Hacky support for Linux 5.6+ and the Jetson AGX Orin

Works around change in parameters to proc initialization functions
via a hacky function which rewrites the layout. This also required
making all the struct file_operations writable.

Also start reducing dependency on nvgpu headers.

Known issues:
- Incorrect message printed in log after module is loaded. Unclear
  if this is because the register detection logic is broken, or if
  the layout of the data at NV_MC_BOOT_0 has changed.
- Not tested

1 files changed, 13 insertions, 1 deletions

diff --git a/nvdebug.h b/nvdebug.h
index 1882756..968a60b 100644
--- a/nvdebug.h
+++ b/nvdebug.h
@@ -4,8 +4,10 @@
 
 // TODO(jbakita): Don't depend on these.
 #include <nvgpu/gk20a.h>  // For struct gk20a
-#include <os/linux/os_linux.h>  // For struct nvgpu_os_linux
 #include <linux/proc_fs.h>  // For PDE_DATA() macro
+#include <linux/device.h>   // For dev_get_drvdata()
+#include <linux/version.h>  // For KERNEL_VERSION and LINUX_VERSION_CODE
+#include <asm/io.h>
 
 /* Runlist Channel
   A timeslice group (TSG) is composed of channels. Each channel is a FIFO queue
@@ -943,7 +945,17 @@ static inline int file2parentgpuidx(const struct file *f) {
         return (uintptr_t)PDE_DATA(file_dentry(f)->d_parent->d_inode);
 }
 
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(5,6,0)
+// Commit 643eb158a3 in nvgpu moved the mapped registers to the second entry
+// of the gk20a struct (after a function pointer). This change was made as L4T
+// was upgraded from Linux 4.9 to 5.10 (r32 -> r34+)
+// Note that this is wrong if nvgpu was built without CONFIG_NVGPU_NON_FUSA
+// i.e. if FUSA was enabled, this is wrong.
+#define gk20a_regs(gk20a) ((void*)gk20a + sizeof(void(*)(void)))
+#else
+#include <os/linux/os_linux.h>  // For struct nvgpu_os_linux, which holds regs
 #define gk20a_regs(gk20a) (container_of(gk20a, struct nvgpu_os_linux, g)->regs)
+#endif
 
 // Similar to nvgpu_readl()
 // (except we don't try to resolve situations where regs is NULL)