On Sunday 15 August 2021 17:56:04 Marc Zyngier wrote:
> On Sun, 15 Aug 2021 11:36:23 +0100,
> Pali Rohár <pali@xxxxxxxxxx> wrote:
> >
> > Masking of individual MSI interrupts is done via PCIE_MSI_MASK_REG
> > register. At the driver probe time mask all MSI interrupts and then let
> > kernel IRQ chip code to unmask particular MSI interrupt when needed.
> >
> > Signed-off-by: Pali Rohár <pali@xxxxxxxxxx>
> > Cc: stable@xxxxxxxxxxxxxxx # f21a8b1b6837 ("PCI: aardvark: Move to MSI handling using generic MSI support")
> > ---
> > drivers/pci/controller/pci-aardvark.c | 44 ++++++++++++++++++++++++---
> > 1 file changed, 40 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
> > index bacfccee44fe..96580e1e4539 100644
> > --- a/drivers/pci/controller/pci-aardvark.c
> > +++ b/drivers/pci/controller/pci-aardvark.c
> > @@ -480,12 +480,10 @@ static void advk_pcie_setup_hw(struct advk_pcie *pcie)
> > advk_writel(pcie, PCIE_ISR1_ALL_MASK, PCIE_ISR1_REG);
> > advk_writel(pcie, PCIE_IRQ_ALL_MASK, HOST_CTRL_INT_STATUS_REG);
> >
> > - /* Disable All ISR0/1 Sources */
> > + /* Disable All ISR0/1 and MSI Sources */
> > advk_writel(pcie, PCIE_ISR0_ALL_MASK, PCIE_ISR0_MASK_REG);
> > advk_writel(pcie, PCIE_ISR1_ALL_MASK, PCIE_ISR1_MASK_REG);
> > -
> > - /* Unmask all MSIs */
> > - advk_writel(pcie, ~(u32)PCIE_MSI_ALL_MASK, PCIE_MSI_MASK_REG);
> > + advk_writel(pcie, PCIE_MSI_ALL_MASK, PCIE_MSI_MASK_REG);
> >
> > /* Unmask summary MSI interrupt */
> > reg = advk_readl(pcie, PCIE_ISR0_MASK_REG);
> > @@ -1026,6 +1024,40 @@ static int advk_msi_set_affinity(struct irq_data *irq_data,
> > return -EINVAL;
> > }
> >
> > +static void advk_msi_irq_mask(struct irq_data *d)
> > +{
> > + struct advk_pcie *pcie = d->domain->host_data;
> > + irq_hw_number_t hwirq = irqd_to_hwirq(d);
> > + u32 mask;
> > +
> > + mask = advk_readl(pcie, PCIE_MSI_MASK_REG);
> > + mask |= BIT(hwirq);
> > + advk_writel(pcie, mask, PCIE_MSI_MASK_REG);
>
> This isn't atomic, and will results in corruption when two MSIs are
> masked/unmasked concurrently.
Does it mean that also current implementation of masking legacy
interrupt is incorrect?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/pci/controller/pci-aardvark.c?h=v5.13#n874
>
> M.
>
> --
> Without deviation from the norm, progress is not possible.
