Messages in this thread | | | Subject | Re: [PATCH v3 3/3] pci: dra7xx: use pdata callbacks to perform reset | From | Kishon Vijay Abraham I <> | Date | Tue, 23 Feb 2016 17:27:03 +0530 |
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Hi Paul,
On Monday 22 February 2016 03:25 PM, Kishon Vijay Abraham I wrote: > Hi Paul, > > On Monday 22 February 2016 12:01 PM, Paul Walmsley wrote: >> Kishon, >> >> On Mon, 22 Feb 2016, Kishon Vijay Abraham I wrote: >> >>> Sekhar, >>> >>> On Thursday 18 February 2016 07:51 PM, Sekhar Nori wrote: >>>> On Friday 12 February 2016 10:50 PM, Suman Anna wrote: >>>>> Sekhar, >>>>> 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?
-Kishon
> > Thanks > Kishon > > [1] -> http://pastebin.ubuntu.com/15169387/ > -- > To unsubscribe from this list: send the line "unsubscribe linux-omap" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
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