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

[Matthias Brugger]

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?
Should we use a define for the subcommon as well?

Regards,
Matthias

>  };
>  
>  struct mtk_iommu_domain;
>