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From: Arnd Bergmann <arnd@arndb.de>
To: zhichang <zhichang.yuan02@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org,
	Zhichang Yuan <yuanzhichang@hisilicon.com>,
	linuxarm@huawei.com, linux-kernel@vger.kernel.org,
	lorenzo.pieralisi@arm.com, minyard@acm.org,
	benh@kernel.crashing.org, gabriele.paoloni@huawei.com,
	john.garry@huawei.com, liviu.dudau@arm.com,
	zourongrong@gmail.com
Subject: Re: [PATCH V2 4/4] ARM64 LPC: support earlycon for UART connected to LPC
Date: Wed, 14 Sep 2016 14:36:39 +0200	[thread overview]
Message-ID: <2263975.sR08tijMiD@wuerfel> (raw)
In-Reply-To: <6e890161-0cd8-6027-f4e5-a222ceddd597@gmail.com>

On Wednesday, September 14, 2016 7:26:22 PM CEST zhichang wrote:
> 
> > 
> >> Hip06 LPC uart need two base addresses for earlycon.
> >> 2. the IO type is mmio to introduce a memory base address to access LPC register file. But the real uart
> >> IO type is UPIO_PORT. This is spcial...
> > 
> > This sounds like a deficiency in the of_setup_earlycon() function,
> > which can only handle MMIO addresses, and won't actually
> > be able to understand nodes without a "ranges" property like
> > you have here.
> > 
> Yes.
> The current of_setup_earlycon only support MMIO and the first reg property must be memory.
> 
> We can not support our LPC uart without any new code.
> But we can implement a private earlycon setup function and register
> it to the __earlycon_table, things will be ok.

I still think you should adapt of_setup_earlycon instead to handle IORESOURCE_IO
registers.

	Arnd

WARNING: multiple messages have this Message-ID (diff)
From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH V2 4/4] ARM64 LPC: support earlycon for UART connected to LPC
Date: Wed, 14 Sep 2016 14:36:39 +0200	[thread overview]
Message-ID: <2263975.sR08tijMiD@wuerfel> (raw)
In-Reply-To: <6e890161-0cd8-6027-f4e5-a222ceddd597@gmail.com>

On Wednesday, September 14, 2016 7:26:22 PM CEST zhichang wrote:
> 
> > 
> >> Hip06 LPC uart need two base addresses for earlycon.
> >> 2. the IO type is mmio to introduce a memory base address to access LPC register file. But the real uart
> >> IO type is UPIO_PORT. This is spcial...
> > 
> > This sounds like a deficiency in the of_setup_earlycon() function,
> > which can only handle MMIO addresses, and won't actually
> > be able to understand nodes without a "ranges" property like
> > you have here.
> > 
> Yes.
> The current of_setup_earlycon only support MMIO and the first reg property must be memory.
> 
> We can not support our LPC uart without any new code.
> But we can implement a private earlycon setup function and register
> it to the __earlycon_table, things will be ok.

I still think you should adapt of_setup_earlycon instead to handle IORESOURCE_IO
registers.

	Arnd

  reply	other threads:[~2016-09-14 12:37 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-07 13:33 [PATCH V2 0/4] ARM64 LPC: legacy ISA I/O support Zhichang Yuan
2016-09-07 13:33 ` Zhichang Yuan
2016-09-07 13:33 ` [PATCH V2 1/4] ARM64 LPC: Indirect ISA port IO introduced Zhichang Yuan
2016-09-07 13:33   ` Zhichang Yuan
2016-09-07 15:06   ` Arnd Bergmann
2016-09-07 15:06     ` Arnd Bergmann
2016-09-08  7:45     ` zhichang.yuan
2016-09-08  7:45       ` zhichang.yuan
2016-09-08  7:45       ` zhichang.yuan
2016-09-08 13:23       ` Arnd Bergmann
2016-09-08 13:23         ` Arnd Bergmann
2016-09-13  6:08         ` zhichang
2016-09-13  6:08           ` zhichang
2016-09-07 15:21   ` kbuild test robot
2016-09-07 15:21     ` kbuild test robot
2016-09-07 13:33 ` [PATCH V2 2/4] ARM64 LPC: LPC driver implementation on Hip06 Zhichang Yuan
2016-09-07 13:33   ` Zhichang Yuan
2016-09-07 15:27   ` Arnd Bergmann
2016-09-07 15:27     ` Arnd Bergmann
2016-09-08  8:06     ` zhichang.yuan
2016-09-08  8:06       ` zhichang.yuan
2016-09-08 10:00       ` Arnd Bergmann
2016-09-08 10:00         ` Arnd Bergmann
2016-09-13  6:31         ` zhichang
2016-09-13  6:31           ` zhichang
2016-09-14 12:34           ` Arnd Bergmann
2016-09-14 12:34             ` Arnd Bergmann
2016-09-07 17:51   ` kbuild test robot
2016-09-07 17:51     ` kbuild test robot
2016-09-07 13:33 ` [PATCH V2 3/4] ARM64 LPC: support serial based on low-pin-count Zhichang Yuan
2016-09-07 13:33   ` Zhichang Yuan
2016-09-07 14:50   ` Arnd Bergmann
2016-09-07 14:50     ` Arnd Bergmann
2016-09-08  9:51     ` zhichang
2016-09-08  9:51       ` zhichang
2016-09-08  9:58       ` Arnd Bergmann
2016-09-08  9:58         ` Arnd Bergmann
2016-09-14 11:48         ` zhichang.yuan
2016-09-14 11:48           ` zhichang.yuan
2016-09-14 12:07           ` Arnd Bergmann
2016-09-14 12:07             ` Arnd Bergmann
2016-09-07 13:33 ` [PATCH V2 4/4] ARM64 LPC: support earlycon for UART connected to LPC Zhichang Yuan
2016-09-07 13:33   ` Zhichang Yuan
2016-09-07 14:52   ` Arnd Bergmann
2016-09-07 14:52     ` Arnd Bergmann
2016-09-08 10:04     ` zhichang
2016-09-08 10:04       ` zhichang
2016-09-08 11:04       ` Arnd Bergmann
2016-09-08 11:04         ` Arnd Bergmann
2016-09-14 11:26         ` zhichang
2016-09-14 11:26           ` zhichang
2016-09-14 12:36           ` Arnd Bergmann [this message]
2016-09-14 12:36             ` Arnd Bergmann
2016-09-08  9:26   ` kbuild test robot
2016-09-08  9:26     ` kbuild test robot

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