> -----Original Message-----
> From: Robin Murphy [mailto:[email protected]]
> Sent: Thursday, June 30, 2016 16:26
> To: Nipun Gupta <[email protected]>; [email protected]; Stuart Yoder
> <[email protected]>; [email protected]; linux-arm-
> [email protected]
> Cc: Bharat Bhushan <[email protected]>
> Subject: Re: [RFC PATCH 1/2] fsl-mc: Added header file to provide fsl-mc bus
> iommu group creation
>
> On 29/06/16 18:14, Nipun Gupta wrote:
> > Added a header file fsl_mc_smmu.h to provide basic support of creating
> > an IOMMU group for a fsl-mc type device and also provide helper macro
> > to get the stream ID of fsl-mc tyoe device.
> >
> > Signed-off-by: Nipun Gupta <[email protected]>
> > Signed-off-by: Bharat Bhushan <[email protected]>
> > ---
> > drivers/staging/fsl-mc/include/fsl_mc_smmu.h | 45
> > ++++++++++++++++++++++++++++
> > 1 file changed, 45 insertions(+)
> > create mode 100644 drivers/staging/fsl-mc/include/fsl_mc_smmu.h
> >
> > diff --git a/drivers/staging/fsl-mc/include/fsl_mc_smmu.h
> > b/drivers/staging/fsl-mc/include/fsl_mc_smmu.h
> > new file mode 100644
> > index 0000000..9dff5ba
> > --- /dev/null
> > +++ b/drivers/staging/fsl-mc/include/fsl_mc_smmu.h
> > @@ -0,0 +1,45 @@
> > +/*
> > + * Copyright (C) 2016 Freescale Semiconductor, Inc.
> > + * Author: Nipun Gupta <[email protected]>
> > + *
> > + * This file is licensed under the terms of the GNU General Public
> > + * License version 2. This program is licensed "as is" without any
> > + * warranty of any kind, whether express or implied.
> > + */
> > +
> > +#ifndef _FSL_MC_SMMU_H_
> > +#define _FSL_MC_SMMU_H_
> > +
> > +#include <../drivers/staging/fsl-mc/include/mc.h>
> > +
> > +/* Macro to get the MC device ICID (Stream ID) */ #define
> > +fslmc_dev_streamid(_dev) (to_fsl_mc_device(_dev)->icid)
>
> Is the the full 15-bit ICID from the MC's point of view, just the 7 bits that
> are
> actually routed to the SMMU, or the actual stream ID seen by the SMMU? None
> of those three are necessarily the same, and unless it's the third then I
> don't see
> the point of patches adding incomplete code which isn't going to work.
Hi Robin,
It's the second one where just 7 bits are maintained in the
'fsl_mc_device--->icid' which is programmed in SMMU. Right, once the SMR
masking support is there then only these patches would make more sense.
We have sent these patches to get some early comments and to have you guys well
informed beforehand about the changes which we require in the SMMU driver
specific to fsl-mc bus :).
Thanks,
Nipun
>
> > +/* Macro to get the container device of a MC device */ #define
> > +fslmc_cont_dev(_dev) ((to_fsl_mc_device(dev)->flags & \
> > + FSL_MC_IS_DPRC) ? (_dev) : (_dev->parent))
> > +
> > +/* Macro to check if a device is a container device */ #define
> > +is_cont_dev(_dev) (to_fsl_mc_device(_dev)->flags & FSL_MC_IS_DPRC)
> > +
> > +static struct iommu_group *fslmc_device_group(struct device *dev) {
> > + struct device *cont_dev = fslmc_cont_dev(dev);
> > + struct iommu_group *group;
> > +
> > + /* Container device is responsible for creating the iommu group */
> > + if (is_cont_dev(dev)) {
> > + group = iommu_group_alloc();
> > +
> > + if (IS_ERR(group))
> > + return NULL;
> > + } else {
> > + get_device(cont_dev);
> > + group = iommu_group_get(cont_dev);
> > + put_device(cont_dev);
> > + }
> > +
> > + return group;
> > +}
>
> In isolation, though, this part seems perfectly reasonable.
>
> Robin.
>
> > +
> > +#endif /* _FSL_MC_SMMU_H_ */
> >
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