From f3e827d73ed454053d2ce6a4bf021b5adde3ac54 Mon Sep 17 00:00:00 2001 From: Yong Wu Date: Fri, 26 Jan 2018 15:11:28 +0800 Subject: [PATCH] iommu/mediatek: Move attach_device after iommu-group is ready for M4Uv1 In the commit 05f80300dc8b ("iommu: Finish making iommu_group support mandatory"), the iommu framework has supposed all the iommu drivers have their owner iommu-group, it get rid of the FIXME workarounds while the group is NULL. But the flow of Mediatek M4U gen1 looks a bit trick that it will hang at this case: ========================================== Unable to handle kernel NULL pointer dereference at virtual address 00000030 pgd = c0004000 [00000030] *pgd=00000000 PC is at mutex_lock+0x28/0x54 LR is at iommu_attach_device+0xa4/0xd4 pc : [] lr : [] psr: 60000013 sp : df0edbb8 ip : df0edbc8 fp : df0edbc4 r10: c114da14 r9 : df2a3e40 r8 : 00000003 r7 : df27a210 r6 : df2a90c4 r5 : 00000030 r4 : 00000000 r3 : df0f8000 r2 : fffff000 r1 : df29c610 r0 : 00000030 Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none xxx (mutex_lock) from [] (iommu_attach_device+0xa4/0xd4) (iommu_attach_device) from [] (__arm_iommu_attach_device+0x28/0x90) (__arm_iommu_attach_device) from [] (arm_iommu_attach_device+0x1c/0x30) (arm_iommu_attach_device) from [] (mtk_iommu_add_device+0xfc/0x214) (mtk_iommu_add_device) from [] (add_iommu_group+0x3c/0x68) (add_iommu_group) from [] (bus_for_each_dev+0x78/0xac) (bus_for_each_dev) from [] (bus_set_iommu+0xb0/0xec) (bus_set_iommu) from [] (mtk_iommu_probe+0x328/0x368) (mtk_iommu_probe) from [] (platform_drv_probe+0x5c/0xc0) (platform_drv_probe) from [] (driver_probe_device+0x2f4/0x4d8) (driver_probe_device) from [] (__driver_attach+0x10c/0x128) (__driver_attach) from [] (bus_for_each_dev+0x78/0xac) (bus_for_each_dev) from [] (driver_attach+0x2c/0x30) (driver_attach) from [] (bus_add_driver+0x1e0/0x278) (bus_add_driver) from [] (driver_register+0x88/0x108) (driver_register) from [] (__platform_driver_register+0x50/0x58) (__platform_driver_register) from [] (m4u_init+0x24/0x28) (m4u_init) from [] (do_one_initcall+0xf0/0x17c) ========================= The root cause is that the device's iommu-group is NULL while arm_iommu_attach_device is called. This patch prepare a new iommu-group for the iommu consumer devices to fix this issue. CC: Robin Murphy CC: Honghui Zhang Fixes: 05f80300dc8b ("iommu: Finish making iommu_group support mandatory") Reported-by: Ryder Lee Signed-off-by: Yong Wu Signed-off-by: Joerg Roedel --- drivers/iommu/mtk_iommu_v1.c | 54 ++++++++++++++---------------------- 1 file changed, 21 insertions(+), 33 deletions(-) diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c index 542930cd183d..1b1b77594897 100644 --- a/drivers/iommu/mtk_iommu_v1.c +++ b/drivers/iommu/mtk_iommu_v1.c @@ -418,20 +418,12 @@ static int mtk_iommu_create_mapping(struct device *dev, m4udev->archdata.iommu = mtk_mapping; } - ret = arm_iommu_attach_device(dev, mtk_mapping); - if (ret) - goto err_release_mapping; - return 0; - -err_release_mapping: - arm_iommu_release_mapping(mtk_mapping); - m4udev->archdata.iommu = NULL; - return ret; } static int mtk_iommu_add_device(struct device *dev) { + struct dma_iommu_mapping *mtk_mapping; struct of_phandle_args iommu_spec; struct of_phandle_iterator it; struct mtk_iommu_data *data; @@ -452,15 +444,30 @@ static int mtk_iommu_add_device(struct device *dev) if (!dev->iommu_fwspec || dev->iommu_fwspec->ops != &mtk_iommu_ops) return -ENODEV; /* Not a iommu client device */ - data = dev->iommu_fwspec->iommu_priv; - iommu_device_link(&data->iommu, dev); - - group = iommu_group_get_for_dev(dev); + /* + * This is a short-term bodge because the ARM DMA code doesn't + * understand multi-device groups, but we have to call into it + * successfully (and not just rely on a normal IOMMU API attach + * here) in order to set the correct DMA API ops on @dev. + */ + group = iommu_group_alloc(); if (IS_ERR(group)) return PTR_ERR(group); + err = iommu_group_add_device(group, dev); iommu_group_put(group); - return 0; + if (err) + return err; + + data = dev->iommu_fwspec->iommu_priv; + mtk_mapping = data->dev->archdata.iommu; + err = arm_iommu_attach_device(dev, mtk_mapping); + if (err) { + iommu_group_remove_device(dev); + return err; + } + + return iommu_device_link(&data->iommu, dev);; } static void mtk_iommu_remove_device(struct device *dev) @@ -477,24 +484,6 @@ static void mtk_iommu_remove_device(struct device *dev) iommu_fwspec_free(dev); } -static struct iommu_group *mtk_iommu_device_group(struct device *dev) -{ - struct mtk_iommu_data *data = dev->iommu_fwspec->iommu_priv; - - if (!data) - return ERR_PTR(-ENODEV); - - /* All the client devices are in the same m4u iommu-group */ - if (!data->m4u_group) { - data->m4u_group = iommu_group_alloc(); - if (IS_ERR(data->m4u_group)) - dev_err(dev, "Failed to allocate M4U IOMMU group\n"); - } else { - iommu_group_ref_get(data->m4u_group); - } - return data->m4u_group; -} - static int mtk_iommu_hw_init(const struct mtk_iommu_data *data) { u32 regval; @@ -547,7 +536,6 @@ static struct iommu_ops mtk_iommu_ops = { .iova_to_phys = mtk_iommu_iova_to_phys, .add_device = mtk_iommu_add_device, .remove_device = mtk_iommu_remove_device, - .device_group = mtk_iommu_device_group, .pgsize_bitmap = ~0UL << MT2701_IOMMU_PAGE_SHIFT, };