Re: [PATCH v5 2/2] PCI: brcmstb: Use reset/rearm instead of deassert/assert

From: Florian Fainelli <f.fainelli@gmail.com>
To: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Jim Quinlan <jim2101024@gmail.com>,
	Bjorn Helgaas <helgaas@kernel.org>,
	linux-pci@vger.kernel.org,
	Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
	bcm-kernel-feedback-list@broadcom.com,
	james.quinlan@broadcom.com, Rob Herring <robh@kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	Jim Quinlan <jquinlan@broadcom.com>,
	"moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" 
	<linux-rpi-kernel@lists.infradead.org>,
	"moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" 
	<linux-arm-kernel@lists.infradead.org>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v5 2/2] PCI: brcmstb: Use reset/rearm instead of deassert/assert
Date: Mon, 29 Mar 2021 10:01:48 -0700	[thread overview]
Message-ID: <e602340f-c13d-0cda-25cf-960dd546857e@gmail.com> (raw)
In-Reply-To: <20210329165847.GA10454@lpieralisi>

On 3/29/21 9:58 AM, Lorenzo Pieralisi wrote:
> On Mon, Mar 29, 2021 at 09:50:13AM -0700, Florian Fainelli wrote:
>> On 3/29/21 9:10 AM, Lorenzo Pieralisi wrote:
>>> On Fri, Mar 12, 2021 at 03:45:55PM -0500, Jim Quinlan wrote:
>>>> The Broadcom STB PCIe RC uses a reset control "rescal" for certain chips.
>>>> The "rescal" implements a "pulse reset" so using assert/deassert is wrong
>>>> for this device.  Instead, we use reset/rearm.  We need to use rearm so
>>>> that we can reset it after a suspend/resume cycle; w/o using "rearm", the
>>>> "rescal" device will only ever fire once.
>>>>
>>>> Of course for suspend/resume to work we also need to put the reset/rearm
>>>> calls in the suspend and resume routines.
>>>
>>> Actually - I am sorry but it looks like you will have to split the patch
>>> in two since this is two logical changes.
>>
>> I do not believe this can be easily split, since there is currently a
>> misused of the reset controller API and this patch fixes all call sites
>> at once. It would not really make sense to fix probe/remove and then
>> leave suspend/resume broken in the same manner.
> 
> Right - I was reading the previous versions of the set, it makes sense
> to keep it in one logical change.
> 
> Do you want me to take it or you prefer an ACK so that it can go via
> a different tree ?

I would be comfortable with you taking this via the PCI driver trees, we
would want an Ack from Jens that he is okay with taking the ahci_brcm.c
change as well through your tree.

Thank you!
-- 
Florian