1 files changed, 50 insertions, 0 deletions
diff --git a/tools/rmq/wpr2_reset.c b/tools/rmq/wpr2_reset.c
new file mode 100644
index 0000000..4435843
--- /dev/null
+++ b/tools/rmq/wpr2_reset.c
@@ -0,0 +1,50 @@
+/* wpr2_reset - clear GPU WPR2 registers via BAR0 MMIO to unstick GSP boot.
+ *
+ * When nvidia.ko is unloaded, GSP firmware can remain resident in WPR2
+ * (write-protected region 2 in FB). The next RmInitAdapter then fails with
+ * "unexpected WPR2 already up". FLR does not clear WPR2; only a cold (power)
+ * reset does. This tool pokes WPR2_ADDR_LO/HI to zero directly through
+ * /sys/bus/pci/devices/<dev>/resource0 while no driver is bound.
+ *
+ * Usage: sudo ./wpr2_reset [pci.bdf]   (default 0000:01:00.0)
+ */
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/mman.h>
+
+#define NV_PFB_PRI_MMU_WPR2_ADDR_LO 0x1fa824
+#define NV_PFB_PRI_MMU_WPR2_ADDR_HI 0x1fa828
+
+int main(int argc, char **argv)
+{
+    const char *bdf = argc > 1 ? argv[1] : "0000:01:00.0";
+    char path[256];
+    snprintf(path, sizeof(path), "/sys/bus/pci/devices/%s/resource0", bdf);
+
+    int fd = open(path, O_RDWR | O_SYNC);
+    if (fd < 0) { perror(path); return 1; }
+    void *bar = mmap(NULL, 0x200000, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+    if (bar == MAP_FAILED) { perror("mmap"); return 1; }
+
+    volatile uint32_t *lo = (volatile uint32_t *)((char *)bar + NV_PFB_PRI_MMU_WPR2_ADDR_LO);
+    volatile uint32_t *hi = (volatile uint32_t *)((char *)bar + NV_PFB_PRI_MMU_WPR2_ADDR_HI);
+
+    printf("before: WPR2_ADDR_LO=0x%08x WPR2_ADDR_HI=0x%08x\n", *lo, *hi);
+    *lo = 0;
+    *hi = 0;
+    /* read back */
+    printf("after : WPR2_ADDR_LO=0x%08x WPR2_ADDR_HI=0x%08x\n", *lo, *hi);
+
+    if (*hi == 0)
+        printf("WPR2 cleared - driver load should now boot GSP cleanly\n");
+    else
+        printf("write dropped (PLM?) - WPR2 still up\n");
+
+    munmap(bar, 0x200000);
+    close(fd);
+    return *hi ? 1 : 0;
+}