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Date: Thu, 30 Oct 2008 15:13:07 -0500
From: James Bottomley <James.Bottomley@...senPartnership.com>
To: Arjan van de Ven <arjan@...radead.org>
Cc: Ingo Molnar <mingo@...e.hu>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Glauber Costa <gcosta@...hat.com>,
linux-kernel <linux-kernel@...r.kernel.org>,
Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH] x86 separate PCI out from DMA operations
This splits pci-dma.c into two pieces (a PCI specific pci-dma.c and a
generic dma.c) and conditions the compile of the PCI specific piece on
CONFIG_PCI.
This has the benefit of sweeping all the IOMMU glue into PCI specific
files.
Signed-off-by: James Bottomley <James.Bottomley@...senPartnership.com>
---
Note: it's possible to merge pci-nommu into this if desired, since that
file really has nothing to do with PCI and everything to do with generic
dma operations.
Also, I used the CONFIG_PCI conditioning dma_supported() rather than
weak symbol trickery because of the EXPORT_SYMBOL() requirements.
James
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 58814cc..be44178 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -34,7 +34,8 @@ obj-$(CONFIG_X86_32) += sys_i386_32.o i386_ksyms_32.o
obj-$(CONFIG_X86_64) += sys_x86_64.o x8664_ksyms_64.o
obj-$(CONFIG_X86_64) += syscall_64.o vsyscall_64.o
obj-y += bootflag.o e820.o
-obj-y += pci-dma.o quirks.o i8237.o topology.o kdebugfs.o
+obj-$(CONFIG_PCI) += pci-dma.o
+obj-y += dma.o quirks.o i8237.o topology.o kdebugfs.o
obj-y += alternative.o i8253.o pci-nommu.o
obj-y += tsc.o io_delay.o rtc.o
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 1926248..8cbf10c 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -11,9 +11,6 @@
static int forbid_dac __read_mostly;
-struct dma_mapping_ops *dma_ops;
-EXPORT_SYMBOL(dma_ops);
-
static int iommu_sac_force __read_mostly;
#ifdef CONFIG_IOMMU_DEBUG
@@ -35,30 +32,6 @@ int iommu_detected __read_mostly = 0;
int iommu_bio_merge __read_mostly = 0;
EXPORT_SYMBOL(iommu_bio_merge);
-dma_addr_t bad_dma_address __read_mostly = 0;
-EXPORT_SYMBOL(bad_dma_address);
-
-/* Dummy device used for NULL arguments (normally ISA). Better would
- be probably a smaller DMA mask, but this is bug-to-bug compatible
- to older i386. */
-struct device x86_dma_fallback_dev = {
- .bus_id = "fallback device",
- .coherent_dma_mask = DMA_32BIT_MASK,
- .dma_mask = &x86_dma_fallback_dev.coherent_dma_mask,
-};
-EXPORT_SYMBOL(x86_dma_fallback_dev);
-
-int dma_set_mask(struct device *dev, u64 mask)
-{
- if (!dev->dma_mask || !dma_supported(dev, mask))
- return -EIO;
-
- *dev->dma_mask = mask;
-
- return 0;
-}
-EXPORT_SYMBOL(dma_set_mask);
-
#ifdef CONFIG_X86_64
static __initdata void *dma32_bootmem_ptr;
static unsigned long dma32_bootmem_size __initdata = (128ULL<<20);
@@ -134,37 +107,6 @@ unsigned long iommu_nr_pages(unsigned long addr, unsigned long len)
EXPORT_SYMBOL(iommu_nr_pages);
#endif
-void *dma_generic_alloc_coherent(struct device *dev, size_t size,
- dma_addr_t *dma_addr, gfp_t flag)
-{
- unsigned long dma_mask;
- struct page *page;
- dma_addr_t addr;
-
- dma_mask = dma_alloc_coherent_mask(dev, flag);
-
- flag |= __GFP_ZERO;
-again:
- page = alloc_pages_node(dev_to_node(dev), flag, get_order(size));
- if (!page)
- return NULL;
-
- addr = page_to_phys(page);
- if (!is_buffer_dma_capable(dma_mask, addr, size)) {
- __free_pages(page, get_order(size));
-
- if (dma_mask < DMA_32BIT_MASK && !(flag & GFP_DMA)) {
- flag = (flag & ~GFP_DMA32) | GFP_DMA;
- goto again;
- }
-
- return NULL;
- }
-
- *dma_addr = addr;
- return page_address(page);
-}
-
/*
* See <Documentation/x86_64/boot-options.txt> for the iommu kernel parameter
* documentation.
@@ -232,16 +174,15 @@ static __init int iommu_setup(char *p)
}
early_param("iommu", iommu_setup);
+/* the non PCI version of this file is in dma.c */
int dma_supported(struct device *dev, u64 mask)
{
struct dma_mapping_ops *ops = get_dma_ops(dev);
-#ifdef CONFIG_PCI
if (mask > 0xffffffff && forbid_dac > 0) {
dev_info(dev, "PCI: Disallowing DAC for device\n");
return 0;
}
-#endif
if (ops->dma_supported)
return ops->dma_supported(dev, mask);
@@ -273,7 +214,7 @@ int dma_supported(struct device *dev, u64 mask)
}
EXPORT_SYMBOL(dma_supported);
-static int __init pci_iommu_init(void)
+void __init pci_iommu_init(void)
{
calgary_iommu_init();
@@ -283,18 +224,15 @@ static int __init pci_iommu_init(void)
gart_iommu_init();
- no_iommu_init();
- return 0;
+ if (!dma_ops)
+ force_iommu = 0;
}
void pci_iommu_shutdown(void)
{
gart_iommu_shutdown();
}
-/* Must execute after PCI subsystem */
-fs_initcall(pci_iommu_init);
-#ifdef CONFIG_PCI
/* Many VIA bridges seem to corrupt data for DAC. Disable it here */
static __devinit void via_no_dac(struct pci_dev *dev)
@@ -306,4 +244,3 @@ static __devinit void via_no_dac(struct pci_dev *dev)
}
}
DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID, via_no_dac);
-#endif
diff --git a/arch/x86/kernel/pci-nommu.c b/arch/x86/kernel/pci-nommu.c
index c70ab5a..5e7dd85 100644
--- a/arch/x86/kernel/pci-nommu.c
+++ b/arch/x86/kernel/pci-nommu.c
@@ -90,7 +90,5 @@ void __init no_iommu_init(void)
{
if (dma_ops)
return;
-
- force_iommu = 0; /* no HW IOMMU */
dma_ops = &nommu_dma_ops;
}
diff --git a/dev/null b/arch/x86/kernel/dma.c
new file mode 100644
index 0000000..0896152
--- /dev/null
+++ b/arch/x86/kernel/dma.c
@@ -0,0 +1,104 @@
+#include <linux/dma-mapping.h>
+#include <linux/dmar.h>
+#include <linux/bootmem.h>
+
+#include <asm/proto.h>
+#include <asm/dma.h>
+#include <asm/iommu.h>
+
+struct dma_mapping_ops *dma_ops;
+EXPORT_SYMBOL(dma_ops);
+
+dma_addr_t bad_dma_address __read_mostly = 0;
+EXPORT_SYMBOL(bad_dma_address);
+
+/* Dummy device used for NULL arguments (normally ISA). Better would
+ be probably a smaller DMA mask, but this is bug-to-bug compatible
+ to older i386. */
+struct device x86_dma_fallback_dev = {
+ .bus_id = "fallback device",
+ .coherent_dma_mask = DMA_32BIT_MASK,
+ .dma_mask = &x86_dma_fallback_dev.coherent_dma_mask,
+};
+EXPORT_SYMBOL(x86_dma_fallback_dev);
+
+int dma_set_mask(struct device *dev, u64 mask)
+{
+ if (!dev->dma_mask || !dma_supported(dev, mask))
+ return -EIO;
+
+ *dev->dma_mask = mask;
+
+ return 0;
+}
+EXPORT_SYMBOL(dma_set_mask);
+
+void *dma_generic_alloc_coherent(struct device *dev, size_t size,
+ dma_addr_t *dma_addr, gfp_t flag)
+{
+ unsigned long dma_mask;
+ struct page *page;
+ dma_addr_t addr;
+
+ dma_mask = dma_alloc_coherent_mask(dev, flag);
+
+ flag |= __GFP_ZERO;
+again:
+ page = alloc_pages_node(dev_to_node(dev), flag, get_order(size));
+ if (!page)
+ return NULL;
+
+ addr = page_to_phys(page);
+ if (!is_buffer_dma_capable(dma_mask, addr, size)) {
+ __free_pages(page, get_order(size));
+
+ if (dma_mask < DMA_32BIT_MASK && !(flag & GFP_DMA)) {
+ flag = (flag & ~GFP_DMA32) | GFP_DMA;
+ goto again;
+ }
+
+ return NULL;
+ }
+
+ *dma_addr = addr;
+ return page_address(page);
+}
+
+#ifndef CONFIG_PCI
+int dma_supported(struct device *dev, u64 mask)
+{
+ struct dma_mapping_ops *ops = get_dma_ops(dev);
+
+ if (ops->dma_supported)
+ return ops->dma_supported(dev, mask);
+
+ /* Copied from i386. Doesn't make much sense, because it will
+ only work for pci_alloc_coherent.
+ The caller just has to use GFP_DMA in this case. */
+ if (mask < DMA_24BIT_MASK)
+ return 0;
+
+ return 1;
+}
+EXPORT_SYMBOL(dma_supported);
+#endif
+
+/* dummy weak initialisation function. If CONFIG_PCI is selected
+ * pci-dma.c has a strong version of this which gets called instead */
+void __init __weak pci_iommu_init(void)
+{
+}
+
+static __init int dma_init(void)
+{
+ pci_iommu_init();
+
+ no_iommu_init();
+
+ return 0;
+}
+
+/* Must execute after PCI subsystem */
+fs_initcall(dma_init);
+
+
--
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