mailbox: pcc: Fix can't clear level interrupt of type3 in cornor case

The mbox_chan_received_data() will call Rx callback of mbox client driver
using type3 to set the flag of command completion. Then driver can continue
to do something like sending a new command. In this case, the rest of the
interrupt handler function may be concurrent with pcc_send_data().

The 'chan_in_use' flag of a channel is true after sending a command. And
the flag of the new command may be cleared by the running interrupt handler
in cornor case. As a result, the interrupt being level triggered can't be
cleared in pcc_mbox_irq() and it will be disabled after the number of
handled times exceeds the specified value. The error log is as follows:

[519082.811553] kunpeng_hccs HISI04B2:00: PCC command executed timeout!
[519082.828532] kunpeng_hccs HISI04B2:00: get port link status info failed, ret = -110.
[519082.833438] irq 13: nobody cared (try booting with the "irqpoll" option)
[519082.844622] CPU: 304 PID: 15206 Comm: systemd-journal Kdump: loaded Tainted: G           OE     5.10.0 #5
[519082.854959] Hardware name: To be filled by O.E.M. To be filled by O.E.M./To be filled by O.E.M., BIOS Nezha B800 V3.1.0 01/02/2024
[519082.867467] Call trace:
[519082.870709]  dump_backtrace+0x0/0x210
[519082.875145]  show_stack+0x1c/0x2c
[519082.879240]  dump_stack+0xec/0x130
[519082.883421]  __report_bad_irq+0x50/0x190
[519082.888122]  note_interrupt+0x1e4/0x260
[519082.892740]  handle_irq_event+0x144/0x17c
[519082.897519]  handle_fasteoi_irq+0xd0/0x240
[519082.902386]  __handle_domain_irq+0x80/0xf0
[519082.907255]  gic_handle_irq+0x74/0x2d0
[519082.911774]  el1_irq+0xbc/0x140
[519082.915698]  mnt_clone_write+0x0/0x70
[519082.920131]  file_update_time+0xcc/0x160
[519082.924832]  fault_dirty_shared_page+0xe8/0x150
[519082.930133]  do_shared_fault+0x80/0x1d0
[519082.934737]  do_fault+0x118/0x1a4
[519082.938821]  handle_pte_fault+0x154/0x230
[519082.943600]  __handle_mm_fault+0x1ac/0x390
[519082.948465]  handle_mm_fault+0xf0/0x250
[519082.953075]  do_page_fault+0x184/0x454
[519082.957595]  do_translation_fault+0xac/0xd4
[519082.962555]  do_mem_abort+0x44/0xb4
[519082.966817]  el0_da+0x40/0x74
[519082.970554]  el0_sync_handler+0x60/0xb4
[519082.975160]  el0_sync+0x168/0x180
[519082.979243] handlers:
[519082.982300] [<0000000039882697>] pcc_mbox_irq
[519082.987433] Disabling IRQ torvalds#13

To solve this issue, pcc_mbox_irq() clear 'chann_in_use' flag immediately
after clearing interrupt ack register.

Signed-off-by: Huisong Li <lihuisong@huawei.com>

drivers/mailbox/pcc.c

@@ -333,10 +333,20 @@ static irqreturn_t pcc_mbox_irq(int irq, void *p)
 	if (pcc_chan_reg_read_modify_write(&pchan->plat_irq_ack))
 		return IRQ_NONE;
 
+	/*
+	 * The mbox_chan_received_data() will call Rx callback of mbox
+	 * client driver using type3 to set the flag of command completion.
+	 * Then driver can continue to do something like sending a new
+	 * command. In this case, the rest of the interrupt handler
+	 * function may be concurrent with pcc_send_data().
+	 * To avoid the 'chan_in_use' flag of new command being cleared by
+	 * interrupt handler, clear this flag immediately after clearing
+	 * interrupt ack register.
+	 */
+	pchan->chan_in_use = false;
 	mbox_chan_received_data(chan, NULL);
 
 	check_and_ack(pchan, chan);
-	pchan->chan_in_use = false;
 
 	return IRQ_HANDLED;
 }