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PCI: pci-bridge-emul: Fix emulation of W1C bits

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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>
This commit is contained in:
Marek Behún 2021-10-28 20:56:53 +02:00 committed by Lorenzo Pieralisi
parent 2b650b7ff2
commit 7a41ae80bd
1 changed files with 13 additions and 0 deletions
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13
drivers/pci/pci-bridge-emul.c
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@ -431,8 +431,21 @@ int pci_bridge_emul_conf_write(struct pci_bridge_emul *bridge, int where,
/* 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);