USB: musb: AM35x: Workaround for fifo read issue

AM35x supports only 32bit read operations so we need to have
workaround for 8bit and 16bit read operations.

Signed-off-by: Ajay Kumar Gupta <ajay.gupta@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 32 insertions, 0 deletions

diff --git a/drivers/usb/musb/am35x.c b/drivers/usb/musb/am35x.c
index 53962a0389eb..b0aabf3a606f 100644
--- a/drivers/usb/musb/am35x.c
+++ b/drivers/usb/musb/am35x.c
@@ -492,3 +492,33 @@ void musb_platform_restore_context(struct musb *musb,
         phy_on();
 }
 #endif
+
+/* AM35x supports only 32bit read operation */
+void musb_read_fifo(struct musb_hw_ep *hw_ep, u16 len, u8 *dst)
+{
+        void __iomem *fifo = hw_ep->fifo;
+        u32             val;
+        int             i;
+
+        /* Read for 32bit-aligned destination address */
+        if (likely((0x03 & (unsigned long) dst) == 0) && len >= 4) {
+                readsl(fifo, dst, len >> 2);
+                dst += len & ~0x03;
+                len &= 0x03;
+        }
+        /*
+         * Now read the remaining 1 to 3 byte or complete length if
+         * unaligned address.
+         */
+        if (len > 4) {
+                for (i = 0; i < (len >> 2); i++) {
+                        *(u32 *) dst = musb_readl(fifo, 0);
+                        dst += 4;
+                }
+                len &= 0x03;
+        }
+        if (len > 0) {
+                val = musb_readl(fifo, 0);
+                memcpy(dst, &val, len);
+        }
+}
diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index 7e2c353755d2..c9f9024c5515 100644
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -272,6 +272,7 @@ void musb_write_fifo(struct musb_hw_ep *hw_ep, u16 len, const u8 *src)
         }
 }
 
+#if !defined(CONFIG_USB_MUSB_AM35X)
 /*
  * Unload an endpoint's FIFO
  */
@@ -309,6 +310,7 @@ void musb_read_fifo(struct musb_hw_ep *hw_ep, u16 len, u8 *dst)
                 readsb(fifo, dst, len);
         }
 }
+#endif
 
 #endif  /* normal PIO */