Commit 5123d675 authored by Huisong Li's avatar Huisong Li Committed by Zhang Zekun
Browse files

ACPI: PCC: replace wait_for_completion() 

mainline inclusion
from mainline-v6.1-rc1
commit 91cefefb
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I9VPZ8

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=91cefefb699120efd0a5ba345d12626b688f86ce



----------------------------------------

Currently, the function waiting for completion of mailbox operation is
'wait_for_completion()'.  The PCC method will be permanently blocked if
this mailbox message fails to execute. So this patch replaces it with
'wait_for_completion_timeout()'. And set the timeout interval to an
arbitrary retries on top of nominal to prevent the remote processor is
slow to respond to PCC commands.

Fixes: 77e2a047 ("ACPI: PCC: Implement OperationRegion handler for the PCC Type 3 subtype")
Signed-off-by: default avatarHuisong Li <lihuisong@huawei.com>
Reviewed-by: default avatarSudeep Holla <sudeep.holla@arm.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: default avatarZhang Zekun <zhangzekun11@huawei.com>
parent 195cb7ac

drivers/acpi/acpi_pcc.c

+21 −2
Original line number Diff line number Diff line
@@ -23,6 +23,12 @@ 


#include <acpi/pcc.h>



/*

 * Arbitrary retries in case the remote processor is slow to respond

 * to PCC commands

 */

#define PCC_CMD_WAIT_RETRIES_NUM	500



struct pcc_data {

	struct pcc_mbox_chan *pcc_chan;

	void __iomem *pcc_comm_addr;
@@ -89,6 +95,7 @@ acpi_pcc_address_space_handler(u32 function, acpi_physical_address addr, 
{

	int ret;

	struct pcc_data *data = region_context;

	u64 usecs_lat;



	reinit_completion(&data->done);
@@ -99,8 +106,20 @@ acpi_pcc_address_space_handler(u32 function, acpi_physical_address addr, 
	if (ret < 0)

		return AE_ERROR;



	if (data->pcc_chan->mchan->mbox->txdone_irq)

		wait_for_completion(&data->done);

	if (data->pcc_chan->mchan->mbox->txdone_irq) {

		/*

		 * pcc_chan->latency is just a Nominal value. In reality the remote

		 * processor could be much slower to reply. So add an arbitrary

		 * amount of wait on top of Nominal.

		 */

		usecs_lat = PCC_CMD_WAIT_RETRIES_NUM * data->pcc_chan->latency;

		ret = wait_for_completion_timeout(&data->done,

						  usecs_to_jiffies(usecs_lat));

		if (ret == 0) {

			pr_err("PCC command executed timeout!\n");

			return AE_TIME;

		}

	}



	mbox_client_txdone(data->pcc_chan->mchan, ret);