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 <ajo...@ventanamicro.com>
---
Reviewed-by: Daniel Henrique Barboza <dbarb...@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,
