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From: Bjorn Helgaas <helgaas@kernel.org>
To: Tomasz Nowicki <tn@semihalf.com>
Cc: arnd@arndb.de, will.deacon@arm.com, catalin.marinas@arm.com,
	rafael@kernel.org, hanjun.guo@linaro.org,
	Lorenzo.Pieralisi@arm.com, okaya@codeaurora.org,
	jchandra@broadcom.com, robert.richter@caviumnetworks.com,
	mw@semihalf.com, Liviu.Dudau@arm.com, ddaney@caviumnetworks.com,
	wangyijing@huawei.com, Suravee.Suthikulpanit@amd.com,
	msalter@redhat.com, linux-pci@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org,
	linux-kernel@vger.kernel.org, linaro-acpi@lists.linaro.org,
	jcm@redhat.com, andrea.gallo@linaro.org, dhdang@apm.com,
	jeremy.linton@arm.com, liudongdong3@huawei.com,
	cov@codeaurora.org
Subject: Re: [PATCH V9 09/11] ARM64/PCI: ACPI support for legacy IRQs parsing and consolidation with DT code
Date: Fri, 10 Jun 2016 18:36:12 -0500	[thread overview]
Message-ID: <20160610233612.GB7671@localhost> (raw)
In-Reply-To: <1465588519-11334-10-git-send-email-tn@semihalf.com>

On Fri, Jun 10, 2016 at 09:55:17PM +0200, Tomasz Nowicki wrote:
> To enable PCI legacy IRQs on platforms booting with ACPI, arch code
> should include ACPI specific callbacks that parse and set-up the
> device IRQ number, equivalent to the DT boot path. Owing to the current
> ACPI core scan handlers implementation, ACPI PCI legacy IRQs bindings
> cannot be parsed at device add time, since that would trigger ACPI scan
> handlers ordering issues depending on how the ACPI tables are defined.

Uh, OK :)  I can't figure out exactly what the problem is here -- I
don't know where to look if I wanted to fix the scan handler ordering
issues, and I don't know how I could tell if it would ever be safe to
move this from driver probe-time back to device add-time.

I also notice that x86 and ia64 call acpi_pci_irq_enable() even later,
when the driver *enables* the device.  Is there a reason you didn't do
it at the same time as x86 and ia64?  This is another of those pcibios
hooks that really don't do anything arch-specific, so I can imagine
refactoring this somehow, someday.

Did we have this conversation before?  It seems vaguely familiar, so I
apologize if you already explained this once.

> To solve this problem and consolidate FW PCI legacy IRQs parsing in
> one single pcibios callback (pending final removal), this patch moves
> DT PCI IRQ parsing to the pcibios_alloc_irq() callback (called by
> PCI core code at device probe time) and adds ACPI PCI legacy IRQs
> parsing to the same callback too, so that FW PCI legacy IRQs parsing
> is confined in one single arch callback that can be easily removed
> when code parsing PCI legacy IRQs is consolidated and moved to core
> PCI code.
> 
> Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
> Suggested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> ---
>  arch/arm64/kernel/pci.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c
> index d5d3d26..b3b8a2c 100644
> --- a/arch/arm64/kernel/pci.c
> +++ b/arch/arm64/kernel/pci.c
> @@ -51,11 +51,16 @@ int pcibios_enable_device(struct pci_dev *dev, int mask)
>  }
>  
>  /*
> - * Try to assign the IRQ number from DT when adding a new device
> + * Try to assign the IRQ number when probing a new device
>   */
> -int pcibios_add_device(struct pci_dev *dev)
> +int pcibios_alloc_irq(struct pci_dev *dev)
>  {
> -	dev->irq = of_irq_parse_and_map_pci(dev, 0, 0);
> +	if (acpi_disabled)
> +		dev->irq = of_irq_parse_and_map_pci(dev, 0, 0);
> +#ifdef CONFIG_ACPI
> +	else
> +		return acpi_pci_irq_enable(dev);
> +#endif
>  
>  	return 0;
>  }
> -- 
> 1.9.1
> 

  reply	other threads:[~2016-06-10 23:36 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-10 19:55 [PATCH V9 00/11] Support for ARM64 ACPI based PCI host controller Tomasz Nowicki
2016-06-10 19:55 ` [PATCH V9 01/11] PCI/ECAM: Move ecam.h to linux/include/pci-ecam.h Tomasz Nowicki
2016-06-10 19:55 ` [PATCH V9 02/11] PCI/ECAM: Add parent device field to pci_config_window Tomasz Nowicki
2016-06-10 19:55 ` [PATCH V9 03/11] PCI: Add new function to unmap IO resources Tomasz Nowicki
2016-06-10 19:55 ` [PATCH V9 04/11] ACPI/PCI: Support IO resources when parsing PCI host bridge resources Tomasz Nowicki
2016-06-10 19:55 ` [PATCH V9 05/11] ACPI/PCI: Add generic MCFG table handling Tomasz Nowicki
2016-06-10 23:25   ` Bjorn Helgaas
2016-06-10 19:55 ` [PATCH V9 06/11] PCI: Refactor generic bus domain assignment Tomasz Nowicki
2016-06-10 20:50   ` Lorenzo Pieralisi
2016-06-10 19:55 ` [PATCH V9 07/11] PCI: Factor DT specific pci_bus_find_domain_nr() code out Tomasz Nowicki
2016-06-10 20:51   ` Lorenzo Pieralisi
2016-06-10 19:55 ` [PATCH V9 08/11] ARM64/PCI: Add ACPI hook to assign domain number Tomasz Nowicki
2016-06-10 19:55 ` [PATCH V9 09/11] ARM64/PCI: ACPI support for legacy IRQs parsing and consolidation with DT code Tomasz Nowicki
2016-06-10 23:36   ` Bjorn Helgaas [this message]
2016-06-13 10:00     ` Tomasz Nowicki
2016-06-13 10:40     ` Lorenzo Pieralisi
2016-06-13 15:56       ` Liviu.Dudau
2016-06-13 20:01       ` Duc Dang
2016-06-14  9:30         ` Lorenzo Pieralisi
2016-06-10 19:55 ` [PATCH V9 10/11] ARM64/PCI: Implement ACPI low-level calls to access PCI_Config region from AML Tomasz Nowicki
2016-06-10 20:54   ` Lorenzo Pieralisi
2016-06-10 19:55 ` [PATCH V9 11/11] ARM64/PCI: Support for ACPI based PCI host controller Tomasz Nowicki
2016-11-22 23:13   ` Bjorn Helgaas
2016-11-23 11:21     ` Tomasz Nowicki
2016-11-23 18:22       ` Bjorn Helgaas
2016-11-24 11:10         ` Tomasz Nowicki
2016-06-10 23:41 ` [PATCH V9 00/11] Support for ARM64 " Bjorn Helgaas
2016-06-10 23:50   ` Jon Masters
2016-06-10 23:58   ` [Linaro-acpi] " Jon Masters
2016-06-11  9:51   ` Tomasz Nowicki

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