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From: Marek Vasut <marex@denx.de>
To: "Zhu Richard-R65037" <r65037@freescale.com>
Cc: Tim Harvey <tharvey@gateworks.com>,
	Yinghai Lu <yinghai@kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	Shawn Guo <shawn.guo@linaro.org>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	Frank Li <lznuaa@gmail.com>, Sean Cross <xobs@kosagi.com>,
	Sascha Hauer <s.hauer@pengutronix.de>
Subject: Re: [PATCH v7 0/2] Add PCIe support for i.MX6q
Date: Sat, 12 Oct 2013 04:30:04 +0200	[thread overview]
Message-ID: <201310120430.04282.marex@denx.de> (raw)
In-Reply-To: <0E83723C55F66F43A6041464FE31119D40A9C9@039-SN2MPN1-011.039d.mgd.msft.net>

Hi Richard,

> Hi Tim:
> As I know that the clock of pcie controller should be always running.
> There are not clock gate on/off operations in host driver after the
> initialization.

I think the problem might happen when the PCIe device (Ethernet adapter) is bus-
master and either initiates PCIe->AXI->memory write or memory->AXI->PCIe read 
transfer. This is because when the Intel ethernet (igb) is probed, it only uses 
the MEM window that's mapped into the AXI space (that window at 0x01100000). On 
the other hand, when some packet is transfered, the Intel controller operates 
with structures in DRAM directly. And the stall only happens when the interface 
either receives or attempts to send a packet.

Is this theory of mine even reasonable? If this doesn't work properly, could 
this stall the CPU? How can I check if this works correctly? What can I try if 
it does not?

Thanks!

btw. Please be careful about the top-posting ;-)

Best regards,
Marek Vasut

      reply	other threads:[~2013-10-12  2:30 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-26  3:24 [PATCH v7 0/2] Add PCIe support for i.MX6q Shawn Guo
2013-09-26  3:24 ` [PATCH v7 1/2] ARM: imx6q: Add PCIe bits to GPR syscon definition Shawn Guo
2013-09-26  3:24 ` [PATCH v7 2/2] PCI: imx6: Add support for i.MX6 PCIe controller Shawn Guo
2013-09-27 19:24 ` [PATCH v7 0/2] Add PCIe support for i.MX6q Bjorn Helgaas
2013-09-28  6:56   ` Shawn Guo
2013-10-08 20:56   ` Marek Vasut
2013-10-09  5:23     ` Zhu Richard-R65037
2013-10-10 10:25       ` Marek Vasut
2013-10-10 10:40         ` Zhu Richard-R65037
2013-10-10 12:59           ` Marek Vasut
2013-10-10 20:33           ` Tim Harvey
2013-10-10 20:40             ` Marek Vasut
2013-10-10 13:27         ` Bjorn Helgaas
2013-10-10 13:43           ` Marek Vasut
2013-10-10 15:58           ` Marek Vasut
2013-10-10 17:17             ` Bjorn Helgaas
2013-10-10 17:39               ` Marek Vasut
2013-10-10 17:56                 ` Bjorn Helgaas
2013-10-11  2:12                   ` [PATCH 1/2] PCI: imx6: Make reset-gpio optional Marek Vasut
2013-10-11  2:12                     ` [PATCH 2/2] PCI: imx6: Fix the clock for PCIe Marek Vasut
2013-10-11  7:20                       ` Jingoo Han
2013-10-11 11:55                         ` Marek Vasut
2013-10-12  7:13                           ` Shawn Guo
2013-10-11  7:09                     ` [PATCH 1/2] PCI: imx6: Make reset-gpio optional Jingoo Han
2013-10-12  7:20                     ` Shawn Guo
2013-10-12  9:28                       ` Marek Vasut
2013-10-14  0:02                         ` Jingoo Han
2013-10-14  0:44                           ` Marek Vasut
2013-10-14  1:17                             ` Marek Vasut
2013-10-14  2:33                               ` Jingoo Han
2013-10-14  3:23                                 ` Marek Vasut
2013-10-11  2:13                   ` [PATCH v7 0/2] Add PCIe support for i.MX6q Marek Vasut
2013-10-11  2:18                     ` Marek Vasut
2013-10-11  2:29                       ` Zhu Richard-R65037
2013-10-11  4:44                       ` Yinghai Lu
2013-10-11 14:44                         ` Marek Vasut
2013-10-11 15:24                           ` Tim Harvey
2013-10-11 20:13                             ` Marek Vasut
2013-10-12  2:16                             ` Zhu Richard-R65037
2013-10-12  2:30                               ` Marek Vasut [this message]

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