musb_hdrc: Transfer remaining bytes with PIO

DMA callback can manually transfer remaining 1 - 31 bytes
after DMA transfer using PIO. This allows transferring
a wider range of sizes with DMA.

This needs to be tested with sync DMA transfers as
PIO may not be mixed with sync DMA.

Signed-off-by: Tony Lindgren <tony@atomide.com>

diff --git a/drivers/usb/musb/tusb6010_omap.c b/drivers/usb/musb/tusb6010_omap.c
index 8e864d6c9a8e79f0bfb09ad55992f6d884a610ba..1d9d80f374c81ef33d456873dbadff7f44ed908e 100644 (file)
--- a/drivers/usb/musb/tusb6010_omap.c
+++ b/drivers/usb/musb/tusb6010_omap.c
@@ -146,7 +146,7 @@ static void tusb_omap_dma_cb(int lch, u16 ch_status, void *data)
        struct musb_hw_ep       *hw_ep = chdat->hw_ep;
        void __iomem            *ep_conf = hw_ep->conf;
        void __iomem            *musb_base = musb->pRegs;
-       unsigned long           remaining, flags;
+       unsigned long           remaining, flags, pio;
        int                     ch;
 
        spin_lock_irqsave(&musb->Lock, flags);
@@ -170,21 +170,25 @@ static void tusb_omap_dma_cb(int lch, u16 ch_status, void *data)
 
        remaining = TUSB_EP_CONFIG_XFR_SIZE(remaining);
        channel->dwActualLength = chdat->transfer_len - remaining;
+       pio = chdat->len - channel->dwActualLength;
 
        DBG(2, "DMA remaining %lu/%u\n", remaining, chdat->transfer_len);
 
-       /* Transfer remaining 1 - 31 bytes if DMA worked */
-       if (remaining == 0) {
-               u32     pio;
+       /* Transfer remaining 1 - 31 bytes */
+       if (pio > 0 && pio < 32) {
                u8      *buf;
 
-               pio = chdat->len - channel->dwActualLength;
-               buf = phys_to_virt((u32)chdat->dma_addr)
-                               + chdat->transfer_len;
-               if (chdat->tx)
+               DBG(2, "Using PIO for remaining %i bytes\n", pio);
+               buf = phys_to_virt((u32)chdat->dma_addr) + chdat->transfer_len;
+               if (chdat->tx) {
+                       consistent_sync(phys_to_virt((u32)chdat->dma_addr),
+                                       chdat->transfer_len, DMA_TO_DEVICE);
                        musb_write_fifo(hw_ep, pio, buf);
-               else
+               } else {
                        musb_read_fifo(hw_ep, pio, buf);
+                       consistent_sync(phys_to_virt((u32)chdat->dma_addr),
+                                       chdat->transfer_len, DMA_FROM_DEVICE);
+               }
                channel->dwActualLength += pio;
        }
 
@@ -201,7 +205,7 @@ static void tusb_omap_dma_cb(int lch, u16 ch_status, void *data)
        if (!chdat->tx)
                musb_dma_completion(musb, chdat->epnum, chdat->tx);
 
-       /* We musb terminate short tx transfers manually by setting TXPKTRDY.
+       /* We must terminate short tx transfers manually by setting TXPKTRDY.
         * REVISIT: This same problem may occur with other MUSB dma as well.
         * Easy to test with g_ether by pinging the MUSB board with ping -s54.
         */
@@ -239,7 +243,7 @@ static int tusb_omap_dma_program(struct dma_channel *channel, u16 packet_sz,
        s8                              dmareq;
        s8                              sync_dev;
 
-       if (unlikely(dma_addr & 0x1) || len < 32)
+       if (unlikely(dma_addr & 0x1) || (len < 32) || (len > packet_sz))
                return FALSE;
 
        chdat->transfer_len = len & ~0x1f;