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    Subject[PATCH 4.4 44/65] ARM: cns3xxx: Fix writing to wrong PCI config registers after alignment
    Date
    4.4-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Koen Vandeputte <koen.vandeputte@ncentric.com>

    commit 65dbb423cf28232fed1732b779249d6164c5999b upstream.

    Originally, cns3xxx used its own functions for mapping, reading and
    writing config registers.

    Commit 802b7c06adc7 ("ARM: cns3xxx: Convert PCI to use generic config
    accessors") removed the internal PCI config write function in favor of
    the generic one:

    cns3xxx_pci_write_config() --> pci_generic_config_write()

    cns3xxx_pci_write_config() expected aligned addresses, being produced by
    cns3xxx_pci_map_bus() while the generic one pci_generic_config_write()
    actually expects the real address as both the function and hardware are
    capable of byte-aligned writes.

    This currently leads to pci_generic_config_write() writing to the wrong
    registers.

    For instance, upon ath9k module loading:

    - driver ath9k gets loaded
    - The driver wants to write value 0xA8 to register PCI_LATENCY_TIMER,
    located at 0x0D
    - cns3xxx_pci_map_bus() aligns the address to 0x0C
    - pci_generic_config_write() effectively writes 0xA8 into register 0x0C
    (CACHE_LINE_SIZE)

    Fix the bug by removing the alignment in the cns3xxx mapping function.

    Fixes: 802b7c06adc7 ("ARM: cns3xxx: Convert PCI to use generic config accessors")
    Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
    [lorenzo.pieralisi@arm.com: updated commit log]
    Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
    Acked-by: Krzysztof Halasa <khalasa@piap.pl>
    Acked-by: Tim Harvey <tharvey@gateworks.com>
    Acked-by: Arnd Bergmann <arnd@arndb.de>
    CC: stable@vger.kernel.org # v4.0+
    CC: Bjorn Helgaas <bhelgaas@google.com>
    CC: Olof Johansson <olof@lixom.net>
    CC: Robin Leblon <robin.leblon@ncentric.com>
    CC: Rob Herring <robh@kernel.org>
    CC: Russell King <linux@armlinux.org.uk>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    arch/arm/mach-cns3xxx/pcie.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    --- a/arch/arm/mach-cns3xxx/pcie.c
    +++ b/arch/arm/mach-cns3xxx/pcie.c
    @@ -83,7 +83,7 @@ static void __iomem *cns3xxx_pci_map_bus
    } else /* remote PCI bus */
    base = cnspci->cfg1_regs + ((busno & 0xf) << 20);

    - return base + (where & 0xffc) + (devfn << 12);
    + return base + where + (devfn << 12);
    }

    static int cns3xxx_pci_read_config(struct pci_bus *bus, unsigned int devfn,

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