bus: ixp4xx: fix IXP4XX_EXP_T1_MASK

The IXP4XX_EXP_T1_MASK was shifted one bit to the right, overlapping
IXP4XX_EXP_T2_MASK and leaving bit 29 unused. The offset being wrong is
also confirmed at least by the datasheet of IXP45X/46X [1].

Fix this by aligning it to IXP4XX_EXP_T1_SHIFT.

[1] https://www.intel.com/content/dam/www/public/us/en/documents/manuals/ixp45x-ixp46x-developers-manual.pdf

Cc: stable@vger.kernel.org
Fixes: 1c953bda90ca ("bus: ixp4xx: Add a driver for IXP4xx expansion bus")
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Link: https://lore.kernel.org/r/20230624112958.27727-1-jonas.gorski@gmail.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20230624122139.3229642-1-linus.walleij@linaro.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

bus: ixp4xx: remove MODULE_LICENSE in non-modules

Since commit 8b41fc4454e ("kbuild: create modules.builtin without
Makefile.modbuiltin or tristate.conf"), MODULE_LICENSE declarations
are used to identify modules. As a consequence, uses of the macro
in non-modules will cause modprobe to misidentify their containing
object file as a module when it is not (false positives), and modprobe
might succeed rather than failing with a suitable error message.

So remove it in the files in this commit, none of which can be built as
modules.

Signed-off-by: Nick Alcock <nick.alcock@oracle.com>
Suggested-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: linux-modules@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Hitomi Hasegawa <hasegawa-hitomi@fujitsu.com>
Cc: Linus Walleij <linusw@kernel.org>
Cc: Imre Kaloz <kaloz@openwrt.org>
Cc: Krzysztof Halasa <khalasa@piap.pl>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

bus: ixp4xx: Don't touch bit 7 on IXP42x

We face some regressions on a few IXP42x systems when
accessing flash, the following unrelated error prints
appear from the PCI driver:

ixp4xx-pci c0000000.pci: PCI: abort_handler addr = 0xff9ffb5f,
isr = 0x0, status = 0x22a0
ixp4xx-pci c0000000.pci: imprecise abort
(...)

It turns out that while bit 7 is masked "reserved" it is
not unused, so masking it off as zero is dangerous, and
breaks flash access on some systems such as the NSLU2.
Be more careful and avoid masking off any of the reserved
bits 7, 8, 9 or 30. Only keep masking EXP_WORD (bit 2)
on IXP43x which is necessary in some setups.

Fixes: 1c953bda90ca ("bus: ixp4xx: Add a driver for IXP4xx expansion bus")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20221122134411.2030372-1-linus.walleij@linaro.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

bus: ixp4xx: return on error in ixp4xx_exp_probe()

This code was intended to return an error code if regmap_read() fails
but the return statement was missing.

Fixes: 1c953bda90ca ("bus: ixp4xx: Add a driver for IXP4xx expansion bus")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20210807230016.3607666-1-linus.walleij@linaro.org'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

bus: ixp4xx: Add a driver for IXP4xx expansion bus

The Intel IXP4xx SoCs have an expansion bus that is usually just
used for flash memory and configured by the boot loaders and can
be accessed using the "simple-bus".

However some devices need more elaborate configuration and then we
need to provide a proper 3-unit address space indicating chip
select for each device and provide timing and similar information.

Cc: Marc Zyngier <maz@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>