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From: Josh Cartwright <josh.cartwright@ni.com>
To: Nick Bowler <nbowler@elliptictech.com>
Cc: arm@kernel.org, Arnd Bergmann <arnd@arndb.de>,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	John Linn <john.linn@xilinx.com>,
	Michal Simek <michal.simek@xilinx.com>
Subject: Re: [PATCH v4 5/5] zynq: move static peripheral mappings
Date: Thu, 25 Oct 2012 20:03:03 -0500	[thread overview]
Message-ID: <20121026010303.GA13669@beefymiracle.amer.corp.natinst.com> (raw)
In-Reply-To: <20121025224108.GA30705@elliptictech.com>

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On Thu, Oct 25, 2012 at 06:41:08PM -0400, Nick Bowler wrote:
> On 2012-10-25 16:29 -0500, Josh Cartwright wrote:
> > On Thu, Oct 25, 2012 at 04:17:01PM -0400, Nick Bowler wrote:
> > > Did you test this on any real hardware?  I can't get the ZC702 to work
> > > with the UART mapped at this address (this ends up being mapped at
> > > 0xFEFFF000), although I can't for the life of me figure out why the
> > > virtual address even matters.  Note that for the ZC702, the physical
> > > address of the "main" UART is 0xE0001000.

Good news is you're not crazy; I was able to duplicate the problem here.

> If I were to guess, I would guess that, except for when it "Works",
> the really really early printk stuff isn't actually hitting the uart
> at all.  The "Fails" case would then be due to the stray writes
> crashing the board, and the "Truncated" case due to the stray writes
> being (ostensibly) benign.

If I'm not mistaken, this hypothesis is predicated on the early bootup
code establishing a (linear?) mapping for addresses > VMALLOC_START;
before the mdesc->map_io() is even handled.  That seems odd to me.

> But I really have no way right now to test this hypothesis, since I
> can't print anything in the failing case.

Not sure if I'll be able to get anything meaningful out of it yet (I've
not historically had good luck with Xilinx's debugging tools), but I did
finally get a JTAG debugger hooked up to the zc702.  I'll see if I can
get any useful information tomorrow.

Thanks,

  Josh

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  parent reply	other threads:[~2012-10-26  1:03 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-24 20:02 [PATCH v4 0/5] zynq subarch cleanups Josh Cartwright
2012-10-24 20:03 ` [PATCH v4 1/5] zynq: use GIC device tree bindings Josh Cartwright
2012-10-27 13:39   ` Michal Simek
2012-10-27 14:00     ` Josh Cartwright
2012-10-27 14:06       ` Michal Simek
2012-10-27 14:42         ` Josh Cartwright
2012-10-27 15:20           ` Michal Simek
2012-11-05 18:35             ` Josh Cartwright
2012-11-07 12:05               ` Michal Simek
2012-11-07 14:17                 ` Josh Cartwright
2012-11-08  0:38                   ` John Linn
2012-10-24 20:03 ` [PATCH v4 2/5] zynq: use pl310 " Josh Cartwright
2012-10-27 13:40   ` Michal Simek
2012-10-24 20:04 ` [PATCH v4 3/5] zynq: remove use of CLKDEV_LOOKUP Josh Cartwright
2012-10-27 16:47   ` Michal Simek
2012-10-24 20:04 ` [PATCH v4 4/5] ARM: annotate VMALLOC_END definition with _AC Josh Cartwright
2012-10-27 13:59   ` Michal Simek
2012-10-30 22:22     ` Arnd Bergmann
2012-10-31  8:43       ` Michal Simek
2012-10-31 11:36         ` Josh Cartwright
2012-10-24 20:04 ` [PATCH v4 5/5] zynq: move static peripheral mappings Josh Cartwright
2012-10-25 20:17   ` Nick Bowler
2012-10-25 21:29     ` Josh Cartwright
2012-10-25 22:41       ` Nick Bowler
2012-10-25 22:47         ` [PATCH] ARM: zynq: Allow UART1 to be used as DEBUG_LL console Nick Bowler
2012-10-29 16:56           ` Josh Cartwright
2012-10-29 18:13             ` Nick Bowler
2012-10-26  1:03         ` Josh Cartwright [this message]
2012-10-27 16:52           ` [PATCH v4 5/5] zynq: move static peripheral mappings Michal Simek
2012-10-28 23:26 [PATCH v4 0/5] zynq subarch cleanups Josh Cartwright
2012-10-22  2:15 ` [PATCH v4 5/5] zynq: move static peripheral mappings Josh Cartwright
2012-10-29  8:00   ` Michal Simek

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