Re: [RESEND,PATCH 03/13] iommu/mediatek: Add mtk_iommu_pgtable structure

chao hao
2019-12-31T09:40:16Z

On Mon, 2019-12-16 at 20:13 +0800, Yong Wu wrote:
> On Mon, 2019-11-04 at 19:52 +0800, Chao Hao wrote:
> > Start with this patch, we will change the SW architecture
> > to support multiple domains. SW architecture will has a big change,
> > so we need to modify a little bit by more than one patch.
> > The new SW overall architecture is as below:
> >
> > iommu0 iommu1
> > | |
> > -----------
> > |
> > mtk_iommu_pgtable
> > |
> > ------------------------------------------
> > | | |
> > mtk_iommu_domain1 mtk_iommu_domain2 mtk_iommu_domain3
> > | | |
> > iommu_group1 iommu_group2 iommu_group3
> > | | |
> > iommu_domain1 iommu_domain2 iommu_domain3
> > | | |
> > iova region1(normal) iova region2(CCU) iova region3(VPU)
> >
> > For current structure, no matter how many iommus there are,
> > they use the same page table to simplify the usage of module.
> > In order to make the software architecture more explicit, this
> > patch will create a global mtk_iommu_pgtable structure to describe
> > page table and all the iommus use it.
>
> Thanks for the hard work of this file. Actually this patch and the later
> ones confuse me. Why do you make this flow change?
> for making the code "more explicit" or for adding multi-domain support
> in 13/13.
>
> IMHO, the change is unnecessary.
> a) For me, this change has no improvement. currently we use a global
> mtk_iommu_get_m4u_data to get the M4U data. I will be very glad if you
> could get rid of it. But in this patchset, You use a another global
> mtk_iommu_pgtable to instead. For me. It has no improvement.

Thanks for you advice!

For current SW arch, all the IOMMU HW use the same page table, we can
use a global mtk_iommu_pgtable to discribe the information of page table
and all the IOMMU attach it, I think that it is more clear and
unambiguous. For beginners, it maybe more easily explicable?

>
> b) This patchset break the original flow. device_group give you a
> software chance for initializing, then you move pagetable allocating
> code into it. But it isn't device_group job.
>

As is shown above diagram, mtk_iommu_pgtable includes iommu_group and
iommu_domain,so we need to allocate mtk_iommu_pgtable and initialize it
in device_group firstly,and then execute the original flow, it only
changes place for creating mtk_iommu_pgtable and don't break original
device_group flow.

> I can not decide if your flow is right. But if you only want to add
> support multi-domain, I guess you could extend the current "m4u_group"
> to a array "m4u_group[N]". It may be more simple. To make mt6779
> progress easily, I suggest you can use this way to support multi-domain
> firstly. Then you could send this new mtk_iommu_pgtable patchset for the
> code "more explicit" if you insist.
>
> > The diagram is as below:
> >
> > mtk_iommu_data1(MM) mtk_iommu_data2(APU)
> > | |
> > | |
> > ------mtk_iommu_pgtable-----
> >
> > We need to create global mtk_iommu_pgtable to include all the iova
> > regions firstly and special iova regions by divided based on it,
> > so the information of pgtable needs to be created in device_group.
> >
> > Signed-off-by: Chao Hao <chao.hao@mediatek.com>
> > ---
> > drivers/iommu/mtk_iommu.c | 84 +++++++++++++++++++++++++++++++++++++++
> > drivers/iommu/mtk_iommu.h | 1 +
> > 2 files changed, 85 insertions(+)
> >
> > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > index f2847e661137..fcbde6b0f58d 100644
> > --- a/drivers/iommu/mtk_iommu.c
> > +++ b/drivers/iommu/mtk_iommu.c
> > @@ -123,6 +123,12 @@ struct mtk_iommu_domain {
> > struct iommu_domain domain;
> > };
> >
> > +struct mtk_iommu_pgtable {
> > + struct io_pgtable_cfg cfg;
> > + struct io_pgtable_ops *iop;
> > +};
> > +
> > +static struct mtk_iommu_pgtable *share_pgtable;
> > static const struct iommu_ops mtk_iommu_ops;
> >
> > /*
> > @@ -170,6 +176,11 @@ static struct mtk_iommu_data *mtk_iommu_get_m4u_data(void)
> > return NULL;
> > }
> >
> > +static struct mtk_iommu_pgtable *mtk_iommu_get_pgtable(void)
> > +{
> > + return share_pgtable;
> > +}
> > +
> > static struct mtk_iommu_domain *to_mtk_domain(struct iommu_domain *dom)
> > {
> > return container_of(dom, struct mtk_iommu_domain, domain);
> > @@ -322,6 +333,13 @@ static int mtk_iommu_domain_finalise(struct mtk_iommu_domain *dom)
> > {
> > struct mtk_iommu_data *data = mtk_iommu_get_m4u_data();
> >
> > + if (data->pgtable) {
> > + dom->cfg = data->pgtable->cfg;
> > + dom->iop = data->pgtable->iop;
> > + dom->domain.pgsize_bitmap = data->pgtable->cfg.pgsize_bitmap;
> > + return 0;
> > + }
> > +
> > dom->cfg = (struct io_pgtable_cfg) {
> > .quirks = IO_PGTABLE_QUIRK_ARM_NS |
> > IO_PGTABLE_QUIRK_NO_PERMS |
> > @@ -345,6 +363,61 @@ static int mtk_iommu_domain_finalise(struct mtk_iommu_domain *dom)
> > return 0;
> > }
> >
> > +static struct mtk_iommu_pgtable *create_pgtable(struct mtk_iommu_data *data)
> > +{
> > + struct mtk_iommu_pgtable *pgtable;
> > +
> > + pgtable = kzalloc(sizeof(*pgtable), GFP_KERNEL);
> > + if (!pgtable)
> > + return ERR_PTR(-ENOMEM);
> > +
> > + pgtable->cfg = (struct io_pgtable_cfg) {
> > + .quirks = IO_PGTABLE_QUIRK_ARM_NS |
> > + IO_PGTABLE_QUIRK_NO_PERMS |
> > + IO_PGTABLE_QUIRK_TLBI_ON_MAP |
> > + IO_PGTABLE_QUIRK_ARM_MTK_EXT,
> > + .pgsize_bitmap = mtk_iommu_ops.pgsize_bitmap,
> > + .ias = 32,
> > + .oas = 34,
> > + .tlb = &mtk_iommu_flush_ops,
> > + .iommu_dev = data->dev,
> > + };
> > +
> > + pgtable->iop = alloc_io_pgtable_ops(ARM_V7S, &pgtable->cfg, data);
> > + if (!pgtable->iop) {
> > + dev_err(data->dev, "Failed to alloc io pgtable\n");
> > + return ERR_PTR(-EINVAL);
> > + }
> > +
> > + dev_info(data->dev, "%s create pgtable done\n", __func__);
> > +
> > + return pgtable;
> > +}
> > +
> > +static int mtk_iommu_attach_pgtable(struct mtk_iommu_data *data,
> > + struct device *dev)
> > +{
> > + struct mtk_iommu_pgtable *pgtable = mtk_iommu_get_pgtable();
> > +
> > + /* create share pgtable */
> > + if (!pgtable) {
> > + pgtable = create_pgtable(data);
> > + if (IS_ERR(pgtable)) {
> > + dev_err(data->dev, "Failed to create pgtable\n");
> > + return -ENOMEM;
> > + }
> > +
> > + share_pgtable = pgtable;
> > + }
> > +
> > + /* binding to pgtable */
> > + data->pgtable = pgtable;
> > +
> > + dev_info(data->dev, "m4u%d attach_pgtable done!\n", data->m4u_id);
> > +
> > + return 0;
> > +}
> > +
> > static struct iommu_domain *mtk_iommu_domain_alloc(unsigned type)
> > {
> > struct mtk_iommu_domain *dom;
> > @@ -508,10 +581,21 @@ static void mtk_iommu_remove_device(struct device *dev)
> > static struct iommu_group *mtk_iommu_device_group(struct device *dev)
> > {
> > struct mtk_iommu_data *data = mtk_iommu_get_m4u_data();
> > + struct mtk_iommu_pgtable *pgtable;
> > + int ret = 0;
> >
> > if (!data)
> > return ERR_PTR(-ENODEV);
> >
> > + pgtable = data->pgtable;
> > + if (!pgtable) {
> > + ret = mtk_iommu_attach_pgtable(data, dev);
> > + if (ret) {
> > + dev_err(data->dev, "Failed to device_group\n");
> > + return NULL;
> > + }
> > + }
> > +
> > /* All the client devices are in the same m4u iommu-group */
> > if (!data->m4u_group) {
> > data->m4u_group = iommu_group_alloc();
> > diff --git a/drivers/iommu/mtk_iommu.h b/drivers/iommu/mtk_iommu.h
> > index 132dc765a40b..dd5f19f78b62 100644
> > --- a/drivers/iommu/mtk_iommu.h
> > +++ b/drivers/iommu/mtk_iommu.h
> > @@ -61,6 +61,7 @@ struct mtk_iommu_data {
> > struct clk *bclk;
> > phys_addr_t protect_base; /* protect memory base */
> > struct mtk_iommu_suspend_reg reg;
> > + struct mtk_iommu_pgtable *pgtable;
> > struct mtk_iommu_domain *m4u_dom;
> > struct iommu_group *m4u_group;
> > bool enable_4GB;
>
>