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From: "lihuisong (C)" <lihuisong@huawei.com>
To: Sudeep Holla <sudeep.holla@arm.com>, <linux-acpi@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>
Cc: Adam Young <admiyo@os.amperecomputing.com>,
	Robbie King <robbiek@xsightlabs.com>,
	Jassi Brar <jassisinghbrar@gmail.com>,
	"Cristian Marussi" <cristian.marussi@arm.com>
Subject: Re: [PATCH 5/6] mailbox: pcc: Initialize SHMEM before binding the channel with the client
Date: Mon, 20 Oct 2025 12:15:38 +0800	[thread overview]
Message-ID: <ceb9f28b-c935-476b-bd67-a5a9da9989f6@huawei.com> (raw)
In-Reply-To: <20251016-pcc_mb_updates-v1-5-0fba69616f69@arm.com>


在 2025/10/17 3:08, Sudeep Holla 写道:
> The PCC channel's shared memory region must be set up before the
> mailbox controller binds the channel with the client, as the binding
> process may trigger client operations like startup() that may rely on
> SHMEM being initialized.
>
> Reorder the setup sequence to ensure the shared memory is ready before
> binding. Initialize and map the PCC shared memory (SHMEM) prior to
> calling mbox_bind_client() so that clients never observe an uninitialized
> or NULL SHMEM during bind-time callbacks or early use in startup().
>
> This makes the PCC mailbox channel bring-up order consistent and
> eliminates a race between SHMEM setup and client binding.

I don't think this race exists. The above reason is enough.

This patch should be for patch 6/6, right?

>
> This will be needed in channel startup to clear/acknowledge any pending
> interrupts before enabling them.
>
> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: lihuisong@huawei.com
> ---
>   drivers/mailbox/pcc.c | 18 ++++++++++--------
>   1 file changed, 10 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
> index 33bd2d05704b..2829ec51b47f 100644
> --- a/drivers/mailbox/pcc.c
> +++ b/drivers/mailbox/pcc.c
> @@ -378,18 +378,20 @@ pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id)

>

  parent reply	other threads:[~2025-10-20  4:15 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-16 19:08 [PATCH 0/6] mailbox: pcc: Refactor and improve initialisation and interrupt handling Sudeep Holla
2025-10-16 19:08 ` [PATCH 1/6] Revert "mailbox/pcc: support mailbox management of the shared buffer" Sudeep Holla
2025-10-17 16:54   ` Adam Young
2025-10-20  3:46   ` lihuisong (C)
2025-10-16 19:08 ` [PATCH 2/6] mailbox: pcc: Wire up ->last_tx_done() for PCC channels Sudeep Holla
2025-10-17 16:48   ` Adam Young
2025-10-17 16:59     ` Adam Young
2025-10-20  4:01   ` lihuisong (C)
2025-10-16 19:08 ` [PATCH 3/6] mailbox: pcc: Set txdone_irq/txdone_poll based on PCCT flags Sudeep Holla
2025-10-17 17:16   ` Adam Young
2025-10-20  4:02   ` lihuisong (C)
2025-10-16 19:08 ` [PATCH 4/6] mailbox: pcc: Mark Tx as complete in PCC IRQ handler Sudeep Holla
2025-10-17 16:54   ` Adam Young
2025-10-20  4:08   ` lihuisong (C)
2025-10-16 19:08 ` [PATCH 5/6] mailbox: pcc: Initialize SHMEM before binding the channel with the client Sudeep Holla
2025-10-17 16:59   ` Adam Young
2025-10-20  4:15   ` lihuisong (C) [this message]
2025-10-16 19:08 ` [PATCH 6/6] mailbox: pcc: Clear any pending responder interrupts before enabling it Sudeep Holla
2025-10-17 17:03   ` Adam Young
2025-10-17 16:49 ` [PATCH 0/6] mailbox: pcc: Refactor and improve initialisation and interrupt handling Adam Young

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