From: Sudeep Holla Date: Thu, 16 Oct 2025 19:08:19 +0000 (+0100) Subject: mailbox: pcc: Initialize SHMEM before binding the channel with the client X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9f3bbbb72ad03378c45523b8045ac82d1ba28ae6;p=thirdparty%2Fkernel%2Flinux.git mailbox: pcc: Initialize SHMEM before binding the channel with the client 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. This will be needed in channel startup to clear/acknowledge any pending interrupts before enabling them. Signed-off-by: Sudeep Holla Acked-by: lihuisong@huawei.com Tested-by: Adam Young Signed-off-by: Jassi Brar --- diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c index 025c4cdd8d26..d8739eca5ac0 100644 --- a/drivers/mailbox/pcc.c +++ b/drivers/mailbox/pcc.c @@ -377,18 +377,20 @@ pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id) return ERR_PTR(-EBUSY); } - rc = mbox_bind_client(chan, cl); - if (rc) - return ERR_PTR(rc); - pcc_mchan = &pchan->chan; pcc_mchan->shmem = acpi_os_ioremap(pcc_mchan->shmem_base_addr, pcc_mchan->shmem_size); - if (pcc_mchan->shmem) - return pcc_mchan; + if (!pcc_mchan->shmem) + return ERR_PTR(-ENXIO); - mbox_free_channel(chan); - return ERR_PTR(-ENXIO); + rc = mbox_bind_client(chan, cl); + if (rc) { + iounmap(pcc_mchan->shmem); + pcc_mchan->shmem = NULL; + return ERR_PTR(rc); + } + + return pcc_mchan; } EXPORT_SYMBOL_GPL(pcc_mbox_request_channel);