On Tue, Mar 30, 2021 at 11:33:13AM +0100, Marc Zyngier wrote: > [+Lorenzo, +Julien on an actual email address] > > On Tue, 30 Mar 2021 11:06:19 +0100, > Lecopzer Chen <lecopzer.c...@mediatek.com> wrote: > > > > When pseudo-NMI enabled, register_nmi() set priority of specific IRQ > > by byte ops, and this doesn't work in GIC-600. > > > > We have asked ARM Support [1]: > > > Please refer to following description in > > > "2.1.2 Distributor ACE-Lite slave interface" of GIC-600 TRM for > > > the GIC600 ACE-lite slave interface supported sizes: > > > "The GIC-600 only accepts single beat accesses of the sizes for > > > each register that are shown in the Programmers model, > > > see Chapter 4 Programmer's model on page 4-102. > > > All other accesses are rejected and given either an > > > OKAY or SLVERR response that is based on the GICT_ERR0CTLR.UE bit.". > > > > Thus the register needs to be written by double word operation and > > the step will be: read 32bit, set byte and write it back. > > > > [1] https://services.arm.com/support/s/case/5003t00001L4Pba > > You do realise that this link: > > - is unusable for most people as it is behind a registration interface > - discloses confidential information to other people > > I strongly suggest you stop posting such links. > > > > > Signed-off-by: Lecopzer Chen <lecopzer.c...@mediatek.com> > > --- > > drivers/irqchip/irq-gic-v3.c | 13 ++++++++++++- > > 1 file changed, 12 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c > > index eb0ee356a629..cfc5a6ad30dc 100644 > > --- a/drivers/irqchip/irq-gic-v3.c > > +++ b/drivers/irqchip/irq-gic-v3.c > > @@ -440,10 +440,21 @@ static void gic_irq_set_prio(struct irq_data *d, u8 > > prio) > > { > > void __iomem *base = gic_dist_base(d); > > u32 offset, index; > > + u32 val, prio_offset_mask, prio_offset_shift; > > > > offset = convert_offset_index(d, GICD_IPRIORITYR, &index); > > > > - writeb_relaxed(prio, base + offset + index); > > + /* > > + * GIC-600 memory mapping register doesn't support byte opteration, > > + * thus read 32-bits from register, set bytes and wtire back to it. > > + */ > > + prio_offset_shift = (index & 0x3) * 8; > > + prio_offset_mask = GENMASK(prio_offset_shift + 7, prio_offset_shift); > > + index &= ~0x3; > > + val = readl_relaxed(base + offset + index); > > + val &= ~prio_offset_mask; > > + val |= prio << prio_offset_shift; > > + writel_relaxed(val, base + offset + index); > > } > > > > static u32 gic_get_ppi_index(struct irq_data *d) > > From the architecture spec: > > <quote> > 11.1.3 GIC memory-mapped register access > > In any system, access to the following registers must be supported: > > [...] > * Byte accesses to: > - GICD_IPRIORITYR<n>. > - GICD_ITARGETSR<n>. > - GICD_SPENDSGIR<n>. > - GICD_CPENDSGIR<n>. > - GICR_IPRIORITYR<n>. > </quote> > > So if GIC600 doesn't follow this architectural requirement, this is a > HW erratum, and I want an actual description of the HW issue together > with an erratum number. > > Lorenzo, can you please investigate on your side?
Sure - I will look into it and report back. Thanks, Lorenzo
