drm: Add a helper function for printing a debugfs_regset32.

The debugfs_regset32 is nice to use for reducing boilerplate in
dumping a bunch of regs in debugfs, but we also want to be able to
print to dmesg them at runtime for driver debugging.  drm_printer lets
us format debugfs and the printk the same way.

v2: Add some kerneldoc for the function (requested by danvet)

Signed-off-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20190220210343.28157-1-eric@anholt.net
Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com> (v1)
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
index 0e7fc3e7dfb48878671cbf709063e1489485186b..f5cb0aabfe35ba1e295a2d706c6ae3b22d7f8707 100644 (file)
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -253,3 +253,31 @@ void drm_err(const char *format, ...)
        va_end(args);
 }
 EXPORT_SYMBOL(drm_err);
+
+/**
+ * drm_print_regset32 - print the contents of registers to a
+ * &drm_printer stream.
+ *
+ * @p: the &drm printer
+ * @regset: the list of registers to print.
+ *
+ * Often in driver debug, it's useful to be able to either capture the
+ * contents of registers in the steady state using debugfs or at
+ * specific points during operation.  This lets the driver have a
+ * single list of registers for both.
+ */
+void drm_print_regset32(struct drm_printer *p, struct debugfs_regset32 *regset)
+{
+       int namelen = 0;
+       int i;
+
+       for (i = 0; i < regset->nregs; i++)
+               namelen = max(namelen, (int)strlen(regset->regs[i].name));
+
+       for (i = 0; i < regset->nregs; i++) {
+               drm_printf(p, "%*s = 0x%08x\n",
+                          namelen, regset->regs[i].name,
+                          readl(regset->base + regset->regs[i].offset));
+       }
+}
+EXPORT_SYMBOL(drm_print_regset32);

diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
index afbc3beef089a38f3ada870c9002c3e730a8f296..3a4247319e63df041c613c47ea9e16be894448f7 100644 (file)
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -30,6 +30,7 @@
 #include <linux/printk.h>
 #include <linux/seq_file.h>
 #include <linux/device.h>
+#include <linux/debugfs.h>
 
 /**
  * DOC: print
@@ -84,6 +85,7 @@ void __drm_printfn_debug(struct drm_printer *p, struct va_format *vaf);
 __printf(2, 3)
 void drm_printf(struct drm_printer *p, const char *f, ...);
 void drm_puts(struct drm_printer *p, const char *str);
+void drm_print_regset32(struct drm_printer *p, struct debugfs_regset32 *regset);
 
 __printf(2, 0)
 /**