[PATCH v2 09/11] iommu/ipmmu-vmsa: Make IMBUSCTR setup optional

[Magnus Damm]

From: Magnus Damm <damm+rene...@opensource.se>

Introduce a feature to allow opt-out of setting up
IMBUSCR. The default case is unchanged.

Signed-off-by: Magnus Damm <damm+rene...@opensource.se>
---

 Changes since V1:
 - Updated the commit message
 - Reworked patch to coexist with the multi context feature

 drivers/iommu/ipmmu-vmsa.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

--- 0023/drivers/iommu/ipmmu-vmsa.c
+++ work/drivers/iommu/ipmmu-vmsa.c     2016-06-06 11:04:39.800607110 +0900
@@ -37,6 +37,7 @@ struct ipmmu_features {
        bool use_ns_alias_offset;
        bool has_cache_leaf_nodes;
        bool has_eight_ctx;
+       bool setup_imbuscr;
 };
 
 struct ipmmu_vmsa_device {
@@ -438,10 +439,10 @@ static int ipmmu_domain_init_context(str
        ipmmu_ctx_write(domain, IMMAIR0, domain->cfg.arm_lpae_s1_cfg.mair[0]);
 
        /* IMBUSCR */
-       ipmmu_ctx_write(domain, IMBUSCR,
-                       ipmmu_ctx_read(domain, IMBUSCR) &
-                       ~(IMBUSCR_DVM | IMBUSCR_BUSSEL_MASK));
-
+       if (domain->root->features->setup_imbuscr)
+               ipmmu_ctx_write(domain, IMBUSCR,
+                               ipmmu_ctx_read(domain, IMBUSCR) &
+                               ~(IMBUSCR_DVM | IMBUSCR_BUSSEL_MASK));
        /*
         * IMSTR
         * Clear all interrupt flags.
@@ -1057,6 +1058,7 @@ static const struct ipmmu_features ipmmu
        .use_ns_alias_offset = true,
        .has_cache_leaf_nodes = false,
        .has_eight_ctx = false,
+       .setup_imbuscr = true,
 };
 
 static const struct of_device_id ipmmu_of_ids[] = {