iommu/arm-smmu: Add a stream map entry iterator

We iterate over the SMEs associated with a master config quite a lot in
various places, and are about to do so even more. Let's wrap the idiom
in a handy iterator macro before the repetition gets out of hand.

Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

1 files changed, 12 insertions, 14 deletions

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index b6e26dba2dec..f402f9e126a8 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -324,6 +324,8 @@ struct arm_smmu_master_cfg {
         s16                             smendx[MAX_MASTER_STREAMIDS];
 };
 #define INVALID_SMENDX                  -1
+#define for_each_cfg_sme(cfg, i, idx) \
+        for (i = 0; idx = cfg->smendx[i], i < cfg->num_streamids; ++i)
 
 struct arm_smmu_device {
         struct device                   *dev;
@@ -1090,8 +1092,8 @@ static int arm_smmu_master_alloc_smes(struct arm_smmu_device *smmu,
         int i, idx;
 
         /* Allocate the SMRs on the SMMU */
-        for (i = 0; i < cfg->num_streamids; ++i) {
-                if (cfg->smendx[i] != INVALID_SMENDX)
+        for_each_cfg_sme(cfg, i, idx) {
+                if (idx != INVALID_SMENDX)
                         return -EEXIST;
 
                 /* ...except on stream indexing hardware, of course */
@@ -1115,8 +1117,8 @@ static int arm_smmu_master_alloc_smes(struct arm_smmu_device *smmu,
                 return 0;
 
         /* It worked! Now, poke the actual hardware */
-        for (i = 0; i < cfg->num_streamids; ++i)
-                arm_smmu_write_smr(smmu, cfg->smendx[i]);
+        for_each_cfg_sme(cfg, i, idx)
+                arm_smmu_write_smr(smmu, idx);
 
         return 0;
 
@@ -1131,15 +1133,13 @@ err_free_smrs:
 static void arm_smmu_master_free_smes(struct arm_smmu_master_cfg *cfg)
 {
         struct arm_smmu_device *smmu = cfg->smmu;
-        int i;
+        int i, idx;
 
         /*
          * We *must* clear the S2CR first, because freeing the SMR means
          * that it can be re-allocated immediately.
          */
-        for (i = 0; i < cfg->num_streamids; ++i) {
-                int idx = cfg->smendx[i];
-
+        for_each_cfg_sme(cfg, i, idx) {
                 /* An IOMMU group is torn down by the first device to be removed */
                 if (idx == INVALID_SMENDX)
                         return;
@@ -1151,9 +1151,9 @@ static void arm_smmu_master_free_smes(struct arm_smmu_master_cfg *cfg)
         __iowmb();
 
         /* Invalidate the SMRs before freeing back to the allocator */
-        for (i = 0; i < cfg->num_streamids; ++i) {
+        for_each_cfg_sme(cfg, i, idx) {
                 if (smmu->smrs)
-                        arm_smmu_free_smr(smmu, cfg->smendx[i]);
+                        arm_smmu_free_smr(smmu, idx);
 
                 cfg->smendx[i] = INVALID_SMENDX;
         }
@@ -1162,7 +1162,7 @@ static void arm_smmu_master_free_smes(struct arm_smmu_master_cfg *cfg)
 static int arm_smmu_domain_add_master(struct arm_smmu_domain *smmu_domain,
                                       struct arm_smmu_master_cfg *cfg)
 {
-        int i, ret = 0;
+        int i, idx, ret = 0;
         struct arm_smmu_device *smmu = smmu_domain->smmu;
         struct arm_smmu_s2cr *s2cr = smmu->s2crs;
         enum arm_smmu_s2cr_type type = S2CR_TYPE_TRANS;
@@ -1182,9 +1182,7 @@ static int arm_smmu_domain_add_master(struct arm_smmu_domain *smmu_domain,
         if (smmu_domain->domain.type == IOMMU_DOMAIN_DMA)
                 type = S2CR_TYPE_BYPASS;
 
-        for (i = 0; i < cfg->num_streamids; ++i) {
-                int idx = cfg->smendx[i];
-
+        for_each_cfg_sme(cfg, i, idx) {
                 /* Devices in an IOMMU group may already be configured */
                 if (type == s2cr[idx].type && cbndx == s2cr[idx].cbndx)
                         break;