amd-iommu: add amd_iommu_dump parameter

This kernel parameter will be useful to get some AMD IOMMU related
information in dmesg that is not necessary for the default user but may
be helpful in debug situations.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

2 files changed, 16 insertions, 0 deletions

diff --git a/arch/x86/include/asm/amd_iommu_types.h b/arch/x86/include/asm/amd_iommu_types.h
index 95c8cd9d22b5..89dfb3793edd 100644
--- a/arch/x86/include/asm/amd_iommu_types.h
+++ b/arch/x86/include/asm/amd_iommu_types.h
@@ -194,6 +194,12 @@
 #define PD_DMA_OPS_MASK         (1UL << 0) /* domain used for dma_ops */
 #define PD_DEFAULT_MASK         (1UL << 1) /* domain is a default dma_ops
                                               domain for an IOMMU */
+extern bool amd_iommu_dump;
+#define DUMP_printk(format, arg...)                                     \
+        do {                                                            \
+                if (amd_iommu_dump)                                             \
+                        printk(KERN_INFO "AMD IOMMU: " format, ## arg); \
+        } while(0);
 
 /*
  * This structure contains generic data for  IOMMU protection domains
diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index 8c0be0902dac..57fb7a7cb6e8 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -115,6 +115,8 @@ struct ivmd_header {
         u64 range_length;
 } __attribute__((packed));
 
+bool amd_iommu_dump;
+
 static int __initdata amd_iommu_detected;
 
 u16 amd_iommu_last_bdf;                 /* largest PCI device id we have
@@ -1211,6 +1213,13 @@ void __init amd_iommu_detect(void)
  *
  ****************************************************************************/
 
+static int __init parse_amd_iommu_dump(char *str)
+{
+        amd_iommu_dump = true;
+
+        return 1;
+}
+
 static int __init parse_amd_iommu_options(char *str)
 {
         for (; *str; ++str) {
@@ -1235,5 +1244,6 @@ static int __init parse_amd_iommu_size_options(char *str)
         return 1;
 }
 
+__setup("amd_iommu_dump", parse_amd_iommu_dump);
 __setup("amd_iommu=", parse_amd_iommu_options);
 __setup("amd_iommu_size=", parse_amd_iommu_size_options);