Mark Zhang <nvmarkzhang@xxxxxxxxx> wrote @ Wed, 5 Dec 2012 07:29:42 +0100:
> On 12/05/2012 02:37 AM, Hiroshi Doyu wrote:
> > Most of platform devices are IOMMU'able in Tegra30 SoC. Registering
> > all IOMMU'able devices manually isn't nice. This patch allows
> > platform bus_notifier to register IOMMU devices. Map info can be
> > passed from DT. Info format is:
> >
> > dma-window = <0 0x40000000>;
> >
> > TODO:
> > A map can be shared with mutiple devices. This info also could be
> > passed from DT or default map can be set in advance.
> >
> > Signed-off-by: Hiroshi Doyu <hdoyu@xxxxxxxxxx>
> > ---
> > v3: Added bus_unregister_notifier
> > ---
> > drivers/iommu/tegra-smmu.c | 48 +++++++++++++++++++++++++++++++++++++++++++-
> > 1 file changed, 47 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
> > index 25c1210..8fec9be 100644
> > --- a/drivers/iommu/tegra-smmu.c
> > +++ b/drivers/iommu/tegra-smmu.c
> > @@ -38,6 +38,7 @@
> >
> > #include <asm/page.h>
> > #include <asm/cacheflush.h>
> > +#include <asm/dma-iommu.h>
> >
> > enum smmu_hwgrp {
> > HWGRP_AFI,
> > @@ -1273,13 +1274,58 @@ static struct platform_driver tegra_smmu_driver = {
> > },
> > };
> >
> > +static int tegra_smmu_device_notifier(struct notifier_block *nb,
> > + unsigned long event, void *_dev)
> > +{
> > + struct dma_iommu_mapping *map = NULL;
> > + struct device *dev = _dev;
> > + dma_addr_t base;
> > + size_t size;
> > + int err;
> > +
> > + switch (event) {
> > + case BUS_NOTIFY_ADD_DEVICE:
> > + err = of_get_dma_window(dev->of_node, NULL, 0, NULL, &base,
> > + &size);
> > + if (!err)
> > + map = arm_iommu_create_mapping(&platform_bus_type,
> > + base, size, 0);
> > + if (IS_ERR_OR_NULL(map))
> > + break;
> > + if (arm_iommu_attach_device(dev, map)) {
> > + arm_iommu_release_mapping(map);
> > + dev_err(dev, "Failed to attach %s\n", dev_name(dev));
> > + }
> > + dev_dbg(dev, "Attached %s to map %p\n", dev_name(dev), map);
>
> If "arm_iommu_attach_device" fails, the "dev_err" and "dev_dbg" will all
> be called.
>
> > + break;
> > + default:
> > + break;
> > + }
> > + return NOTIFY_DONE;
> > +}
> > +
> > +static struct notifier_block tegra_smmu_device_nb = {
> > + .notifier_call = tegra_smmu_device_notifier,
> > +};
> > +
> > static int __devinit tegra_smmu_init(void)
> > {
> > - return platform_driver_register(&tegra_smmu_driver);
> > + int err;
> > +
> > + err = platform_driver_register(&tegra_smmu_driver);
> > + if (err)
> > + return err;
> > + if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU))
> > + bus_register_notifier(&platform_bus_type,
> > + &tegra_smmu_device_nb);
> > + return 0;
> > }
> >
> > static void __exit tegra_smmu_exit(void)
> > {
> > + if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU))
> > + bus_unregister_notifier(&platform_bus_type,
> > + &tegra_smmu_device_nb);
>
> Okay. Here unregister the notifier, but where is the
> "arm_iommu_release_mapping" for every IOMMU'able devices?
True. I think that this could be solved with:
static void __exit tegra_smmu_exit(void)
{
+ if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)) {
+ bus_for_each_dev(&platform_bus_type, NULL, NULL,
+ tegra_smmu_remove_map);
+ bus_unregister_notifier(&platform_bus_type,
+ &tegra_smmu_device_nb);
+ }
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