From: Bjorn Andersson <bjorn.andersson@linaro.org>
To: Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Joerg Roedel <joro@8bytes.org>,
Thierry Reding <thierry.reding@gmail.com>,
Laurentiu Tudor <laurentiu.tudor@nxp.com>
Cc: linux-arm-msm@vger.kernel.org, iommu@lists.linux-foundation.org,
Jonathan Marek <jonathan@marek.ca>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH 4/5] iommu/arm-smmu-qcom: Consstently initialize stream mappings
Date: Wed, 8 Jul 2020 22:01:44 -0700 [thread overview]
Message-ID: <20200709050145.3520931-5-bjorn.andersson@linaro.org> (raw)
In-Reply-To: <20200709050145.3520931-1-bjorn.andersson@linaro.org>
Firmware that traps writes to S2CR to translate BYPASS into FAULT also
ignores writes of type FAULT. As such booting with "disable_bypass" set
will result in all S2CR registers left as configured by the bootloader.
This has been seen to result in indeterministic results, as these
mappings might linger and reference context banks that Linux is
reconfiguring.
Use the fact that BYPASS writes result in FAULT type to force all stream
mappings to FAULT.
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---
drivers/iommu/arm-smmu-qcom.c | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/arm-smmu-qcom.c b/drivers/iommu/arm-smmu-qcom.c
index e8a36054e912..86b1917459a4 100644
--- a/drivers/iommu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm-smmu-qcom.c
@@ -27,6 +27,7 @@ static int qcom_smmu_cfg_probe(struct arm_smmu_device *smmu)
{
unsigned int last_s2cr = ARM_SMMU_GR0_S2CR(smmu->num_mapping_groups - 1);
u32 reg;
+ int i;
/*
* With some firmware writes to S2CR of type FAULT are ignored, and
@@ -37,9 +38,24 @@ static int qcom_smmu_cfg_probe(struct arm_smmu_device *smmu)
FIELD_PREP(ARM_SMMU_S2CR_CBNDX, 0xff) |
FIELD_PREP(ARM_SMMU_S2CR_PRIVCFG, S2CR_PRIVCFG_DEFAULT));
reg = arm_smmu_gr0_read(smmu, last_s2cr);
- if (FIELD_GET(ARM_SMMU_S2CR_TYPE, reg) != S2CR_TYPE_BYPASS)
+ if (FIELD_GET(ARM_SMMU_S2CR_TYPE, reg) != S2CR_TYPE_BYPASS) {
smmu->qcom_bypass_quirk = true;
+ /*
+ * With firmware ignoring writes of type FAULT, booting the
+ * Linux kernel with disable_bypass disabled (i.e. "enable
+ * bypass") the initialization during probe will leave mappings
+ * in an inconsistent state. Avoid this by configuring all
+ * S2CRs to BYPASS.
+ */
+ for (i = 0; i < smmu->num_mapping_groups; i++) {
+ smmu->s2crs[i].type = S2CR_TYPE_BYPASS;
+ smmu->s2crs[i].privcfg = S2CR_PRIVCFG_DEFAULT;
+ smmu->s2crs[i].cbndx = 0xff;
+ smmu->s2crs[i].count = 0;
+ }
+ }
+
return 0;
}
--
2.26.2
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-07-09 5:03 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-09 5:01 [PATCH 0/5] iommu/arm-smmu: Support maintaining bootloader mappings Bjorn Andersson
2020-07-09 5:01 ` [PATCH 1/5] iommu/arm-smmu: Make all valid stream mappings BYPASS Bjorn Andersson
2020-07-13 21:25 ` kernel test robot
2020-07-13 21:25 ` [RFC PATCH] iommu/arm-smmu: arm_smmu_setup_identity() can be static kernel test robot
2020-07-15 23:20 ` [PATCH 1/5] iommu/arm-smmu: Make all valid stream mappings BYPASS kernel test robot
2020-07-09 5:01 ` [PATCH 2/5] iommu/arm-smmu: Emulate bypass by using context banks Bjorn Andersson
2020-07-09 16:17 ` Rob Clark
2020-07-09 16:48 ` Bjorn Andersson
2020-07-09 16:56 ` Rob Clark
2020-07-09 18:55 ` Rob Clark
2020-07-09 19:40 ` Bjorn Andersson
2020-07-09 5:01 ` [PATCH 3/5] iommu/arm-smmu: Move SMR and S2CR definitions to header file Bjorn Andersson
2020-07-09 5:01 ` Bjorn Andersson [this message]
2020-07-09 7:32 ` [PATCH 4/5] iommu/arm-smmu-qcom: Consstently initialize stream mappings Vinod Koul
2020-07-09 5:01 ` [PATCH 5/5] iommu/arm-smmu: Setup identity domain for boot mappings Bjorn Andersson
2020-07-09 15:50 ` Laurentiu Tudor
2020-07-09 19:57 ` Bjorn Andersson
2020-07-28 15:27 ` Laurentiu Tudor
2020-07-09 7:33 ` [PATCH 0/5] iommu/arm-smmu: Support maintaining bootloader mappings Vinod Koul
2020-07-10 5:25 ` John Stultz
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200709050145.3520931-5-bjorn.andersson@linaro.org \
--to=bjorn.andersson@linaro.org \
--cc=iommu@lists.linux-foundation.org \
--cc=jonathan@marek.ca \
--cc=joro@8bytes.org \
--cc=laurentiu.tudor@nxp.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=robin.murphy@arm.com \
--cc=thierry.reding@gmail.com \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).