1 files changed, 108 insertions, 5 deletions

diff --git a/drivers/usb/musb/musb_cppi41.c b/drivers/usb/musb/musb_cppi41.c
index 83a8a1d125ac..a12bd30401e0 100644
--- a/drivers/usb/musb/musb_cppi41.c
+++ b/drivers/usb/musb/musb_cppi41.c
@@ -38,6 +38,7 @@ struct cppi41_dma_channel {
         u32 prog_len;
         u32 transferred;
         u32 packet_sz;
+        struct list_head tx_check;
 };
 
 #define MUSB_DMA_NUM_CHANNELS 15
@@ -47,6 +48,8 @@ struct cppi41_dma_controller {
         struct cppi41_dma_channel rx_channel[MUSB_DMA_NUM_CHANNELS];
         struct cppi41_dma_channel tx_channel[MUSB_DMA_NUM_CHANNELS];
         struct musb *musb;
+        struct hrtimer early_tx;
+        struct list_head early_tx_list;
         u32 rx_mode;
         u32 tx_mode;
         u32 auto_req;
@@ -96,11 +99,23 @@ static void update_rx_toggle(struct cppi41_dma_channel *cppi41_channel)
         cppi41_channel->usb_toggle = toggle;
 }
 
+static bool musb_is_tx_fifo_empty(struct musb_hw_ep *hw_ep)
+{
+        u8              epnum = hw_ep->epnum;
+        struct musb     *musb = hw_ep->musb;
+        void __iomem    *epio = musb->endpoints[epnum].regs;
+        u16             csr;
+
+        csr = musb_readw(epio, MUSB_TXCSR);
+        if (csr & MUSB_TXCSR_TXPKTRDY)
+                return false;
+        return true;
+}
+
 static void cppi41_dma_callback(void *private_data);
 
-static void cppi41_trans_done(struct dma_channel *channel)
+static void cppi41_trans_done(struct cppi41_dma_channel *cppi41_channel)
 {
-        struct cppi41_dma_channel *cppi41_channel = channel->private_data;
         struct musb_hw_ep *hw_ep = cppi41_channel->hw_ep;
         struct musb *musb = hw_ep->musb;
 
@@ -138,7 +153,7 @@ static void cppi41_trans_done(struct dma_channel *channel)
                         return;
 
                 dma_desc->callback = cppi41_dma_callback;
-                dma_desc->callback_param = channel;
+                dma_desc->callback_param = &cppi41_channel->channel;
                 cppi41_channel->cookie = dma_desc->tx_submit(dma_desc);
                 dma_async_issue_pending(dc);
 
@@ -150,6 +165,41 @@ static void cppi41_trans_done(struct dma_channel *channel)
         }
 }
 
+static enum hrtimer_restart cppi41_recheck_tx_req(struct hrtimer *timer)
+{
+        struct cppi41_dma_controller *controller;
+        struct cppi41_dma_channel *cppi41_channel, *n;
+        struct musb *musb;
+        unsigned long flags;
+        enum hrtimer_restart ret = HRTIMER_NORESTART;
+
+        controller = container_of(timer, struct cppi41_dma_controller,
+                        early_tx);
+        musb = controller->musb;
+
+        spin_lock_irqsave(&musb->lock, flags);
+        list_for_each_entry_safe(cppi41_channel, n, &controller->early_tx_list,
+                        tx_check) {
+                bool empty;
+                struct musb_hw_ep *hw_ep = cppi41_channel->hw_ep;
+
+                empty = musb_is_tx_fifo_empty(hw_ep);
+                if (empty) {
+                        list_del_init(&cppi41_channel->tx_check);
+                        cppi41_trans_done(cppi41_channel);
+                }
+        }
+
+        if (!list_empty(&controller->early_tx_list)) {
+                ret = HRTIMER_RESTART;
+                hrtimer_forward_now(&controller->early_tx,
+                                ktime_set(0, 150 * NSEC_PER_USEC));
+        }
+
+        spin_unlock_irqrestore(&musb->lock, flags);
+        return ret;
+}
+
 static void cppi41_dma_callback(void *private_data)
 {
         struct dma_channel *channel = private_data;
@@ -159,6 +209,7 @@ static void cppi41_dma_callback(void *private_data)
         unsigned long flags;
         struct dma_tx_state txstate;
         u32 transferred;
+        bool empty;
 
         spin_lock_irqsave(&musb->lock, flags);
 
@@ -177,8 +228,52 @@ static void cppi41_dma_callback(void *private_data)
                         transferred < cppi41_channel->packet_sz)
                 cppi41_channel->prog_len = 0;
 
-        cppi41_trans_done(channel);
-
+        empty = musb_is_tx_fifo_empty(hw_ep);
+        if (empty) {
+                cppi41_trans_done(cppi41_channel);
+        } else {
+                struct cppi41_dma_controller *controller;
+                /*
+                 * On AM335x it has been observed that the TX interrupt fires
+                 * too early that means the TXFIFO is not yet empty but the DMA
+                 * engine says that it is done with the transfer. We don't
+                 * receive a FIFO empty interrupt so the only thing we can do is
+                 * to poll for the bit. On HS it usually takes 2us, on FS around
+                 * 110us - 150us depending on the transfer size.
+                 * We spin on HS (no longer than than 25us and setup a timer on
+                 * FS to check for the bit and complete the transfer.
+                 */
+                controller = cppi41_channel->controller;
+
+                if (musb->g.speed == USB_SPEED_HIGH) {
+                        unsigned wait = 25;
+
+                        do {
+                                empty = musb_is_tx_fifo_empty(hw_ep);
+                                if (empty)
+                                        break;
+                                wait--;
+                                if (!wait)
+                                        break;
+                                udelay(1);
+                        } while (1);
+
+                        empty = musb_is_tx_fifo_empty(hw_ep);
+                        if (empty) {
+                                cppi41_trans_done(cppi41_channel);
+                                goto out;
+                        }
+                }
+                list_add_tail(&cppi41_channel->tx_check,
+                                &controller->early_tx_list);
+                if (!hrtimer_active(&controller->early_tx)) {
+                        hrtimer_start_range_ns(&controller->early_tx,
+                                ktime_set(0, 140 * NSEC_PER_USEC),
+                                40 * NSEC_PER_USEC,
+                                HRTIMER_MODE_REL);
+                }
+        }
+out:
         spin_unlock_irqrestore(&musb->lock, flags);
 }
 
@@ -377,6 +472,8 @@ static int cppi41_is_compatible(struct dma_channel *channel, u16 maxpacket,
                 WARN_ON(1);
                 return 1;
         }
+        if (cppi41_channel->hw_ep->ep_in.type != USB_ENDPOINT_XFER_BULK)
+                return 0;
         if (cppi41_channel->is_tx)
                 return 1;
         /* AM335x Advisory 1.0.13. No workaround for device RX mode */
@@ -401,6 +498,7 @@ static int cppi41_dma_channel_abort(struct dma_channel *channel)
         if (cppi41_channel->channel.status == MUSB_DMA_STATUS_FREE)
                 return 0;
 
+        list_del_init(&cppi41_channel->tx_check);
         if (is_tx) {
                 csr = musb_readw(epio, MUSB_TXCSR);
                 csr &= ~MUSB_TXCSR_DMAENAB;
@@ -508,6 +606,7 @@ static int cppi41_dma_controller_start(struct cppi41_dma_controller *controller)
                 cppi41_channel->controller = controller;
                 cppi41_channel->port_num = port;
                 cppi41_channel->is_tx = is_tx;
+                INIT_LIST_HEAD(&cppi41_channel->tx_check);
 
                 musb_dma = &cppi41_channel->channel;
                 musb_dma->private_data = cppi41_channel;
@@ -533,6 +632,7 @@ void dma_controller_destroy(struct dma_controller *c)
         struct cppi41_dma_controller *controller = container_of(c,
                         struct cppi41_dma_controller, controller);
 
+        hrtimer_cancel(&controller->early_tx);
         cppi41_dma_controller_stop(controller);
         kfree(controller);
 }
@@ -552,6 +652,9 @@ struct dma_controller *dma_controller_create(struct musb *musb,
         if (!controller)
                 goto kzalloc_fail;
 
+        hrtimer_init(&controller->early_tx, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+        controller->early_tx.function = cppi41_recheck_tx_req;
+        INIT_LIST_HEAD(&controller->early_tx_list);
         controller->musb = musb;
 
         controller->controller.channel_alloc = cppi41_dma_channel_allocate;