| From 2f9f22ee86489ed5207d01762f0d17a108712a28 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Sun, 31 May 2020 09:12:13 +1000 |
| Subject: m68k: mac: Don't send IOP message until channel is idle |
| |
| From: Finn Thain <fthain@telegraphics.com.au> |
| |
| [ Upstream commit aeb445bf2194d83e12e85bf5c65baaf1f093bd8f ] |
| |
| 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(). |
| |
| Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") |
| Signed-off-by: Finn Thain <fthain@telegraphics.com.au> |
| Tested-by: Stan Johnson <userm57@yahoo.com> |
| Cc: Joshua Thompson <funaho@jurai.org> |
| Link: https://lore.kernel.org/r/6d667c39e53865661fa5a48f16829d18ed8abe54.1590880333.git.fthain@telegraphics.com.au |
| Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| 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 9bfa170157688..d8f2282978f9c 100644 |
| --- a/arch/m68k/mac/iop.c |
| +++ b/arch/m68k/mac/iop.c |
| @@ -416,7 +416,8 @@ 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); |
| } |
| |
| /* |
| @@ -490,16 +491,12 @@ 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; |
| } |
| |
| -- |
| 2.25.1 |
| |