[PATCH AUTOSEL 4.19 510/671] iommu/mediatek: Fix iova_to_phys PA start for 4GB mode

Sasha Levin
2020-01-16T18:44:15Z

From: Yong Wu <yong.wu@mediatek.com>

[ Upstream commit 76ce65464fcd2c21db84391572b7938b716aceb0 ]

In M4U 4GB mode, the physical address is remapped as below:

CPU Physical address:

====================

0 1G 2G 3G 4G 5G
|---A---|---B---|---C---|---D---|---E---|
+--I/O--+------------Memory-------------+

IOMMU output physical address:
=============================

4G 5G 6G 7G 8G
|---E---|---B---|---C---|---D---|
+------------Memory-------------+

The Region 'A'(I/O) can not be mapped by M4U; For Region 'B'/'C'/'D', the
bit32 of the CPU physical address always is needed to set, and for Region
'E', the CPU physical address keep as is. something looks like this:
CPU PA -> M4U OUTPUT PA
0x4000_0000 0x1_4000_0000 (Add bit32)
0x8000_0000 0x1_8000_0000 ...
0xc000_0000 0x1_c000_0000 ...
0x1_0000_0000 0x1_0000_0000 (No change)

Additionally, the iommu consumers always use the CPU phyiscal address.

The PA in the iova_to_phys that is got from v7s always is u32, But
from the CPU point of view, PA only need add BIT(32) when PA < 0x4000_0000.

Fixes: 30e2fccf9512 ("iommu/mediatek: Enlarge the validate PA range
for 4GB mode")
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iommu/mtk_iommu.c | 26 +++++++++++++++++++++++++-
1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index f9f69f7111a9..c88cc299e3c9 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -115,6 +115,30 @@ struct mtk_iommu_domain {

static struct iommu_ops mtk_iommu_ops;

+/*
+ * In M4U 4GB mode, the physical address is remapped as below:
+ *
+ * CPU Physical address:
+ * ====================
+ *
+ * 0 1G 2G 3G 4G 5G
+ * |---A---|---B---|---C---|---D---|---E---|
+ * +--I/O--+------------Memory-------------+
+ *
+ * IOMMU output physical address:
+ * =============================
+ *
+ * 4G 5G 6G 7G 8G
+ * |---E---|---B---|---C---|---D---|
+ * +------------Memory-------------+
+ *
+ * The Region 'A'(I/O) can NOT be mapped by M4U; For Region 'B'/'C'/'D', the
+ * bit32 of the CPU physical address always is needed to set, and for Region
+ * 'E', the CPU physical address keep as is.
+ * Additionally, The iommu consumers always use the CPU phyiscal address.
+ */
+#define MTK_IOMMU_4GB_MODE_REMAP_BASE 0x40000000
+
static LIST_HEAD(m4ulist); /* List all the M4U HWs */

#define for_each_m4u(data) list_for_each_entry(data, &m4ulist, list)
@@ -409,7 +433,7 @@ static phys_addr_t mtk_iommu_iova_to_phys(struct iommu_domain *domain,
pa = dom->iop->iova_to_phys(dom->iop, iova);
spin_unlock_irqrestore(&dom->pgtlock, flags);

- if (data->enable_4GB)
+ if (data->enable_4GB && pa < MTK_IOMMU_4GB_MODE_REMAP_BASE)
pa |= BIT_ULL(32);

return pa;
--
2.20.1