[PATCH v6 07/17] powerpc/vas: Define vas_win_paste_addr()

[Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>]

Define an interface that the NX drivers can use to find the physical
paste address of a send window. This interface is expected to be used
with the mmap() operation of the NX driver's device. i.e the user space
process can use driver's mmap() operation to map the send window's paste
address into their address space and then use copy and paste instructions
to submit the CRBs to the NX engine.

Note that kernel drivers will use vas_paste_crb() directly and don't need
this interface.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/vas.h              |  7 +++++++
 arch/powerpc/platforms/powernv/vas-window.c | 10 ++++++++++
 2 files changed, 17 insertions(+)

diff --git a/arch/powerpc/include/asm/vas.h b/arch/powerpc/include/asm/vas.h
index 2c8558a..2b35b95 100644
--- a/arch/powerpc/include/asm/vas.h
+++ b/arch/powerpc/include/asm/vas.h
@@ -12,6 +12,8 @@
 
 #include <uapi/asm/vas.h>
 
+struct vas_window;
+
 /*
  * Min and max FIFO sizes are based on Version 1.05 Section 3.1.4.25
  * (Local FIFO Size Register) of the VAS workbook.
@@ -32,4 +34,9 @@ enum vas_cop_type {
 	VAS_COP_TYPE_MAX,
 };
 
+/*
+ * Return the power bus paste address associated with @win so the caller
+ * can map that address into their address space.
+ */
+extern uint64_t vas_win_paste_addr(struct vas_window *win);
 #endif /* _MISC_VAS_H */
diff --git a/arch/powerpc/platforms/powernv/vas-window.c b/arch/powerpc/platforms/powernv/vas-window.c
index 9c12919..3a4599f 100644
--- a/arch/powerpc/platforms/powernv/vas-window.c
+++ b/arch/powerpc/platforms/powernv/vas-window.c
@@ -35,6 +35,16 @@ void compute_paste_address(struct vas_window *window, uint64_t *addr, int *len)
 	pr_debug("Txwin #%d: Paste addr 0x%llx\n", winid, *addr);
 }
 
+uint64_t vas_win_paste_addr(struct vas_window *win)
+{
+	uint64_t addr;
+
+	compute_paste_address(win, &addr, NULL);
+
+	return addr;
+}
+EXPORT_SYMBOL(vas_win_paste_addr);
+
 static inline void get_hvwc_mmio_bar(struct vas_window *window,
 			uint64_t *start, int *len)
 {
-- 
2.7.4