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Intel IOMMU: Iommu floppy workaround

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This config option (DMAR_FLPY_WA) sets up 1:1 mapping for the floppy device so
that the floppy device which does not use DMA api's will continue to work.

Once the floppy driver starts using DMA api's this config option can be turn
off or this patch can be yanked out of kernel at that time.

[akpm@linux-foundation.org: cleanups, rename things, build fix]
[jengelh@computergmbh.de: Kconfig fixes]
Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Muli Ben-Yehuda <muli@il.ibm.com>
Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Jan Engelhardt <jengelh@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Keshavamurthy, Anil S 2007-10-21 16:41:57 -07:00 committed by Linus Torvalds
parent e820482cd2
commit 49a0429e53
2 changed files with 37 additions and 0 deletions
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10
arch/x86_64/Kconfig
View file

@ -772,6 +772,16 @@ config DMAR_GFX_WA
all the OS-visible memory. Hence the driver can continue
to use physical addresses for DMA.
config DMAR_FLOPPY_WA
bool
depends on DMAR
default y
help
Floppy disk drivers are know to bypass DMA API calls
thereby failing to work when IOMMU is enabled. This
workaround will setup a 1:1 mapping for the first
16M to make floppy (an ISA device) work.
source "drivers/pci/pcie/Kconfig"
source "drivers/pci/Kconfig"

27
drivers/pci/intel-iommu.c
View file

@ -1632,6 +1632,31 @@ error:
}
#endif
#ifdef CONFIG_DMAR_FLOPPY_WA
static inline void iommu_prepare_isa(void)
{
struct pci_dev *pdev;
int ret;
pdev = pci_get_class(PCI_CLASS_BRIDGE_ISA << 8, NULL);
if (!pdev)
return;
printk(KERN_INFO "IOMMU: Prepare 0-16M unity mapping for LPC\n");
ret = iommu_prepare_identity_map(pdev, 0, 16*1024*1024);
if (ret)
printk("IOMMU: Failed to create 0-64M identity map, "
"floppy might not work\n");
}
#else
static inline void iommu_prepare_isa(void)
{
return;
}
#endif /* !CONFIG_DMAR_FLPY_WA */
int __init init_dmars(void)
{
struct dmar_drhd_unit *drhd;
@ -1697,6 +1722,8 @@ int __init init_dmars(void)
iommu_prepare_gfx_mapping();
iommu_prepare_isa();
/*
* for each drhd
* enable fault log