[PATCH 2/6] drm: add helper for printing to log or seq_file

[Rob Clark]

Sometimes it is nice not to duplicate equivalent printk() and
seq_printf() code.

Signed-off-by: Rob Clark <robdclark at gmail.com>
---
 drivers/gpu/drm/Makefile    |  3 ++-
 drivers/gpu/drm/drm_print.c | 54 +++++++++++++++++++++++++++++++++++++++
 include/drm/drm_print.h     | 62 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 118 insertions(+), 1 deletion(-)
 create mode 100644 drivers/gpu/drm/drm_print.c
 create mode 100644 include/drm/drm_print.h

diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index e3dba6f..4894ebb 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -12,7 +12,8 @@ drm-y       :=	drm_auth.o drm_bufs.o drm_cache.o \
 		drm_info.o drm_debugfs.o drm_encoder_slave.o \
 		drm_trace_points.o drm_global.o drm_prime.o \
 		drm_rect.o drm_vma_manager.o drm_flip_work.o \
-		drm_modeset_lock.o drm_atomic.o drm_bridge.o
+		drm_modeset_lock.o drm_atomic.o drm_bridge.o \
+		drm_print.o
 
 drm-$(CONFIG_COMPAT) += drm_ioc32.o
 drm-$(CONFIG_DRM_GEM_CMA_HELPER) += drm_gem_cma_helper.o
diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
new file mode 100644
index 0000000..ddcb437
--- /dev/null
+++ b/drivers/gpu/drm/drm_print.c
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2016 Red Hat
+ *
+ * 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 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 COPYRIGHT HOLDER(S) OR AUTHOR(S) 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.
+ *
+ * Authors:
+ * Rob Clark <robdclark at gmail.com>
+ */
+
+#include <linux/seq_file.h>
+#include <drm/drmP.h>
+#include <drm/drm_print.h>
+
+void __drm_printfn_seq_file(struct drm_print *p, const char *f, va_list args)
+{
+	seq_vprintf(p->arg, f, args);
+}
+
+void __drm_printfn_info(struct drm_print *p, const char *f, va_list args)
+{
+	const char *hdr = KERN_INFO "[" DRM_NAME "] ";
+	char fmt[strlen(hdr) + strlen(f) + 1];
+
+	memcpy(fmt, hdr, strlen(hdr));
+	memcpy(fmt + strlen(hdr), f, strlen(f));
+	fmt[strlen(hdr) + strlen(f)] = 0;
+
+	vprintk(fmt, args);
+}
+
+void drm_printf(struct drm_print *p, const char *f, ...)
+{
+	va_list args;
+
+	va_start(args, f);
+	p->printfn(p, f, args);
+	va_end(args);
+}
diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
new file mode 100644
index 0000000..f294a9a
--- /dev/null
+++ b/include/drm/drm_print.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2016 Red Hat
+ *
+ * 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 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 COPYRIGHT HOLDER(S) OR AUTHOR(S) 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.
+ *
+ * Authors:
+ * Rob Clark <robdclark at gmail.com>
+ */
+
+#ifndef DRM_PRINT_H_
+#define DRM_PRINT_H_
+
+#include <stdarg.h>
+#include <linux/seq_file.h>
+
+/* A simple wrapper to abstract seq_file vs printk, so same logging code
+ * does not have to be duplicated.
+ */
+struct drm_print {
+	void (*printfn)(struct drm_print *p, const char *f, va_list args);
+	void *arg;
+};
+
+void __drm_printfn_seq_file(struct drm_print *p, const char *f, va_list args);
+void __drm_printfn_info(struct drm_print *p, const char *f, va_list args);
+
+void drm_printf(struct drm_print *p, const char *f, ...);
+
+static inline struct drm_print drm_print_seq_file(struct seq_file *f)
+{
+	struct drm_print p = {
+		.printfn = __drm_printfn_seq_file,
+		.arg = f,
+	};
+	return p;
+}
+
+static inline struct drm_print drm_print_info(void)
+{
+	struct drm_print p = {
+		.printfn = __drm_printfn_info,
+	};
+	return p;
+}
+
+#endif /* DRM_PRINT_H_ */
-- 
2.7.4