Hi Marek: Best Regards Richard Zhu > -----Original Message----- > From: Marek Vasut [mailto:marex@xxxxxxx] > Sent: Friday, November 29, 2013 1:56 AM > To: Jingoo Han > Cc: 'Tim Harvey'; 'Pratyush Anand'; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; > linux-pci@xxxxxxxxxxxxxxx; 'Bjorn Helgaas'; 'Frank Li'; 'Harro Haan'; 'Mohit > KUMAR DCG'; Zhu Richard-R65037; 'Sascha Hauer'; 'Sean Cross'; 'Shawn Guo'; > 'Siva Reddy Kallam'; 'Srikanth T Shivanand'; 'Troy Kisky'; 'Yinghai Lu' > Subject: Re: [PATCH 2/7] [RFC] PCI: imx6: remove outbound io/mem ATU region > mapping > > Dear Jingoo Han, > > > On Wednesday, November 27, 2013 5:44 PM, Marek Vasut wrote: > > > Wednesday, November 27, 2013 1:30 PM, Pratyush Anand wrote: > > > > On Wed, Nov 27, 2013 at 05:10:43AM +0800, Marek Vasut wrote: > > > > > From: Tim Harvey <tharvey@xxxxxxxxxxxxx> > > > > > > > > > > The IMX6 iATU is used for address translation between the AXI > > > > > bus address space and PCI address space. This is used for type0 > > > > > and > > > > > type1 config cycles but is not necessary for outbound io/mem > > > > > regions. > > > > > > > > > > This patch removes the calls that inappropriately re-configures > > > > > the ATU viewport for outbound memory and IO after config cycles > > > > > and removes them altogether as they are not necessary. > > > > > > > > Yes, they are not necessary for all the cases where translation is > > > > one to one. So so for sure all the platform till now introduced > > > > should work. > > > > But, what about a platform where memory translation is not one to one? > > > > > > > > Existing code should work with all sort of memory translation on a > > > > platform having atleast two viewports capable of programming any > > > > type of outbound transaction. > > > > > > Full ACK, that's why it's called RFC. > > > > > > > > This resolves issues with PCI devices behind switches and has > > > > > been tested with a Gige device behind a PLX PEX860x switch. > > > > > More testing is needed for other configurations. > > > > > > > > I do not understand if MX6 has 4 Outbound Viewport then how this > > > > patch helps? > > > > -- PCI devices behind switches would not have been working because > > > > CFG1 transaction would not have been correct. > > > > -- It works with this patch. This patch changes viewport for CFG1 > > > > from > > > > 1 to 0. > > > > -- Can it be possible that MX6 has some restriction on viewport > > > > programming capability. I mean,like only viewport0 can be > > > > programmed for CFG0/1? > > > > > > Tim ? > > > > > > Here is the MX6 datasheet [1], the section 48.3.9.1.1 and 48.3.9.1.2 > > > describe the iATU configuration on MX6. My understanding from this > > > description is that the MX6 has 4 inbound and 4 outbound iATU regions. > > > Am I wrong ? > > > > The numbers of inbound and outbound are hardware-configurable features. > > Thus, these numbers can be confirmed by Freescale hardware engineers. > > How about asking Freescale hardware engineers, if possible? > > Richard is on the CC. Richard, can you please confirm those? > [Richard] One Pericom PI7C9X2G303EL pcie switch, and two pcie ep deivces(one is intel e1000e nic, the other is one xhci device) are tested on imx6q sabresd board. Without removing outbound io/mem regions view map during the cfg0/1 read/write cycle, both of these devices can't work well at my side. Works well after remove them during the cfg0/1 read/write cycles. Same to Tim's situation about switch implementation. > Thanks! > > > Best regards, > > Jingoo Han > > > > > [1] > > > http://cache.freescale.com/files/32bit/doc/ref_manual/IMX6DQRM.pdf > > > > > > > Otherwise I do not find any convincing reason that why this patch > > > > helps in resolving issues with PCI devices behind switches. > > Best regards, > Marek Vasut -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
