iommu/arm-smmu-qcom: Read back stream mappings

The Qualcomm boot loader configures stream mapping for the peripherals
that it accesses and in particular it sets up the stream mapping for the
display controller to be allowed to scan out a splash screen or EFI
framebuffer.

Read back the stream mappings during initialization and make the
arm-smmu driver maintain the streams in bypass mode.

Cc: <stable@vger.kernel.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Tested-by: Steev Klimaszewski <steev@kali.org>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20201019182323.3162386-3-bjorn.andersson@linaro.org
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
index be4318044f96c19d1055a07231f87dc911f8ebe5..48627fcf6bede31b1e3069a4993e6070097977da 100644 (file)
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
@@ -23,6 +23,28 @@ static const struct of_device_id qcom_smmu_client_of_match[] __maybe_unused = {
        { }
 };
 
+static int qcom_smmu_cfg_probe(struct arm_smmu_device *smmu)
+{
+       u32 smr;
+       int i;
+
+       for (i = 0; i < smmu->num_mapping_groups; i++) {
+               smr = arm_smmu_gr0_read(smmu, ARM_SMMU_GR0_SMR(i));
+
+               if (FIELD_GET(ARM_SMMU_SMR_VALID, smr)) {
+                       smmu->smrs[i].id = FIELD_GET(ARM_SMMU_SMR_ID, smr);
+                       smmu->smrs[i].mask = FIELD_GET(ARM_SMMU_SMR_MASK, smr);
+                       smmu->smrs[i].valid = true;
+
+                       smmu->s2crs[i].type = S2CR_TYPE_BYPASS;
+                       smmu->s2crs[i].privcfg = S2CR_PRIVCFG_DEFAULT;
+                       smmu->s2crs[i].cbndx = 0xff;
+               }
+       }
+
+       return 0;
+}
+
 static int qcom_smmu_def_domain_type(struct device *dev)
 {
        const struct of_device_id *match =
@@ -61,6 +83,7 @@ static int qcom_smmu500_reset(struct arm_smmu_device *smmu)
 }
 
 static const struct arm_smmu_impl qcom_smmu_impl = {
+       .cfg_probe = qcom_smmu_cfg_probe,
        .def_domain_type = qcom_smmu_def_domain_type,
        .reset = qcom_smmu500_reset,
 };