Currently any device tree passed with -dtb option in QEMU, was ignored
by the PowerNV code.
Read and pass the passed -dtb to the kernel, thus enabling easier
debugging with custom DTBs.
The existing behaviour when -dtb is 'not' passed, is preserved as-is.
But when a '-dtb' is passed, it completely overrides any dtb nodes or
changes QEMU might have done, such as '-append' arguments to the kernel
(which are mentioned in /chosen/bootargs in the dtb), hence add warning
when -dtb is being used
Signed-off-by: Aditya Gupta <adit...@linux.ibm.com>
---
This is an RFC patch, and hence might not be the final implementation,
though this current one is a solution which works
---
---
hw/ppc/pnv.c | 29 ++++++++++++++++++++++++++---
1 file changed, 26 insertions(+), 3 deletions(-)
diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
index 3526852685b4..12cc909b9e26 100644
--- a/hw/ppc/pnv.c
+++ b/hw/ppc/pnv.c
@@ -714,6 +714,8 @@ static void pnv_reset(MachineState *machine, ShutdownCause
reason)
PnvMachineState *pnv = PNV_MACHINE(machine);
IPMIBmc *bmc;
void *fdt;
+ FILE *fdt_file;
+ uint32_t fdt_size;
qemu_devices_reset(reason);
@@ -736,10 +738,31 @@ static void pnv_reset(MachineState *machine,
ShutdownCause reason)
}
}
- fdt = pnv_dt_create(machine);
+ if (machine->dtb) {
+ warn_report("with manually passed dtb, some options like '-append'"
+ " might ignored and the dtb passed will be used as-is");
- /* Pack resulting tree */
- _FDT((fdt_pack(fdt)));
+ fdt = g_malloc0(FDT_MAX_SIZE);
+
+ /* read the file 'machine->dtb', and load it into 'fdt' buffer */
+ fdt_file = fopen(machine->dtb, "r");
+ if (fdt_file != NULL) {
+ fdt_size = fread(fdt, sizeof(char), FDT_MAX_SIZE, fdt_file);
+ if (ferror(fdt_file) != 0) {
+ error_report("Could not load dtb '%s'",
+ machine->dtb);
+ exit(1);
+ }
+
+ /* mark end of the fdt buffer with '\0' */
+ ((char *)fdt)[fdt_size] = '\0';
+ }
+ } else {
+ fdt = pnv_dt_create(machine);
+
+ /* Pack resulting tree */
+ _FDT((fdt_pack(fdt)));
+ }
qemu_fdt_dumpdtb(fdt, fdt_totalsize(fdt));
cpu_physical_memory_write(PNV_FDT_ADDR, fdt, fdt_totalsize(fdt));
--
2.45.2
