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From: swarren@wwwdotorg•org (Stephen Warren)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCHv7 03/12] iommu/of: check if dependee iommu is ready or not
Date: Mon, 16 Dec 2013 11:34:12 -0700	[thread overview]
Message-ID: <52AF47A4.6010501@wwwdotorg.org> (raw)
In-Reply-To: <1386835033-4701-4-git-send-email-hdoyu@nvidia.com>

On 12/12/2013 12:57 AM, Hiroshi Doyu wrote:
> IOMMU devices on the bus need to be poplulated first, then iommu
> master devices are done later.
> 
> With CONFIG_OF_IOMMU, "iommus=" DT binding would be used to identify
> whether a device can be an iommu msater or not. If a device can, we'll
> defer to populate that device till an depending iommu device is
> populated.

> diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c

> +int of_iommu_attach(struct device *dev)
> +{
> +	const __be32 *cur, *end;
> +	struct of_phandle_args args;
> +
> +	of_property_for_each_phandle_with_args(dev->of_node, "iommus",
> +				       "#iommu-cells", 0, args, cur, end) {
> +		if (!of_find_iommu_by_node(args.np))
> +			return -EPROBE_DEFER;

I think that since of_find_iommu_by_node() should be calling
iommu_get(iommu), the error-case here should loop over the IOMMUs that
have successfully been acquired, and call iommu_put().

You'd also want to implement of_iommu_detach() or iommu_detach() to undo
the iommu_get()s that happen within this function.

  reply	other threads:[~2013-12-16 18:34 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-12-12  7:57 [PATCHv7 00/12] Unifying SMMU driver among Tegra SoCs Hiroshi Doyu
2013-12-12  7:57 ` [PATCHv7 01/12] of: introduce of_property_for_each_phandle_with_args() Hiroshi Doyu
2013-12-16 18:29   ` Stephen Warren
2013-12-12  7:57 ` [PATCHv7 02/12] iommu/of: introduce a global iommu device list Hiroshi Doyu
2013-12-16 18:32   ` Stephen Warren
2013-12-12  7:57 ` [PATCHv7 03/12] iommu/of: check if dependee iommu is ready or not Hiroshi Doyu
2013-12-16 18:34   ` Stephen Warren [this message]
2013-12-12  7:57 ` [PATCHv7 04/12] driver/core: populate devices in order for IOMMUs Hiroshi Doyu
2013-12-12 11:39   ` Grant Likely
2013-12-13  2:14     ` Greg KH
2013-12-14 12:24       ` Thierry Reding
2013-12-14 14:28         ` Hiroshi Doyu
2013-12-16 18:26       ` Stephen Warren
2013-12-12  7:57 ` [PATCHv7 05/12] iommu/core: add ops->{bound,unbind}_driver() Hiroshi Doyu
2013-12-16 18:42   ` Stephen Warren
2013-12-30 13:45   ` Joerg Roedel
2013-12-12  7:57 ` [PATCHv7 06/12] ARM: tegra: create a DT header defining SWGROUP ID Hiroshi Doyu
2013-12-18  8:02   ` Mark Zhang
2013-12-18 16:27     ` Stephen Warren
2013-12-20 12:35       ` Thierry Reding
2013-12-20 17:36         ` Stephen Warren
2013-12-12  7:57 ` [PATCHv7 07/12] iommu/tegra: smmu: register device to iommu dynamically Hiroshi Doyu
2013-12-16 18:46   ` Stephen Warren
2013-12-12  7:57 ` [PATCHv7 08/12] iommu/tegra: smmu: calculate ASID register offset by ID Hiroshi Doyu
2013-12-16 19:02   ` Stephen Warren
2013-12-12  7:57 ` [PATCHv7 09/12] iommu/tegra: smmu: get swgroups from DT "iommus=" Hiroshi Doyu
2013-12-16 19:09   ` Stephen Warren
2013-12-12  7:57 ` [PATCHv7 10/12] iommu/tegra: smmu: allow duplicate ASID wirte Hiroshi Doyu
2013-12-16 19:19   ` Stephen Warren
2013-12-12  7:57 ` [PATCHv7 11/12] iommu/tegra: smmu: Rename hwgrp -> swgroups Hiroshi Doyu
2013-12-12  7:57 ` [PATCHv7 12/12] iommu/tegra: smmu: add SMMU to an global iommu list Hiroshi Doyu

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