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Date: Thu, 29 Oct 2015 16:05:04 +0530
From: Pratyush Anand <panand@redhat.com>
Subject: Re: [PATCH V2 11/11] arm64: wait for transmit completion before next
 character transmission
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To: Geoff Levand <geoff@infradead.org>
Cc: takahiro.akashi@linaro.org, kexec@lists.infradead.org

Hi Geoff,

On 20/10/2015:10:04:54 AM, Geoff Levand wrote:
> Hi,
> 
> On Tue, 2015-10-20 at 08:11 +0530, Pratyush Anand wrote:
> > On 19/10/2015:03:29:55 PM, Geoff Levand wrote:
> > I tested this on the foundation model and it hangs.
> > 
> > Thanks for testing it.
> > 
> > Which uart model has been used in foundation model?
> 
> I only tested it, but did not look into it.  The
> documentation should be on the ARM developer's site.

Line status register offset for pl011(which is in foundation model) and 8250
based uart are not same. I think, in that case we should keep separate argument
for lsr. Can you please try patch[1] and let me know your feedback.

If you are using UART0 of foundation model, then you would be passing
--port=0x1C090000. With patch[1], you may pass one more argument
--port-lsr=0x1C090018,0x80. Even if --port-lsr is not passed to kexec() system
call, it will not hang. However, one may not see all the printed character
without --port-lsr.

~Pratyush

[1] https://github.com/pratyushanand/kexec-tools/commit/57344a8516447cefabc2372daf9a6b0b04bd9851

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