From 13d63de59bf31119f3d47e638a64b27da86e1a5f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= <clg@kaod.org>
Date: Fri, 17 Dec 2021 17:57:17 +0100
Subject: [PATCH] ppc/ppc405: Rework FW load
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QEMU installs a custom U-Boot in-memory descriptor to share board
information with Linux, which means that the QEMU machine was
initially designed to support booting Linux directly without using the
loaded FW. But, it's not that simple because the CPU still starts at
address 0xfffffffc where nothing is currently mapped. Support must
have been broken these last years.

Since we can not find a "ppc405_rom.bin" firmware file, request one to
be specified on the command line. A consequence of this change is that
the machine can be booted directly from Linux without any FW being
loaded. This is still broken and the CPU start address will be fixed
in the next changes.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20211206103712.1866296-10-clg@kaod.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
---
 hw/ppc/ppc405_boards.c | 45 +++++++++++++++++++-----------------------
 1 file changed, 20 insertions(+), 25 deletions(-)

diff --git a/hw/ppc/ppc405_boards.c b/hw/ppc/ppc405_boards.c
index a385e8f150..cfed43dba2 100644
--- a/hw/ppc/ppc405_boards.c
+++ b/hw/ppc/ppc405_boards.c
@@ -139,24 +139,19 @@ static void ref405ep_fpga_init(MemoryRegion *sysmem, uint32_t base)
 static void ref405ep_init(MachineState *machine)
 {
     MachineClass *mc = MACHINE_GET_CLASS(machine);
-    const char *bios_name = machine->firmware ?: BIOS_FILENAME;
     const char *kernel_filename = machine->kernel_filename;
     const char *kernel_cmdline = machine->kernel_cmdline;
     const char *initrd_filename = machine->initrd_filename;
-    char *filename;
     ppc4xx_bd_info_t bd;
     PowerPCCPU *cpu;
     CPUPPCState *env;
     DeviceState *dev;
     SysBusDevice *s;
-    MemoryRegion *bios;
     MemoryRegion *sram = g_new(MemoryRegion, 1);
     ram_addr_t bdloc;
     MemoryRegion *ram_memories = g_new(MemoryRegion, 2);
     hwaddr ram_bases[2], ram_sizes[2];
-    long bios_size;
-    //int phy_addr = 0;
-    //static int phy_addr = 1;
+    long bios_size = -1;
     target_ulong kernel_base, initrd_base;
     long kernel_size, initrd_size;
     int linux_boot;
@@ -190,31 +185,31 @@ static void ref405ep_init(MachineState *machine)
     memory_region_add_subregion(sysmem, PPC405EP_SRAM_BASE, sram);
 
     /* allocate and load BIOS */
-    {
-        bios = g_new(MemoryRegion, 1);
+    if (machine->firmware) {
+        MemoryRegion *bios = g_new(MemoryRegion, 1);
+        g_autofree char *filename;
+
         memory_region_init_rom(bios, NULL, "ef405ep.bios", BIOS_SIZE,
                                &error_fatal);
 
-        filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_name);
-        if (filename) {
-            bios_size = load_image_size(filename,
-                                        memory_region_get_ram_ptr(bios),
-                                        BIOS_SIZE);
-            g_free(filename);
-            if (bios_size < 0) {
-                error_report("Could not load PowerPC BIOS '%s'", bios_name);
-                exit(1);
-            }
-            bios_size = (bios_size + 0xfff) & ~0xfff;
-            memory_region_add_subregion(sysmem, (uint32_t)(-bios_size), bios);
-        } else if (!qtest_enabled() || kernel_filename != NULL) {
-            error_report("Could not load PowerPC BIOS '%s'", bios_name);
+        filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, machine->firmware);
+        if (!filename) {
+            error_report("Could not find firmware '%s'", machine->firmware);
             exit(1);
-        } else {
-            /* Avoid an uninitialized variable warning */
-            bios_size = -1;
         }
+
+        bios_size = load_image_size(filename,
+                                    memory_region_get_ram_ptr(bios),
+                                    BIOS_SIZE);
+        if (bios_size < 0) {
+            error_report("Could not load PowerPC BIOS '%s'", machine->firmware);
+            exit(1);
+        }
+
+        bios_size = (bios_size + 0xfff) & ~0xfff;
+        memory_region_add_subregion(sysmem, (uint32_t)(-bios_size), bios);
     }
+
     /* Register FPGA */
     ref405ep_fpga_init(sysmem, PPC405EP_FPGA_BASE);
     /* Register NVRAM */