| From 7a41ae80bdcb17e14dd7d83239b8a0cf368f18be Mon Sep 17 00:00:00 2001 |
| From: =?UTF-8?q?Marek=20Beh=C3=BAn?= <kabel@kernel.org> |
| Date: Thu, 28 Oct 2021 20:56:53 +0200 |
| Subject: PCI: pci-bridge-emul: Fix emulation of W1C bits |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=UTF-8 |
| Content-Transfer-Encoding: 8bit |
| |
| 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 |
| @@ -432,8 +432,21 @@ 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); |
| |