hw/openrisc/openrisc_sim: Add automatic device tree generation

Using the device tree means that qemu can now directly tell
the kernel what hardware is configured rather than use having
to maintain and update a separate device tree file.

This patch adds automatic device tree generation support for the
OpenRISC simulator.  A device tree is built up based on the state of the
configure openrisc simulator.

This is then dumped to memory and the load address is passed to the
kernel in register r3.

Signed-off-by: Stafford Horne <shorne@gmail.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

3 files changed, 176 insertions, 16 deletions

diff --git a/configs/targets/or1k-softmmu.mak b/configs/targets/or1k-softmmu.mak
index 1dfb93e46d..9e1d4a1fb1 100644
--- a/configs/targets/or1k-softmmu.mak
+++ b/configs/targets/or1k-softmmu.mak
@@ -1,2 +1,3 @@
 TARGET_ARCH=openrisc
 TARGET_WORDS_BIGENDIAN=y
+TARGET_NEED_FDT=y
diff --git a/hw/openrisc/meson.build b/hw/openrisc/meson.build
index 947f63ee08..ec48172c9d 100644
--- a/hw/openrisc/meson.build
+++ b/hw/openrisc/meson.build
@@ -1,5 +1,5 @@
 openrisc_ss = ss.source_set()
 openrisc_ss.add(files('cputimer.c'))
-openrisc_ss.add(when: 'CONFIG_OR1K_SIM', if_true: files('openrisc_sim.c'))
+openrisc_ss.add(when: 'CONFIG_OR1K_SIM', if_true: [files('openrisc_sim.c'), fdt])
 
 hw_arch += {'openrisc': openrisc_ss}
diff --git a/hw/openrisc/openrisc_sim.c b/hw/openrisc/openrisc_sim.c
index 8cfb92bec6..e0e71c0faa 100644
--- a/hw/openrisc/openrisc_sim.c
+++ b/hw/openrisc/openrisc_sim.c
@@ -29,15 +29,20 @@
 #include "net/net.h"
 #include "hw/loader.h"
 #include "hw/qdev-properties.h"
+#include "exec/address-spaces.h"
+#include "sysemu/device_tree.h"
 #include "sysemu/sysemu.h"
 #include "hw/sysbus.h"
 #include "sysemu/qtest.h"
 #include "sysemu/reset.h"
 #include "hw/core/split-irq.h"
 
+#include <libfdt.h>
+
 #define KERNEL_LOAD_ADDR 0x100
 
 #define OR1KSIM_CPUS_MAX 4
+#define OR1KSIM_CLK_MHZ 20000000
 
 #define TYPE_OR1KSIM_MACHINE MACHINE_TYPE_NAME("or1k-sim")
 #define OR1KSIM_MACHINE(obj) \
@@ -48,6 +53,8 @@ typedef struct Or1ksimState {
     MachineState parent_obj;
 
     /*< public >*/
+    void *fdt;
+    int fdt_size;
 
 } Or1ksimState;
 
@@ -76,6 +83,7 @@ static const struct MemmapEntry {
 
 static struct openrisc_boot_info {
     uint32_t bootstrap_pc;
+    uint32_t fdt_addr;
 } boot_info;
 
 static void main_cpu_reset(void *opaque)
@@ -86,6 +94,7 @@ static void main_cpu_reset(void *opaque)
     cpu_reset(CPU(cpu));
 
     cpu_set_pc(cs, boot_info.bootstrap_pc);
+    cpu_set_gpr(&cpu->env, 3, boot_info.fdt_addr);
 }
 
 static qemu_irq get_cpu_irq(OpenRISCCPU *cpus[], int cpunum, int irq_pin)
@@ -93,12 +102,77 @@ static qemu_irq get_cpu_irq(OpenRISCCPU *cpus[], int cpunum, int irq_pin)
     return qdev_get_gpio_in_named(DEVICE(cpus[cpunum]), "IRQ", irq_pin);
 }
 
-static void openrisc_sim_net_init(hwaddr base, hwaddr descriptors,
+static void openrisc_create_fdt(Or1ksimState *state,
+                                const struct MemmapEntry *memmap,
+                                int num_cpus, uint64_t mem_size,
+                                const char *cmdline)
+{
+    void *fdt;
+    int cpu;
+    char *nodename;
+    int pic_ph;
+
+    fdt = state->fdt = create_device_tree(&state->fdt_size);
+    if (!fdt) {
+        error_report("create_device_tree() failed");
+        exit(1);
+    }
+
+    qemu_fdt_setprop_string(fdt, "/", "compatible", "opencores,or1ksim");
+    qemu_fdt_setprop_cell(fdt, "/", "#address-cells", 0x1);
+    qemu_fdt_setprop_cell(fdt, "/", "#size-cells", 0x1);
+
+    nodename = g_strdup_printf("/memory@%" HWADDR_PRIx,
+                               memmap[OR1KSIM_DRAM].base);
+    qemu_fdt_add_subnode(fdt, nodename);
+    qemu_fdt_setprop_cells(fdt, nodename, "reg",
+                           memmap[OR1KSIM_DRAM].base, mem_size);
+    qemu_fdt_setprop_string(fdt, nodename, "device_type", "memory");
+    g_free(nodename);
+
+    qemu_fdt_add_subnode(fdt, "/cpus");
+    qemu_fdt_setprop_cell(fdt, "/cpus", "#size-cells", 0x0);
+    qemu_fdt_setprop_cell(fdt, "/cpus", "#address-cells", 0x1);
+
+    for (cpu = 0; cpu < num_cpus; cpu++) {
+        nodename = g_strdup_printf("/cpus/cpu@%d", cpu);
+        qemu_fdt_add_subnode(fdt, nodename);
+        qemu_fdt_setprop_string(fdt, nodename, "compatible",
+                                "opencores,or1200-rtlsvn481");
+        qemu_fdt_setprop_cell(fdt, nodename, "reg", cpu);
+        qemu_fdt_setprop_cell(fdt, nodename, "clock-frequency",
+                              OR1KSIM_CLK_MHZ);
+        g_free(nodename);
+    }
+
+    nodename = (char *)"/pic";
+    qemu_fdt_add_subnode(fdt, nodename);
+    pic_ph = qemu_fdt_alloc_phandle(fdt);
+    qemu_fdt_setprop_string(fdt, nodename, "compatible",
+                            "opencores,or1k-pic-level");
+    qemu_fdt_setprop_cell(fdt, nodename, "#interrupt-cells", 1);
+    qemu_fdt_setprop(fdt, nodename, "interrupt-controller", NULL, 0);
+    qemu_fdt_setprop_cell(fdt, nodename, "phandle", pic_ph);
+
+    qemu_fdt_setprop_cell(fdt, "/", "interrupt-parent", pic_ph);
+
+    qemu_fdt_add_subnode(fdt, "/chosen");
+    if (cmdline) {
+        qemu_fdt_setprop_string(fdt, "/chosen", "bootargs", cmdline);
+    }
+
+    /* Create aliases node for use by devices. */
+    qemu_fdt_add_subnode(fdt, "/aliases");
+}
+
+static void openrisc_sim_net_init(Or1ksimState *state, hwaddr base, hwaddr size,
                                   int num_cpus, OpenRISCCPU *cpus[],
                                   int irq_pin, NICInfo *nd)
 {
+    void *fdt = state->fdt;
     DeviceState *dev;
     SysBusDevice *s;
+    char *nodename;
     int i;
 
     dev = qdev_new("open_eth");
@@ -118,14 +192,28 @@ static void openrisc_sim_net_init(hwaddr base, hwaddr descriptors,
         sysbus_connect_irq(s, 0, get_cpu_irq(cpus, 0, irq_pin));
     }
     sysbus_mmio_map(s, 0, base);
-    sysbus_mmio_map(s, 1, descriptors);
+    sysbus_mmio_map(s, 1, base + 0x400);
+
+    /* Init device tree node for ethoc. */
+    nodename = g_strdup_printf("/ethoc@%" HWADDR_PRIx, base);
+    qemu_fdt_add_subnode(fdt, nodename);
+    qemu_fdt_setprop_string(fdt, nodename, "compatible", "opencores,ethoc");
+    qemu_fdt_setprop_cells(fdt, nodename, "reg", base, size);
+    qemu_fdt_setprop_cell(fdt, nodename, "interrupts", irq_pin);
+    qemu_fdt_setprop(fdt, nodename, "big-endian", NULL, 0);
+
+    qemu_fdt_setprop_string(fdt, "/aliases", "enet0", nodename);
+    g_free(nodename);
 }
 
-static void openrisc_sim_ompic_init(hwaddr base, int num_cpus,
+static void openrisc_sim_ompic_init(Or1ksimState *state, hwaddr base,
+                                    hwaddr size, int num_cpus,
                                     OpenRISCCPU *cpus[], int irq_pin)
 {
+    void *fdt = state->fdt;
     DeviceState *dev;
     SysBusDevice *s;
+    char *nodename;
     int i;
 
     dev = qdev_new("or1k-ompic");
@@ -137,11 +225,24 @@ static void openrisc_sim_ompic_init(hwaddr base, int num_cpus,
         sysbus_connect_irq(s, i, get_cpu_irq(cpus, i, irq_pin));
     }
     sysbus_mmio_map(s, 0, base);
+
+    /* Add device tree node for ompic. */
+    nodename = g_strdup_printf("/ompic@%" HWADDR_PRIx, base);
+    qemu_fdt_add_subnode(fdt, nodename);
+    qemu_fdt_setprop_string(fdt, nodename, "compatible", "openrisc,ompic");
+    qemu_fdt_setprop_cells(fdt, nodename, "reg", base, size);
+    qemu_fdt_setprop(fdt, nodename, "interrupt-controller", NULL, 0);
+    qemu_fdt_setprop_cell(fdt, nodename, "#interrupt-cells", 0);
+    qemu_fdt_setprop_cell(fdt, nodename, "interrupts", irq_pin);
+    g_free(nodename);
 }
 
-static void openrisc_sim_serial_init(hwaddr base, int num_cpus,
+static void openrisc_sim_serial_init(Or1ksimState *state, hwaddr base,
+                                     hwaddr size, int num_cpus,
                                      OpenRISCCPU *cpus[], int irq_pin)
 {
+    void *fdt = state->fdt;
+    char *nodename;
     qemu_irq serial_irq;
     int i;
 
@@ -158,29 +259,45 @@ static void openrisc_sim_serial_init(hwaddr base, int num_cpus,
     }
     serial_mm_init(get_system_memory(), base, 0, serial_irq, 115200,
                    serial_hd(0), DEVICE_NATIVE_ENDIAN);
-}
 
+    /* Add device tree node for serial. */
+    nodename = g_strdup_printf("/serial@%" HWADDR_PRIx, base);
+    qemu_fdt_add_subnode(fdt, nodename);
+    qemu_fdt_setprop_string(fdt, nodename, "compatible", "ns16550a");
+    qemu_fdt_setprop_cells(fdt, nodename, "reg", base, size);
+    qemu_fdt_setprop_cell(fdt, nodename, "interrupts", irq_pin);
+    qemu_fdt_setprop_cell(fdt, nodename, "clock-frequency", OR1KSIM_CLK_MHZ);
+    qemu_fdt_setprop(fdt, nodename, "big-endian", NULL, 0);
+
+    /* The /chosen node is created during fdt creation. */
+    qemu_fdt_setprop_string(fdt, "/chosen", "stdout-path", nodename);
+    qemu_fdt_setprop_string(fdt, "/aliases", "uart0", nodename);
+    g_free(nodename);
+}
 
-static void openrisc_load_kernel(ram_addr_t ram_size,
-                                 const char *kernel_filename)
+static hwaddr openrisc_load_kernel(ram_addr_t ram_size,
+                                   const char *kernel_filename)
 {
     long kernel_size;
     uint64_t elf_entry;
+    uint64_t high_addr;
     hwaddr entry;
 
     if (kernel_filename && !qtest_enabled()) {
         kernel_size = load_elf(kernel_filename, NULL, NULL, NULL,
-                               &elf_entry, NULL, NULL, NULL, 1, EM_OPENRISC,
-                               1, 0);
+                               &elf_entry, NULL, &high_addr, NULL, 1,
+                               EM_OPENRISC, 1, 0);
         entry = elf_entry;
         if (kernel_size < 0) {
             kernel_size = load_uimage(kernel_filename,
                                       &entry, NULL, NULL, NULL, NULL);
+            high_addr = entry + kernel_size;
         }
         if (kernel_size < 0) {
             kernel_size = load_image_targphys(kernel_filename,
                                               KERNEL_LOAD_ADDR,
                                               ram_size - KERNEL_LOAD_ADDR);
+            high_addr = KERNEL_LOAD_ADDR + kernel_size;
         }
 
         if (entry <= 0) {
@@ -192,7 +309,38 @@ static void openrisc_load_kernel(ram_addr_t ram_size,
             exit(1);
         }
         boot_info.bootstrap_pc = entry;
+
+        return high_addr;
     }
+    return 0;
+}
+
+static uint32_t openrisc_load_fdt(Or1ksimState *state, hwaddr load_start,
+                                  uint64_t mem_size)
+{
+    void *fdt = state->fdt;
+    uint32_t fdt_addr;
+    int ret;
+    int fdtsize = fdt_totalsize(fdt);
+
+    if (fdtsize <= 0) {
+        error_report("invalid device-tree");
+        exit(1);
+    }
+
+    /* We put fdt right after the kernel and/or initrd. */
+    fdt_addr = ROUND_UP(load_start, 4);
+
+    ret = fdt_pack(fdt);
+    /* Should only fail if we've built a corrupted tree */
+    g_assert(ret == 0);
+    /* copy in the device tree */
+    qemu_fdt_dumpdtb(fdt, fdtsize);
+
+    rom_add_blob_fixed_as("fdt", fdt, fdtsize, fdt_addr,
+                          &address_space_memory);
+
+    return fdt_addr;
 }
 
 static void openrisc_sim_init(MachineState *machine)
@@ -200,7 +348,9 @@ static void openrisc_sim_init(MachineState *machine)
     ram_addr_t ram_size = machine->ram_size;
     const char *kernel_filename = machine->kernel_filename;
     OpenRISCCPU *cpus[OR1KSIM_CPUS_MAX] = {};
+    Or1ksimState *state = OR1KSIM_MACHINE(machine);
     MemoryRegion *ram;
+    hwaddr load_addr;
     int n;
     unsigned int smp_cpus = machine->smp.cpus;
 
@@ -221,22 +371,31 @@ static void openrisc_sim_init(MachineState *machine)
     memory_region_init_ram(ram, NULL, "openrisc.ram", ram_size, &error_fatal);
     memory_region_add_subregion(get_system_memory(), 0, ram);
 
+    openrisc_create_fdt(state, or1ksim_memmap, smp_cpus, machine->ram_size,
+                        machine->kernel_cmdline);
+
     if (nd_table[0].used) {
-        openrisc_sim_net_init(or1ksim_memmap[OR1KSIM_ETHOC].base,
-                              or1ksim_memmap[OR1KSIM_ETHOC].base + 0x400,
+        openrisc_sim_net_init(state, or1ksim_memmap[OR1KSIM_ETHOC].base,
+                              or1ksim_memmap[OR1KSIM_ETHOC].size,
                               smp_cpus, cpus,
                               OR1KSIM_ETHOC_IRQ, nd_table);
     }
 
     if (smp_cpus > 1) {
-        openrisc_sim_ompic_init(or1ksim_memmap[OR1KSIM_OMPIC].base, smp_cpus,
-                                cpus, OR1KSIM_OMPIC_IRQ);
+        openrisc_sim_ompic_init(state, or1ksim_memmap[OR1KSIM_OMPIC].base,
+                                or1ksim_memmap[OR1KSIM_UART].size,
+                                smp_cpus, cpus, OR1KSIM_OMPIC_IRQ);
     }
 
-    openrisc_sim_serial_init(or1ksim_memmap[OR1KSIM_UART].base, smp_cpus, cpus,
+    openrisc_sim_serial_init(state, or1ksim_memmap[OR1KSIM_UART].base,
+                             or1ksim_memmap[OR1KSIM_UART].size, smp_cpus, cpus,
                              OR1KSIM_UART_IRQ);
 
-    openrisc_load_kernel(ram_size, kernel_filename);
+    load_addr = openrisc_load_kernel(ram_size, kernel_filename);
+    if (load_addr > 0) {
+        boot_info.fdt_addr = openrisc_load_fdt(state, load_addr,
+                                               machine->ram_size);
+    }
 }
 
 static void openrisc_sim_machine_init(ObjectClass *oc, void *data)