Extract out device-tree generation and compilation into an exported api. (#197)

1 files changed, 156 insertions, 0 deletions

diff --git a/riscv/dts.cc b/riscv/dts.cc
new file mode 100644
index 0000000..b8a5f9d
--- /dev/null
+++ b/riscv/dts.cc
@@ -0,0 +1,156 @@
+// See LICENSE for license details.
+
+#include "dts.h"
+#include <iostream>
+#include <sstream>
+#include <signal.h>
+#include <unistd.h>
+#include <sys/wait.h>
+#include <sys/types.h>
+
+std::string make_dts(size_t insns_per_rtc_tick, size_t cpu_hz,
+                     std::vector<processor_t*> procs,
+                     std::vector<std::pair<reg_t, mem_t*>> mems)
+{
+  std::stringstream s;
+  s << std::dec <<
+         "/dts-v1/;\n"
+         "\n"
+         "/ {\n"
+         "  #address-cells = <2>;\n"
+         "  #size-cells = <2>;\n"
+         "  compatible = \"ucbbar,spike-bare-dev\";\n"
+         "  model = \"ucbbar,spike-bare\";\n"
+         "  cpus {\n"
+         "    #address-cells = <1>;\n"
+         "    #size-cells = <0>;\n"
+         "    timebase-frequency = <" << (cpu_hz/insns_per_rtc_tick) << ">;\n";
+  for (size_t i = 0; i < procs.size(); i++) {
+    s << "    CPU" << i << ": cpu@" << i << " {\n"
+         "      device_type = \"cpu\";\n"
+         "      reg = <" << i << ">;\n"
+         "      status = \"okay\";\n"
+         "      compatible = \"riscv\";\n"
+         "      riscv,isa = \"" << procs[i]->get_isa_string() << "\";\n"
+         "      mmu-type = \"riscv," << (procs[i]->get_max_xlen() <= 32 ? "sv32" : "sv48") << "\";\n"
+         "      clock-frequency = <" << cpu_hz << ">;\n"
+         "      CPU" << i << "_intc: interrupt-controller {\n"
+         "        #interrupt-cells = <1>;\n"
+         "        interrupt-controller;\n"
+         "        compatible = \"riscv,cpu-intc\";\n"
+         "      };\n"
+         "    };\n";
+  }
+  s <<   "  };\n";
+  for (auto& m : mems) {
+    s << std::hex <<
+         "  memory@" << m.first << " {\n"
+         "    device_type = \"memory\";\n"
+         "    reg = <0x" << (m.first >> 32) << " 0x" << (m.first & (uint32_t)-1) <<
+                   " 0x" << (m.second->size() >> 32) << " 0x" << (m.second->size() & (uint32_t)-1) << ">;\n"
+         "  };\n";
+  }
+  s <<   "  soc {\n"
+         "    #address-cells = <2>;\n"
+         "    #size-cells = <2>;\n"
+         "    compatible = \"ucbbar,spike-bare-soc\", \"simple-bus\";\n"
+         "    ranges;\n"
+         "    clint@" << CLINT_BASE << " {\n"
+         "      compatible = \"riscv,clint0\";\n"
+         "      interrupts-extended = <" << std::dec;
+  for (size_t i = 0; i < procs.size(); i++)
+    s << "&CPU" << i << "_intc 3 &CPU" << i << "_intc 7 ";
+  reg_t clintbs = CLINT_BASE;
+  reg_t clintsz = CLINT_SIZE;
+  s << std::hex << ">;\n"
+         "      reg = <0x" << (clintbs >> 32) << " 0x" << (clintbs & (uint32_t)-1) <<
+                     " 0x" << (clintsz >> 32) << " 0x" << (clintsz & (uint32_t)-1) << ">;\n"
+         "    };\n"
+         "  };\n"
+         "  htif {\n"
+         "    compatible = \"ucb,htif0\";\n"
+         "  };\n"
+         "};\n";
+  return s.str();
+}
+
+std::string dts_compile(const std::string& dts)
+{
+  // Convert the DTS to DTB
+  int dts_pipe[2];
+  pid_t dts_pid;
+
+  if (pipe(dts_pipe) != 0 || (dts_pid = fork()) < 0) {
+    std::cerr << "Failed to fork dts child: " << strerror(errno) << std::endl;
+    exit(1);
+  }
+
+  // Child process to output dts
+  if (dts_pid == 0) {
+    close(dts_pipe[0]);
+    int step, len = dts.length();
+    const char *buf = dts.c_str();
+    for (int done = 0; done < len; done += step) {
+      step = write(dts_pipe[1], buf+done, len-done);
+      if (step == -1) {
+        std::cerr << "Failed to write dts: " << strerror(errno) << std::endl;
+        exit(1);
+      }
+    }
+    close(dts_pipe[1]);
+    exit(0);
+  }
+
+  pid_t dtb_pid;
+  int dtb_pipe[2];
+  if (pipe(dtb_pipe) != 0 || (dtb_pid = fork()) < 0) {
+    std::cerr << "Failed to fork dtb child: " << strerror(errno) << std::endl;
+    exit(1);
+  }
+
+  // Child process to output dtb
+  if (dtb_pid == 0) {
+    dup2(dts_pipe[0], 0);
+    dup2(dtb_pipe[1], 1);
+    close(dts_pipe[0]);
+    close(dts_pipe[1]);
+    close(dtb_pipe[0]);
+    close(dtb_pipe[1]);
+    execl(DTC, DTC, "-O", "dtb", 0);
+    std::cerr << "Failed to run " DTC ": " << strerror(errno) << std::endl;
+    exit(1);
+  }
+
+  close(dts_pipe[1]);
+  close(dts_pipe[0]);
+  close(dtb_pipe[1]);
+
+  // Read-out dtb
+  std::stringstream dtb;
+
+  int got;
+  char buf[4096];
+  while ((got = read(dtb_pipe[0], buf, sizeof(buf))) > 0) {
+    dtb.write(buf, got);
+  }
+  if (got == -1) {
+    std::cerr << "Failed to read dtb: " << strerror(errno) << std::endl;
+    exit(1);
+  }
+  close(dtb_pipe[0]);
+
+  // Reap children
+  int status;
+  waitpid(dts_pid, &status, 0);
+  if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
+    std::cerr << "Child dts process failed" << std::endl;
+    exit(1);
+  }
+  waitpid(dtb_pid, &status, 0);
+  if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
+    std::cerr << "Child dtb process failed" << std::endl;
+    exit(1);
+  }
+
+  return dtb.str();
+}