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From: Alexey Brodkin <Alexey.Brodkin@synopsys.com>
To: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Cc: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-snps-arc@lists.infradead.org" 
	<linux-snps-arc@lists.infradead.org>
Subject: Re: [PATCHi v2] arc: Mask individual IRQ lines during core INTC init
Date: Fri, 25 Aug 2017 17:22:41 +0000	[thread overview]
Message-ID: <1503681760.10779.75.camel@synopsys.com> (raw)
In-Reply-To: <afd8ed16-638d-c176-b84e-503ee0ece668@synopsys.com>

Hi Vineet,

On Fri, 2017-08-25 at 10:13 -0700, Vineet Gupta wrote:
> On 08/25/2017 07:22 AM, Alexey Brodkin wrote:
> > 
> > From: Alexey Brodkin <Alexey.Brodkin@synopsys.com>
> > 
> > ARC cores on reset have all interrupt lines of built-in INTC enabled.
> > Which means once we globally enable interrupts (very early on boot)
> > faulty hardware blocks may trigger an interrupt that Linux kernel
> > cannot handle yet as corresponding handler is not yet installed.
> > 
> > In that case system falls in "interrupt storm" and basically never
> > does anything useful except entering and exiting generic IRQ handling
> > code.
> > 
> > One real example of that kind of problematic hardware is DW GMAC which
> > also has interrupts enabled on reset and if Ethernet PHY informs GMAC
> > about link state, GMAC immediately reports that upstream to ARC core
> > and here we are.
> > 
> > Now with that change we mask all individual IRQ lines making entire
> > system more fool-proof.
> > 
> > [This patch was motivated by Adaptrum platform support]
> > 
> > Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
> > Cc: Eugeniy Paltsev <paltsev@synopsys.com>
> > Tested-by: Alexandru Gagniuc <alex.g@adaptrum.com>
> > Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
> 
> v1 was merged in mainline this week - please provide a fixup patch on top of 
> mainline / for-curr !

Ooops, didn't see that.
Will do shortly.

-Alexey

  reply	other threads:[~2017-08-25 17:23 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-25 14:22 [PATCHi v2] arc: Mask individual IRQ lines during core INTC init Alexey Brodkin
2017-08-25 17:13 ` Vineet Gupta
2017-08-25 17:22   ` Alexey Brodkin [this message]
2017-08-25 20:35 ` Vineet Gupta

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