[PATCH v2 2/4] iommu/arm-smmu: Tidy up context bank indexing

Jordan Crouse jcrouse at codeaurora.org
Thu Mar 30 11:40:48 PDT 2017


On Thu, Mar 30, 2017 at 05:56:30PM +0100, Robin Murphy wrote:
> ARM_AMMU_CB() is calculated relative to ARM_SMMU_CB_BASE(), but the
> latter is never of use on its own, and what we end up with is the same
> ARM_SMMU_CB_BASE() + ARM_AMMU_CB() expression being duplicated at every
> callsite. Folding the two together gives us a self-contained context
> bank accessor which is much more pleasant to work with.
> 
> Secondly, we might as well simplify CB_BASE itself at the same time.
> We use the address space size for its own sake precisely once, at probe
> time, and every other usage is to dynamically calculate CB_BASE over
> and over and over again. Let's flip things around so that we just
> maintain the CB_BASE address directly.

Reviewed-by: Jordan Crouse <jcrouse at codeaurora.org>

> Signed-off-by: Robin Murphy <robin.murphy at arm.com>
> ---
> 
> v2: No change
> 
>  drivers/iommu/arm-smmu.c | 29 ++++++++++++++---------------
>  1 file changed, 14 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index 34b745bf59f2..e79b623f9165 100644
> --- a/drivers/iommu/arm-smmu.c
> +++ b/drivers/iommu/arm-smmu.c
> @@ -216,8 +216,7 @@ enum arm_smmu_s2cr_privcfg {
>  #define CBA2R_VMID_MASK			0xffff
>  
>  /* Translation context bank */
> -#define ARM_SMMU_CB_BASE(smmu)		((smmu)->base + ((smmu)->size >> 1))
> -#define ARM_SMMU_CB(smmu, n)		((n) * (1 << (smmu)->pgshift))
> +#define ARM_SMMU_CB(smmu, n)	((smmu)->cb_base + ((n) << (smmu)->pgshift))
>  
>  #define ARM_SMMU_CB_SCTLR		0x0
>  #define ARM_SMMU_CB_ACTLR		0x4
> @@ -344,7 +343,7 @@ struct arm_smmu_device {
>  	struct device			*dev;
>  
>  	void __iomem			*base;
> -	unsigned long			size;
> +	void __iomem			*cb_base;
>  	unsigned long			pgshift;
>  
>  #define ARM_SMMU_FEAT_COHERENT_WALK	(1 << 0)
> @@ -603,7 +602,7 @@ static void arm_smmu_tlb_inv_context(void *cookie)
>  	void __iomem *base;
>  
>  	if (stage1) {
> -		base = ARM_SMMU_CB_BASE(smmu) + ARM_SMMU_CB(smmu, cfg->cbndx);
> +		base = ARM_SMMU_CB(smmu, cfg->cbndx);
>  		writel_relaxed(cfg->asid, base + ARM_SMMU_CB_S1_TLBIASID);
>  	} else {
>  		base = ARM_SMMU_GR0(smmu);
> @@ -623,7 +622,7 @@ static void arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size,
>  	void __iomem *reg;
>  
>  	if (stage1) {
> -		reg = ARM_SMMU_CB_BASE(smmu) + ARM_SMMU_CB(smmu, cfg->cbndx);
> +		reg = ARM_SMMU_CB(smmu, cfg->cbndx);
>  		reg += leaf ? ARM_SMMU_CB_S1_TLBIVAL : ARM_SMMU_CB_S1_TLBIVA;
>  
>  		if (cfg->fmt != ARM_SMMU_CTX_FMT_AARCH64) {
> @@ -642,7 +641,7 @@ static void arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size,
>  			} while (size -= granule);
>  		}
>  	} else if (smmu->version == ARM_SMMU_V2) {
> -		reg = ARM_SMMU_CB_BASE(smmu) + ARM_SMMU_CB(smmu, cfg->cbndx);
> +		reg = ARM_SMMU_CB(smmu, cfg->cbndx);
>  		reg += leaf ? ARM_SMMU_CB_S2_TLBIIPAS2L :
>  			      ARM_SMMU_CB_S2_TLBIIPAS2;
>  		iova >>= 12;
> @@ -672,7 +671,7 @@ static irqreturn_t arm_smmu_context_fault(int irq, void *dev)
>  	struct arm_smmu_device *smmu = smmu_domain->smmu;
>  	void __iomem *cb_base;
>  
> -	cb_base = ARM_SMMU_CB_BASE(smmu) + ARM_SMMU_CB(smmu, cfg->cbndx);
> +	cb_base = ARM_SMMU_CB(smmu, cfg->cbndx);
>  	fsr = readl_relaxed(cb_base + ARM_SMMU_CB_FSR);
>  
>  	if (!(fsr & FSR_FAULT))
> @@ -725,7 +724,7 @@ static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain,
>  
>  	gr1_base = ARM_SMMU_GR1(smmu);
>  	stage1 = cfg->cbar != CBAR_TYPE_S2_TRANS;
> -	cb_base = ARM_SMMU_CB_BASE(smmu) + ARM_SMMU_CB(smmu, cfg->cbndx);
> +	cb_base = ARM_SMMU_CB(smmu, cfg->cbndx);
>  
>  	if (smmu->version > ARM_SMMU_V1) {
>  		if (cfg->fmt == ARM_SMMU_CTX_FMT_AARCH64)
> @@ -1007,7 +1006,7 @@ static void arm_smmu_destroy_domain_context(struct iommu_domain *domain)
>  	 * Disable the context bank and free the page tables before freeing
>  	 * it.
>  	 */
> -	cb_base = ARM_SMMU_CB_BASE(smmu) + ARM_SMMU_CB(smmu, cfg->cbndx);
> +	cb_base = ARM_SMMU_CB(smmu, cfg->cbndx);
>  	writel_relaxed(0, cb_base + ARM_SMMU_CB_SCTLR);
>  
>  	if (cfg->irptndx != INVALID_IRPTNDX) {
> @@ -1358,7 +1357,7 @@ static phys_addr_t arm_smmu_iova_to_phys_hard(struct iommu_domain *domain,
>  	u64 phys;
>  	unsigned long va;
>  
> -	cb_base = ARM_SMMU_CB_BASE(smmu) + ARM_SMMU_CB(smmu, cfg->cbndx);
> +	cb_base = ARM_SMMU_CB(smmu, cfg->cbndx);
>  
>  	/* ATS1 registers can only be written atomically */
>  	va = iova & ~0xfffUL;
> @@ -1685,7 +1684,7 @@ static void arm_smmu_device_reset(struct arm_smmu_device *smmu)
>  
>  	/* Make sure all context banks are disabled and clear CB_FSR  */
>  	for (i = 0; i < smmu->num_context_banks; ++i) {
> -		cb_base = ARM_SMMU_CB_BASE(smmu) + ARM_SMMU_CB(smmu, i);
> +		cb_base = ARM_SMMU_CB(smmu, i);
>  		writel_relaxed(0, cb_base + ARM_SMMU_CB_SCTLR);
>  		writel_relaxed(FSR_FAULT, cb_base + ARM_SMMU_CB_FSR);
>  		/*
> @@ -1865,11 +1864,11 @@ static int arm_smmu_device_cfg_probe(struct arm_smmu_device *smmu)
>  
>  	/* Check for size mismatch of SMMU address space from mapped region */
>  	size = 1 << (((id >> ID1_NUMPAGENDXB_SHIFT) & ID1_NUMPAGENDXB_MASK) + 1);
> -	size *= 2 << smmu->pgshift;
> -	if (smmu->size != size)
> +	size <<= smmu->pgshift;
> +	if (smmu->cb_base != gr0_base + size)
>  		dev_warn(smmu->dev,
>  			"SMMU address space size (0x%lx) differs from mapped region size (0x%lx)!\n",
> -			size, smmu->size);
> +			size * 2, (smmu->cb_base - gr0_base) * 2);
>  
>  	smmu->num_s2_context_banks = (id >> ID1_NUMS2CB_SHIFT) & ID1_NUMS2CB_MASK;
>  	smmu->num_context_banks = (id >> ID1_NUMCB_SHIFT) & ID1_NUMCB_MASK;
> @@ -2105,7 +2104,7 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
>  	smmu->base = devm_ioremap_resource(dev, res);
>  	if (IS_ERR(smmu->base))
>  		return PTR_ERR(smmu->base);
> -	smmu->size = resource_size(res);
> +	smmu->cb_base = smmu->base + resource_size(res) / 2;
>  
>  	num_irqs = 0;
>  	while ((res = platform_get_resource(pdev, IORESOURCE_IRQ, num_irqs))) {
> -- 
> 2.11.0.dirty
> 
> _______________________________________________
> iommu mailing list
> iommu at lists.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/iommu

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