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x86/amd-iommu: Add reset function for command buffers

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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 <joerg.roedel@amd.com>
This commit is contained in:
Joerg Roedel 2009-09-03 14:50:20 +02:00
parent d586d7852c
commit 93f1cc67cf
2 changed files with 18 additions and 5 deletions
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3
arch/x86/include/asm/amd_iommu_types.h
View File

@ -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 */

20
arch/x86/kernel/amd_iommu_init.c
View File

@ -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)