The 10Gigabit ethernet device drivers appear to be able to chew
up all 256MB of TCE mappings on pSeries systems, as evidenced by
numerous error messages:

 iommu_alloc failed, tbl c0000000010d5c48 vaddr c0000000d875eff0 npages 1

Some experimentation indicates that this is essentially because
one 1500 byte ethernet MTU gets mapped as a 64K DMA region when
the large 64K pages are enabled. Thus, it doesn't take much to
exhaust all of the available DMA mappings for a high-speed card.

This patch changes the iommu allocator to work with its own
unique, distinct page size. Although the patch is long, its
actually quite simple: it just #defines a distinct IOMMU_PAGE_SIZE
and then uses this in all the places that matter.

As a side effect, it also dramatically improves network performance
on platforms with H-calls on iommu translation inserts/removes (since
we no longer call it 16 times for a 1500 bytes packet when the iommu HW
is still 4k).

In the future, we might want to make the IOMMU_PAGE_SIZE a variable
in the iommu_table instance, thus allowing support for different HW
page sizes in the iommu itself.
Signed-off-by: NLinas Vepstas <linas@austin.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: NOlof Johansson <olof@lixom.net>
Acked-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

It seems that the occasional data corruption observed with the tg3
driver wasn't due to missing barriers after all, but rather seems to
be due to the DART (= IOMMU) in the U4 northbridge reading stale
IOMMU table entries from memory due to a race.  This fixes it by
making the CPU read the entry back from memory before using it.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Signed-off-by: NJörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>

Better late than never...

Respin based on previous comment. Only remaining issue last time was an
extra mb() that I've taken out.
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Allocate IOMMU tables local to the relevant node.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Acked-by: NOlof Johansson <olof@lixom.net>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Turn on the DART already at 1GB. This is needed because of crippled
devices in some systems, i.e. Airport Extreme cards, only supporting
30-bit DMA addresses.

Otherwise, users with between 1 and 2GB of memory will need to manually
enable it with iommu=force, and that's no good.

Some simple performance tests show that there's a slight impact of
enabling DART, but it's in the 1-3% range (kernel build with disk I/O
as well as over NFS).

iommu=off can still be used for those who don't want to deal with the
overhead (and don't need it for any devices).
Signed-off-by: NOlof Johansson <olof@lixom.net>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

it's int __iomem *, not int * __iomem...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Currently most callers of lmb_alloc() don't check if it worked or not, if it
ever does weird bad things will probably happen. The few callers who do check
just panic or BUG_ON.

So make lmb_alloc() panic internally, to catch bugs at the source. The few
callers who did check the result no longer need to.

The only caller that did anything interesting with the return result was
careful_allocation(). For it we create __lmb_alloc_base() which _doesn't_ panic
automatically, a little messy, but passable.
Signed-off-by: NMichael Ellerman <michael@ellerman.id.au>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Rpn is assigned every time in the loop, no need to increase it too.
Signed-off-by: NOlof Johansson <olof@lixom.net>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

The patch enabling the new G5's with U4 broke initialization of the DART
driver, causing it to trigger a BUG_ON for a case that is actually
valid. This patch fixes it:
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

This adds some very basic support for the new machines, including the
Quad G5 (tested), and other new dual core based machines and iMac G5
iSight (untested). This is still experimental !  There is no thermal
control yet, there is no proper handing of MSIs, etc.. but it
boots, I have all 4 cores up on my machine. Compared to the previous
version of this patch, this one adds DART IOMMU support for the U4
chipset and thus should work fine on setups with more than 2Gb of RAM.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Email address update, changing old work address to personal (permanent)
one.
Signed-off-by: NOlof Johansson <olof@lixom.net>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

That DART (U3 iommu) code didn't properly scale the number of entries
when using !4k pages. That caused crashes when booting G5s with more
than 2Gb of RAM. This fixes it.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

The ancient ppcdebug/PPCDBG mechanism is now only used in two places.
First, in the hash setup code, one of the bits allows the size of the
hash table to be reduced by a factor of 8 - which would be better
accomplished with a command line option for that purpose.  The other
was a bunch of bus walking related messages in the iSeries code, which
would seem to be insufficient reason to keep the mechanism.

This patch removes the last traces of this mechanism.

Built and booted on iSeries and pSeries POWER5 LPAR (ARCH=powerpc).
Signed-off-by: NDavid Gibson <dwg@au1.ibm.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

asm-ppc64/dart.h is included in exactly one place -
arch/powerpc/sysdev/u3_iommu.c.  This patch, therefore, moves it into
arch/powerpc/sysdev.  While we're at it, update the #ifndef/#define
protecting the include, and the filename in the comments of
u3_iommu.c.

Built and booted on pSeries and G5, built for ppc32 powermac.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Signed-off-by: NPaul Mackerras <paulus@samba.org>

and rename it to pci.c.  This also required moving
arch/ppc64/kernel/pci.h into include/asm-powerpc (called
ppc-pci.h.
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>

There are potential cases in the future where the IOMMU might be
mapping smaller pages than the regular MMU is using. Keep the
allocator working on MMU pagesizes, but the low-level mapping
functions need to map more than one TCE entry per page to deal with
this.
Signed-off-by: NOlof Johansson <olof@lixom.net>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Split out the implementation-specific parts of include/asm-ppc64/iommu.h
to separate include files (tce.h and dart.h respectively).

The generic iommu code really doesn't care about the underlying
implementation, and the TCE and DART stuff is completely different.
Signed-off-by: NOlof Johansson <olof@lixom.net>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

This patch pulls the PCI-related junk out of struct device_node and
puts it in a separate structure, struct pci_dn.  The device_node now
just has a void * pointer in it, which points to a struct pci_dn for
nodes that represent PCI devices.  It could potentially be used in
future for device-specific data for other sorts of devices, such as
virtual I/O devices.
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!