When we fix all the opensource gfx drivers to use the DMA api's,
at that time we can yank this config options out.

Signed-off-by: Anil S Keshavamurthy <[EMAIL PROTECTED]>
---
 Documentation/Intel-IOMMU.txt |    5 +++++
 arch/x86_64/Kconfig           |   11 +++++++++++
 arch/x86_64/kernel/e820.c     |   19 +++++++++++++++++++
 drivers/pci/intel-iommu.c     |   33 +++++++++++++++++++++++++++++++++
 drivers/pci/intel-iommu.h     |    7 +++++++
 5 files changed, 75 insertions(+)

Index: linux-2.6.22-rc4-mm2/Documentation/Intel-IOMMU.txt
===================================================================
--- linux-2.6.22-rc4-mm2.orig/Documentation/Intel-IOMMU.txt     2007-06-18 
15:45:08.000000000 -0700
+++ linux-2.6.22-rc4-mm2/Documentation/Intel-IOMMU.txt  2007-06-18 
15:45:08.000000000 -0700
@@ -57,6 +57,11 @@
 If you encounter issues with graphics devices, you can try adding
 option intel_iommu=igfx_off to turn off the integrated graphics engine.
 
+If it happens to be a PCI device included in the INCLUDE_ALL Engine,
+then try enabling CONFIG_DMAR_GFX_WA to setup a 1-1 map. We hear
+graphics drivers may be in process of using DMA api's in the near
+future and at that time this option can be yanked out.
+
 Some exceptions to IOVA
 -----------------------
 Interrupt ranges are not address translated, (0xfee00000 - 0xfeefffff).
Index: linux-2.6.22-rc4-mm2/arch/x86_64/Kconfig
===================================================================
--- linux-2.6.22-rc4-mm2.orig/arch/x86_64/Kconfig       2007-06-18 
15:45:07.000000000 -0700
+++ linux-2.6.22-rc4-mm2/arch/x86_64/Kconfig    2007-06-18 15:45:08.000000000 
-0700
@@ -741,6 +741,17 @@
          and includes pci device scope covered by these DMA
          remapping device.
 
+config DMAR_GFX_WA
+       bool "Support for Graphics workaround"
+       depends on DMAR
+       default y
+       help
+        Current Graphics drivers tend to use physical address
+        for DMA and avoid using DMA api's. Setting this config
+        option permits the IOMMU driver to set a unity map for
+        all the OS visible memory. Hence the driver can continue
+        to use physical addresses for DMA.
+
 source "drivers/pci/pcie/Kconfig"
 
 source "drivers/pci/Kconfig"
Index: linux-2.6.22-rc4-mm2/arch/x86_64/kernel/e820.c
===================================================================
--- linux-2.6.22-rc4-mm2.orig/arch/x86_64/kernel/e820.c 2007-06-18 
15:44:44.000000000 -0700
+++ linux-2.6.22-rc4-mm2/arch/x86_64/kernel/e820.c      2007-06-18 
15:45:08.000000000 -0700
@@ -723,3 +723,22 @@
        printk(KERN_INFO "Allocating PCI resources starting at %lx (gap: 
%lx:%lx)\n",
                pci_mem_start, gapstart, gapsize);
 }
+
+int __init arch_get_ram_range(int slot, u64 *addr, u64 *size)
+{
+       int i;
+
+       if (slot < 0 || slot >= e820.nr_map)
+               return -1;
+       for (i = slot; i < e820.nr_map; i++) {
+               if (e820.map[i].type != E820_RAM)
+                       continue;
+               break;
+       }
+       if (i == e820.nr_map || e820.map[i].addr > (max_pfn << PAGE_SHIFT))
+               return -1;
+       *addr = e820.map[i].addr;
+       *size = min_t(u64, e820.map[i].size + e820.map[i].addr,
+               max_pfn << PAGE_SHIFT) - *addr;
+       return i + 1;
+}
Index: linux-2.6.22-rc4-mm2/drivers/pci/intel-iommu.c
===================================================================
--- linux-2.6.22-rc4-mm2.orig/drivers/pci/intel-iommu.c 2007-06-18 
15:45:08.000000000 -0700
+++ linux-2.6.22-rc4-mm2/drivers/pci/intel-iommu.c      2007-06-18 
15:45:08.000000000 -0700
@@ -1601,6 +1601,36 @@
                rmrr->end_address + 1);
 }
 
+#ifdef CONFIG_DMAR_GFX_WA
+extern int arch_get_ram_range(int slot, u64 *addr, u64 *size);
+static void __init iommu_prepare_gfx_mapping(void)
+{
+       struct pci_dev *pdev = NULL;
+       u64 base, size;
+       int slot;
+       int ret;
+
+       for_each_pci_dev(pdev) {
+               if (pdev->sysdata == DUMMY_DEVICE_DOMAIN_INFO ||
+                               !IS_GFX_DEVICE(pdev))
+                       continue;
+               printk(KERN_INFO "IOMMU: gfx device %s 1-1 mapping\n",
+                       pci_name(pdev));
+               slot = arch_get_ram_range(0, &base, &size);
+               while (slot >= 0) {
+                       ret = iommu_prepare_identity_map(pdev,
+                                       base, base + size);
+                       if (ret)
+                               goto error;
+                       slot = arch_get_ram_range(slot, &base, &size);
+               }
+               continue;
+error:
+               printk(KERN_ERR "IOMMU: mapping reserved region failed\n");
+       }
+}
+#endif
+
 int __init init_dmars(void)
 {
        struct dmar_drhd_unit *drhd;
@@ -1664,6 +1694,8 @@
                }
        }
 
+       iommu_prepare_gfx_mapping();
+
        /*
         * for each drhd
         *   enable fault log
@@ -2175,3 +2207,4 @@
        dma_ops = &intel_dma_ops;
        return 0;
 }
+
Index: linux-2.6.22-rc4-mm2/drivers/pci/intel-iommu.h
===================================================================
--- linux-2.6.22-rc4-mm2.orig/drivers/pci/intel-iommu.h 2007-06-18 
15:45:08.000000000 -0700
+++ linux-2.6.22-rc4-mm2/drivers/pci/intel-iommu.h      2007-06-18 
15:45:08.000000000 -0700
@@ -315,4 +315,11 @@
        struct sys_device sysdev;
 };
 
+#ifndef CONFIG_DMAR_GFX_WA
+static inline void iommu_prepare_gfx_mapping(void)
+{
+       return;
+}
+#endif /* !CONFIG_DMAR_GFX_WA */
+
 #endif

-- 
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