1 files changed, 61 insertions, 0 deletions

diff --git a/nvdebug_linux.c b/nvdebug_linux.c
new file mode 100644
index 0000000..1d76bc9
--- /dev/null
+++ b/nvdebug_linux.c
@@ -0,0 +1,61 @@
+/* Copyright 2024 Joshua Bakita
+ * Implementation of Kernel-specific function implementations
+ */
+#include "nvdebug_linux.h"
+#include <asm/io.h> // For read[l,q] and write[l,q]
+
+// Similar to nvgpu_readl()
+// (except we don't try to resolve situations where regs is NULL)
+u32 nvdebug_readl(struct nvdebug_state *s, u32 r) {
+        u32 ret;
+        if (unlikely(!s->regs || (s->g && !gk20a_regs(s->g)))) {
+                printk(KERN_ERR "[nvdebug] nvdebug_readl: Unable to read; registers unavailable. Is GPU on?\n");
+                return -1;
+        }
+        ret = readl(s->regs + r);
+        // It seems like the GPU returns this as a flag value for bad addresses
+        if (ret == 0xbadf5040) {
+                printk(KERN_ERR "[nvdebug] nvdebug_readl: Unable to read from register offset %#x; bad data\n", r);
+                return -1;
+        }
+        return ret;
+}
+
+// quadword version of nvdebug_readl()
+u64 nvdebug_readq(struct nvdebug_state *s, u32 r) {
+        u64 ret;
+        if (unlikely(!s->regs || (s->g && !gk20a_regs(s->g)))) {
+                printk(KERN_ERR "[nvdebug] nvdebug_readq: Unable to read; registers unavailable. Is GPU on?\n");
+                return -1;
+        }
+        // readq seems to always return the uppermost 32 bits as 0, so workaround with readl
+        ret = readl(s->regs + r);
+        ret |= ((u64)readl(s->regs + r + 4)) << 32;
+        // It seems like the GPU returns this as a flag value for bad addresses
+        if ((ret & 0xffffffffull) == 0xbadf5040ull) {
+                printk(KERN_ERR "[nvdebug] nvdebug_readq: Unable to read from register offset %#x; bad data\n", r);
+                return -1;
+        }
+        return ret;
+}
+
+// Similar to nvgpu_writel()
+void nvdebug_writel(struct nvdebug_state *s, u32 r, u32 v) {
+        if (unlikely(!s->regs || (s->g && !gk20a_regs(s->g)))) {
+                printk(KERN_ERR "[nvdebug] nvdebug_writel: Unable to write; registers unavailable. Is GPU on?\n");
+                return;
+        }
+        writel_relaxed(v, s->regs + r);
+        wmb();
+}
+
+// quadword version of nvdebug_writel()
+// XXX: This probably doesn't work XXX: Untested
+void nvdebug_writeq(struct nvdebug_state *s, u32 r, u64 v) {
+        if (unlikely(!s->regs || (s->g && !gk20a_regs(s->g)))) {
+                printk(KERN_ERR "[nvdebug] nvdebug_writeq: Unable to write; registers unavailable. Is GPU on?\n");
+                return;
+        }
+        writeq_relaxed(v, s->regs + r);
+        wmb();
+}