Re: [PATCH v12 3/4] iommu/arm-smmu: Add the device_link between masters and smmu
From: Rafael J. Wysocki <hidden>
Date: 2018-07-11 09:55:23
Also in:
linux-arm-msm, linux-iommu, linux-pm, lkml
On Sunday, July 8, 2018 7:34:12 PM CEST Vivek Gautam wrote:
quoted hunk ↗ jump to hunk
From: Sricharan R <redacted> Finally add the device link between the master device and smmu, so that the smmu gets runtime enabled/disabled only when the master needs it. This is done from add_device callback which gets called once when the master is added to the smmu. Signed-off-by: Sricharan R <redacted> Signed-off-by: Vivek Gautam <redacted> Reviewed-by: Tomasz Figa <tfiga@chromium.org> Cc: Rafael J. Wysocki <redacted> Cc: Lukas Wunner <lukas@wunner.de> --- - Change since v11 * Replaced DL_FLAG_AUTOREMOVE flag with DL_FLAG_AUTOREMOVE_SUPPLIER. drivers/iommu/arm-smmu.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index 09265e206e2d..916cde4954d2 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c@@ -1461,8 +1461,20 @@ static int arm_smmu_add_device(struct device *dev) iommu_device_link(&smmu->iommu, dev); + if (pm_runtime_enabled(smmu->dev) &&
Why does the creation of the link depend on whether or not runtime PM is enabled for the MMU device? What about system-wide PM and system shutdown? Are they always guaranteed to happen in the right order without the link?
+ !device_link_add(dev, smmu->dev,
+ DL_FLAG_PM_RUNTIME | DL_FLAG_AUTOREMOVE_SUPPLIER)) {
+ dev_err(smmu->dev, "Unable to add link to the consumer %s\n",
+ dev_name(dev));
+ ret = -ENODEV;
+ goto out_unlink;
+ }
+
return 0;
+out_unlink:
+ iommu_device_unlink(&smmu->iommu, dev);
+ arm_smmu_master_free_smes(fwspec);
out_cfg_free:
kfree(cfg);
out_free: