From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CEBEF14A4E1; Thu, 16 May 2024 14:17:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715869064; cv=none; b=JOurS6o+en6O0xuj6KJcjtOFc4/tIJYUUtnx0rmoDmtfR+blWDxURUjDmLDFcLLi66ofA0GVewkLOULKbFHe+5Uckd16YOHXfgvXTOX52bH+99QVYhCSBk6JOE7DRKNPze9SRrhSjhZMtkyku928SxvnsIk8vFg/9scV325ZO9c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715869064; c=relaxed/simple; bh=xMv7XT50PYQKLPovqBhh7bmTIxuh18H6PUJ2EPoy6u8=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=MyHtm/fjn4JoMqEnA8JfFvz2CI25o0KwqTWEnjYbmxPSXII0ohS/WLwryraXiyHK5WIQWDqxPGpsbJsrDouF++zYoO1Jz8UnmztUlMly5KIXSeymhwr7H7YIggR88zlufGp3Yg8X0GdnGP4OT2xgGXA/v8dJsYKxjN8oJ+QWKO8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Kjfc0Ikh; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Kjfc0Ikh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EC60AC113CC; Thu, 16 May 2024 14:17:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1715869064; bh=xMv7XT50PYQKLPovqBhh7bmTIxuh18H6PUJ2EPoy6u8=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=Kjfc0IkhMHVHFnfxmOd2jro4rjH+gKB/gy2doI4HcBeGt0EUDniqlL0+B53yKUoQS iP+x9qB/rqsFwNPjy7TzFDVo76JhA0/2ZRrm9vUfIS62+zCbpgTgJU5Hv9Y8r1+8SF hMv2Xuiq0DLYIt+NlHbvelhpnSVzvSzuk5Wr5ElZIvtR6SYooK01prdKH8hrTgXlYp YbDSH/wZFUIQFEQgIdHApYFg+KXkyPku6hzF2pg4s9SfO1ECfIGq9KG5n2B/LdoGut 93R9egqzEpqLQRkDWP68NHSc0SD4jSZnGAtGR+Gdg+wDcikonmxoUujdlKCpwQKdQz 4LzP4wGNeksJg== Date: Thu, 16 May 2024 09:17:42 -0500 From: Bjorn Helgaas To: Siddharth Vadapalli Cc: lpieralisi@kernel.org, kw@linux.com, robh@kernel.org, bhelgaas@google.com, manivannan.sadhasivam@linaro.org, fancer.lancer@gmail.com, u.kleine-koenig@pengutronix.de, cassel@kernel.org, dlemoal@kernel.org, yoshihiro.shimoda.uh@renesas.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, srk@ti.com Subject: Re: [PATCH v7 2/2] PCI: keystone: Fix pci_ops for AM654x SoC Message-ID: <20240516141742.GA2204499@bhelgaas> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Thu, May 16, 2024 at 11:07:27AM +0530, Siddharth Vadapalli wrote: > On Wed, May 15, 2024 at 02:26:14PM -0500, Bjorn Helgaas wrote: > > On Tue, May 14, 2024 at 04:14:54PM -0500, Bjorn Helgaas wrote: > > > On Tue, May 14, 2024 at 05:41:48PM +0530, Siddharth Vadapalli wrote: > > > > On Mon, May 13, 2024 at 04:53:50PM -0500, Bjorn Helgaas wrote: > > > ... > > > > > > > I'm not quite clear on the mechanism, but it would be helpful to at > > > > > least know what's wrong and on what platform. E.g., currently v4.90 > > > > > suffers Completion Timeouts and 45 second boot delays? And this patch > > > > > fixes that? > > > > > > > > Yes, the Completion Timeouts cause the 45 second boot delays and this > > > > patch fixes that. > > > > > > And this problem happens on AM654x/v4.90a, right? I really want the > > > commit log to say what platform is affected! > > > > > > Maybe something like this? > > > > > > PCI: keystone: Enable BAR 0 only for v3.65a > > > > > > The BAR 0 initialization done by ks_pcie_v3_65_add_bus() should > > > happen for v3.65a devices only. On other devices, BAR 0 should be > > > left disabled, as it is by dw_pcie_setup_rc(). > > > > > > After 6ab15b5e7057 ("PCI: dwc: keystone: Convert .scan_bus() > > > callback to use add_bus"), ks_pcie_v3_65_add_bus() enabled BAR 0 for > > > both v3.65a and v4.90a devices. On the AM654x SoC, which uses > > > v4.90a, enabling BAR 0 causes Completion Timeouts when setting up > > > MSI-X. These timeouts delay boot of the AM654x by about 45 seconds. > > > > > > Move the BAR 0 initialization to ks_pcie_msi_host_init(), which is > > > only used for v3.65a devices, and remove ks_pcie_v3_65_add_bus(). > > > > I haven't heard anything so I amended it to the above. But please > > correct me if it's wrong. > > I would suggest specifying the failing combination since I do not know > if there is another device that is using v4.90a but doesn't see this > issue. What is certain is that this issue is seen with the v4.90a > controller on AM654x platform. Despite the PCIe Controller version > remaining the same across different platforms, it might be possible > that not all features supported by the PCIe Controller are enabled on > all platforms. For that reason, it appears to me that the subject could > be: > > PCI: keystone: Don't enable BAR 0 for AM654x > > which implicitly indicates the combination as well (v4.90a on AM654x). > > The commit message's contents could be reduced to: > > After 6ab15b5e7057 ("PCI: dwc: keystone: Convert .scan_bus() > callback to use add_bus"), ks_pcie_v3_65_add_bus() enabled BAR 0 for > both v3.65a and v4.90a devices. On the AM654x SoC, which uses > v4.90a, enabling BAR 0 causes Completion Timeouts when setting up > MSI-X. These timeouts delay boot of the AM654x by about 45 seconds. > > Move the BAR 0 initialization to ks_pcie_msi_host_init(), which is > only used for v3.65a devices, and remove ks_pcie_v3_65_add_bus(). > > by dropping: > > The BAR 0 initialization done by ks_pcie_v3_65_add_bus() should > happen for v3.65a devices only. On other devices, BAR 0 should be > left disabled, as it is by dw_pcie_setup_rc(). > > The reason behind dropping the above paragraph is that BAR 0 could > probably be enabled on other controller versions as well, but not on the > v4.90a controller on the AM654x SoC. Thanks, that makes good sense, I changed the subject and dropped that paragraph. Bjorn