From 04229da7466d0cbc8edd756cbfaf985d1d385456 Mon Sep 17 00:00:00 2001
From: Zack Buhman <zack@buhman.org>
Date: Sat, 11 Oct 2025 20:08:54 -0500
Subject: [PATCH] add pci_user

---
 drm/main.c      | 13 +++++++++++++
 pci_user/main.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+)
 create mode 100644 pci_user/main.c

diff --git a/drm/main.c b/drm/main.c
index 31ed24a..4c455f0 100644
--- a/drm/main.c
+++ b/drm/main.c
@@ -361,6 +361,19 @@ int main()
   assert(write_length == mmap_args.size);
   close(out_fd);
 
+  int mm_fd = open("/sys/kernel/debug/radeon_vram_mm", O_RDONLY);
+  assert(mm_fd >= 0);
+  char buf[4096];
+  while (true) {
+    ssize_t read_length = read(mm_fd, buf, 4096);
+    assert(read_length >= 0);
+    write(STDOUT_FILENO, buf, read_length);
+    if (read_length < 4096) {
+      break;
+    }
+  }
+  close(mm_fd);
+
   munmap(ptr, mmap_args.size);
 
   close(fd);
diff --git a/pci_user/main.c b/pci_user/main.c
new file mode 100644
index 0000000..4e00d25
--- /dev/null
+++ b/pci_user/main.c
@@ -0,0 +1,50 @@
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <assert.h>
+#include <fcntl.h>
+#include <math.h>
+
+static inline uint32_t rreg(void * rmmio, uint32_t offset)
+{
+  uint32_t value = *((volatile uint32_t *)(((uintptr_t)rmmio) + offset));
+  asm volatile ("" ::: "memory");
+}
+
+static inline uint32_t wreg(void * rmmio, uint32_t offset, uint32_t value)
+{
+  *((volatile uint32_t *)(((uintptr_t)rmmio) + offset)) = value;
+  asm volatile ("" ::: "memory");
+}
+
+int main()
+{
+  ////////////////////////////////////////////////////////////////////////
+  // PCI resource0
+  ////////////////////////////////////////////////////////////////////////
+  const char * resource2_path = "/sys/bus/pci/devices/0000:01:00.0/resource2";
+  int resource2_fd = open(resource2_path, O_RDWR | O_SYNC);
+  assert(resource2_fd >= 0);
+
+  uint32_t resource2_size = 0x10000;
+  void * resource2_base = mmap(0, resource2_size, PROT_READ | PROT_WRITE, MAP_SHARED, resource2_fd, 0);
+  assert(resource2_base != MAP_FAILED);
+
+  void * rmmio = resource2_base;
+
+  uint32_t value1 = rreg(rmmio, 0x6110);
+  printf("[r500] D1GRPH_PRIMARY_SURFACE_ADDRESS %08x\n", value1);
+  uint32_t value2 = rreg(rmmio, 0x6110 + 0x800);
+  printf("[r500] D2GRPH_PRIMARY_SURFACE_ADDRESS %08x\n", value2);
+
+  uint32_t value3 = rreg(rmmio, 0x6118);
+  printf("[r500] D1GRPH_SECONDARY_SURFACE_ADDRESS %08x\n", value3);
+  uint32_t value4 = rreg(rmmio, 0x6118 + 0x800);
+  printf("[r500] D2GRPH_SECONDARY_SURFACE_ADDRESS %08x\n", value4);
+
+  wreg(rmmio, 0x6110, 0x813000);
+  wreg(rmmio, 0x6118, 0x813000);
+}