[PATCH 1/2] iommu/io-pgtable: Add MTK 4GB mode in Short-descriptor

Yong Wu
2016-02-24T07:03:34Z

Mediatek extend bit9 in the lvl1 and lvl2 pgtable descriptor of the
Short-descriptor as the 4GB mode in which the dram size will be
over 4GB.

We add a special quirk for this MTK-4GB mode, And in the standard
spec, Bit9 in the lvl1 is "IMPLEMENTATION DEFINED", while it's AP[2]
in the lvl2, therefore if this quirk is enabled, NO_PERMS is also
expected.

Signed-off-by: Yong Wu <yong.wu@mediatek.com>
---
In arm_v7s_init_pte, We add bit9 if the 4GB mode is enabled no matter
the current pa is over 4GB or not.

drivers/iommu/io-pgtable-arm-v7s.c | 14 +++++++++++++-
drivers/iommu/io-pgtable.h | 6 ++++++
2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c
index 9fcceb1..bf6a6f0 100644
--- a/drivers/iommu/io-pgtable-arm-v7s.c
+++ b/drivers/iommu/io-pgtable-arm-v7s.c
@@ -121,6 +121,8 @@
#define ARM_V7S_TEX_MASK 0x7
#define ARM_V7S_ATTR_TEX(val) (((val) & ARM_V7S_TEX_MASK) << ARM_V7S_TEX_SHIFT)

+#define ARM_V7S_ATTR_MTK_4GB BIT(9) /* MTK extend it for 4GB mode */
+
/* *well, except for TEX on level 2 large pages, of course :( */
#define ARM_V7S_CONT_PAGE_TEX_SHIFT 6
#define ARM_V7S_CONT_PAGE_TEX_MASK (ARM_V7S_TEX_MASK << ARM_V7S_CONT_PAGE_TEX_SHIFT)
@@ -364,6 +366,9 @@ static int arm_v7s_init_pte(struct arm_v7s_io_pgtable *data,
if (lvl == 1 && (cfg->quirks & IO_PGTABLE_QUIRK_ARM_NS))
pte |= ARM_V7S_ATTR_NS_SECTION;

+ if (cfg->quirks & IO_PGTABLE_QUIRK_MTK_4GB_EXT)
+ pte |= ARM_V7S_ATTR_MTK_4GB;
+
if (num_entries > 1)
pte = arm_v7s_pte_to_cont(pte, lvl);

@@ -625,9 +630,16 @@ static struct io_pgtable *arm_v7s_alloc_pgtable(struct io_pgtable_cfg *cfg,

if (cfg->quirks & ~(IO_PGTABLE_QUIRK_ARM_NS |
IO_PGTABLE_QUIRK_NO_PERMS |
- IO_PGTABLE_QUIRK_TLBI_ON_MAP))
+ IO_PGTABLE_QUIRK_TLBI_ON_MAP |
+ IO_PGTABLE_QUIRK_MTK_4GB_EXT))
return NULL;

+ /* If MTK_4GB_EXT is enabled, the NO_PERMS is also expected. */
+ if (cfg->quirks & IO_PGTABLE_QUIRK_MTK_4GB_EXT) {
+ if (!(cfg->quirks & IO_PGTABLE_QUIRK_NO_PERMS))
+ return NULL;
+ }
+
data = kmalloc(sizeof(*data), GFP_KERNEL);
if (!data)
return NULL;
diff --git a/drivers/iommu/io-pgtable.h b/drivers/iommu/io-pgtable.h
index d4f5027..a84a60a 100644
--- a/drivers/iommu/io-pgtable.h
+++ b/drivers/iommu/io-pgtable.h
@@ -60,10 +60,16 @@ struct io_pgtable_cfg {
* IO_PGTABLE_QUIRK_TLBI_ON_MAP: If the format forbids caching invalid
* (unmapped) entries but the hardware might do so anyway, perform
* TLB maintenance when mapping as well as when unmapping.
+ *
+ * IO_PGTABLE_QUIRK_MTK_4GB_EXT: Mediatek extend bit9 in the lvl1 and
+ * lvl2 descriptor of the Short-descriptor as the 4GB mode.
+ * Note that: Bit9 in the lvl1 is "IMPLEMENTATION DEFINED", while
+ * it is AP[2] in the lvl2.
*/
#define IO_PGTABLE_QUIRK_ARM_NS BIT(0)
#define IO_PGTABLE_QUIRK_NO_PERMS BIT(1)
#define IO_PGTABLE_QUIRK_TLBI_ON_MAP BIT(2)
+ #define IO_PGTABLE_QUIRK_MTK_4GB_EXT BIT(3)
unsigned long quirks;
unsigned long pgsize_bitmap;
unsigned int ias;
--
1.8.1.1.dirty