Patch from Lennert Buytenhek
Introduce ixp2000_reg_wrb, which is a variant of ixp2000_reg_write
that does a readback from the target register, to make sure that
the write has been flushed out of the write buffer.
Unlike the previous (ineffective) readback in ixp2000_reg_write, this
readback is followed by an instruction that depends on the value of
the readback so that the CPU actually stalls until the readback has
completed.
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Deepak Saxena <dsaxena@plexity.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Lennert Buytenhek
Turn ixp2000_reg_read into an inline function.
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Deepak Saxena <dsaxena@plexity.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Lennert Buytenhek
The workaround that we do for avoiding triggering ixp2400 erratum #66
involves mapping I/O pages using XCB=101 instead of XCB=000 so that we
prevent the I/O signal to the gasket from being asserted (which can
cause data corruption.) But XCB=101 mappings are write-buffered while
mappings using XCB=000 are not, which is why if we use XCB=101 mappings
we do a readback for every CSR store in an attempt to make sure that
the store has been pushed out of the xscale core and the gasket.
Unfortunately, there are two issues with this:
- we do a readback for every CSR store, which is wrong, because the
register we are writing to might have unwanted side-effects on read,
for example, in the case of the scratchpad ring enqueue/dequeue
registers; and
- the readback is totally ineffective in the way we currently do it,
because we just issue a load but do not issue any instruction that
depends on the return value of that load, so the xscale core does
not wait for the load to complete before continuing.
See this linux-arm-kernel mailing list post for further information:
http://lists.arm.linux.org.uk/pipermail/linux-arm-kernel/2005-September/031314.html
This means that my ixp2400 boxes have been running for many months
without a working readback in ixp2000_reg_write, without any apparent
adverse effects. Two of them have been running for a week now with
the actual readback deleted from ixp2000_reg_write, also without any
apparent ill effects.
So, because in its current form it does more harm than good, the
readback in ixp2000_reg_write should simply be killed, as the patch
below does.
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Deepak Saxena <dsaxena@plexity.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Lennert Buytenhek
The intel docs call it IXP2000_PRODUCT_ID, and we have a definition
for IXP2000_PRODUCT_ID as well, so IXP2000_PROD_ID can go. It's only
used in one place.
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Deepak Saxena <dsaxena@plexity.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Lennert Buytenhek
This patch:
- changes the ixp2000_reg_write accessor to take a 'volatile void *'
instead of a 'volatile unsigned long *', which then allows passing in
a u32 * as first argument without being greeted with a warning; and
- adds an ixp2000_reg_read accessor.
We can then use these accessors in ixp2000 code to access on-chip
peripherals, instead of directly dereferencing pointers. This is for
use by the ixp2000 microengine driver which was recently announced on
netdev. We can't use readl/writel on the ixp2000 since it is usually
run in big-endian mode, and on big-endian platforms, readl/writel
perform byteswapping.
A future patch will remove the readback from ixp2000_reg_write, since
it's not needed to prevent erratum #66, and add manual readbacks to the
places that need them (writes are not synchronous since we map in device
space using XCB=101 nowadays), such as interrupt disabling and GPIO
manipulation. See also:
http://lists.arm.linux.org.uk/pipermail/linux-arm-kernel/2005-February/027084.html
Patch has been ACKed by Jeff Garzik.
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Lennert Buytenhek
This patch converts the ixp2000 serial port over to a platform
serial device.
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Deepak Saxena <dsaxena@plexity.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Lennert Buytenhek
This patch cleans up the ixp2000 gpio irq code and implements the
set_irq_type method for gpio irqs so that users can select for which
events (falling edge/rising edge/level low/level high) on the gpio
pin they want the corresponding gpio irq to be triggered.
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Deepak Saxena
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Lennert Buytenhek
Export ixp2000_pci_config_addr, to be used by the IXDP2800 platform
setup code to coordinate booting the master and slave NPU.
Signed-off-by: Lennert Buytenhek
Signed-off-by: Deepak Saxena
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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!
Lennert Buytenhek