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Commit 0da4babc authored by Chris Lew's avatar Chris Lew Committed by Gerrit - the friendly Code Review server
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mailbox: msm_qmp: Add msgram readback 



On some device memory used by msm_qmp, there can be an early ack of a
write to memory succeeding. This may cause the outgoing interrupt to be
triggered before the msgram reflects the write.

Add a readback to ensure the data is flushed to device memory before
triggering the ipc interrupt.

Change-Id: I37618f2921dc34d969a04de80badf1820a188351
Signed-off-by: default avatarChris Lew <clew@codeaurora.org>
parent e4a0e446

drivers/mailbox/msm_qmp.c

+5 −2
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * Copyright (c) 2017-2019, The Linux Foundation. All rights reserved.

 * Copyright (c) 2017-2020, The Linux Foundation. All rights reserved.

 */



#include <linux/io.h>
@@ -377,6 +377,7 @@ static int qmp_send_data(struct mbox_chan *chan, void *data) 
	struct qmp_pkt *pkt = (struct qmp_pkt *)data;

	void __iomem *addr;

	unsigned long flags;

	u32 size;

	int i;



	if (!mbox || !data || mbox->local_state != CHANNEL_CONNECTED)
@@ -398,13 +399,15 @@ static int qmp_send_data(struct mbox_chan *chan, void *data) 


	memcpy32_toio(addr + sizeof(pkt->size), pkt->data, pkt->size);

	iowrite32(pkt->size, addr);

	/* readback to ensure write reflects in msgram */

	size = ioread32(addr);

	mbox->tx_sent = true;

	for (i = 0; i < mbox->ctrl.num_chans; i++) {

		if (chan == &mbox->ctrl.chans[i])

			mbox->idx_in_flight = i;

	}

	QMP_INFO(mdev->ilc, "Copied buffer to msgram sz:%d i:%d\n",

		 pkt->size, mbox->idx_in_flight);

		 size, mbox->idx_in_flight);

	send_irq(mdev);

	qmp_schedule_tx_timeout(mbox);

	spin_unlock_irqrestore(&mbox->tx_lock, flags);