lkml.org 
[lkml]   [2021]   [Nov]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.15 140/917] PCI: pci-bridge-emul: Fix emulation of W1C bits
    Date
    From: Marek Behún <kabel@kernel.org>

    commit 7a41ae80bdcb17e14dd7d83239b8a0cf368f18be upstream.

    The pci_bridge_emul_conf_write() function correctly clears W1C bits in
    cfgspace cache, but it does not inform the underlying implementation
    about the clear request: the .write_op() method is given the value with
    these bits cleared.

    This is wrong if the .write_op() needs to know which bits were requested
    to be cleared.

    Fix the value to be passed into the .write_op() method to have requested
    W1C bits set, so that it can clear them.

    Both pci-bridge-emul users (mvebu and aardvark) are compatible with this
    change.

    Link: https://lore.kernel.org/r/20211028185659.20329-2-kabel@kernel.org
    Fixes: 23a5fba4d941 ("PCI: Introduce PCI bridge emulated config space common logic")
    Signed-off-by: Pali Rohár <pali@kernel.org>
    Signed-off-by: Marek Behún <kabel@kernel.org>
    Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
    Cc: stable@vger.kernel.org
    Cc: Russell King <rmk+kernel@armlinux.org.uk>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    drivers/pci/pci-bridge-emul.c | 13 +++++++++++++
    1 file changed, 13 insertions(+)

    --- a/drivers/pci/pci-bridge-emul.c
    +++ b/drivers/pci/pci-bridge-emul.c
    @@ -431,8 +431,21 @@ int pci_bridge_emul_conf_write(struct pc
    /* Clear the W1C bits */
    new &= ~((value << shift) & (behavior[reg / 4].w1c & mask));

    + /* Save the new value with the cleared W1C bits into the cfgspace */
    cfgspace[reg / 4] = cpu_to_le32(new);

    + /*
    + * Clear the W1C bits not specified by the write mask, so that the
    + * write_op() does not clear them.
    + */
    + new &= ~(behavior[reg / 4].w1c & ~mask);
    +
    + /*
    + * Set the W1C bits specified by the write mask, so that write_op()
    + * knows about that they are to be cleared.
    + */
    + new |= (value << shift) & (behavior[reg / 4].w1c & mask);
    +
    if (write_op)
    write_op(bridge, reg, old, new, mask);


    \
     
     \ /
      Last update: 2021-11-16 02:10    [W:4.028 / U:0.252 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site