From 93f1cc67cf3196174412adca87321b25c1c986b0 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Thu, 3 Sep 2009 14:50:20 +0200 Subject: [PATCH] x86/amd-iommu: Add reset function for command buffers This patch factors parts of the command buffer initialization code into a seperate function which can be used to reset the command buffer later. Signed-off-by: Joerg Roedel --- arch/x86/include/asm/amd_iommu_types.h | 3 +++ arch/x86/kernel/amd_iommu_init.c | 20 +++++++++++++++----- 2 files changed, 18 insertions(+), 5 deletions(-) diff --git a/arch/x86/include/asm/amd_iommu_types.h b/arch/x86/include/asm/amd_iommu_types.h index 0c878caaa0a2..c54bc979dc17 100644 --- a/arch/x86/include/asm/amd_iommu_types.h +++ b/arch/x86/include/asm/amd_iommu_types.h @@ -457,4 +457,7 @@ static inline void amd_iommu_stats_init(void) { } #endif /* CONFIG_AMD_IOMMU_STATS */ +/* some function prototypes */ +extern void amd_iommu_reset_cmd_buffer(struct amd_iommu *iommu); + #endif /* _ASM_X86_AMD_IOMMU_TYPES_H */ diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c index c1b17e97252e..1752afef948a 100644 --- a/arch/x86/kernel/amd_iommu_init.c +++ b/arch/x86/kernel/amd_iommu_init.c @@ -434,6 +434,20 @@ static u8 * __init alloc_command_buffer(struct amd_iommu *iommu) return cmd_buf; } +/* + * This function resets the command buffer if the IOMMU stopped fetching + * commands from it. + */ +void amd_iommu_reset_cmd_buffer(struct amd_iommu *iommu) +{ + iommu_feature_disable(iommu, CONTROL_CMDBUF_EN); + + writel(0x00, iommu->mmio_base + MMIO_CMD_HEAD_OFFSET); + writel(0x00, iommu->mmio_base + MMIO_CMD_TAIL_OFFSET); + + iommu_feature_enable(iommu, CONTROL_CMDBUF_EN); +} + /* * This function writes the command buffer address to the hardware and * enables it. @@ -450,11 +464,7 @@ static void iommu_enable_command_buffer(struct amd_iommu *iommu) memcpy_toio(iommu->mmio_base + MMIO_CMD_BUF_OFFSET, &entry, sizeof(entry)); - /* set head and tail to zero manually */ - writel(0x00, iommu->mmio_base + MMIO_CMD_HEAD_OFFSET); - writel(0x00, iommu->mmio_base + MMIO_CMD_TAIL_OFFSET); - - iommu_feature_enable(iommu, CONTROL_CMDBUF_EN); + amd_iommu_reset_cmd_buffer(iommu); } static void __init free_command_buffer(struct amd_iommu *iommu)