Re: [PATCH v4 5/7] iommu/mediatek: Add sub_comm id in translation fault

From: chao hao
Date: Thu Jun 18 2020 - 07:44:50 EST

On Wed, 2020-06-17 at 19:11 +0800, Yong Wu wrote:
> Hi Matthias,
>
> Thanks very much for your review.
>
> On Wed, 2020-06-17 at 11:17 +0200, Matthias Brugger wrote:
> >
> > On 17/06/2020 05:00, Chao Hao wrote:
> > > The max larb number that a iommu HW support is 8(larb0~larb7 in the below
> > > diagram).
> > > If the larb's number is over 8, we use a sub_common for merging
> > > several larbs into one larb. At this case, we will extend larb_id:
> > > bit[11:9] means common-id;
> > > bit[8:7] means subcommon-id;
> > > From these two variable, we could get the real larb number when
> > > translation fault happen.
> > > The diagram is as below:
> > > EMI
> > > |
> > > IOMMU
> > > |
> > > -----------------
> > > | |
> > > common1 common0
> > > | |
> > > -----------------
> > > |
> > > smi common
> > > |
> > > ------------------------------------
> > > | | | | | |
> > > 3'd0 3'd1 3'd2 3'd3 ... 3'd7 <-common_id(max is 8)
> > > | | | | | |
> > > Larb0 Larb1 | Larb3 ... Larb7
> > > |
> > > smi sub common
> > > |
> > > --------------------------
> > > | | | |
> > > 2'd0 2'd1 2'd2 2'd3 <-sub_common_id(max is 4)
> > > | | | |
> > > Larb8 Larb9 Larb10 Larb11
> > >
> > > In this patch we extern larb_remap[] to larb_remap[8][4] for this.
> >
> > extern -> extend
> >
> > > larb_remap[x][y]: x mean common-id above, y means subcommon_id above.
> >
> > mean -> means
> >
> > >
> > > We can also distinguish if the M4U HW has sub_common by has_sub_comm
> > > property.
> > >
> > > Signed-off-by: Chao Hao <chao.hao@xxxxxxxxxxxx>
> > > Reviewed-by: Yong Wu <yong.wu@xxxxxxxxxxxx>
> > > ---
> > > drivers/iommu/mtk_iommu.c | 20 +++++++++++++-------
> > > drivers/iommu/mtk_iommu.h | 3 ++-
> > > 2 files changed, 15 insertions(+), 8 deletions(-)
> > >
> > > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > > index f23919feba4e..a687e8db0e51 100644
> > > --- a/drivers/iommu/mtk_iommu.c
> > > +++ b/drivers/iommu/mtk_iommu.c
> > > @@ -91,6 +91,8 @@
> > > #define REG_MMU1_INVLD_PA 0x148
> > > #define REG_MMU0_INT_ID 0x150
> > > #define REG_MMU1_INT_ID 0x154
> > > +#define F_MMU_INT_ID_COMM_ID(a) (((a) >> 9) & 0x7)
> > > +#define F_MMU_INT_ID_SUB_COMM_ID(a) (((a) >> 7) & 0x3)
> > > #define F_MMU_INT_ID_LARB_ID(a) (((a) >> 7) & 0x7)
> > > #define F_MMU_INT_ID_PORT_ID(a) (((a) >> 2) & 0x1f)
> > >
> > > @@ -229,7 +231,7 @@ static irqreturn_t mtk_iommu_isr(int irq, void *dev_id)
> > > struct mtk_iommu_data *data = dev_id;
> > > struct mtk_iommu_domain *dom = data->m4u_dom;
> > > u32 int_state, regval, fault_iova, fault_pa;
> > > - unsigned int fault_larb, fault_port;
> > > + unsigned int fault_larb, fault_port, sub_comm = 0;
> > > bool layer, write;
> > >
> > > /* Read error info from registers */
> > > @@ -245,10 +247,14 @@ static irqreturn_t mtk_iommu_isr(int irq, void *dev_id)
> > > }
> > > layer = fault_iova & F_MMU_FAULT_VA_LAYER_BIT;
> > > write = fault_iova & F_MMU_FAULT_VA_WRITE_BIT;
> > > - fault_larb = F_MMU_INT_ID_LARB_ID(regval);
> > > fault_port = F_MMU_INT_ID_PORT_ID(regval);
> > > -
> > > - fault_larb = data->plat_data->larbid_remap[fault_larb];
> > > + if (data->plat_data->has_sub_comm) {
> > > + fault_larb = F_MMU_INT_ID_COMM_ID(regval);
> > > + sub_comm = F_MMU_INT_ID_SUB_COMM_ID(regval);
> > > + } else {
> > > + fault_larb = F_MMU_INT_ID_LARB_ID(regval);
> > > + }
> > > + fault_larb = data->plat_data->larbid_remap[fault_larb][sub_comm];
> > >
> > > if (report_iommu_fault(&dom->domain, data->dev, fault_iova,
> > > write ? IOMMU_FAULT_WRITE : IOMMU_FAULT_READ)) {
> > > @@ -778,7 +784,7 @@ static const struct mtk_iommu_plat_data mt2712_data = {
> > > .has_bclk = true,
> > > .has_vld_pa_rng = true,
> > > .inv_sel_reg = REG_MMU_INV_SEL_GEN1,
> > > - .larbid_remap = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9},
> > > + .larbid_remap = {{0}, {1}, {2}, {3}, {4}, {5}, {6}, {7}},
> > > };
> > >
> > > static const struct mtk_iommu_plat_data mt8173_data = {
> > > @@ -787,14 +793,14 @@ static const struct mtk_iommu_plat_data mt8173_data = {
> > > .has_bclk = true,
> > > .reset_axi = true,
> > > .inv_sel_reg = REG_MMU_INV_SEL_GEN1,
> > > - .larbid_remap = {0, 1, 2, 3, 4, 5}, /* Linear mapping. */
> > > + .larbid_remap = {{0}, {1}, {2}, {3}, {4}, {5}}, /* Linear mapping. */
> > > };
> > >
> > > static const struct mtk_iommu_plat_data mt8183_data = {
> > > .m4u_plat = M4U_MT8183,
> > > .reset_axi = true,
> > > .inv_sel_reg = REG_MMU_INV_SEL_GEN1,
> > > - .larbid_remap = {0, 4, 5, 6, 7, 2, 3, 1},
> > > + .larbid_remap = {{0}, {4}, {5}, {6}, {7}, {2}, {3}, {1}},
> > > };
> > >
> > > static const struct of_device_id mtk_iommu_of_ids[] = {
> > > diff --git a/drivers/iommu/mtk_iommu.h b/drivers/iommu/mtk_iommu.h
> > > index afd7a2de5c1e..d51ff99c2c71 100644
> > > --- a/drivers/iommu/mtk_iommu.h
> > > +++ b/drivers/iommu/mtk_iommu.h
> > > @@ -41,10 +41,11 @@ struct mtk_iommu_plat_data {
> > > /* HW will use the EMI clock if there isn't the "bclk". */
> > > bool has_bclk;
> > > bool has_misc_ctrl;
> > > + bool has_sub_comm;
> > > bool has_vld_pa_rng;
> > > bool reset_axi;
> > > u32 inv_sel_reg;
> > > - unsigned char larbid_remap[MTK_LARB_NR_MAX];
> > > + unsigned char larbid_remap[8][4];
> >
> > MTK_LARB_NR_MAX is 16, why do you decrease it to 8?
>
> From the diagram above, the max number of the larbs that could connected
> with a IOMMU HW is 8. thus, 8 is right here for each a IOMMU HW.
>
> as I commented when v3. mt2712 have the larbs over 8 since it has 2
> IOMMU HWes.
>
> and MTK_LARB_NR_MAX means the max larbs number that this SoC support.
> Keep its value as is.
>
>
> > Should we use a define for the subcommon as well?
> >
> > Regards,
> > Matthias
> >

Hi Matthias and yong,
Thanks very much for your review.
HW diagram is as belove and whether we need to use macro definitions to
show it, maybe more clearer? like this:

#define LARB_COMMON_MAX 8
#define LARB_SUB_COMMON_MAX 4
unsigned char larbid_remap[LARB_COMMON_MAX][LARB_SUB_COMMON_MAX];

>
> > > };
> > >
> > > struct mtk_iommu_domain;
> > >
>
>