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When both the old and the new PCI drivers are enabled
in the same kernel, there are a couple of namespace
conflicts that cause a build failure:
drivers/pci/controller/pci-ixp4xx.c:38: error: "IXP4XX_PCI_CSR" redefined [-Werror]
38 | #define IXP4XX_PCI_CSR 0x1c
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In file included from arch/arm/mach-ixp4xx/include/mach/hardware.h:23,
from arch/arm/mach-ixp4xx/include/mach/io.h:15,
from arch/arm/include/asm/io.h:198,
from include/linux/io.h:13,
from drivers/pci/controller/pci-ixp4xx.c:20:
arch/arm/mach-ixp4xx/include/mach/ixp4xx-regs.h:221: note: this is the location of the previous definition
221 | #define IXP4XX_PCI_CSR(x) ((volatile u32 *)(IXP4XX_PCI_CFG_BASE_VIRT+(x)))
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drivers/pci/controller/pci-ixp4xx.c:148:12: error: 'ixp4xx_pci_read' redeclared as different kind of symbol
148 | static int ixp4xx_pci_read(struct ixp4xx_pci *p, u32 addr, u32 cmd, u32 *data)
| ^~~~~~~~~~~~~~~
Rename both the ixp4xx_pci_read/ixp4xx_pci_write functions and the
IXP4XX_PCI_CSR macro. In each case, I went with the version that
has fewer callers to keep the change small.
Fixes: f7821b493458 ("PCI: ixp4xx: Add a new driver for IXP4xx")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: soc@kernel.org
Link: https://lore.kernel.org/r/20210721151546.2325937-1-arnd@kernel.org'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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This adds a new PCI controller driver for the Intel IXP4xx
(IX425, IXP435 etc), based on the XScale microarchitecture.
This replaces the old driver in arch/arm/mach-ixp4xx/common-pci.c
which utilized the ARM-specific BIOS32 PCI framework,
and all parameterization for such things as memory and
IO space as well as interrupt swizzling is done from the
device tree.
The plan is to phase out and delete the old driver piecemal.
The __raw_writel() and __raw_readl() are used for accessing
the PCI controller for the same reason that these accessors
are used in the timer, IRQ and GPIO drivers: the platform
will alter its address bus pattern based on whether the
system is booted in big- or little-endian mode. For this
reason all register on IXP4xx must always be accessed in
native (CPU) endianness.
This driver supports 64MB of PCI memory space, but not the
indirect access of 1GB that is available in the old driver.
We can address that later if and only if there are users
that need all 1GB of PCI address space. Krzysztof reports
having to use indirect MMIO only once for a VGA card. There
is work ongoing for general indirect MMIO. (In practice
the indirect MMIO is performed by writing address and
writing and reading values into/from a controller
register.)
Tested by booting the NSLU2, attaching a USB stick, mounting
and browsing the drive.
Link: https://lore.kernel.org/linux-arm-kernel/m37edwuv8m.fsf@t19.piap.pl/
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Imre Kaloz <kaloz@openwrt.org>
Cc: Krzysztof Halasa <khalasa@piap.pl>
Cc: Zoltan HERPAI <wigyori@uid0.hu>
Cc: Raylynn Knight <rayknight@me.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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