[PATCH 03/10] x86: add initialization code for DMA-API debugging

[Joerg Roedel]

Impact: creates necessary data structures for DMA-API debugging

Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx>
---
 arch/x86/include/asm/dma-mapping.h |    1 +
 arch/x86/include/asm/dma_debug.h   |   14 +++++
 arch/x86/kernel/Makefile           |    2 +
 arch/x86/kernel/pci-dma-debug.c    |  111 ++++++++++++++++++++++++++++++++++++
 arch/x86/kernel/pci-dma.c          |    2 +
 5 files changed, 130 insertions(+), 0 deletions(-)
 create mode 100644 arch/x86/kernel/pci-dma-debug.c

diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
index 7f225a4..83d7b7d 100644
--- a/arch/x86/include/asm/dma-mapping.h
+++ b/arch/x86/include/asm/dma-mapping.h
@@ -9,6 +9,7 @@
 #include <linux/scatterlist.h>
 #include <asm/io.h>
 #include <asm/swiotlb.h>
+#include <asm/dma_debug.h>
 #include <asm-generic/dma-coherent.h>
 
 extern dma_addr_t bad_dma_address;
diff --git a/arch/x86/include/asm/dma_debug.h b/arch/x86/include/asm/dma_debug.h
index d79f024..f2c3d53 100644
--- a/arch/x86/include/asm/dma_debug.h
+++ b/arch/x86/include/asm/dma_debug.h
@@ -38,4 +38,18 @@ struct dma_debug_entry {
 	int direction;
 };
 
+#ifdef CONFIG_DMA_API_DEBUG
+
+extern
+void dma_debug_init(void);
+
+#else /* CONFIG_DMA_API_DEBUG */
+
+static inline
+void dma_debug_init(void)
+{
+}
+
+#endif /* CONFIG_DMA_API_DEBUG */
+
 #endif /* __ASM_X86_DMA_DEBUG */
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index e489ff9..6271cd2 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -105,6 +105,8 @@ microcode-$(CONFIG_MICROCODE_INTEL)	+= microcode_intel.o
 microcode-$(CONFIG_MICROCODE_AMD)	+= microcode_amd.o
 obj-$(CONFIG_MICROCODE)			+= microcode.o
 
+obj-$(CONFIG_DMA_API_DEBUG)             += pci-dma-debug.o
+
 ###
 # 64 bit specific files
 ifeq ($(CONFIG_X86_64),y)
diff --git a/arch/x86/kernel/pci-dma-debug.c b/arch/x86/kernel/pci-dma-debug.c
new file mode 100644
index 0000000..c2d3408
--- /dev/null
+++ b/arch/x86/kernel/pci-dma-debug.c
@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2008 Advanced Micro Devices, Inc.
+ *
+ * Author: Joerg Roedel <joerg.roedel@xxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ */
+
+#include <linux/types.h>
+#include <linux/scatterlist.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/module.h>
+#include <linux/hardirq.h>
+#include <linux/dma-mapping.h>
+#include <asm/bug.h>
+#include <asm/dma-mapping.h>
+#include <asm/dma_debug.h>
+
+#define HASH_SIZE 256
+#define HASH_FN_SHIFT 20
+#define HASH_FN_MASK 0xffULL
+
+/* Hash list to save the allocated dma addresses */
+static struct list_head dma_entry_hash[HASH_SIZE];
+
+/* A slab cache to allocate dma_map_entries fast */
+static struct kmem_cache *dma_entry_cache;
+
+/* lock to protect the data structures */
+static DEFINE_SPINLOCK(dma_lock);
+
+static int hash_fn(struct dma_debug_entry *entry)
+{
+	/*
+	 * Hash function is based on the dma address.
+	 * We use bits 20-27 here as the index into the hash
+	 */
+	BUG_ON(entry->dev_addr == bad_dma_address);
+
+	return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
+}
+
+static struct dma_debug_entry *dma_entry_alloc(void)
+{
+	gfp_t gfp = GFP_KERNEL | __GFP_ZERO;
+
+	if (in_atomic())
+		gfp |= GFP_ATOMIC;
+
+	return kmem_cache_alloc(dma_entry_cache, gfp);
+}
+
+static void dma_entry_free(struct dma_debug_entry *entry)
+{
+	kmem_cache_free(dma_entry_cache, entry);
+}
+
+static struct dma_debug_entry *
+find_dma_entry(struct dma_debug_entry *ref)
+{
+	int idx = hash_fn(ref);
+	struct dma_debug_entry *entry;
+
+	list_for_each_entry(entry, &dma_entry_hash[idx], list) {
+		if ((entry->dev_addr == ref->dev_addr) &&
+				(entry->dev == ref->dev))
+			return entry;
+	}
+
+	return NULL;
+}
+
+static void add_dma_entry(struct dma_debug_entry *entry)
+{
+	int idx = hash_fn(entry);
+
+	list_add_tail(&entry->list, &dma_entry_hash[idx]);
+}
+
+static void remove_dma_entry(struct dma_debug_entry *entry)
+{
+	list_del(&entry->list);
+}
+
+void dma_debug_init(void)
+{
+	int i;
+
+	for (i = 0; i < HASH_SIZE; ++i)
+		INIT_LIST_HEAD(&dma_entry_hash[i]);
+
+	dma_entry_cache = kmem_cache_create("dma_debug_entry_cache",
+			sizeof(struct dma_debug_entry),
+			0, SLAB_PANIC, NULL);
+
+	printk(KERN_INFO "PCI-DMA: DMA API debugging enabled by kernel config\n");
+}
+
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 1926248..94096b8 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -275,6 +275,8 @@ EXPORT_SYMBOL(dma_supported);
 
 static int __init pci_iommu_init(void)
 {
+	dma_debug_init();
+
 	calgary_iommu_init();
 
 	intel_iommu_init();
-- 
1.5.6.4


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