[PATCH v2 11/13] drm/panic: Internalize panic locking in DRM core and helpers

None of the DRM drivers handles panic locking. Declare the interfaces
in an internal header file. Move the trylock required during the panic
into the DRM core's sources.

Signed-off-by: Thomas Zimmermann <[email protected]>
---
 Documentation/gpu/drm-kms.rst        |  3 ++
 MAINTAINERS                          |  3 +-
 drivers/gpu/drm/drm_atomic_helper.c  |  2 +-
 drivers/gpu/drm/drm_drv.c            |  2 +-
 drivers/gpu/drm/drm_panic.c          |  4 ++
 drivers/gpu/drm/drm_panic_internal.h | 55 +++++++++++++++++++++++
 include/drm/drm_panic.h              | 65 ----------------------------
 7 files changed, 66 insertions(+), 68 deletions(-)
 create mode 100644 drivers/gpu/drm/drm_panic_internal.h

diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst
index 0dd440a14946..8988fd64369b 100644
--- a/Documentation/gpu/drm-kms.rst
+++ b/Documentation/gpu/drm-kms.rst
@@ -421,6 +421,9 @@ Plane Panic Functions Reference
 .. kernel-doc:: include/drm/drm_panic.h
    :internal:
 
+.. kernel-doc:: drivers/gpu/drm/drm_panic_internal.h
+   :internal:
+
 .. kernel-doc:: drivers/gpu/drm/drm_panic.c
    :export:
 
diff --git a/MAINTAINERS b/MAINTAINERS
index 472c5c48729d..f3dfdd9314bd 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9018,7 +9018,8 @@ S:	Supported
 T:	git https://gitlab.freedesktop.org/drm/misc/kernel.git
 F:	drivers/gpu/drm/drm_draw.c
 F:	drivers/gpu/drm/drm_draw_internal.h
-F:	drivers/gpu/drm/drm_panic*.c
+F:	drivers/gpu/drm/drm_panic.c
+F:	drivers/gpu/drm/drm_panic_internal.h
 F:	drivers/gpu/drm/tests/drm_panic_test.c
 F:	include/drm/drm_panic.h
 F:	include/drm/drm_panic_helper.h
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 285aac3554df..af3934df3313 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -41,7 +41,6 @@
 #include <drm/drm_drv.h>
 #include <drm/drm_framebuffer.h>
 #include <drm/drm_gem_atomic_helper.h>
-#include <drm/drm_panic.h>
 #include <drm/drm_print.h>
 #include <drm/drm_self_refresh_helper.h>
 #include <drm/drm_vblank.h>
@@ -49,6 +48,7 @@
 
 #include "drm_crtc_helper_internal.h"
 #include "drm_crtc_internal.h"
+#include "drm_panic_internal.h"
 
 /**
  * DOC: overview
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index c808958a2188..02ff02931515 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -50,13 +50,13 @@
 #include <drm/drm_file.h>
 #include <drm/drm_managed.h>
 #include <drm/drm_mode_object.h>
-#include <drm/drm_panic.h>
 #include <drm/drm_print.h>
 #include <drm/drm_privacy_screen_machine.h>
 #include <drm/drm_ras_genl_family.h>
 
 #include "drm_crtc_internal.h"
 #include "drm_internal.h"
+#include "drm_panic_internal.h"
 
 MODULE_AUTHOR("Gareth Hughes, Leif Delgass, José Fonseca, Jon Smirl");
 MODULE_DESCRIPTION("DRM shared core routines");
diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c
index 0fe9a0d67db3..9a6e3704bf09 100644
--- a/drivers/gpu/drm/drm_panic.c
+++ b/drivers/gpu/drm/drm_panic.c
@@ -35,6 +35,7 @@
 
 #include "drm_crtc_internal.h"
 #include "drm_draw_internal.h"
+#include "drm_panic_internal.h"
 
 MODULE_AUTHOR("Jocelyn Falempe");
 MODULE_DESCRIPTION("DRM panic handler");
@@ -976,6 +977,9 @@ int drm_plane_helper_display_panic_screen(struct drm_plane *plane, const char *d
 }
 EXPORT_SYMBOL(drm_plane_helper_display_panic_screen);
 
+#define drm_panic_trylock(dev, flags) \
+	raw_spin_trylock_irqsave(&(dev)->mode_config.panic_lock, flags)
+
 static void drm_panic_display_panic_screen(struct drm_plane *plane, const char *description)
 {
 #if defined(CONFIG_DRM_PANIC_FOREGROUND_COLOR)
diff --git a/drivers/gpu/drm/drm_panic_internal.h b/drivers/gpu/drm/drm_panic_internal.h
new file mode 100644
index 000000000000..c68d64c56e15
--- /dev/null
+++ b/drivers/gpu/drm/drm_panic_internal.h
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0 or MIT */
+
+/*
+ * Copyright (c) 2024 Intel
+ * Copyright (c) 2024 Red Hat
+ */
+
+#ifndef __DRM_PANIC_INTERNAL_H__
+#define __DRM_PANIC_INTERNAL_H__
+
+#include <linux/spinlock.h>
+
+struct drm_device;
+
+#ifdef CONFIG_DRM_PANIC
+
+/**
+ * drm_panic_lock - protect panic printing relevant state
+ * @dev: struct drm_device
+ * @flags: unsigned long irq flags you need to pass to the unlock() counterpart
+ *
+ * This function must be called to protect software and hardware state that the
+ * panic printing code must be able to rely on. The protected sections must be
+ * as small as possible. It uses the irqsave/irqrestore variant, and can be
+ * called from irq handler. Examples include:
+ *
+ * - Access to peek/poke or other similar registers, if that is the way the
+ *   driver prints the pixels into the scanout buffer at panic time.
+ *
+ * - Updates to pointers like &drm_plane.state, allowing the panic handler to
+ *   safely deference these. This is done in drm_atomic_helper_swap_state().
+ *
+ * - An state that isn't invariant and that the driver must be able to access
+ *   during panic printing.
+ */
+#define drm_panic_lock(dev, flags) \
+	raw_spin_lock_irqsave(&(dev)->mode_config.panic_lock, flags)
+
+/**
+ * drm_panic_unlock - end of the panic printing critical section
+ * @dev: struct drm_device
+ * @flags: irq flags that were returned when acquiring the lock
+ *
+ * Unlocks the raw spinlock acquired by either drm_panic_lock() or
+ * drm_panic_trylock().
+ */
+#define drm_panic_unlock(dev, flags) \
+	raw_spin_unlock_irqrestore(&(dev)->mode_config.panic_lock, flags)
+
+#else
+static inline void drm_panic_lock(struct drm_device *dev, unsigned long flags) {}
+static inline void drm_panic_unlock(struct drm_device *dev, unsigned long flags) {}
+#endif
+
+#endif /* __DRM_PANIC_INTERNAL_H__ */
diff --git a/include/drm/drm_panic.h b/include/drm/drm_panic.h
index 430df536de14..99572b7eeab9 100644
--- a/include/drm/drm_panic.h
+++ b/include/drm/drm_panic.h
@@ -8,11 +8,9 @@
 #ifndef __DRM_PANIC_H__
 #define __DRM_PANIC_H__
 
-#include <linux/module.h>
 #include <linux/types.h>
 #include <linux/iosys-map.h>
 
-#include <drm/drm_device.h>
 #include <drm/drm_fourcc.h>
 
 struct page;
@@ -85,71 +83,8 @@ struct drm_scanout_buffer {
 	 * set_pixel()
 	 */
 	void *private;
-
 };
 
-#ifdef CONFIG_DRM_PANIC
-
-/**
- * drm_panic_trylock - try to enter the panic printing critical section
- * @dev: struct drm_device
- * @flags: unsigned long irq flags you need to pass to the unlock() counterpart
- *
- * The panic-printing code calls this function. The panic printing attempt must
- * be aborted if the trylock fails.
- *
- * Return:
- * %0 when failing to acquire the raw spinlock, nonzero on success.
- */
-#define drm_panic_trylock(dev, flags) \
-	raw_spin_trylock_irqsave(&(dev)->mode_config.panic_lock, flags)
-
-/**
- * drm_panic_lock - protect panic printing relevant state
- * @dev: struct drm_device
- * @flags: unsigned long irq flags you need to pass to the unlock() counterpart
- *
- * This function must be called to protect software and hardware state that the
- * panic printing code must be able to rely on. The protected sections must be
- * as small as possible. It uses the irqsave/irqrestore variant, and can be
- * called from irq handler. Examples include:
- *
- * - Access to peek/poke or other similar registers, if that is the way the
- *   driver prints the pixels into the scanout buffer at panic time.
- *
- * - Updates to pointers like &drm_plane.state, allowing the panic handler to
- *   safely deference these. This is done in drm_atomic_helper_swap_state().
- *
- * - An state that isn't invariant and that the driver must be able to access
- *   during panic printing.
- */
-
-#define drm_panic_lock(dev, flags) \
-	raw_spin_lock_irqsave(&(dev)->mode_config.panic_lock, flags)
-
-/**
- * drm_panic_unlock - end of the panic printing critical section
- * @dev: struct drm_device
- * @flags: irq flags that were returned when acquiring the lock
- *
- * Unlocks the raw spinlock acquired by either drm_panic_lock() or
- * drm_panic_trylock().
- */
-#define drm_panic_unlock(dev, flags) \
-	raw_spin_unlock_irqrestore(&(dev)->mode_config.panic_lock, flags)
-
-#else
-
-static inline bool drm_panic_trylock(struct drm_device *dev, unsigned long flags)
-{
-	return true;
-}
-
-static inline void drm_panic_lock(struct drm_device *dev, unsigned long flags) {}
-static inline void drm_panic_unlock(struct drm_device *dev, unsigned long flags) {}
-
-#endif
-
 #if defined(CONFIG_DRM_PANIC_SCREEN_QR_CODE)
 size_t drm_panic_qr_max_data_size(u8 version, size_t url_len);
 
-- 
2.55.0