asm-generic: Add msi.h

To support MSI irq domains we want a generic data structure for
allocation, but we need the option to provide an architecture specific
version of it. So instead of playing #ifdef games in linux/msi.h we
add a generic header file and let architectures decide whether to
include it or to provide their own implementation and provide the
required typedef.

I know that typedefs are not really nice, but in this case there are no
forward declarations required and it's the simplest solution.

Signed-off-by: Thomas Gleixner <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
Cc: Jiang Liu <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: [email protected]
Cc: Bjorn Helgaas <[email protected]>
Cc: Grant Likely <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Yijing Wang <[email protected]>
Cc: Yingjoe Chen <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Matthias Brugger <[email protected]>
Cc: Alexander Gordeev <[email protected]>

1 files changed, 32 insertions, 0 deletions

diff --git a/include/asm-generic/msi.h b/include/asm-generic/msi.h
new file mode 100644
index 000000000000..61c58d8878ce
--- /dev/null
+++ b/include/asm-generic/msi.h
@@ -0,0 +1,32 @@
+#ifndef __ASM_GENERIC_MSI_H
+#define __ASM_GENERIC_MSI_H
+
+#include <linux/types.h>
+
+#ifndef NUM_MSI_ALLOC_SCRATCHPAD_REGS
+# define NUM_MSI_ALLOC_SCRATCHPAD_REGS	2
+#endif
+
+struct msi_desc;
+
+/**
+ * struct msi_alloc_info - Default structure for MSI interrupt allocation.
+ * @desc:	Pointer to msi descriptor
+ * @hwirq:	Associated hw interrupt number in the domain
+ * @scratchpad:	Storage for implementation specific scratch data
+ *
+ * Architectures can provide their own implementation by not including
+ * asm-generic/msi.h into their arch specific header file.
+ */
+typedef struct msi_alloc_info {
+	struct msi_desc			*desc;
+	irq_hw_number_t			hwirq;
+	union {
+		unsigned long		ul;
+		void			*ptr;
+	} scratchpad[NUM_MSI_ALLOC_SCRATCHPAD_REGS];
+} msi_alloc_info_t;
+
+#define GENERIC_MSI_DOMAIN_OPS		1
+
+#endif