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| author | Joerg Roedel <joerg.roedel@amd.com> | 2008-08-14 19:55:15 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-08-15 13:56:46 +0200 |
| commit | 519c31bacf78a969efa8d2e55ed8862848f28590 (patch) | |
| tree | bbeb4cd9f810536beb3bb1c5e6a827fa35a37633 /arch | |
| parent | b635acec48bcaa9183fcbf4e3955616b0d4119b5 (diff) | |
| download | linux-519c31bacf78a969efa8d2e55ed8862848f28590.tar.gz linux-519c31bacf78a969efa8d2e55ed8862848f28590.tar.bz2 linux-519c31bacf78a969efa8d2e55ed8862848f28590.zip | |
x86, AMD IOMMU: use status bit instead of memory write-back for completion wait
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/amd_iommu.c | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c index 22d7d050905d..028e945c68ad 100644 --- a/arch/x86/kernel/amd_iommu.c +++ b/arch/x86/kernel/amd_iommu.c @@ -101,16 +101,13 @@ static int iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd) */ static int iommu_completion_wait(struct amd_iommu *iommu) { - int ret; + int ret, ready = 0; + unsigned status = 0; struct iommu_cmd cmd; - volatile u64 ready = 0; - unsigned long ready_phys = virt_to_phys(&ready); unsigned long i = 0; memset(&cmd, 0, sizeof(cmd)); - cmd.data[0] = LOW_U32(ready_phys) | CMD_COMPL_WAIT_STORE_MASK; - cmd.data[1] = upper_32_bits(ready_phys); - cmd.data[2] = 1; /* value written to 'ready' */ + cmd.data[0] = CMD_COMPL_WAIT_INT_MASK; CMD_SET_TYPE(&cmd, CMD_COMPL_WAIT); iommu->need_sync = 0; @@ -122,9 +119,15 @@ static int iommu_completion_wait(struct amd_iommu *iommu) while (!ready && (i < EXIT_LOOP_COUNT)) { ++i; - cpu_relax(); + /* wait for the bit to become one */ + status = readl(iommu->mmio_base + MMIO_STATUS_OFFSET); + ready = status & MMIO_STATUS_COM_WAIT_INT_MASK; } + /* set bit back to zero */ + status &= ~MMIO_STATUS_COM_WAIT_INT_MASK; + writel(status, iommu->mmio_base + MMIO_STATUS_OFFSET); + if (unlikely((i == EXIT_LOOP_COUNT) && printk_ratelimit())) printk(KERN_WARNING "AMD IOMMU: Completion wait loop failed\n"); |