Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754571AbdGUPrO (ORCPT ); Fri, 21 Jul 2017 11:47:14 -0400 Received: from mail-wm0-f43.google.com ([74.125.82.43]:35107 "EHLO mail-wm0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753913AbdGUPq0 (ORCPT ); Fri, 21 Jul 2017 11:46:26 -0400 MIME-Version: 1.0 In-Reply-To: <1500620142-910-7-git-send-email-anup.patel@broadcom.com> References: <1500620142-910-1-git-send-email-anup.patel@broadcom.com> <1500620142-910-7-git-send-email-anup.patel@broadcom.com> From: Jassi Brar Date: Fri, 21 Jul 2017 21:16:24 +0530 Message-ID: Subject: Re: [PATCH v2 6/7] mailbox: bcm-flexrm-mailbox: Set msg_queue_len for each channel To: Anup Patel Cc: Rob Herring , Mark Rutland , Catalin Marinas , Will Deacon , Florian Fainelli , Scott Branden , Ray Jui , Linux Kernel Mailing List , "linux-arm-kernel@lists.infradead.org" , Devicetree List , BCM Kernel Feedback Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1978 Lines: 45 Hi Anup, On Fri, Jul 21, 2017 at 12:25 PM, Anup Patel wrote: > The Broadcom FlexRM ring (i.e. mailbox channel) can handle > larger number of messages queued in one FlexRM ring hence > this patch sets msg_queue_len for each mailbox channel to > be same as RING_MAX_REQ_COUNT. > > Signed-off-by: Anup Patel > Reviewed-by: Scott Branden > --- > drivers/mailbox/bcm-flexrm-mailbox.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/mailbox/bcm-flexrm-mailbox.c b/drivers/mailbox/bcm-flexrm-mailbox.c > index 9873818..20055a0 100644 > --- a/drivers/mailbox/bcm-flexrm-mailbox.c > +++ b/drivers/mailbox/bcm-flexrm-mailbox.c > @@ -1683,8 +1683,11 @@ static int flexrm_mbox_probe(struct platform_device *pdev) > ret = -ENOMEM; > goto fail_free_debugfs_root; > } > - for (index = 0; index < mbox->num_rings; index++) > + for (index = 0; index < mbox->num_rings; index++) { > + mbox->controller.chans[index].msg_queue_len = > + RING_MAX_REQ_COUNT; > mbox->controller.chans[index].con_priv = &mbox->rings[index]; > + } > While writing mailbox.c I wasn't unaware that there is the option to choose the queue length at runtime. The idea was to keep the code as simple as possible. I am open to making it a runtime thing, but first, please help me understand how that is useful here. I understand FlexRm has a ring buffer of RING_MAX_REQ_COUNT(1024) elements. Any message submitted to mailbox api can be immediately written onto the ringbuffer if there is some space. Is there any mechanism to report back to a client driver, if its message in ringbuffer failed "to be sent"? If there isn't any, then I think, in flexrm_last_tx_done() you should simply return true if there is some space left in the rung-buffer, false otherwise. Thanks