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iommu/amd: Replace two consecutive readl calls with one readq 

Optimize the reigster reading by using readq instead of the two
consecutive readl calls.

Signed-off-by: Adrian Huang <ahuang12@lenovo.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Adrian Huang 2020-01-09 11:02:50 +08:00 committed by Joerg Roedel
parent bde9e6b9ba
commit 62dcee7160
1 changed files with 1 additions and 5 deletions
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6
drivers/iommu/amd_iommu_init.c
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@ -1718,7 +1718,6 @@ static const struct attribute_group *amd_iommu_groups[] = {
static int __init iommu_init_pci(struct amd_iommu *iommu)
{
int cap_ptr = iommu->cap_ptr;
u32 low, high;
int ret;
iommu->dev = pci_get_domain_bus_and_slot(0, PCI_BUS_NUM(iommu->devid),
@ -1736,10 +1735,7 @@ static int __init iommu_init_pci(struct amd_iommu *iommu)
amd_iommu_iotlb_sup = false;
/* read extended feature bits */
low = readl(iommu->mmio_base + MMIO_EXT_FEATURES);
high = readl(iommu->mmio_base + MMIO_EXT_FEATURES + 4);
iommu->features = ((u64)high << 32) | low;
iommu->features = readq(iommu->mmio_base + MMIO_EXT_FEATURES);
if (iommu_feature(iommu, FEATURE_GT)) {
int glxval;