[PATCH 5.10 181/406] PCI: pciehp: Use RMW accessors for changing LNKCTL

Greg Kroah-Hartman
2023-09-17T19:30:34Z

From: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

[ Upstream commit 5f75f96c61039151c193775d776fde42477eace1 ]

As hotplug is not the only driver touching LNKCTL, use the RMW capability
accessor which handles concurrent changes correctly.

Suggested-by: Lukas Wunner <lukas@wunner.de>
Fixes: 7f822999e12a ("PCI: pciehp: Add Disable/enable link functions")
Link: https://lore.kernel.org/r/20230717120503.15276-4-ilpo.jarvinen@linux.intel.com
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/pci/hotplug/pciehp_hpc.c | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index dda9523577472..75c6c72ec32ac 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -332,17 +332,11 @@ int pciehp_check_link_status(struct controller *ctrl)
static int __pciehp_link_set(struct controller *ctrl, bool enable)
{
struct pci_dev *pdev = ctrl_dev(ctrl);
- u16 lnk_ctrl;

- pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &lnk_ctrl);
+ pcie_capability_clear_and_set_word(pdev, PCI_EXP_LNKCTL,
+ PCI_EXP_LNKCTL_LD,
+ enable ? 0 : PCI_EXP_LNKCTL_LD);

- if (enable)
- lnk_ctrl &= ~PCI_EXP_LNKCTL_LD;
- else
- lnk_ctrl |= PCI_EXP_LNKCTL_LD;
-
- pcie_capability_write_word(pdev, PCI_EXP_LNKCTL, lnk_ctrl);
- ctrl_dbg(ctrl, "%s: lnk_ctrl = %x\n", __func__, lnk_ctrl);
return 0;
}

--
2.40.1