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Message-Id: <1213289886.8567.150.camel@alexis>
Date: Thu, 12 Jun 2008 09:58:06 -0700
From: Alexis Bruemmer <alexisb@...ibm.com>
To: FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>
Cc: linux-kernel@...r.kernel.org, muli@...ibm.com, mingo@...e.hu,
akpm@...ux-foundation.org
Subject: Re: [PATCH -mm] x86 calgary: fix handling of devces that aren't
behind the Calgary
On Thu, 2008-06-12 at 16:29 +0900, FUJITA Tomonori wrote:
> On Wed, 11 Jun 2008 18:25:06 -0700
> Alexis Bruemmer <alexisb@...ibm.com> wrote:
>
> > On Sat, 2008-05-31 at 13:31 +0900, FUJITA Tomonori wrote:
> > > The calgary code can give drivers addresses above 4GB which is very
> > > bad for hardware that is only 32bit DMA addressable:
> > >
> > > http://lkml.org/lkml/2008/5/8/423
> > >
> > > This patch tries to fix the problem by using per-device
> > > dma_mapping_ops support. This fixes the calgary code to use swiotlb or
> > > nommu properly for devices which are not behind the Calgary/CalIOC2.
> > >
> > > With this patch, the calgary code sets the global dma_ops to swiotlb
> > > or nommu, and the dma_ops of devices behind the Calgary/CalIOC2 to
> > > calgary_dma_ops. So the calgary code can handle devices safely that
> > > aren't behind the Calgary/CalIOC2.
> > >
> > > I think that bus_register_notifier works nicely for hotplugging (the
> > > calgary code can register a hook to set the device-per ops to
> > > calgary_dma_ops) though I don't know the calgary code needs it.
> > >
> > > This patch is against -mm (depends on the per-device dma_mapping_ops
> > > patchset in -mm).
> > >
> > > This is only compile tested.
> > So this patch dose not completely work. The problem is that devices
> > that are controlled by the CalIO2/calgary are not getting the calgary
> > dma_ops assigned to them. Having the proper changes to pci-dma.c helped
> > (thank you) but still didn't quite get us there. From what I could tell
> > having the per device dma_ops being assigned in calgary_init_one was not
> > correct. The dev being past to calgary_init_one is only ever an IBM
> > CalIO2/calgary device which meant that many devices that are being
> > controlled by the CalI02/calgary, such as the the MegaRAID SAS
> > controller, were not getting the calgary based dma ops assigned to them.
>
> Thanks, now I see what's wrong in my patch.
> > I have attached an updated patch that does assign the per device calgary
> > dma_ops correctly and have successfully tested it on an IBM x3950 M2. I
> > think there is a better way to do this, but this does work.
>
> Looks good though I have one minor comment.
>
Updated and tested patch below.
>
> > Thank you some much for your help and work on this problem!
>
> You're welcome! I just want to improve IOMMUs and dma mapping code.
>
>
> > Alexis
> >
> >
> > > Thanks,
> > >
> > > ==
> > > From: FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>
> > > Subject: [PATCH] x86 calgary: fix handling of devces that aren't behind the Calgary
> > >
> > > The calgary code can give drivers addresses above 4GB which is very
> > > bad for hardware that is only 32bit DMA addressable.
> > >
> > > With this patch, the calgary code sets the global dma_ops to swiotlb
> > > or nommu properly, and the dma_ops of devices behind the
> > > Calgary/CalIOC2 to calgary_dma_ops. So the calgary code can handle
> > > devices safely that aren't behind the Calgary/CalIOC2.
> > >
> > > Signed-off-by: FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>
> > > ---
<snip>
Signed-off-by: Alexis Bruemmer <alexisb@...ibm.com>
Index: linux-2.6.26-rc4/arch/x86/kernel/pci-calgary_64.c
===================================================================
--- linux-2.6.26-rc4.orig/arch/x86/kernel/pci-calgary_64.c
+++ linux-2.6.26-rc4/arch/x86/kernel/pci-calgary_64.c
@@ -36,6 +36,7 @@
#include <linux/delay.h>
#include <linux/scatterlist.h>
#include <linux/iommu-helper.h>
+#include <asm/iommu.h>
#include <asm/gart.h>
#include <asm/calgary.h>
#include <asm/tce.h>
@@ -410,22 +411,6 @@ static void calgary_unmap_sg(struct devi
}
}
-static int calgary_nontranslate_map_sg(struct device* dev,
- struct scatterlist *sg, int nelems, int direction)
-{
- struct scatterlist *s;
- int i;
-
- for_each_sg(sg, s, nelems, i) {
- struct page *p = sg_page(s);
-
- BUG_ON(!p);
- s->dma_address = virt_to_bus(sg_virt(s));
- s->dma_length = s->length;
- }
- return nelems;
-}
-
static int calgary_map_sg(struct device *dev, struct scatterlist *sg,
int nelems, int direction)
{
@@ -436,9 +421,6 @@ static int calgary_map_sg(struct device
unsigned long entry;
int i;
- if (!translation_enabled(tbl))
- return calgary_nontranslate_map_sg(dev, sg, nelems, direction);
-
for_each_sg(sg, s, nelems, i) {
BUG_ON(!sg_page(s));
@@ -474,7 +456,6 @@ error:
static dma_addr_t calgary_map_single(struct device *dev, phys_addr_t paddr,
size_t size, int direction)
{
- dma_addr_t dma_handle = bad_dma_address;
void *vaddr = phys_to_virt(paddr);
unsigned long uaddr;
unsigned int npages;
@@ -483,12 +464,7 @@ static dma_addr_t calgary_map_single(str
uaddr = (unsigned long)vaddr;
npages = num_dma_pages(uaddr, size);
- if (translation_enabled(tbl))
- dma_handle = iommu_alloc(dev, tbl, vaddr, npages, direction);
- else
- dma_handle = virt_to_bus(vaddr);
-
- return dma_handle;
+ return iommu_alloc(dev, tbl, vaddr, npages, direction);
}
static void calgary_unmap_single(struct device *dev, dma_addr_t dma_handle,
@@ -497,9 +473,6 @@ static void calgary_unmap_single(struct
struct iommu_table *tbl = find_iommu_table(dev);
unsigned int npages;
- if (!translation_enabled(tbl))
- return;
-
npages = num_dma_pages(dma_handle, size);
iommu_free(tbl, dma_handle, npages);
}
@@ -522,18 +495,12 @@ static void* calgary_alloc_coherent(stru
goto error;
memset(ret, 0, size);
- if (translation_enabled(tbl)) {
- /* set up tces to cover the allocated range */
- mapping = iommu_alloc(dev, tbl, ret, npages, DMA_BIDIRECTIONAL);
- if (mapping == bad_dma_address)
- goto free;
-
- *dma_handle = mapping;
- } else /* non translated slot */
- *dma_handle = virt_to_bus(ret);
-
+ /* set up tces to cover the allocated range */
+ mapping = iommu_alloc(dev, tbl, ret, npages, DMA_BIDIRECTIONAL);
+ if (mapping == bad_dma_address)
+ goto free;
+ *dma_handle = mapping;
return ret;
-
free:
free_pages((unsigned long)ret, get_order(size));
ret = NULL;
@@ -1230,6 +1197,16 @@ static int __init calgary_init(void)
goto error;
} while (1);
+ dev = NULL;
+ for_each_pci_dev(dev) {
+ struct iommu_table *tbl;
+
+ tbl = find_iommu_table(&dev->dev);
+
+ if(translation_enabled(tbl))
+ dev->dev.archdata.dma_ops = &calgary_dma_ops;
+ }
+
return ret;
error:
@@ -1251,6 +1228,7 @@ error:
calgary_disable_translation(dev);
calgary_free_bus(dev);
pci_dev_put(dev); /* Undo calgary_init_one()'s pci_dev_get() */
+ dev->dev.archdata.dma_ops = NULL;
} while (1);
return ret;
@@ -1430,6 +1408,10 @@ void __init detect_calgary(void)
printk(KERN_INFO "PCI-DMA: Calgary TCE table spec is %d, "
"CONFIG_IOMMU_DEBUG is %s.\n", specified_table_size,
debugging ? "enabled" : "disabled");
+
+ /* swiotlb for devices that aren't behind the Calgary. */
+ if (end_pfn > MAX_DMA32_PFN)
+ swiotlb = 1;
}
return;
@@ -1446,7 +1428,7 @@ int __init calgary_iommu_init(void)
{
int ret;
- if (no_iommu || swiotlb)
+ if (no_iommu || (swiotlb && !calgary_detected))
return -ENODEV;
if (!calgary_detected)
@@ -1459,15 +1441,15 @@ int __init calgary_iommu_init(void)
if (ret) {
printk(KERN_ERR "PCI-DMA: Calgary init failed %d, "
"falling back to no_iommu\n", ret);
- if (end_pfn > MAX_DMA32_PFN)
- printk(KERN_ERR "WARNING more than 4GB of memory, "
- "32bit PCI may malfunction.\n");
return ret;
}
force_iommu = 1;
bad_dma_address = 0x0;
- dma_ops = &calgary_dma_ops;
+
+ /* dma_ops is set to swiotlb or nommu */
+ if (!dma_ops)
+ dma_ops = &nommu_dma_ops;
return 0;
}
Index: linux-2.6.26-rc4/include/asm-x86/iommu.h
===================================================================
--- linux-2.6.26-rc4.orig/include/asm-x86/iommu.h
+++ linux-2.6.26-rc4/include/asm-x86/iommu.h
@@ -3,6 +3,7 @@
extern void pci_iommu_shutdown(void);
extern void no_iommu_init(void);
+extern struct dma_mapping_ops nommu_dma_ops;
extern int force_iommu, no_iommu;
extern int iommu_detected;
#ifdef CONFIG_IOMMU
--
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