On 17/05/2022 11:26, AngeloGioacchino Del Regno wrote:
Il 17/05/22 11:08, Yong Wu ha scritto:
On Fri, 2022-05-13 at 17:14 +0200, AngeloGioacchino Del Regno wrote:
Add support for the M4Us found in the MT6795 Helio X10 SoC.
Signed-off-by: AngeloGioacchino Del Regno <
angelogioacchino.delregno@xxxxxxxxxxxxx>
---
drivers/iommu/mtk_iommu.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 71b2ace74cd6..3d802dd3f377 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -157,6 +157,7 @@
enum mtk_iommu_plat {
M4U_MT2712,
M4U_MT6779,
+ M4U_MT6795,
M4U_MT8167,
M4U_MT8173,
M4U_MT8183,
@@ -953,7 +954,8 @@ static int mtk_iommu_hw_init(const struct
mtk_iommu_data *data, unsigned int ban
* Global control settings are in bank0. May re-init these
global registers
* since no sure if there is bank0 consumers.
*/
- if (data->plat_data->m4u_plat == M4U_MT8173) {
+ if (data->plat_data->m4u_plat == M4U_MT6795 ||
+ data->plat_data->m4u_plat == M4U_MT8173) {
regval = F_MMU_PREFETCH_RT_REPLACE_MOD |
F_MMU_TF_PROT_TO_PROGRAM_ADDR_MT8173;
} else {
@@ -1138,6 +1140,9 @@ static int mtk_iommu_probe(struct
platform_device *pdev)
case M4U_MT2712:
p = "mediatek,mt2712-infracfg";
break;
+ case M4U_MT6795:
+ p = "mediatek,mt6795-infracfg";
+ break;
case M4U_MT8173:
p = "mediatek,mt8173-infracfg";
break;
@@ -1404,6 +1409,18 @@ static const struct mtk_iommu_plat_data
mt6779_data = {
.larbid_remap = {{0}, {1}, {2}, {3}, {5}, {7, 8}, {10}, {9}},
};
+static const struct mtk_iommu_plat_data mt6795_data = {
+ .m4u_plat = M4U_MT6795,
+ .flags = HAS_4GB_MODE | HAS_BCLK | RESET_AXI |
+ HAS_LEGACY_IVRP_PADDR | MTK_IOMMU_TYPE_MM,
+ .inv_sel_reg = REG_MMU_INV_SEL_GEN1,
+ .banks_num = 1,
+ .banks_enable = {true},
+ .iova_region = single_domain,
+ .iova_region_nr = ARRAY_SIZE(single_domain),
+ .larbid_remap = {{0}, {1}, {2}, {3}, {4}}, /* Linear mapping.
*/
+};
This is nearly same with mt8173_data. mt8173 has one more larb than
mt6795, its larbid_remap is also ok for mt6795.
I think that we should be explicit about the larbid_remap property,
since mt6795 has one less larb, we should explicitly say that like
I did there... that's only for human readability I admit ... but,
still, I wouldn't want to see people thinking that MT6795 has 6 LARBs
because they've read that larbid_remap having 6 entries.
thus it looks we could use mt8173 as the backward compatible.
compatible = "mediatek,mt6795-m4u",
"mediatek,mt8173-m4u";
After this, the only thing is about "mediatek,mt6795-infracfg". we have
to try again with mediatek,mt6795-infracfg after mediatek,mt8173-
infracfg fail. I think we should allow the backward case in 4GB mode
judgment if we have.
What's your opinion? or some other suggestion?
Thanks.
I know, I may have a plan for that, but I wanted to have a good reason to
propose such a thing, as if it's just about two SoCs needing that, there
would be no good reason to get things done differently.
...so, in order to provide a good cleanup, we have two possible roads to
follow here: either we add a generic "mediatek,infracfg" compatible to the
infra node (but I don't like that), or we can do it like it was previously
done in mtk-pm-domains.c (I prefer that approach):
iommu: iommu@somewhere {
... something ...
mediatek,infracfg = <&infracfg>;
};
infracfg = syscon_regmap_lookup_by_compatible(node, "mediatek,infracfg");
if (IS_ERR(infracfg)) {
/* try with the older way */
switch (...) {
case .... p = "mediatek,mt2712-infracfg";
... blah blah ...
}
/* legacy also failed, ouch! */
if (IS_ERR(infracfg))
return PTR_ERR(infracfg);
}
ret = regmap_read ... etc etc etc
I prefer that approach as well.
Regards,
Matthias
Cheers,
Angelo
