diff mbox

include: Move ascii85 functions from i915 to linux/ascii85.h

Message ID 1517000362-24164-2-git-send-email-jcrouse@codeaurora.org (mailing list archive)
State New, archived
Headers show

Commit Message

Jordan Crouse Jan. 26, 2018, 8:59 p.m. UTC
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.

Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
---
 drivers/gpu/drm/i915/i915_gpu_error.c | 24 +---------------
 include/linux/ascii85.h               | 52 +++++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 23 deletions(-)
 create mode 100644 include/linux/ascii85.h

Comments

Chris Wilson Jan. 26, 2018, 9:13 p.m. UTC | #1
Quoting Jordan Crouse (2018-01-26 20:59:22)
> 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.
> 
> Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
> ---
>  drivers/gpu/drm/i915/i915_gpu_error.c | 24 +---------------
>  include/linux/ascii85.h               | 52 +++++++++++++++++++++++++++++++++++
>  2 files changed, 53 insertions(+), 23 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 48418fb..2588f37 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"
>  
> @@ -501,29 +502,6 @@ 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,
> diff --git a/include/linux/ascii85.h b/include/linux/ascii85.h
> new file mode 100644
> index 0000000..7ee39f9
> --- /dev/null
> +++ b/include/linux/ascii85.h
> @@ -0,0 +1,52 @@
> +/*
> + * Copyright (c) 2008 Intel Corporation
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> + * IN THE SOFTWARE.
> + */
> +
> +#ifndef _ASCII85_H_
> +#define _ASCII85_H_
> +
> +#include <linux/kernel.h>
> +
> +static inline int
> +ascii85_encode_len(int len)
> +{
> +       return DIV_ROUND_UP(len, 4);
> +}

Use longs for generic stuff.

> +
> +static inline 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;
> +}

I think you'll want to capture the special case 0 == 'z' in the common
routines.

{
	char buf[ASCII85_BUFSZ];
	int i, len;

	len = ascii85_encode_len(PAGE_SIZE);
	for (i = 0; i < len; i++)
		err_puts(m, ascii85_encode(obj->pages[page][i], buf));
}	

Looks reasonable for the caller, so

#define ASCII85_BUFSZ 6

static inline const char *
ascii85_encode(u32 in, char *out)
{
	int i;

	/* check whether out[0] = 'z'; out[1] = '\0'; generates better code */
	if (in == 0)
		return "z";

	out[5] = '\0';
	for (i = 5; i--; ) {
		out[i] = '!' + in % 85;
		in /= 85;
	}

	return out;
}

-Chris
Chris Wilson Jan. 26, 2018, 9:19 p.m. UTC | #2
Quoting Jordan Crouse (2018-01-26 20:59:22)
> The i915 DRM driver very cleverly used ascii85 encoding for their

All gfx drivers must eventually become PostScript.

> GPU state file. Move the encode functions to a general header file to
> support other drivers that might be interested in the same
> functionality.
> 
> Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
> ---
> diff --git a/include/linux/ascii85.h b/include/linux/ascii85.h
> new file mode 100644
> index 0000000..7ee39f9
> --- /dev/null
> +++ b/include/linux/ascii85.h
> @@ -0,0 +1,52 @@
> +/*
> + * Copyright (c) 2008 Intel Corporation

Just cut this down to
/*
 * SPDX-License-Identifier: GPL-2.0
 *
 * Copyright (c) 2008 Intel Corporation
 * Copyright (c) 2018 My Name Here
 */

Fortunately ideas themselves are not copyrightable, otherwise Adobe has
a strong claim to ownership.
-Chris
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index 48418fb..2588f37 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"
 
@@ -501,29 +502,6 @@  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,
diff --git a/include/linux/ascii85.h b/include/linux/ascii85.h
new file mode 100644
index 0000000..7ee39f9
--- /dev/null
+++ b/include/linux/ascii85.h
@@ -0,0 +1,52 @@ 
+/*
+ * Copyright (c) 2008 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef _ASCII85_H_
+#define _ASCII85_H_
+
+#include <linux/kernel.h>
+
+static inline int
+ascii85_encode_len(int len)
+{
+	return DIV_ROUND_UP(len, 4);
+}
+
+static inline 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;
+}
+
+#endif