powerpc/mpc52xx_lpbfifo: optionally defer fifo transfer start

Currently fifo transfer is started when submitting a transfer
request. Add posibility to defer the fifo transfer and start it
later by calling additional function. This change is backward
compatible, the behaviour of mpc52xx_lpbfifo_submit() is the same
for previous driver users, so there is no need to adapt them.

Signed-off-by: Anatolij Gustschin <agust@denx.de>

diff --git a/arch/powerpc/include/asm/mpc52xx.h b/arch/powerpc/include/asm/mpc52xx.h
index 1f41382..0acc7c7 100644 (file)
--- a/arch/powerpc/include/asm/mpc52xx.h
+++ b/arch/powerpc/include/asm/mpc52xx.h
@@ -307,6 +307,7 @@ struct mpc52xx_lpbfifo_request {
        size_t size;
        size_t pos;     /* current position of transfer */
        int flags;
+       int defer_xfer_start;
 
        /* What to do when finished */
        void (*callback)(struct mpc52xx_lpbfifo_request *);
@@ -323,6 +324,7 @@ struct mpc52xx_lpbfifo_request {
 extern int mpc52xx_lpbfifo_submit(struct mpc52xx_lpbfifo_request *req);
 extern void mpc52xx_lpbfifo_abort(struct mpc52xx_lpbfifo_request *req);
 extern void mpc52xx_lpbfifo_poll(void);
+extern int mpc52xx_lpbfifo_start_xfer(struct mpc52xx_lpbfifo_request *req);
 
 /* mpc52xx_pic.c */
 extern void mpc52xx_init_irq(void);

diff --git a/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c b/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c
index d61fb1c..2351f9e 100644 (file)
--- a/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c
+++ b/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c
@@ -170,7 +170,8 @@ static void mpc52xx_lpbfifo_kick(struct mpc52xx_lpbfifo_request *req)
        out_be32(lpbfifo.regs + LPBFIFO_REG_CONTROL, bit_fields);
 
        /* Kick it off */
-       out_8(lpbfifo.regs + LPBFIFO_REG_PACKET_SIZE, 0x01);
+       if (!lpbfifo.req->defer_xfer_start)
+               out_8(lpbfifo.regs + LPBFIFO_REG_PACKET_SIZE, 0x01);
        if (dma)
                bcom_enable(lpbfifo.bcom_cur_task);
 }
@@ -421,6 +422,38 @@ int mpc52xx_lpbfifo_submit(struct mpc52xx_lpbfifo_request *req)
 }
 EXPORT_SYMBOL(mpc52xx_lpbfifo_submit);
 
+int mpc52xx_lpbfifo_start_xfer(struct mpc52xx_lpbfifo_request *req)
+{
+       unsigned long flags;
+
+       if (!lpbfifo.regs)
+               return -ENODEV;
+
+       spin_lock_irqsave(&lpbfifo.lock, flags);
+
+       /*
+        * If the req pointer is already set and a transfer was
+        * started on submit, then this transfer is in progress
+        */
+       if (lpbfifo.req && !lpbfifo.req->defer_xfer_start) {
+               spin_unlock_irqrestore(&lpbfifo.lock, flags);
+               return -EBUSY;
+       }
+
+       /*
+        * If the req was previously submitted but not
+        * started, start it now
+        */
+       if (lpbfifo.req && lpbfifo.req == req &&
+           lpbfifo.req->defer_xfer_start) {
+               out_8(lpbfifo.regs + LPBFIFO_REG_PACKET_SIZE, 0x01);
+       }
+
+       spin_unlock_irqrestore(&lpbfifo.lock, flags);
+       return 0;
+}
+EXPORT_SYMBOL(mpc52xx_lpbfifo_start_xfer);
+
 void mpc52xx_lpbfifo_abort(struct mpc52xx_lpbfifo_request *req)
 {
        unsigned long flags;