Previously, DCR support was configured at compile time to either use
MMIO or native dcr instructions.  Although this works for most
platforms, it fails on FPGA platforms:

1) Systems may include more than one DCR bus.
2) Systems may be native DCR capable and still use memory mapped DCR interface.

This patch provides runtime support based on the device trees for the
case where CONFIG_PPC_DCR_MMIO and CONFIG_PPC_DCR_NATIVE are both
selected.  Previously, this was a poorly defined configuration, which
happened to provide NATIVE support.  The runtime selection is made
based on the dcr-controller having a 'dcr-access-method' attribute
in the device tree.  If only one of the above options is selected,
then the code uses #defines to select only the used code in order to
avoid introducing overhead in existing usage.
Signed-off-by: NStephen Neuendorffer <stephen.neuendorffer@xilinx.com>
Signed-off-by: NJosh Boyer <jwboyer@linux.vnet.ibm.com>

The include/asm-powerpc/dcr-native.h declares extern spinlock_t dcr_ind_lock;
but it's actually isn't defined. This patch adds a missing dcr_ind_lock.
Signed-off-by: NValentine Barshak <vbarshak@ru.mvista.com>
Signed-off-by: NJosh Boyer <jwboyer@linux.vnet.ibm.com>

With the base stored in dcr_host_t, there's no need for callers to pass
the dcr_n into dcr_unmap(). In fact this removes the possibility of them
passing the incorrect value, which would then be iounmap()'ed.
Signed-off-by: NMichael Ellerman <michael@ellerman.id.au>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

In its current form, dcr_map() doesn't remember the base address you passed
it, which means you need to store it somewhere else.  Rather than adding the
base to another struct it seems simpler to store it in the dcr_host_t.
Signed-off-by: NMichael Ellerman <michael@ellerman.id.au>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

In order to compile drivers as modules that uses some of the
DCR functions, we need to export the symbols.  Example, EMAC
driver and other drivers that are under development use these
functions.
Signed-off-by: NMurali Iyer <mniyer@us.ibm.com>
Acked-by: NArnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Fix a bug in dcr_unmap().

At unmap time the DCR offset need to be added instead of substracted.
Signed-off-by: NJean-Christophe Dubois <jdubois@mc.com>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

This patch adds new dcr_map/dcr_read/dcr_write accessors for DCRs that
can be used by drivers to transparently address either native DCRs or
memory mapped DCRs. The implementation for memory mapped DCRs is done
after the binding being currently worked on for SLOF and the Axon
chipset. This patch enables it for the cell native platform
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>