| Message ID | 20240925163908.215456-2-ajones@ventanamicro.com |
|---|---|
| State | New |
| Headers | show |
| Series | hw/riscv/virt: Comment absence of #msi-cells | expand |
On 9/25/24 1:39 PM, Andrew Jones wrote: > commit 6df664f87c73 ("Revert "hw/riscv/virt.c: imsics DT: add > '#msi-cells'"") removed #msi-cells. Now that we have a Linux > commit to reference add a comment explaining why it was removed > to avoid it getting added back due to DT validation failures. > > Signed-off-by: Andrew Jones <ajones@ventanamicro.com> > --- Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com> > hw/riscv/virt.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c > index cef41c150aaf..4fd9c0edf038 100644 > --- a/hw/riscv/virt.c > +++ b/hw/riscv/virt.c > @@ -552,6 +552,16 @@ static void create_fdt_one_imsic(RISCVVirtState *s, hwaddr base_addr, > FDT_IMSIC_INT_CELLS); > qemu_fdt_setprop(ms->fdt, imsic_name, "interrupt-controller", NULL, 0); > qemu_fdt_setprop(ms->fdt, imsic_name, "msi-controller", NULL, 0); > + /* > + * Per the DT binding, we should also add #msi-cells with a value of zero. > + * But, Linux which does not include commit db8e81132cf0 ("of/irq: Support > + * #msi-cells=<0> in of_msi_get_domain") does not properly handle #msi-cells > + * with a value of zero. For this reason, the property has intentionally > + * been left out. It's harmless to not add it since the absence of the > + * property and a value of zero for the property mean the same thing. > + * However, since the DT binding requires the property, DT validation may > + * fail. > + */ > qemu_fdt_setprop(ms->fdt, imsic_name, "interrupts-extended", > imsic_cells, ms->smp.cpus * sizeof(uint32_t) * 2); > qemu_fdt_setprop(ms->fdt, imsic_name, "reg", imsic_regs,
diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c index cef41c150aaf..4fd9c0edf038 100644 --- a/hw/riscv/virt.c +++ b/hw/riscv/virt.c @@ -552,6 +552,16 @@ static void create_fdt_one_imsic(RISCVVirtState *s, hwaddr base_addr, FDT_IMSIC_INT_CELLS); qemu_fdt_setprop(ms->fdt, imsic_name, "interrupt-controller", NULL, 0); qemu_fdt_setprop(ms->fdt, imsic_name, "msi-controller", NULL, 0); + /* + * Per the DT binding, we should also add #msi-cells with a value of zero. + * But, Linux which does not include commit db8e81132cf0 ("of/irq: Support + * #msi-cells=<0> in of_msi_get_domain") does not properly handle #msi-cells + * with a value of zero. For this reason, the property has intentionally + * been left out. It's harmless to not add it since the absence of the + * property and a value of zero for the property mean the same thing. + * However, since the DT binding requires the property, DT validation may + * fail. + */ qemu_fdt_setprop(ms->fdt, imsic_name, "interrupts-extended", imsic_cells, ms->smp.cpus * sizeof(uint32_t) * 2); qemu_fdt_setprop(ms->fdt, imsic_name, "reg", imsic_regs,
commit 6df664f87c73 ("Revert "hw/riscv/virt.c: imsics DT: add '#msi-cells'"") removed #msi-cells. Now that we have a Linux commit to reference add a comment explaining why it was removed to avoid it getting added back due to DT validation failures. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> --- hw/riscv/virt.c | 10 ++++++++++ 1 file changed, 10 insertions(+)