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Re: [Qemu-arm] [Qemu-devel] [PATCH] BCM2837 and machine raspi3


From: bzt bzt
Subject: Re: [Qemu-arm] [Qemu-devel] [PATCH] BCM2837 and machine raspi3
Date: Thu, 18 Jan 2018 22:39:22 +0100

Dear All,

Since you still haven't merged Alistair's patch, I decided to include it in my own.
I've shrinked the number of modified files to two, that's the bare minimum to support "-M raspi3" switch. Bcm2836.c modified minimally, the rest is in raspi.c. I've renamed raspi2_init() to raspi_init() 'cos now it initializes raspi3 as well, no additional function.

diff --git a/hw/arm/bcm2836.c b/hw/arm/bcm2836.c
index 8c43291112..5119e00051 100644
--- a/hw/arm/bcm2836.c
+++ b/hw/arm/bcm2836.c
@@ -15,6 +15,7 @@
 #include "hw/arm/bcm2836.h"
 #include "hw/arm/raspi_platform.h"
 #include "hw/sysbus.h"
+#include "hw/boards.h"
 #include "exec/address-spaces.h"
 
 /* Peripheral base address seen by the CPU */
@@ -30,7 +31,7 @@ static void bcm2836_init(Object *obj)
 
     for (n = 0; n < BCM2836_NCPUS; n++) {
         object_initialize(&s->cpus[n], sizeof(s->cpus[n]),
-                          "cortex-a15-" TYPE_ARM_CPU);
+                          current_machine->cpu_type);
         object_property_add_child(obj, "cpu[*]", OBJECT(&s->cpus[n]),
                                   &error_abort);
     }
diff --git a/hw/arm/raspi.c b/hw/arm/raspi.c
index cd5fa8c3dc..24a9243440 100644
--- a/hw/arm/raspi.c
+++ b/hw/arm/raspi.c
@@ -5,6 +5,8 @@
  * Rasperry Pi 2 emulation Copyright (c) 2015, Microsoft
  * Written by Andrew Baumann
  *
+ * Raspberry Pi 3 emulation Copyright (c) 2018 by bzt
+ *
  * This code is licensed under the GNU GPLv2 and later.
  */
 
@@ -22,10 +24,11 @@
 #define SMPBOOT_ADDR    0x300 /* this should leave enough space for ATAGS */
 #define MVBAR_ADDR      0x400 /* secure vectors */
 #define BOARDSETUP_ADDR (MVBAR_ADDR + 0x20) /* board setup code */
-#define FIRMWARE_ADDR   0x8000 /* Pi loads kernel.img here by default */
+#define FIRMWARE_ADDR_2    0x8000 /* Pi 2 loads kernel.img here by default */
+#define FIRMWARE_ADDR_3   0x80000 /* Pi 3 loads kernel8.img here by default */
 
 /* Table of Linux board IDs for different Pi versions */
-static const int raspi_boardid[] = {[1] = 0xc42, [2] = 0xc43};
+static const int raspi_boardid[] = {[1] = 0xc42, [2] = 0xc43, [3] = 0xc44};
 
 typedef struct RasPiState {
     BCM2836State soc;
@@ -83,8 +86,8 @@ static void setup_boot(MachineState *machine, int version, size_t ram_size)
     binfo.secure_board_setup = true;
     binfo.secure_boot = true;
 
-    /* Pi2 requires SMP setup */
-    if (version == 2) {
+    /* Pi2 and Pi3 requires SMP setup */
+    if (version >= 2) {
         binfo.smp_loader_start = SMPBOOT_ADDR;
         binfo.write_secondary_boot = write_smpboot;
         binfo.secondary_cpu_reset_hook = reset_secondary;
@@ -94,15 +97,15 @@ static void setup_boot(MachineState *machine, int version, size_t ram_size)
      * the normal Linux boot process
      */
     if (machine->firmware) {
+        binfo.entry = version==3? FIRMWARE_ADDR_3 : FIRMWARE_ADDR_2;
         /* load the firmware image (typically kernel.img) */
-        r = load_image_targphys(machine->firmware, FIRMWARE_ADDR,
-                                ram_size - FIRMWARE_ADDR);
+        r = load_image_targphys(machine->firmware, binfo.entry,
+                                ram_size - binfo.entry);
         if (r < 0) {
             error_report("Failed to load firmware from %s", machine->firmware);
             exit(1);
         }
 
-        binfo.entry = FIRMWARE_ADDR;
         binfo.firmware_loaded = true;
     } else {
         binfo.kernel_filename = machine->kernel_filename;
@@ -113,7 +116,7 @@ static void setup_boot(MachineState *machine, int version, size_t ram_size)
     arm_load_kernel(ARM_CPU(first_cpu), &binfo);
 }
 
-static void raspi2_init(MachineState *machine)
+static void raspi_init(MachineState *machine)
 {
     RasPiState *s = g_new0(RasPiState, 1);
     uint32_t vcram_size;
@@ -121,6 +124,7 @@ static void raspi2_init(MachineState *machine)
     BlockBackend *blk;
     BusState *bus;
     DeviceState *carddev;
+    int version = machine->cpu_type==ARM_CPU_TYPE_NAME("cortex-a15")? 2 : 3;
 
     object_initialize(&s->soc, sizeof(s->soc), TYPE_BCM2836);
     object_property_add_child(OBJECT(machine), "soc", OBJECT(&s->soc),
@@ -137,8 +141,8 @@ static void raspi2_init(MachineState *machine)
                                    &error_abort);
     object_property_set_int(OBJECT(&s->soc), smp_cpus, "enabled-cpus",
                             &error_abort);
-    object_property_set_int(OBJECT(&s->soc), 0xa21041, "board-rev",
-                            &error_abort);
+    object_property_set_int(OBJECT(&s->soc), version==3 ? 0xa02082 : 0xa21041,
+                            "board-rev", &error_abort);
     object_property_set_bool(OBJECT(&s->soc), true, "realized", &error_abort);
 
     /* Create and plug in the SD cards */
@@ -155,21 +159,39 @@ static void raspi2_init(MachineState *machine)
 
     vcram_size = object_property_get_uint(OBJECT(&s->soc), "vcram-size",
                                           &error_abort);
-    setup_boot(machine, 2, machine->ram_size - vcram_size);
+    setup_boot(machine, version, machine->ram_size - vcram_size);
 }
 
 static void raspi2_machine_init(MachineClass *mc)
 {
     mc->desc = "Raspberry Pi 2";
-    mc->init = raspi2_init;
+    mc->init = raspi_init;
     mc->block_default_type = IF_SD;
     mc->no_parallel = 1;
     mc->no_floppy = 1;
     mc->no_cdrom = 1;
     mc->max_cpus = BCM2836_NCPUS;
     mc->min_cpus = BCM2836_NCPUS;
     mc->default_cpus = BCM2836_NCPUS;
+    mc->default_cpu_type = ARM_CPU_TYPE_NAME("cortex-a15");
     mc->default_ram_size = 1024 * 1024 * 1024;
     mc->ignore_memory_transaction_failures = true;
 };
 DEFINE_MACHINE("raspi2", raspi2_machine_init)
+
+static void raspi3_machine_init(MachineClass *mc)
+{
+    mc->desc = "Raspberry Pi 3";
+    mc->init = raspi_init;
+    mc->block_default_type = IF_SD;
+    mc->no_parallel = 1;
+    mc->no_floppy = 1;
+    mc->no_cdrom = 1;
+    mc->max_cpus = BCM2836_NCPUS;
+    mc->min_cpus = BCM2836_NCPUS;
+    mc->default_cpus = BCM2836_NCPUS;
+    mc->default_cpu_type = ARM_CPU_TYPE_NAME("cortex-a53");
+    mc->default_ram_size = 1024 * 1024 * 1024;
+    mc->ignore_memory_transaction_failures = true;
+};
+DEFINE_MACHINE("raspi3", raspi3_machine_init)

Hope it's simple enough to be reviewed easily, and it uses CPU type strings as requested.

Cheers,
bzt


On Wed, Nov 29, 2017 at 8:52 AM, bzt bzt <address@hidden> wrote:


On Tue, Nov 28, 2017 at 6:54 PM, Andrew Baumann <address@hidden> wrote:
> From: bzt bzt [mailto:address@hidden]
> Sent: Tuesday, 28 November 2017 03:27

> Yes, I agree. I've provided a parameterised version on Oct 24, which does not
> have a separate bcm2837 implementation. Is that patch ok?

That patch was moving in the right direction, but I think there were two problems with it. First, the right way to pass a parameter is via a property field (as Peter explained). Second, IMO the parameter should be the CPU model string to instantiate and not the Pi version number.

Thanks!
 

> Or should I wait
> for Alistair's patch (https://lists.gnu.org/archive/html/qemu-devel/2017-
> 10/msg04153.html)?

Alistair's patch doesn't actually help you as far as I can see, since it doesn't change what CPU bcm2836 instantiates. I think it just means that if the user specifies a different CPU type they get an error rather than being silently ignored.

It does add the CPU model string, which can and should be used in bcm2836 to decide which CPU to instatiate (regardless the method of passing that parameter). If I add yet another CPU model string, the two patch will be in conflict containing redundant information. Also I'm sure would raspi3 use different cpus, we should always instantiate the one the user specified. Although here is only one possible CPU model, still that seems to be the correct behavior. Don't get me wrong, I don't criticize, I just want to find the best solution. Setting the CPU model only once for each version seems right. I was thinking: if there's going to be a user specified CPU model string anyway, why not use that one?

bzt
 

Andrew



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