1 files changed, 149 insertions, 0 deletions
diff --git a/drivers/parrot/video/avi_logger.c b/drivers/parrot/video/avi_logger.c
new file mode 100644
index 00000000000000..3c1e58b74a31b2
--- /dev/null
+++ b/drivers/parrot/video/avi_logger.c
@@ -0,0 +1,149 @@
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/spinlock.h>
+#include <linux/vmalloc.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/seq_file.h>
+#include <linux/module.h>
+
+#include "avi_logger.h"
+
+/* Must be a power of two */
+#define AVI_LOGGER_BUF_SZ  0x4000
+
+struct avi_register_access {
+	/* I store the direction in reg's lsb */
+	u32	reg;
+	u32	val;
+};
+
+struct avi_logger {
+	unsigned long			 head;
+	unsigned long			 nwrap;
+	spinlock_t			 lock;
+	struct avi_register_access	*log;
+};
+
+static struct avi_logger avi_logger = {
+	.head  = 0,
+	.nwrap = 0,
+	.lock  = __SPIN_LOCK_UNLOCKED(avi_logger.lock),
+	.log   = NULL,
+};
+
+int avi_log_init(void)
+{
+	avi_logger.log =
+		vmalloc(AVI_LOGGER_BUF_SZ * sizeof(*avi_logger.log));
+
+	if (avi_logger.log == NULL)
+		return -ENOMEM;
+
+	memset(avi_logger.log,
+	       0,
+	       AVI_LOGGER_BUF_SZ * sizeof(*avi_logger.log));
+
+	return 0;
+}
+EXPORT_SYMBOL(avi_log_init);
+
+void avi_log_access(u32 reg, u32 val, enum avi_log_type type)
+{
+	unsigned long			flags;
+	struct avi_register_access	*a;
+
+	/* The register must be 32bit aligned */
+	BUG_ON(reg & 3);
+	BUG_ON(type > 3);
+
+	/* Cram the type into the register value to save space */
+	reg |= type;
+
+	spin_lock_irqsave(&avi_logger.lock, flags);
+
+	if (avi_logger.log == NULL)
+		/* No log available */
+		goto unlock;
+
+	avi_logger.head = (avi_logger.head + 1) % AVI_LOGGER_BUF_SZ;
+
+	if (avi_logger.head == 0)
+		/* We wrapped around */
+		avi_logger.nwrap++;
+
+	a = &avi_logger.log[avi_logger.head];
+	a->reg = reg;
+	a->val = val;
+
+ unlock:
+	spin_unlock_irqrestore(&avi_logger.lock, flags);
+}
+EXPORT_SYMBOL(avi_log_access);
+
+static void avi_log_format(struct seq_file *s,
+                           struct avi_register_access *log,
+                           unsigned long head,
+                           unsigned long index)
+{
+	struct avi_register_access	*a;
+	enum avi_log_type		 t;
+	unsigned long			 i;
+
+	for (i = (head + 1) % AVI_LOGGER_BUF_SZ;
+	     i != head;
+	     i = (i + 1) % AVI_LOGGER_BUF_SZ) {
+		a = &log[i];
+
+		t = a->reg & 3;
+		a->reg &= ~3UL;
+
+		if (t != AVI_LOG_NONE)
+			seq_printf(s, "[%8lx] %c 0x%08x @ 0x%08x\n",
+			           index,
+			           (t == AVI_LOG_READ) ? 'R' : 'W',
+			           a->val,
+			           a->reg);
+
+		index++;
+	}
+}
+
+int avi_log_display(struct seq_file *s)
+{
+	struct avi_register_access	*log;
+	unsigned long			 head;
+	unsigned long			 index;
+	unsigned long			 flags;
+	int				 ret = 0;
+
+	/* We make a copy of the log before formating it to limit the time we
+	 * spend holding the lock */
+	log = vmalloc(AVI_LOGGER_BUF_SZ * sizeof(*avi_logger.log));
+	if (log == NULL)
+		return -ENOMEM;
+
+	memset(log, 0, AVI_LOGGER_BUF_SZ * sizeof(*log));
+
+	spin_lock_irqsave(&avi_logger.lock, flags);
+
+	if (avi_logger.log == NULL) {
+		/* No log available */
+		ret = -ENODEV;
+		goto copy_done;
+	}
+
+	memcpy(log, avi_logger.log, AVI_LOGGER_BUF_SZ * sizeof(*log));
+	head = avi_logger.head;
+	index = avi_logger.nwrap * AVI_LOGGER_BUF_SZ + avi_logger.head - 1;
+
+ copy_done:
+	spin_unlock_irqrestore(&avi_logger.lock, flags);
+
+	if (ret == 0)
+		avi_log_format(s, log, head, index);
+
+	vfree(log);
+	return ret;
+}
+EXPORT_SYMBOL(avi_log_display);