From: Kishon Vijay Abraham I <kishon@ti.com>
To: Paul Walmsley <paul@pwsan.com>
Cc: Sekhar Nori <nsekhar@ti.com>, Suman Anna <s-anna@ti.com>,
<d-gerlach@ti.com>, Tony Lindgren <tony@atomide.com>,
Bjorn Helgaas <bhelgaas@google.com>, <richardcochran@gmail.com>,
Russell King <linux@arm.linux.org.uk>,
<linux-omap@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 3/3] pci: dra7xx: use pdata callbacks to perform reset
Date: Wed, 24 Feb 2016 11:51:21 +0530 [thread overview]
Message-ID: <56CD4BE1.3010701@ti.com> (raw)
In-Reply-To: <alpine.DEB.2.02.1602231827300.27173@utopia.booyaka.com>
Hi Paul,
On Tuesday 23 February 2016 11:58 PM, Paul Walmsley wrote:
> Kishon
>
> On Tue, 23 Feb 2016, Kishon Vijay Abraham I wrote:
>
>> On Monday 22 February 2016 03:25 PM, Kishon Vijay Abraham I wrote:
>>> On Monday 22 February 2016 12:01 PM, Paul Walmsley wrote:
>>>> On Mon, 22 Feb 2016, Kishon Vijay Abraham I wrote:
>>>>> On Thursday 18 February 2016 07:51 PM, Sekhar Nori wrote:
>>>>>> On Friday 12 February 2016 10:50 PM, Suman Anna wrote:
>>>>>>> Will you be following up with above suggestion since Kishon is gonna be out?
>>>>>>
>>>>>> Alright, noticed this action for me :) Went through the thread, and
>>>>>> looks like this is what we want to see?
>>>>>>
>>>>>> Thanks,
>>>>>> Sekhar
>>>>>>
>>>>>> ---8<---
>>>>>> From e3ba368f2235e1bf38a22ba8ea4e5c12aaafda19 Mon Sep 17 00:00:00 2001
>>>>>> Message-Id: <e3ba368f2235e1bf38a22ba8ea4e5c12aaafda19.1455803758.git.nsekhar@ti.com>
>>>>>> From: Sekhar Nori <nsekhar@ti.com>
>>>>>> Date: Thu, 18 Feb 2016 16:49:56 +0530
>>>>>> Subject: [PATCH 1/1] ARM: DRA7: hwmod: Add custom reset handler for PCIeSS
>>>>>>
>>>>>> Add a custom reset handler for DRA7x PCIeSS. This
>>>>>> handler is required to deassert PCIe hardreset lines
>>>>>> after they have been asserted.
>>>>>>
>>>>>> This enables the PCIe driver to access registers after
>>>>>> PCIeSS has been runtime enabled without having to
>>>>>> deassert hardreset lines itself.
>>>>>>
>>>>>> With this patch applied, used lspci to make sure
>>>>>> connected PCIe device enumerates on DRA74x and DRA72x
>>>>>> EVMs.
>>>>>>
>>>>>> Signed-off-by: Sekhar Nori <nsekhar@ti.com>
>>>>>> ---
>>>>>> Applies to tag for-v4.6/omap-hwmod-a of Paul W's tree.
>>>>>>
>>>>>> arch/arm/mach-omap2/omap_hwmod_7xx_data.c | 23 +++++++++++++++++++++++
>>>>>> 1 file changed, 23 insertions(+)
>>>>>>
>>>>>> diff --git a/arch/arm/mach-omap2/omap_hwmod_7xx_data.c b/arch/arm/mach-omap2/omap_hwmod_7xx_data.c
>>>>>> index b61355e2a771..252b74633e31 100644
>>>>>> --- a/arch/arm/mach-omap2/omap_hwmod_7xx_data.c
>>>>>> +++ b/arch/arm/mach-omap2/omap_hwmod_7xx_data.c
>>>>>> @@ -1526,8 +1526,31 @@ static struct omap_hwmod dra7xx_ocp2scp3_hwmod = {
>>>>>> *
>>>>>> */
>>>>>>
>>>>>> +/*
>>>>>> + * As noted in documentation for _reset() in omap_hwmod.c, the stock reset
>>>>>> + * functionality of OMAP HWMOD layer does not deassert the hardreset lines
>>>>>> + * associated with an IP automatically leaving the driver to handle that
>>>>>> + * by itself. This does not work for PCIeSS which needs the reset lines
>>>>>> + * deasserted for the driver to start accessing registers.
>>>>>> + *
>>>>>> + * We use a PCIeSS HWMOD class specific reset handler to deassert the hardreset
>>>>>> + * lines after asserting them.
>>>>>> + */
>>>>>> +static int dra7xx_pciess_reset(struct omap_hwmod *oh)
>>>>>> +{
>>>>>> + int i;
>>>>>> +
>>>>>> + for (i = 0; i < oh->rst_lines_cnt; i++) {
>>>>>> + omap_hwmod_assert_hardreset(oh, oh->rst_lines[i].name);
>>>>>> + omap_hwmod_deassert_hardreset(oh, oh->rst_lines[i].name);
>>>>>> + }
>>>>>> +
>>>>>> + return 0;
>>>>>> +}
>>>>>> +
>>>>>> static struct omap_hwmod_class dra7xx_pciess_hwmod_class = {
>>>>>> .name = "pcie",
>>>>>> + .reset = dra7xx_pciess_reset,
>>>>>> };
>>>>>
>>>>> Thanks for the patch.
>>>>
>>>> Could you please test the bind/unbind functionality just to make sure it
>>>> works?
>>>
>>> The pci-dra7xx driver neither expose the bind/unbind sysfs entry nor can be
>>> built as module.
>>>
>>> However I hacked the pci-dra7xx driver to be built as module [and reverted
>>> Commit 5de85b9d57ab ("PM / runtime: Re-init runtime PM states at probe error
>>> and driver unbind")] and I don't see an abort when the PCI registers are
>>> accessed after rmmod/modprobe cycle (that was the issue that Sekhar's patch
>>> tried to solve). However PCI as such doesn't work after rmmod/modprobe cycle
>>> [1], but this is a different issue most likely in PCIe core and has to debugged.
>>>
>>> In summary, there are other issues in PCI across rmmod/modprobe cycle but the
>>> reset of pci-dra7xx happens fine with this patch.
>>
>> Do you expect any other testing from me?
>
> No I think that's sufficient for the time being, thanks - but, two
> questions:
>
> 1. Can I add your Tested-by: ?
sure..
Tested-by: Kishon Vijay Abraham I <kishon@ti.com>
>
> 2. Are you going to follow up with these PCIe core issues with the PCIe
> core developers?
yeah, I see efforts have already started to convert the PCI drivers from
built-in to module [1] and issues arising out of that will be debugged.
Thanks
Kishon
[1] -> http://lkml.iu.edu/hypermail/linux/kernel/1602.0/06011.html
>
>
> - Paul
>
next prev parent reply other threads:[~2016-02-24 6:22 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-14 14:11 [PATCH v3 0/3] dra7xx: get pcie working in mainline Kishon Vijay Abraham I
2016-01-14 14:11 ` [PATCH v3 1/3] ARM: DRA7: hwmod: Add reset data for PCIe Kishon Vijay Abraham I
2016-02-08 1:50 ` Paul Walmsley
2016-01-14 14:11 ` [PATCH v3 2/3] ARM: DRA7: add pdata-quirks to do reset of PCIe Kishon Vijay Abraham I
2016-01-15 19:19 ` Suman Anna
2016-01-15 19:22 ` Tony Lindgren
2016-01-15 19:41 ` Suman Anna
2016-01-18 9:12 ` Sekhar Nori
2016-01-27 17:23 ` Tony Lindgren
2016-01-14 14:11 ` [PATCH v3 3/3] pci: dra7xx: use pdata callbacks to perform reset Kishon Vijay Abraham I
2016-01-27 17:31 ` Tony Lindgren
2016-01-27 18:16 ` Suman Anna
2016-01-27 18:56 ` Tony Lindgren
2016-01-27 23:16 ` Suman Anna
2016-01-28 18:31 ` Tony Lindgren
2016-01-28 21:15 ` Suman Anna
2016-02-02 10:40 ` Kishon Vijay Abraham I
2016-02-05 4:19 ` Kishon Vijay Abraham I
2016-02-08 2:48 ` Paul Walmsley
2016-02-08 20:56 ` Suman Anna
2016-02-09 8:49 ` Paul Walmsley
2016-02-09 17:40 ` Suman Anna
2016-02-09 19:36 ` Paul Walmsley
2016-02-10 1:42 ` Suman Anna
2016-02-10 5:38 ` Kishon Vijay Abraham I
2016-02-11 19:27 ` Paul Walmsley
2016-02-11 22:04 ` Suman Anna
2016-02-12 6:49 ` Kishon Vijay Abraham I
2016-02-12 17:20 ` Suman Anna
2016-02-18 14:21 ` Sekhar Nori
2016-02-18 17:23 ` Paul Walmsley
2016-02-18 18:27 ` Suman Anna
2016-02-22 6:18 ` Kishon Vijay Abraham I
2016-02-22 6:31 ` Paul Walmsley
2016-02-22 9:55 ` Kishon Vijay Abraham I
2016-02-23 11:57 ` Kishon Vijay Abraham I
2016-02-23 18:28 ` Paul Walmsley
2016-02-24 6:21 ` Kishon Vijay Abraham I [this message]
2016-03-01 8:25 ` Paul Walmsley
2016-03-01 11:55 ` Kishon Vijay Abraham I
2016-03-01 14:43 ` Bjorn Helgaas
2016-03-01 16:55 ` Suman Anna
2016-02-11 20:43 ` Suman Anna
2016-02-12 6:55 ` Kishon Vijay Abraham I
2016-02-10 5:36 ` Kishon Vijay Abraham I
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