[PATCH v3 3/3] iommu/arm-smmu-v3: Reserving the entire SMMU register space

[Robin Murphy]

On 2021-01-27 11:32, Zhen Lei wrote:
> commit 52f3fab0067d ("iommu/arm-smmu-v3: Don't reserve implementation
> defined register space") only reserves the basic SMMU register space. So
> the ECMDQ register space is not covered, it should be mapped again. Due
> to the size of this ECMDQ resource is not fixed, depending on
> SMMU_IDR6.CMDQ_CONTROL_PAGE_LOG2NUMQ. Processing its resource reservation
> to avoid resource conflict with PMCG is a bit more complicated.
> 
> Therefore, the resources of the PMCG are not reserved, and the entire SMMU
> resources are reserved.

This is the opposite of what I suggested. My point was that it will make 
the most sense to map the ECMDQ pages as a separate request anyway, 
therefore there is no reason to stop mapping page 0 and page 1 
separately either.

If we need to expand the page 0 mapping to cover more of page 0 to reach 
the SMMU_CMDQ_CONTROL_PAGE_* registers, we can do that when we actually 
add ECMDQ support.

Robin.

> Suggested-by: Robin Murphy <robin.murphy at arm.com>
> Signed-off-by: Zhen Lei <thunder.leizhen at huawei.com>
> ---
>   drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 24 ++++--------------------
>   drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h |  2 --
>   2 files changed, 4 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> index f04c55a7503c790..fde24403b06a9e3 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -3476,14 +3476,6 @@ static int arm_smmu_set_bus_ops(struct iommu_ops *ops)
>   	return err;
>   }
>   
> -static void __iomem *arm_smmu_ioremap(struct device *dev, resource_size_t start,
> -				      resource_size_t size)
> -{
> -	struct resource res = DEFINE_RES_MEM(start, size);
> -
> -	return devm_ioremap_resource(dev, &res);
> -}
> -
>   static int arm_smmu_device_probe(struct platform_device *pdev)
>   {
>   	int irq, ret;
> @@ -3519,22 +3511,14 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
>   	}
>   	ioaddr = res->start;
>   
> -	/*
> -	 * Don't map the IMPLEMENTATION DEFINED regions, since they may contain
> -	 * the PMCG registers which are reserved by the PMU driver.
> -	 */
> -	smmu->base = arm_smmu_ioremap(dev, ioaddr, ARM_SMMU_REG_SZ);
> +	smmu->base = devm_ioremap_resource(dev, res);
>   	if (IS_ERR(smmu->base))
>   		return PTR_ERR(smmu->base);
>   
> -	if (arm_smmu_resource_size(smmu) > SZ_64K) {
> -		smmu->page1 = arm_smmu_ioremap(dev, ioaddr + SZ_64K,
> -					       ARM_SMMU_REG_SZ);
> -		if (IS_ERR(smmu->page1))
> -			return PTR_ERR(smmu->page1);
> -	} else {
> +	if (arm_smmu_resource_size(smmu) > SZ_64K)
> +		smmu->page1 = smmu->base + SZ_64K;
> +	else
>   		smmu->page1 = smmu->base;
> -	}
>   
>   	/* Interrupt lines */
>   
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> index da525f46dab4fc1..63f2b476987d6ae 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> @@ -152,8 +152,6 @@
>   #define ARM_SMMU_PRIQ_IRQ_CFG1		0xd8
>   #define ARM_SMMU_PRIQ_IRQ_CFG2		0xdc
>   
> -#define ARM_SMMU_REG_SZ			0xe00
> -
>   /* Common MSI config fields */
>   #define MSI_CFG0_ADDR_MASK		GENMASK_ULL(51, 2)
>   #define MSI_CFG2_SH			GENMASK(5, 4)
>