[PATCH 5.15 128/135] PCI: aardvark: Optimize writing PCI_EXP_RTCTL_PMEIE and PCI_EXP_RTSTA_PME on emulated bridge

Greg Kroah-Hartman
2022-05-10T14:16:30Z

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From: Pali Rohár <pali@kernel.org>

commit 7122bcb33295228c882c0aa32a04b2547beba2c3 upstream.

To optimize advk_pci_bridge_emul_pcie_conf_write() code, touch
PCIE_ISR0_REG and PCIE_ISR0_MASK_REG registers only when it is really
needed, when processing PCI_EXP_RTCTL_PMEIE and PCI_EXP_RTSTA_PME bits.

Link: https://lore.kernel.org/r/20220110015018.26359-16-kabel@kernel.org
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>
Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/pci/controller/pci-aardvark.c | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)

--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -925,19 +925,21 @@ advk_pci_bridge_emul_pcie_conf_write(str
advk_pcie_wait_for_retrain(pcie);
break;

- case PCI_EXP_RTCTL: {
+ case PCI_EXP_RTCTL:
/* Only mask/unmask PME interrupt */
- u32 val = advk_readl(pcie, PCIE_ISR0_MASK_REG) &
- ~PCIE_MSG_PM_PME_MASK;
- if ((new & PCI_EXP_RTCTL_PMEIE) == 0)
- val |= PCIE_MSG_PM_PME_MASK;
- advk_writel(pcie, val, PCIE_ISR0_MASK_REG);
+ if (mask & PCI_EXP_RTCTL_PMEIE) {
+ u32 val = advk_readl(pcie, PCIE_ISR0_MASK_REG);
+ if (new & PCI_EXP_RTCTL_PMEIE)
+ val &= ~PCIE_MSG_PM_PME_MASK;
+ else
+ val |= PCIE_MSG_PM_PME_MASK;
+ advk_writel(pcie, val, PCIE_ISR0_MASK_REG);
+ }
break;
- }

case PCI_EXP_RTSTA:
- new = (new & PCI_EXP_RTSTA_PME) >> 9;
- advk_writel(pcie, new, PCIE_ISR0_REG);
+ if (new & PCI_EXP_RTSTA_PME)
+ advk_writel(pcie, PCIE_MSG_PM_PME_MASK, PCIE_ISR0_REG);
break;