send" channel is not in the IOP_MSG_IDLE state:

iop_ism_irq()
iop_handle_send()
(msg->handler)()
iop_send_message()
iop_do_send()

Avoid this by testing the channel state before calling iop_do_send().

When sending, and iop_send_queue is empty, call iop_do_send() because
the channel is idle. If iop_send_queue is not empty, iop_do_send() will
get called later by iop_handle_send().

Cc: Joshua Thompson <funaho@jurai.org>
Tested-by: Stan Johnson <userm57@yahoo.com>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
---
arch/m68k/mac/iop.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/arch/m68k/mac/iop.c b/arch/m68k/mac/iop.c
index d99c7ea08d8c..22c4e2b8bdf2 100644
--- a/arch/m68k/mac/iop.c
+++ b/arch/m68k/mac/iop.c
@@ -415,7 +415,8 @@ static void iop_handle_send(uint iop_num, uint chan)
msg->status = IOP_MSGSTATUS_UNUSED;
msg = msg->next;
iop_send_queue[iop_num][chan] = msg;
- if (msg) iop_do_send(msg);
+ if (msg && iop_readb(iop, IOP_ADDR_SEND_STATE + chan) == IOP_MSG_IDLE)
+ iop_do_send(msg);
}

/*
@@ -489,16 +490,12 @@ int iop_send_message(uint iop_num, uint chan, void *privdata,

if (!(q = iop_send_queue[iop_num][chan])) {
iop_send_queue[iop_num][chan] = msg;
+ iop_do_send(msg);
} else {
while (q->next) q = q->next;
q->next = msg;
}

- if (iop_readb(iop_base[iop_num],
- IOP_ADDR_SEND_STATE + chan) == IOP_MSG_IDLE) {
- iop_do_send(msg);
- }
-
return 0;
}

--
2.26.2
\
 
 \ /
  Last update: 2020-05-31 01:17    [W:0.073 / U:0.620 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site