usb: dwc2: alloc dma aligned buffer for isoc split in

[ Upstream commit af424a410749ed7e0c2bffd3cedbc7c274d0ff6f ]

The commit 3bc04e28a030 ("usb: dwc2: host: Get aligned DMA in
a more supported way") rips out a lot of code to simply the
allocation of aligned DMA. However, it also introduces a new
issue when use isoc split in transfer.

In my test case, I connect the dwc2 controller with an usb hs
Hub (GL852G-12), and plug an usb fs audio device (Plantronics
headset) into the downstream port of Hub. Then use the usb mic
to record, we can find noise when playback.

It's because that the usb Hub uses an MDATA for the first
transaction and a DATA0 for the second transaction for the isoc
split in transaction. An typical isoc split in transaction sequence
like this:

- SSPLIT IN transaction
- CSPLIT IN transaction
  - MDATA packet
- CSPLIT IN transaction
  - DATA0 packet

The DMA address of MDATA (urb->dma) is always DWORD-aligned, but
the DMA address of DATA0 (urb->dma + qtd->isoc_split_offset) may
not be DWORD-aligned, it depends on the qtd->isoc_split_offset (the
length of MDATA). In my test case, the length of MDATA is usually
unaligned, this cause DATA0 packet transmission error.

This patch use kmem_cache to allocate aligned DMA buf for isoc
split in transaction. Note that according to usb 2.0 spec, the
maximum data payload size is 1023 bytes for each fs isoc ep,
and the maximum allowable interrupt data payload size is 64 bytes
or less for fs interrupt ep. So we set the size of object to be
1024 bytes in the kmem cache.

Tested-by: Gevorg Sahakyan <sahakyan@synopsys.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Minas Harutyunyan hminas@synopsys.com>
Signed-off-by: William Wu <william.wu@rock-chips.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 84 insertions, 5 deletions

diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
index 46d3b0fc00c5..fa20ec43a187 100644
--- a/drivers/usb/dwc2/hcd.c
+++ b/drivers/usb/dwc2/hcd.c
@@ -1544,11 +1544,20 @@ static void dwc2_hc_start_transfer(struct dwc2_hsotg *hsotg,
 	}
 
 	if (hsotg->params.host_dma) {
-		dwc2_writel((u32)chan->xfer_dma,
-			    hsotg->regs + HCDMA(chan->hc_num));
+		dma_addr_t dma_addr;
+
+		if (chan->align_buf) {
+			if (dbg_hc(chan))
+				dev_vdbg(hsotg->dev, "align_buf\n");
+			dma_addr = chan->align_buf;
+		} else {
+			dma_addr = chan->xfer_dma;
+		}
+		dwc2_writel((u32)dma_addr, hsotg->regs + HCDMA(chan->hc_num));
+
 		if (dbg_hc(chan))
 			dev_vdbg(hsotg->dev, "Wrote %08lx to HCDMA(%d)\n",
-				 (unsigned long)chan->xfer_dma, chan->hc_num);
+				 (unsigned long)dma_addr, chan->hc_num);
 	}
 
 	/* Start the split */
@@ -2604,6 +2613,35 @@ static void dwc2_hc_init_xfer(struct dwc2_hsotg *hsotg,
 	}
 }
 
+static int dwc2_alloc_split_dma_aligned_buf(struct dwc2_hsotg *hsotg,
+					    struct dwc2_qh *qh,
+					    struct dwc2_host_chan *chan)
+{
+	if (!hsotg->unaligned_cache ||
+	    chan->max_packet > DWC2_KMEM_UNALIGNED_BUF_SIZE)
+		return -ENOMEM;
+
+	if (!qh->dw_align_buf) {
+		qh->dw_align_buf = kmem_cache_alloc(hsotg->unaligned_cache,
+						    GFP_ATOMIC | GFP_DMA);
+		if (!qh->dw_align_buf)
+			return -ENOMEM;
+	}
+
+	qh->dw_align_buf_dma = dma_map_single(hsotg->dev, qh->dw_align_buf,
+					      DWC2_KMEM_UNALIGNED_BUF_SIZE,
+					      DMA_FROM_DEVICE);
+
+	if (dma_mapping_error(hsotg->dev, qh->dw_align_buf_dma)) {
+		dev_err(hsotg->dev, "can't map align_buf\n");
+		chan->align_buf = 0;
+		return -EINVAL;
+	}
+
+	chan->align_buf = qh->dw_align_buf_dma;
+	return 0;
+}
+
 #define DWC2_USB_DMA_ALIGN 4
 
 static void dwc2_free_dma_aligned_buffer(struct urb *urb)
@@ -2783,6 +2821,32 @@ static int dwc2_assign_and_init_hc(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
 	/* Set the transfer attributes */
 	dwc2_hc_init_xfer(hsotg, chan, qtd);
 
+	/* For non-dword aligned buffers */
+	if (hsotg->params.host_dma && qh->do_split &&
+	    chan->ep_is_in && (chan->xfer_dma & 0x3)) {
+		dev_vdbg(hsotg->dev, "Non-aligned buffer\n");
+		if (dwc2_alloc_split_dma_aligned_buf(hsotg, qh, chan)) {
+			dev_err(hsotg->dev,
+				"Failed to allocate memory to handle non-aligned buffer\n");
+			/* Add channel back to free list */
+			chan->align_buf = 0;
+			chan->multi_count = 0;
+			list_add_tail(&chan->hc_list_entry,
+				      &hsotg->free_hc_list);
+			qtd->in_process = 0;
+			qh->channel = NULL;
+			return -ENOMEM;
+		}
+	} else {
+		/*
+		 * We assume that DMA is always aligned in non-split
+		 * case or split out case. Warn if not.
+		 */
+		WARN_ON_ONCE(hsotg->params.host_dma &&
+			     (chan->xfer_dma & 0x3));
+		chan->align_buf = 0;
+	}
+
 	if (chan->ep_type == USB_ENDPOINT_XFER_INT ||
 	    chan->ep_type == USB_ENDPOINT_XFER_ISOC)
 		/*
@@ -5277,6 +5341,19 @@ int dwc2_hcd_init(struct dwc2_hsotg *hsotg)
 		}
 	}
 
+	if (hsotg->params.host_dma) {
+		/*
+		 * Create kmem caches to handle non-aligned buffer
+		 * in Buffer DMA mode.
+		 */
+		hsotg->unaligned_cache = kmem_cache_create("dwc2-unaligned-dma",
+						DWC2_KMEM_UNALIGNED_BUF_SIZE, 4,
+						SLAB_CACHE_DMA, NULL);
+		if (!hsotg->unaligned_cache)
+			dev_err(hsotg->dev,
+				"unable to create dwc2 unaligned cache\n");
+	}
+
 	hsotg->otg_port = 1;
 	hsotg->frame_list = NULL;
 	hsotg->frame_list_dma = 0;
@@ -5311,8 +5388,9 @@ int dwc2_hcd_init(struct dwc2_hsotg *hsotg)
 	return 0;
 
 error4:
-	kmem_cache_destroy(hsotg->desc_gen_cache);
+	kmem_cache_destroy(hsotg->unaligned_cache);
 	kmem_cache_destroy(hsotg->desc_hsisoc_cache);
+	kmem_cache_destroy(hsotg->desc_gen_cache);
 error3:
 	dwc2_hcd_release(hsotg);
 error2:
@@ -5353,8 +5431,9 @@ void dwc2_hcd_remove(struct dwc2_hsotg *hsotg)
 	usb_remove_hcd(hcd);
 	hsotg->priv = NULL;
 
-	kmem_cache_destroy(hsotg->desc_gen_cache);
+	kmem_cache_destroy(hsotg->unaligned_cache);
 	kmem_cache_destroy(hsotg->desc_hsisoc_cache);
+	kmem_cache_destroy(hsotg->desc_gen_cache);
 
 	dwc2_hcd_release(hsotg);
 	usb_put_hcd(hcd);