From: Kishon Vijay Abraham I <email@example.com> To: Marc Zyngier <firstname.lastname@example.org> Cc: Bjorn Helgaas <email@example.com>, Rob Herring <firstname.lastname@example.org>, Lorenzo Pieralisi <email@example.com>, Tom Joseph <firstname.lastname@example.org>, <email@example.com>, <firstname.lastname@example.org>, <email@example.com>, <firstname.lastname@example.org>, <email@example.com>, Lokesh Vutla <firstname.lastname@example.org> Subject: Re: [PATCH v2 2/3] PCI: j721e: Add PCI legacy interrupt support for J721E Date: Wed, 11 Aug 2021 17:37:19 +0530 [thread overview] Message-ID: <email@example.com> (raw) In-Reply-To: <firstname.lastname@example.org> Hi Marc, On 10/08/21 6:03 pm, Marc Zyngier wrote: > On Mon, 09 Aug 2021 15:58:38 +0100, > Kishon Vijay Abraham I <email@example.com> wrote: >> >> Hi Marc, >> >> On 09/08/21 3:09 pm, Marc Zyngier wrote: >>> On Mon, 09 Aug 2021 05:50:10 +0100, >>> Kishon Vijay Abraham I <firstname.lastname@example.org> wrote: >>>> >>>> Hi Marc, >>>> >>>> On 04/08/21 8:43 pm, Marc Zyngier wrote: >>>>> On Wed, 04 Aug 2021 14:29:11 +0100, >>>>> Kishon Vijay Abraham I <email@example.com> wrote: >>>>>> >>>>>> Add PCI legacy interrupt support for J721E. J721E has a single HW >>>>>> interrupt line for all the four legacy interrupts INTA/INTB/INTC/INTD. >>>>>> The HW interrupt line connected to GIC is a pulse interrupt whereas >>>>>> the legacy interrupts by definition is level interrupt. In order to >>>>>> provide level interrupt functionality to edge interrupt line, PCIe >>>>>> in J721E has provided IRQ_EOI register. >>>>>> >>>>>> However due to Errata ID #i2094 (), EOI feature is not enabled in HW >>>>>> and only a single pulse interrupt will be generated for every >>>>>> ASSERT_INTx/DEASSERT_INTx. >>>>> >>>>> So my earlier remark stands. If you get a single edge, how do you >>>>> handle a level that is still high after having handled the interrupt >>>>> on hardware that has this bug? >>>> >>>> Right, this hardware (J721E) has a bug but was fixed in J7200 (Patch 3/3 >>>> handles that). >>> >>> But how do you make it work with J721E? Is it even worth supporting if >>> (as I expect) it is unreliable? >> >> I've seen at-least the NVMe devices triggers the interrupts again and >> the data transfer completes. But I agree, this is unreliable. > > Then I don't think you should add INTx support for this system. It is > bound to be a support burden, and will reflect badly on the whole > platform. Focusing on J7200 is probably the best thing to do. Okay, will drop this patch from the series and have INTx support only for J7200. Thanks Kishon
next prev parent reply other threads:[~2021-08-11 12:07 UTC|newest] Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-08-04 13:29 [PATCH v2 0/3] PCI: Add legacy interrupt support in pci-j721e Kishon Vijay Abraham I 2021-08-04 13:29 ` [PATCH v2 1/3] dt-bindings: PCI: ti,j721e: Add bindings to specify legacy interrupts Kishon Vijay Abraham I 2021-08-04 15:05 ` Marc Zyngier 2021-08-09 4:38 ` Kishon Vijay Abraham I 2021-08-13 17:17 ` Rob Herring 2021-08-18 13:58 ` Kishon Vijay Abraham I 2021-09-23 4:33 ` Kishon Vijay Abraham I 2021-09-23 15:44 ` Rob Herring 2021-08-04 13:29 ` [PATCH v2 2/3] PCI: j721e: Add PCI legacy interrupt support for J721E Kishon Vijay Abraham I 2021-08-04 15:13 ` Marc Zyngier 2021-08-09 4:50 ` Kishon Vijay Abraham I 2021-08-09 9:39 ` Marc Zyngier 2021-08-09 14:58 ` Kishon Vijay Abraham I 2021-08-10 12:33 ` Marc Zyngier 2021-08-11 12:07 ` Kishon Vijay Abraham I [this message] 2021-08-04 13:29 ` [PATCH v2 3/3] PCI: j721e: Add PCI legacy interrupt support for J7200 Kishon Vijay Abraham I
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --subject='Re: [PATCH v2 2/3] PCI: j721e: Add PCI legacy interrupt support for J721E' \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: link
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).