git: f3aa0098a82e - main - Use mtx_lock_spin in the gic driver

[Marcin Wojtas]

Hi Andrew,

wt., 28 wrz 2021 o 14:43 Andrew Turner <andrew at freebsd.org> napisał(a):
>
> The branch main has been updated by andrew:
>
> URL: https://cgit.FreeBSD.org/src/commit/?id=f3aa0098a82ebf7712aa13716d794aa7e4ac59cd
>
> commit f3aa0098a82ebf7712aa13716d794aa7e4ac59cd
> Author:     Andrew Turner <andrew at FreeBSD.org>
> AuthorDate: 2021-09-28 11:36:42 +0000
> Commit:     Andrew Turner <andrew at FreeBSD.org>
> CommitDate: 2021-09-28 11:42:06 +0000
>
>     Use mtx_lock_spin in the gic driver
>
>     The mutex was changed to a spin lock when the MSI/MSI-X handling was
>     moved from the gicv2m to the gic driver. Update the calls to lock
>     and unlock the mutex to the spin variant.
>
>     Submitted by:   jrtc27 ("Change all the mtx_(un)lock(&sc->mutex) to be the _spin versions.")
>     Reported by:    mw, antranigv at freebsd.am
>     Sponsored by:   The FreeBSD Foundation
> ---
>  sys/arm/arm/gic.c | 20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/sys/arm/arm/gic.c b/sys/arm/arm/gic.c
> index d7edd7885404..89db4e324600 100644
> --- a/sys/arm/arm/gic.c
> +++ b/sys/arm/arm/gic.c
> @@ -1056,7 +1056,7 @@ arm_gic_alloc_msi(device_t dev, device_t child, int count, int maxcount,
>
>         sc = device_get_softc(dev);
>
> -       mtx_lock(&sc->mutex);
> +       mtx_lock_spin(&sc->mutex);
>
>         found = false;
>         for (irq = sc->sc_spi_start; irq < sc->sc_spi_end; irq++) {
> @@ -1091,7 +1091,7 @@ arm_gic_alloc_msi(device_t dev, device_t child, int count, int maxcount,
>
>         /* Not enough interrupts were found */
>         if (!found || irq == sc->sc_spi_end) {
> -               mtx_unlock(&sc->mutex);
> +               mtx_unlock_spin(&sc->mutex);
>                 return (ENXIO);
>         }
>
> @@ -1099,7 +1099,7 @@ arm_gic_alloc_msi(device_t dev, device_t child, int count, int maxcount,
>                 /* Mark the interrupt as used */
>                 sc->gic_irqs[irq + i].gi_flags |= GI_FLAG_MSI_USED;
>         }
> -       mtx_unlock(&sc->mutex);
> +       mtx_unlock_spin(&sc->mutex);
>
>         for (i = 0; i < count; i++)
>                 srcs[i] = (struct intr_irqsrc *)&sc->gic_irqs[irq + i];
> @@ -1118,7 +1118,7 @@ arm_gic_release_msi(device_t dev, device_t child, int count,
>
>         sc = device_get_softc(dev);
>
> -       mtx_lock(&sc->mutex);
> +       mtx_lock_spin(&sc->mutex);
>         for (i = 0; i < count; i++) {
>                 gi = (struct gic_irqsrc *)isrc[i];
>
> @@ -1128,7 +1128,7 @@ arm_gic_release_msi(device_t dev, device_t child, int count,
>
>                 gi->gi_flags &= ~GI_FLAG_MSI_USED;
>         }
> -       mtx_unlock(&sc->mutex);
> +       mtx_unlock_spin(&sc->mutex);
>
>         return (0);
>  }
> @@ -1142,7 +1142,7 @@ arm_gic_alloc_msix(device_t dev, device_t child, device_t *pic,
>
>         sc = device_get_softc(dev);
>
> -       mtx_lock(&sc->mutex);
> +       mtx_lock_spin(&sc->mutex);
>         /* Find an unused interrupt */
>         for (irq = sc->sc_spi_start; irq < sc->sc_spi_end; irq++) {
>                 KASSERT((sc->gic_irqs[irq].gi_flags & GI_FLAG_MSI) != 0,
> @@ -1152,13 +1152,13 @@ arm_gic_alloc_msix(device_t dev, device_t child, device_t *pic,
>         }
>         /* No free interrupt was found */
>         if (irq == sc->sc_spi_end) {
> -               mtx_unlock(&sc->mutex);
> +               mtx_unlock_spin(&sc->mutex);
>                 return (ENXIO);
>         }
>
>         /* Mark the interrupt as used */
>         sc->gic_irqs[irq].gi_flags |= GI_FLAG_MSI_USED;
> -       mtx_unlock(&sc->mutex);
> +       mtx_unlock_spin(&sc->mutex);
>
>         *isrcp = (struct intr_irqsrc *)&sc->gic_irqs[irq];
>         *pic = dev;
> @@ -1178,9 +1178,9 @@ arm_gic_release_msix(device_t dev, device_t child, struct intr_irqsrc *isrc)
>         KASSERT((gi->gi_flags & GI_FLAG_MSI_USED) == GI_FLAG_MSI_USED,
>             ("%s: Trying to release an unused MSI-X interrupt", __func__));
>
> -       mtx_lock(&sc->mutex);
> +       mtx_lock_spin(&sc->mutex);
>         gi->gi_flags &= ~GI_FLAG_MSI_USED;
> -       mtx_unlock(&sc->mutex);
> +       mtx_unlock_spin(&sc->mutex);
>
>         return (0);
>  }

Thank you for the patch, it fixes the MSI-X in my setup, but in order
to operate properly on Marvell SoCs (equipped with a standard GICv2m),
I have to remove the asserts, which were added in c6f3076d4405 (Move
the GICv2m msi handling to the parent):

diff --git a/sys/arm/arm/gic.c b/sys/arm/arm/gic.c
index 89db4e324600..b5d72a2a6c49 100644
--- a/sys/arm/arm/gic.c
+++ b/sys/arm/arm/gic.c
@@ -528,8 +528,6 @@ arm_gic_write_ivar(device_t dev, device_t child,
int which, uintptr_t value)
                 * GIC_IVAR_MBI_START must be set once and first. This allows
                 * us to reserve the registers when GIC_IVAR_MBI_COUNT is set.
                 */
-               MPASS(sc->sc_spi_start == 0);
-               MPASS(sc->sc_spi_count == 0);
                MPASS(value >= GIC_FIRST_SPI);
                MPASS(value < sc->nirqs);

@@ -537,7 +535,6 @@ arm_gic_write_ivar(device_t dev, device_t child,
int which, uintptr_t value)
                return (0);
        case GIC_IVAR_MBI_COUNT:
                MPASS(sc->sc_spi_start != 0);
-               MPASS(sc->sc_spi_count == 0);

                sc->sc_spi_count = value;
                sc->sc_spi_end = sc->sc_spi_start + sc->sc_spi_count;

Any thoughts?

Best regards,
Marcin