linux-kernel - Re: [Devel] [PATCH v9 0/3] Cavium ThunderX2 SMMUv3 errata workarounds

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Message-ID: <20170623084325.GA28331@red-moon>
Date:   Fri, 23 Jun 2017 09:43:25 +0100
From:   Lorenzo Pieralisi <lorenzo.pieralisi@....com>
To:     Robert Richter <robert.richter@...ium.com>
Cc:     Robert Richter <rric@...nel.org>,
        Will Deacon <will.deacon@....com>,
        Geetha sowjanya <gakula@...iumnetworks.com>,
        linux-arm-kernel@...ts.infradead.org, robh@...nel.org,
        devel@...ica.org, catalin.marinas@....com,
        Charles.Garcia-Tobin@....com, geethasowjanya.akula@...il.com,
        jcm@...hat.com, linu.cherian@...ium.com, rjw@...ysocki.net,
        linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
        iommu@...ts.linux-foundation.org, sgoutham@...ium.com,
        robin.murphy@....com
Subject: Re: [Devel] [PATCH v9 0/3] Cavium ThunderX2 SMMUv3 errata workarounds

On Fri, Jun 23, 2017 at 06:55:41AM +0200, Robert Richter wrote:
> On 22.06.17 22:04:37, Lorenzo Pieralisi wrote:
> > On Thu, Jun 22, 2017 at 09:35:35PM +0200, Robert Richter wrote:
> > > On 22.06.17 19:58:22, Will Deacon wrote:
> > > > On Thu, Jun 22, 2017 at 07:22:57PM +0100, Will Deacon wrote:
> > > > > On Thu, Jun 22, 2017 at 05:35:35PM +0530, Geetha sowjanya wrote:
> > > > > > Cavium ThunderX2 SMMUv3 implementation has two Silicon Erratas.
> > > > > > 1. Errata ID #74
> > > > > >    SMMU register alias Page 1 is not implemented
> > > > > > 2. Errata ID #126
> > > > > >    SMMU doesnt support unique IRQ lines and also MSI for gerror,
> > > > > >    eventq and cmdq-sync
> > > > > > 
> > > > > > The following patchset does software workaround for these two erratas.
> > > > > 
> > > > > I've picked up the first two patches, and left comments on the final patch.
> > > > 
> > > > ... except that it doesn't build:
> > > > 
> > > > 
> > > > drivers/acpi/arm64/iort.c: In function ‘arm_smmu_v3_resource_size’:
> > > > drivers/acpi/arm64/iort.c:837:21: error: ‘ACPI_IORT_SMMU_V3_CAVIUM_CN99XX’ undeclared (first use in this function)
> > > >   if (smmu->model == ACPI_IORT_SMMU_V3_CAVIUM_CN99XX)
> > > >                      ^
> > > > drivers/acpi/arm64/iort.c:837:21: note: each undeclared identifier is reported only once for each function it appears in
> > > > make[4]: *** [drivers/acpi/arm64/iort.o] Error 1
> > > > 
> > > > 
> > > > I don't see ACPI_IORT_SMMU_V3_CAVIUM_CN99XX defined, even in linux-next.
> > > > 
> > > > What's the plan here?
> > > 
> > > It is defined already in acpica and we actually waiting for the acpi
> > > maintainers to include it:
> > > 
> > >  https://github.com/acpica/acpica/commit/d00a4eb86e64
> > > 
> > > We could add
> > > 
> > > /* Until ACPICA headers cover IORT rev. C */
> > > #ifndef ACPI_IORT_SMMU_V3_CAVIUM_CN99XX
> > > #define ACPI_IORT_SMMU_V3_CAVIUM_CN99XX		0x2
> > > #endif
> > > 
> > > to both files:
> > > 
> > >  drivers/acpi/arm64/iort.c
> > >  drivers/iommu/arm-smmu-v3.c
> > > 
> > 
> > I thought it was a solved problem (and that the IORT patch was based
> > on Robin's workaround) but I was clearly wrong and I apologise to
> > Will about this.
> > 
> > FWIW, you could add the define in include/linux/acpi_iort.h and I will
> > remove it whenever ACPICA changes make it into the kernel.
> 
> Adding it there will still let depend us on acpi maintainers, while I
> think the over 2 files might go through arm64 tree smoothly. A change
> in acpi_iort.h also adds the definition to other archs and I don't
> think that adding arch #ifdefs to avoid that are welcome in that
> header file too.

I do not think it would be a problem but you have a point, it is fine to
add the define in the .c files, it is just a temporary plaster.

Thanks,
Lorenzo

> I am going to resend my patch below with an improved wording.
> 
> Thanks,
> 
> -Robert
> 
> > 
> > Thanks,
> > Lorenzo
> > 
> > > This is similar to what Robin did.
> > > 
> > > (I checked arm64 include files and the closest was
> > > arch/arm64/include/asm/acpi.h, bug this seems not really suitable to
> > > me.)
> > > 
> > > I have created a separate patch to be applied at first below. We can
> > > revert it after acpica was updated.
> > > 
> > > -Robert
> > > 
> > > 
> > > 
> > > 
> > > From ad7f0112a2a71059c32bd315835c33cc7bc660b8 Mon Sep 17 00:00:00 2001
> > > From: Robert Richter <rrichter@...ium.com>
> > > Date: Thu, 22 Jun 2017 21:20:54 +0200
> > > Subject: [PATCH] iommu/arm-smmu-v3: Add temporary Cavium SMMU-V3 model nuber
> > >  definitions
> > > 
> > > The model number is already defined in acpica and we actually waiting
> > > for the acpi maintainers to include it:
> > > 
> > >  https://github.com/acpica/acpica/commit/d00a4eb86e64
> > > 
> > > Adding those temporary definitions until the change makes it into
> > > include/acpi/actbl2.h.
> > > 
> > > Signed-off-by: Robert Richter <rrichter@...ium.com>
> > > ---
> > >  drivers/acpi/arm64/iort.c   | 5 +++++
> > >  drivers/iommu/arm-smmu-v3.c | 5 +++++
> > >  2 files changed, 10 insertions(+)
> > > 
> > > diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> > > index 797b28dc7b34..15491237a657 100644
> > > --- a/drivers/acpi/arm64/iort.c
> > > +++ b/drivers/acpi/arm64/iort.c
> > > @@ -31,6 +31,11 @@
> > >  #define IORT_IOMMU_TYPE		((1 << ACPI_IORT_NODE_SMMU) |	\
> > >  				(1 << ACPI_IORT_NODE_SMMU_V3))
> > >  
> > > +/* Until ACPICA headers cover IORT rev. C */
> > > +#ifndef ACPI_IORT_SMMU_V3_CAVIUM_CN99XX
> > > +#define ACPI_IORT_SMMU_V3_CAVIUM_CN99XX		0x2
> > > +#endif
> > > +
> > >  struct iort_its_msi_chip {
> > >  	struct list_head	list;
> > >  	struct fwnode_handle	*fw_node;
> > > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> > > index 380969aa60d5..c759dfa7442d 100644
> > > --- a/drivers/iommu/arm-smmu-v3.c
> > > +++ b/drivers/iommu/arm-smmu-v3.c
> > > @@ -412,6 +412,11 @@
> > >  #define MSI_IOVA_BASE			0x8000000
> > >  #define MSI_IOVA_LENGTH			0x100000
> > >  
> > > +/* Until ACPICA headers cover IORT rev. C */
> > > +#ifndef ACPI_IORT_SMMU_V3_CAVIUM_CN99XX
> > > +#define ACPI_IORT_SMMU_V3_CAVIUM_CN99XX		0x2
> > > +#endif
> > > +
> > >  static bool disable_bypass;
> > >  module_param_named(disable_bypass, disable_bypass, bool, S_IRUGO);
> > >  MODULE_PARM_DESC(disable_bypass,
> > > -- 
> > > 2.11.0
> > >