drm/i915: abstraction for iosf to compile on all archs

The asm/iosf_mbi.h header is x86-only. Let's make IOSF_MBI kconfig
selection conditional to x86 and provide a header with stubs for other
architectures. This helps getting i915 available for other
architectures in future.
Signed-off-by: Mullati, Siva <siva.mullati@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211022192756.1228354-1-siva.mullati@intel.com

drivers/gpu/drm/i915/Kconfig

@@ -21,7 +21,7 @@ config DRM_I915
 	select ACPI_VIDEO if ACPI
 	select ACPI_BUTTON if ACPI
 	select SYNC_FILE
-	select IOSF_MBI
+	select IOSF_MBI if X86
 	select CRC32
 	select SND_HDA_I915 if SND_HDA_CORE
 	select CEC_CORE if CEC_NOTIFIER

drivers/gpu/drm/i915/i915_iosf_mbi.h

+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2021 Intel Corporation
+ */
+
+#ifndef __I915_IOSF_MBI_H__
+#define __I915_IOSF_MBI_H__
+
+#if IS_ENABLED(CONFIG_IOSF_MBI)
+#include <asm/iosf_mbi.h>
+#else
+
+/* Stubs to compile for all non-x86 archs */
+#define MBI_PMIC_BUS_ACCESS_BEGIN       1
+#define MBI_PMIC_BUS_ACCESS_END         2
+
+struct notifier_block;
+
+static inline void iosf_mbi_punit_acquire(void) {}
+static inline void iosf_mbi_punit_release(void) {}
+static inline void iosf_mbi_assert_punit_acquired(void) {}
+
+static inline
+int iosf_mbi_register_pmic_bus_access_notifier(struct notifier_block *nb)
+{
+	return 0;
+}
+
+static inline int
+iosf_mbi_unregister_pmic_bus_access_notifier_unlocked(struct notifier_block *nb)
+{
+	return 0;
+}
+
+static inline
+int iosf_mbi_unregister_pmic_bus_access_notifier(struct notifier_block *nb)
+{
+	return 0;
+}
+#endif
+
+#endif /* __I915_IOSF_MBI_H__ */

drivers/gpu/drm/i915/intel_uncore.c

@@ -22,11 +22,11 @@
  */
 
 #include <linux/pm_runtime.h>
-#include <asm/iosf_mbi.h>
 
 #include "gt/intel_lrc_reg.h" /* for shadow reg list */
 
 #include "i915_drv.h"
+#include "i915_iosf_mbi.h"
 #include "i915_trace.h"
 #include "i915_vgpu.h"
 #include "intel_pm.h"

drivers/gpu/drm/i915/vlv_sideband.c

@@ -3,9 +3,8 @@
  * Copyright © 2013-2021 Intel Corporation
  */
 
-#include <asm/iosf_mbi.h>
-
 #include "i915_drv.h"
+#include "i915_iosf_mbi.h"
 #include "vlv_sideband.h"
 
 /*