powerpc/vas: Define vas_win_paste_addr()

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>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/include/asm/vas.h b/arch/powerpc/include/asm/vas.h
index 044748f547f5920a222081f0dda0f6592d35f14b..f98ade8a2603228faefa71322cd38c9f17d04346 100644 (file)
--- a/arch/powerpc/include/asm/vas.h
+++ b/arch/powerpc/include/asm/vas.h
@@ -10,6 +10,8 @@
 #ifndef _ASM_POWERPC_VAS_H
 #define _ASM_POWERPC_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.
@@ -165,4 +167,9 @@ int vas_copy_crb(void *crb, int offset);
  */
 int vas_paste_crb(struct vas_window *win, int offset, bool re);
 
+/*
+ * Return the power bus paste address associated with @win so the caller
+ * can map that address into their address space.
+ */
+extern u64 vas_win_paste_addr(struct vas_window *win);
 #endif /* __ASM_POWERPC_VAS_H */

diff --git a/arch/powerpc/platforms/powernv/vas-window.c b/arch/powerpc/platforms/powernv/vas-window.c
index c030d4cf982ea5d944e4ad3b983f1cbb5bab1539..d7d06533a1e9ba05faa1fe6cf5fe611909ed8e39 100644 (file)
--- a/arch/powerpc/platforms/powernv/vas-window.c
+++ b/arch/powerpc/platforms/powernv/vas-window.c
@@ -40,6 +40,16 @@ static void compute_paste_address(struct vas_window *window, u64 *addr, int *len
        pr_debug("Txwin #%d: Paste addr 0x%llx\n", winid, *addr);
 }
 
+u64 vas_win_paste_addr(struct vas_window *win)
+{
+       u64 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,
                        u64 *start, int *len)
 {