[Devel] [PATCH v9 0/3] Cavium ThunderX2 SMMUv3 errata workarounds

[Robert Richter]

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 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 at cavium.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 at cavium.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
> >