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 <tglx@linutronix.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Yijing Wang <wangyijing@huawei.com>
Cc: Yingjoe Chen <yingjoe.chen@mediatek.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Alexander Gordeev <agordeev@redhat.com>

diff --git a/include/asm-generic/msi.h b/include/asm-generic/msi.h
new file mode 100644 (file)
index 0000000..61c58d8
--- /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