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iommu/arm-smmu-qcom: Implement S2CR quirk

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commit f9081b8ff5934b8d69c748d0200e844cadd2c667 upstream.

The firmware found in some Qualcomm platforms intercepts writes to S2CR
in order to replace bypass type streams with fault; and ignore S2CR
updates of type fault.

Detect this behavior and implement a custom write_s2cr function in order
to trick the firmware into supporting bypass streams by the means of
configuring the stream for translation using a reserved and disabled
context bank.

Also circumvent the problem of configuring faulting streams by
configuring the stream as bypass.

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/20201019182323.3162386-4-bjorn.andersson@linaro.org
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Bjorn Andersson 2020-10-19 11:23:23 -07:00 committed by Greg Kroah-Hartman
parent f48e7f7771
commit 1dd44b5e5f
1 changed files with 67 additions and 0 deletions
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67
drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
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@ -10,8 +10,15 @@
struct qcom_smmu {
struct arm_smmu_device smmu;
bool bypass_quirk;
u8 bypass_cbndx;
};
static struct qcom_smmu *to_qcom_smmu(struct arm_smmu_device *smmu)
{
return container_of(smmu, struct qcom_smmu, smmu);
}
static const struct of_device_id qcom_smmu_client_of_match[] __maybe_unused = {
{ .compatible = "qcom,adreno" },
{ .compatible = "qcom,mdp4" },
@ -25,9 +32,33 @@ static const struct of_device_id qcom_smmu_client_of_match[] __maybe_unused = {
static int qcom_smmu_cfg_probe(struct arm_smmu_device *smmu)
{
unsigned int last_s2cr = ARM_SMMU_GR0_S2CR(smmu->num_mapping_groups - 1);
struct qcom_smmu *qsmmu = to_qcom_smmu(smmu);
u32 reg;
u32 smr;
int i;
/*
* With some firmware versions writes to S2CR of type FAULT are
* ignored, and writing BYPASS will end up written as FAULT in the
* register. Perform a write to S2CR to detect if this is the case and
* if so reserve a context bank to emulate bypass streams.
*/
reg = FIELD_PREP(ARM_SMMU_S2CR_TYPE, S2CR_TYPE_BYPASS) |
FIELD_PREP(ARM_SMMU_S2CR_CBNDX, 0xff) |
FIELD_PREP(ARM_SMMU_S2CR_PRIVCFG, S2CR_PRIVCFG_DEFAULT);
arm_smmu_gr0_write(smmu, last_s2cr, reg);
reg = arm_smmu_gr0_read(smmu, last_s2cr);
if (FIELD_GET(ARM_SMMU_S2CR_TYPE, reg) != S2CR_TYPE_BYPASS) {
qsmmu->bypass_quirk = true;
qsmmu->bypass_cbndx = smmu->num_context_banks - 1;
set_bit(qsmmu->bypass_cbndx, smmu->context_map);
reg = FIELD_PREP(ARM_SMMU_CBAR_TYPE, CBAR_TYPE_S1_TRANS_S2_BYPASS);
arm_smmu_gr1_write(smmu, ARM_SMMU_GR1_CBAR(qsmmu->bypass_cbndx), reg);
}
for (i = 0; i < smmu->num_mapping_groups; i++) {
smr = arm_smmu_gr0_read(smmu, ARM_SMMU_GR0_SMR(i));
@ -45,6 +76,41 @@ static int qcom_smmu_cfg_probe(struct arm_smmu_device *smmu)
return 0;
}
static void qcom_smmu_write_s2cr(struct arm_smmu_device *smmu, int idx)
{
struct arm_smmu_s2cr *s2cr = smmu->s2crs + idx;
struct qcom_smmu *qsmmu = to_qcom_smmu(smmu);
u32 cbndx = s2cr->cbndx;
u32 type = s2cr->type;
u32 reg;
if (qsmmu->bypass_quirk) {
if (type == S2CR_TYPE_BYPASS) {
/*
* Firmware with quirky S2CR handling will substitute
* BYPASS writes with FAULT, so point the stream to the
* reserved context bank and ask for translation on the
* stream
*/
type = S2CR_TYPE_TRANS;
cbndx = qsmmu->bypass_cbndx;
} else if (type == S2CR_TYPE_FAULT) {
/*
* Firmware with quirky S2CR handling will ignore FAULT
* writes, so trick it to write FAULT by asking for a
* BYPASS.
*/
type = S2CR_TYPE_BYPASS;
cbndx = 0xff;
}
}
reg = FIELD_PREP(ARM_SMMU_S2CR_TYPE, type) |
FIELD_PREP(ARM_SMMU_S2CR_CBNDX, cbndx) |
FIELD_PREP(ARM_SMMU_S2CR_PRIVCFG, s2cr->privcfg);
arm_smmu_gr0_write(smmu, ARM_SMMU_GR0_S2CR(idx), reg);
}
static int qcom_smmu_def_domain_type(struct device *dev)
{
const struct of_device_id *match =
@ -86,6 +152,7 @@ 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,
.write_s2cr = qcom_smmu_write_s2cr,
};
struct arm_smmu_device *qcom_smmu_impl_init(struct arm_smmu_device *smmu)