From: Will Deacon <will@kernel.org>
To: Konrad Dybcio <konradybcio@gmail.com>
Cc: skrzynka@konradybcio.pl, Robin Murphy <robin.murphy@arm.com>,
Joerg Roedel <joro@8bytes.org>, Rob Herring <robh+dt@kernel.org>,
linux-arm-kernel@lists.infradead.org,
iommu@lists.linux-foundation.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, bjorn.andersson@linaro.org,
jcrouse@codeaurora.org, john.stultz@linaro.org
Subject: Re: [PATCH 1/1] iommu/arm-smmu: Implement qcom,skip-init
Date: Sat, 4 Jul 2020 14:09:23 +0100 [thread overview]
Message-ID: <20200704130922.GB21333@willie-the-truck> (raw)
In-Reply-To: <20200704122809.73794-1-konradybcio@gmail.com>
[Adding Bjorn, Jordan and John because I really don't want a bunch of
different ways to tell the driver that the firmware is screwing things up]
On Sat, Jul 04, 2020 at 02:28:09PM +0200, Konrad Dybcio wrote:
> This adds the downstream property required to support
> SMMUs on SDM630 and other platforms (the need for it
> most likely depends on firmware configuration).
>
> Signed-off-by: Konrad Dybcio <konradybcio@gmail.com>
> ---
> .../devicetree/bindings/iommu/arm,smmu.yaml | 10 ++++++++++
> drivers/iommu/arm-smmu.c | 15 +++++++++------
> 2 files changed, 19 insertions(+), 6 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
> index d7ceb4c34423..9abd6d41a32c 100644
> --- a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
> +++ b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
> @@ -102,6 +102,16 @@ properties:
> access to SMMU configuration registers. In this case non-secure aliases of
> secure registers have to be used during SMMU configuration.
>
> + qcom,skip-init:
> + description: |
> + Disable resetting configuration for all context banks
> + during device reset. This is useful for targets where
> + some context banks are dedicated to other execution
> + environments outside of Linux and those other EEs are
> + programming their own stream match tables, SCTLR, etc.
> + Without setting this option we will trample on their
> + configuration.
It would probably be better to know _which_ context banks we shouldn't
touch, no? Otherwise what happens to the others?
> +
> stream-match-mask:
> $ref: /schemas/types.yaml#/definitions/uint32
> description: |
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index 243bc4cb2705..a5c623d4caf9 100644
> --- a/drivers/iommu/arm-smmu.c
> +++ b/drivers/iommu/arm-smmu.c
> @@ -1655,13 +1655,16 @@ static void arm_smmu_device_reset(struct arm_smmu_device *smmu)
> * Reset stream mapping groups: Initial values mark all SMRn as
> * invalid and all S2CRn as bypass unless overridden.
> */
> - for (i = 0; i < smmu->num_mapping_groups; ++i)
> - arm_smmu_write_sme(smmu, i);
>
> - /* Make sure all context banks are disabled and clear CB_FSR */
> - for (i = 0; i < smmu->num_context_banks; ++i) {
> - arm_smmu_write_context_bank(smmu, i);
> - arm_smmu_cb_write(smmu, i, ARM_SMMU_CB_FSR, ARM_SMMU_FSR_FAULT);
> + if (!of_find_property(smmu->dev->of_node, "qcom,skip-init", NULL)) {
> + for (i = 0; i < smmu->num_mapping_groups; ++i)
> + arm_smmu_write_sme(smmu, i);
> +
> + /* Make sure all context banks are disabled and clear CB_FSR */
> + for (i = 0; i < smmu->num_context_banks; ++i) {
> + arm_smmu_write_context_bank(smmu, i);
> + arm_smmu_cb_write(smmu, i, ARM_SMMU_CB_FSR, ARM_SMMU_FSR_FAULT);
> + }
> }
Do we not need to worry about the SMRs as well?
Will
next prev parent reply other threads:[~2020-07-04 13:09 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-04 12:28 [PATCH 1/1] iommu/arm-smmu: Implement qcom,skip-init Konrad Dybcio
2020-07-04 13:09 ` Will Deacon [this message]
2020-07-04 13:20 ` Konrad Dybcio
2020-07-05 3:35 ` Bjorn Andersson
2020-07-21 15:04 ` Konrad Dybcio
2020-07-21 15:44 ` Jordan Crouse
2020-07-21 16:20 ` Konrad Dybcio
2020-07-21 23:56 ` Bjorn Andersson
2020-07-22 20:11 ` Konrad Dybcio
2020-07-31 5:48 ` Bjorn Andersson
2020-08-03 23:57 ` Konrad Dybcio
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=20200704130922.GB21333@willie-the-truck \
--to=will@kernel.org \
--cc=bjorn.andersson@linaro.org \
--cc=devicetree@vger.kernel.org \
--cc=iommu@lists.linux-foundation.org \
--cc=jcrouse@codeaurora.org \
--cc=john.stultz@linaro.org \
--cc=joro@8bytes.org \
--cc=konradybcio@gmail.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=robh+dt@kernel.org \
--cc=robin.murphy@arm.com \
--cc=skrzynka@konradybcio.pl \
/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).