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path: root/drivers/char/bsr.c
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2009-06-26powerpc/BSR: Fix BSR to allow mmap of small BSR on 64k kernelSonny Rao
On Mon, Nov 17, 2008 at 01:26:13AM -0600, Sonny Rao wrote: > On Fri, Nov 07, 2008 at 04:28:29PM +1100, Paul Mackerras wrote: > > Sonny Rao writes: > > > > > Fix the BSR driver to allow small BSR devices, which are limited to a > > > single 4k space, on a 64k page kernel. Previously the driver would > > > reject the mmap since the size was smaller than PAGESIZE (or because > > > the size was greater than the size of the device). Now, we check for > > > this case use remap_4k_pfn(). Also, take out code to set vm_flags, > > > as the remap_pfn functions will do this for us. > > > > Thanks. > > > > Do we know that the BSR size will always be 4k if it's not a multiple > > of 64k? Is it possible that we could get 8k, 16k or 32k or BSRs? > > If it is possible, what does the user need to be able to do? Do they > > just want to map 4k, or might then want to map the whole thing? > > > Hi Paul, I took a look at changing the driver to reject a request for > mapping more than a single 4k page, however the only indication we get > of the requested size in the mmap function is the vma size, and this > is always one page at minimum. So, it's not possible to determine if > the user wants one 4k page or more. As I noted in my first response, > there is only one case where this is even possible and I don't think > it is a significant concern. > > I did notice that I left out the check to see if the user is trying to > map more than the device length, so I fixed that. Here's the revised > patch. Alright, I've reworked this now so that if we get one of these cases where there's a bsr that's > 4k and < 64k on a 64k kernel we'll only advertise that it is a 4k BSR to userspace. I think this is the best solution since user programs are only supposed to look at sysfs to determine how much can be mapped, and libbsr does this as well. Please consider for 2.6.31 as a fix, thanks. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-06-26powerpc/BSR: add 4096 byte BSR sizeSonny Rao
Add a 4096 byte BSR size which will be used on new machines. Also, remove the warning when we run into an unknown size, as this can spam the kernel log excessively. Signed-off-by: Sonny Rao <sonnyrao@us.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-03-30trivial: drivers/char/bsr.c: Storage class should be before const qualifierTobias Klauser
The C99 specification states in section 6.11.5: The placement of a storage-class specifier other than at the beginning of the declaration specifiers in a declaration is an obsolescent feature. Signed-off-by: Tobias Klauser <tklauser@distanz.ch> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-01-13powerpc: Cleanup from l64 to ll64 change: drivers/charStephen Rothwell
This is a powerpc specific driver. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2008-12-03powerpc/BSR: Support multiple OF-node description of BSRSonny Rao
This adds support for multiple BSR nodes in the OF device tree. Previously, the BSR driver only supported a single OF node describing a BSR. Apparently when an LPAR is set to use "all system resources" the BSR appears as a single node, but when it is handed out in pieces, each 8 byte piece gets its own node. So, this keeps a list of BSR devices instead of the array and includes all nodes. Also, this makes the code be more inclusive of what BSR devices we accept by only checking compatibility and not the device name property (which might change in the future versions of BSR). Signed-off-by: Sonny Rao <sonnyrao@us.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-10-16device create: char: convert device_create_drvdata to device_createGreg Kroah-Hartman
Now that device_create() has been audited, rename things back to the original call to be sane. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-07-15powerpc: Add driver for Barrier Synchronization RegisterSonny Rao
Adds a character driver for BSR support on IBM POWER systems including Power5 and Power6. The BSR is an optional processor facility not currently implemented by any other processors. It's primary purpose is fast large SMP synchronization. More details on the BSR are in comments to the code which follows. This patch adds BSR driver to pseries_defconfig. Signed-off-by: Sonny Rao <sonnyrao@linux.vnet.ibm.com> Signed-off-by: Joel Schopp <jschopp@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>