[v2,4/5] openrisc: Initial SMP support

Commit Message

Stafford Horne Oct. 13, 2017, 1:49 p.m. UTC

Wire in ompic and add basic support for SMP.  The OpenRISC is special in
that interrupts for devices are routed to each core's PIC.  This is
achieved using the qemu_irq_split utility, but this currently limits
OpenRISC to 2 cores.

This models the reference architecture described in the OpenRISC spec
1.2 proposal.

  https://github.com/stffrdhrn/doc/raw/arch-1.2-proposal/openrisc-arch-1.2-rev0.pdf

The changes to the intialization of the sim include:

CPU Reset
 o Reset each cpu to the bootstrap PC rather than only a single cpu as
   done before.
 o During Kernel loading the bootstrap PC is saved in a static global.

Network Initialization
 o Connect the interrupt to each CPU
 o Use more simple sysbus_mmio_map() rather than memory_region_add_subregion()

Sim Initialization
 o Initialize the pic and tick timer per cpu
 o Wire in the OMPIC if SMP is enabled
 o Wire the serial irq to each CPU using qemu_irq_split()

Reviewed-by: Richard Henderson <[e-mail]>
Signed-off-by: Stafford Horne <[e-mail]>
---
 hw/openrisc/openrisc_sim.c | 84 +++++++++++++++++++++++++++++++++-------------
 1 file changed, 61 insertions(+), 23 deletions(-)

Patch

diff --git a/hw/openrisc/openrisc_sim.c b/hw/openrisc/openrisc_sim.c
index e1eeffc490..1794c39005 100644
--- a/hw/openrisc/openrisc_sim.c
+++ b/hw/openrisc/openrisc_sim.c
@@ -35,36 +35,60 @@ 
 
 #define KERNEL_LOAD_ADDR 0x100
 
+static struct openrisc_boot_info {
+    uint32_t bootstrap_pc;
+} boot_info;
+
 static void main_cpu_reset(void *opaque)
 {
     OpenRISCCPU *cpu = opaque;
+    CPUState *cs = CPU(cpu);
 
     cpu_reset(CPU(cpu));
+
+    cpu_set_pc(cs, boot_info.bootstrap_pc);
 }
 
-static void openrisc_sim_net_init(MemoryRegion *address_space,
-                                  hwaddr base,
-                                  hwaddr descriptors,
-                                  qemu_irq irq, NICInfo *nd)
+static void openrisc_sim_net_init(hwaddr base, hwaddr descriptors,
+                                  int num_cpus, qemu_irq **cpu_irqs,
+                                  int irq_pin, NICInfo *nd)
 {
     DeviceState *dev;
     SysBusDevice *s;
+    int i;
 
     dev = qdev_create(NULL, "open_eth");
     qdev_set_nic_properties(dev, nd);
     qdev_init_nofail(dev);
 
     s = SYS_BUS_DEVICE(dev);
-    sysbus_connect_irq(s, 0, irq);
-    memory_region_add_subregion(address_space, base,
-                                sysbus_mmio_get_region(s, 0));
-    memory_region_add_subregion(address_space, descriptors,
-                                sysbus_mmio_get_region(s, 1));
+    for (i = 0; i < num_cpus; i++) {
+        sysbus_connect_irq(s, 0, cpu_irqs[i][irq_pin]);
+    }
+    sysbus_mmio_map(s, 0, base);
+    sysbus_mmio_map(s, 1, descriptors);
 }
 
-static void cpu_openrisc_load_kernel(ram_addr_t ram_size,
-                                     const char *kernel_filename,
-                                     OpenRISCCPU *cpu)
+static void openrisc_sim_ompic_init(hwaddr base, int num_cpus,
+                                    qemu_irq **cpu_irqs, int irq_pin)
+{
+    DeviceState *dev;
+    SysBusDevice *s;
+    int i;
+
+    dev = qdev_create(NULL, "or1k-ompic");
+    qdev_prop_set_uint32(dev, "num-cpus", num_cpus);
+    qdev_init_nofail(dev);
+
+    s = SYS_BUS_DEVICE(dev);
+    for (i = 0; i < num_cpus; i++) {
+        sysbus_connect_irq(s, i, cpu_irqs[i][irq_pin]);
+    }
+    sysbus_mmio_map(s, 0, base);
+}
+
+static void openrisc_load_kernel(ram_addr_t ram_size,
+                                 const char *kernel_filename)
 {
     long kernel_size;
     uint64_t elf_entry;
@@ -83,6 +107,9 @@  static void cpu_openrisc_load_kernel(ram_addr_t ram_size,
             kernel_size = load_image_targphys(kernel_filename,
                                               KERNEL_LOAD_ADDR,
                                               ram_size - KERNEL_LOAD_ADDR);
+        }
+
+        if (entry <= 0) {
             entry = KERNEL_LOAD_ADDR;
         }
 
@@ -91,7 +118,7 @@  static void cpu_openrisc_load_kernel(ram_addr_t ram_size,
                     kernel_filename);
             exit(1);
         }
-        cpu->env.pc = entry;
+        boot_info.bootstrap_pc = entry;
     }
 }
 
@@ -102,6 +129,8 @@  static void openrisc_sim_init(MachineState *machine)
     const char *kernel_filename = machine->kernel_filename;
     OpenRISCCPU *cpu = NULL;
     MemoryRegion *ram;
+    qemu_irq *cpu_irqs[2];
+    qemu_irq serial_irq;
     int n;
 
     if (!cpu_model) {
@@ -114,33 +143,42 @@  static void openrisc_sim_init(MachineState *machine)
             fprintf(stderr, "Unable to find CPU definition!\n");
             exit(1);
         }
+        cpu_openrisc_pic_init(cpu);
+        cpu_irqs[n] = (qemu_irq *) cpu->env.irq;
+
+        cpu_openrisc_clock_init(cpu);
+
         qemu_register_reset(main_cpu_reset, cpu);
-        main_cpu_reset(cpu);
     }
 
     ram = g_malloc(sizeof(*ram));
     memory_region_init_ram(ram, NULL, "openrisc.ram", ram_size, &error_fatal);
     memory_region_add_subregion(get_system_memory(), 0, ram);
 
-    cpu_openrisc_pic_init(cpu);
-    cpu_openrisc_clock_init(cpu);
+    if (nd_table[0].used) {
+        openrisc_sim_net_init(0x92000000, 0x92000400, smp_cpus,
+                              cpu_irqs, 4, nd_table);
+    }
 
-    serial_mm_init(get_system_memory(), 0x90000000, 0, cpu->env.irq[2],
-                   115200, serial_hds[0], DEVICE_NATIVE_ENDIAN);
+    if (smp_cpus > 1) {
+        openrisc_sim_ompic_init(0x98000000, smp_cpus, cpu_irqs, 1);
 
-    if (nd_table[0].used) {
-        openrisc_sim_net_init(get_system_memory(), 0x92000000,
-                              0x92000400, cpu->env.irq[4], nd_table);
+        serial_irq = qemu_irq_split(cpu_irqs[0][2], cpu_irqs[1][2]);
+    } else {
+        serial_irq = cpu_irqs[0][2];
     }
 
-    cpu_openrisc_load_kernel(ram_size, kernel_filename, cpu);
+    serial_mm_init(get_system_memory(), 0x90000000, 0, serial_irq,
+                   115200, serial_hds[0], DEVICE_NATIVE_ENDIAN);
+
+    openrisc_load_kernel(ram_size, kernel_filename);
 }
 
 static void openrisc_sim_machine_init(MachineClass *mc)
 {
     mc->desc = "or1k simulation";
     mc->init = openrisc_sim_init;
-    mc->max_cpus = 1;
+    mc->max_cpus = 2;
     mc->is_default = 1;
 }