[PATCH 1/8] include: Move ascii85 functions from i915 to linux/ascii85.h

[Jordan Crouse]

The i915 DRM driver very cleverly used ascii85 encoding for their
GPU state file. Move the encode functions to a general header file to
support other drivers that might be interested in the same
functionality.

[v2 - Update the API to be cleaner for the caller suggested by
Chris Wilson]

Signed-off-by: Jordan Crouse <jcrouse at codeaurora.org>
---
 drivers/gpu/drm/i915/i915_gpu_error.c | 38 ++++++----------------------------
 include/linux/ascii85.h               | 39 +++++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+), 32 deletions(-)
 create mode 100644 include/linux/ascii85.h

diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index 9440593..8bc72c7 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -31,6 +31,7 @@
 #include <linux/stop_machine.h>
 #include <linux/zlib.h>
 #include <drm/drm_print.h>
+#include <linux/ascii85.h>
 
 #include "i915_drv.h"
 
@@ -502,35 +503,12 @@ void i915_error_printf(struct drm_i915_error_state_buf *e, const char *f, ...)
 	va_end(args);
 }
 
-static int
-ascii85_encode_len(int len)
-{
-	return DIV_ROUND_UP(len, 4);
-}
-
-static bool
-ascii85_encode(u32 in, char *out)
-{
-	int i;
-
-	if (in == 0)
-		return false;
-
-	out[5] = '\0';
-	for (i = 5; i--; ) {
-		out[i] = '!' + in % 85;
-		in /= 85;
-	}
-
-	return true;
-}
-
 static void print_error_obj(struct drm_i915_error_state_buf *m,
 			    struct intel_engine_cs *engine,
 			    const char *name,
 			    struct drm_i915_error_object *obj)
 {
-	char out[6];
+	char out[ASCII85_BUFSZ];
 	int page;
 
 	if (!obj)
@@ -545,19 +523,15 @@ static void print_error_obj(struct drm_i915_error_state_buf *m,
 
 	err_compression_marker(m);
 	for (page = 0; page < obj->page_count; page++) {
-		int i, len;
+		int i;
+		long len = PAGE_SIZE;
 
-		len = PAGE_SIZE;
 		if (page == obj->page_count - 1)
 			len -= obj->unused;
 		len = ascii85_encode_len(len);
 
-		for (i = 0; i < len; i++) {
-			if (ascii85_encode(obj->pages[page][i], out))
-				err_puts(m, out);
-			else
-				err_puts(m, "z");
-		}
+		for (i = 0; i < len; i++)
+			error_puts(m, ascii85_encode(obj->pages[page][i], out));
 	}
 	err_puts(m, "\n");
 }
diff --git a/include/linux/ascii85.h b/include/linux/ascii85.h
new file mode 100644
index 0000000..322bbed
--- /dev/null
+++ b/include/linux/ascii85.h
@@ -0,0 +1,39 @@
+
+/*
+ * SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright (c) 2008 Intel Corporation
+ * Copyright (c) The Linux Foundation. All rights reserved.
+ */
+
+#ifndef _ASCII85_H_
+#define _ASCII85_H_
+
+#include <linux/kernel.h>
+
+#define ASCII85_BUFSZ 6
+
+static inline long
+ascii85_encode_len(long len)
+{
+	return DIV_ROUND_UP(len, 4);
+}
+
+static inline char *
+ascii85_encode(u32 in, char *out)
+{
+	int i;
+
+	if (in == 0)
+		return "z";
+
+	out[5] = '\0';
+	for (i = 5; i--; ) {
+		out[i] = '!' + in % 85;
+		in /= 85;
+	}
+
+	return out;
+}
+
+#endif
-- 
1.9.1