[rfc/rft/patch 19/19] usb: musb: wait for RxPktRdy to get set

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From: Arnaud Mandy <ext-arnaud.2.mandy@xxxxxxxxx>

It seems like the hardware is generating irq before setting RxPktRdy
in the RxCSR register, so let's wait a little bit until that
gets set.

Signed-off-by: Arnaud Mandy <ext-arnaud.2.mandy@xxxxxxxxx>
Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxx>
---
 drivers/usb/musb/musb_gadget.c |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
index 2f09a9e..808a432 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -637,9 +637,21 @@ static void do_pio_rx(struct musb *musb, struct musb_request *req)
 	void __iomem		*epio = musb->endpoints[epnum].regs;
 	unsigned		fifo_count = 0;
 	u16			count = musb_ep->packet_sz;
+	int			retries = 1000;
 
 	csr = musb_readw(epio, MUSB_RXCSR);
 
+	/* RxPktRdy should be the only possibility here.
+	 * Sometimes the IRQ is generated before
+	 * RxPktRdy gets set, so we'll wait a while. */
+	while (!(csr & MUSB_RXCSR_RXPKTRDY)) {
+		if (retries-- == 0) {
+			DBG(1, "RxPktRdy did not get set (CSR %04x)\n", csr);
+			BUG_ON(!(csr & MUSB_RXCSR_RXPKTRDY));
+		}
+		csr = musb_readw(epio, MUSB_RXCSR);
+	}
+
 	musb_ep->busy = 1;
 
 	count = musb_readw(epio, MUSB_RXCOUNT);
-- 
1.6.4.2.253.g0b1fac

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