usb: dwc2: gadget: Increase descriptors count for ISOC's

Some function drivers queueing more than 128 ISOC requests at a time.
To avoid "descriptor chain full" cases, increasing descriptors count
from MAX_DMA_DESC_NUM_GENERIC to MAX_DMA_DESC_NUM_HS_ISOC for ISOC's
only.
Signed-off-by: Minas Harutyunyan <hminas@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc2/gadget.c

@@ -716,13 +716,11 @@ static unsigned int dwc2_gadget_get_chain_limit(struct dwc2_hsotg_ep *hs_ep)
 	unsigned int maxsize;
 
 	if (is_isoc)
-		maxsize = hs_ep->dir_in ? DEV_DMA_ISOC_TX_NBYTES_LIMIT :
-					   DEV_DMA_ISOC_RX_NBYTES_LIMIT;
+		maxsize = (hs_ep->dir_in ? DEV_DMA_ISOC_TX_NBYTES_LIMIT :
+					   DEV_DMA_ISOC_RX_NBYTES_LIMIT) *
+					   MAX_DMA_DESC_NUM_HS_ISOC;
 	else
-		maxsize = DEV_DMA_NBYTES_LIMIT;
-
-	/* Above size of one descriptor was chosen, multiple it */
-	maxsize *= MAX_DMA_DESC_NUM_GENERIC;
+		maxsize = DEV_DMA_NBYTES_LIMIT * MAX_DMA_DESC_NUM_GENERIC;
 
 	return maxsize;
 }
@@ -934,7 +932,7 @@ static int dwc2_gadget_fill_isoc_desc(struct dwc2_hsotg_ep *hs_ep,
 
 	/* Update index of last configured entry in the chain */
 	hs_ep->next_desc++;
-	if (hs_ep->next_desc >= MAX_DMA_DESC_NUM_GENERIC)
+	if (hs_ep->next_desc >= MAX_DMA_DESC_NUM_HS_ISOC)
 		hs_ep->next_desc = 0;
 
 	return 0;
@@ -966,7 +964,7 @@ static void dwc2_gadget_start_isoc_ddma(struct dwc2_hsotg_ep *hs_ep)
 	}
 
 	/* Initialize descriptor chain by Host Busy status */
-	for (i = 0; i < MAX_DMA_DESC_NUM_GENERIC; i++) {
+	for (i = 0; i < MAX_DMA_DESC_NUM_HS_ISOC; i++) {
 		desc = &hs_ep->desc_list[i];
 		desc->status = 0;
 		desc->status |= (DEV_DMA_BUFF_STS_HBUSY
@@ -2173,7 +2171,7 @@ static void dwc2_gadget_complete_isoc_request_ddma(struct dwc2_hsotg_ep *hs_ep)
 		dwc2_hsotg_complete_request(hsotg, hs_ep, hs_req, 0);
 
 		hs_ep->compl_desc++;
-		if (hs_ep->compl_desc > (MAX_DMA_DESC_NUM_GENERIC - 1))
+		if (hs_ep->compl_desc > (MAX_DMA_DESC_NUM_HS_ISOC - 1))
 			hs_ep->compl_desc = 0;
 		desc_sts = hs_ep->desc_list[hs_ep->compl_desc].status;
 	}
@@ -3915,6 +3913,7 @@ static int dwc2_hsotg_ep_enable(struct usb_ep *ep,
 	unsigned int i, val, size;
 	int ret = 0;
 	unsigned char ep_type;
+	int desc_num;
 
 	dev_dbg(hsotg->dev,
 		"%s: ep %s: a 0x%02x, attr 0x%02x, mps 0x%04x, intr %d\n",
@@ -3961,11 +3960,15 @@ static int dwc2_hsotg_ep_enable(struct usb_ep *ep,
 	dev_dbg(hsotg->dev, "%s: read DxEPCTL=0x%08x from 0x%08x\n",
 		__func__, epctrl, epctrl_reg);
 
+	if (using_desc_dma(hsotg) && ep_type == USB_ENDPOINT_XFER_ISOC)
+		desc_num = MAX_DMA_DESC_NUM_HS_ISOC;
+	else
+		desc_num = MAX_DMA_DESC_NUM_GENERIC;
+
 	/* Allocate DMA descriptor chain for non-ctrl endpoints */
 	if (using_desc_dma(hsotg) && !hs_ep->desc_list) {
 		hs_ep->desc_list = dmam_alloc_coherent(hsotg->dev,
-			MAX_DMA_DESC_NUM_GENERIC *
-			sizeof(struct dwc2_dma_desc),
+			desc_num * sizeof(struct dwc2_dma_desc),
 			&hs_ep->desc_list_dma, GFP_ATOMIC);
 		if (!hs_ep->desc_list) {
 			ret = -ENOMEM;
@@ -4108,7 +4111,7 @@ static int dwc2_hsotg_ep_enable(struct usb_ep *ep,
 
 error2:
 	if (ret && using_desc_dma(hsotg) && hs_ep->desc_list) {
-		dmam_free_coherent(hsotg->dev, MAX_DMA_DESC_NUM_GENERIC *
+		dmam_free_coherent(hsotg->dev, desc_num *
 			sizeof(struct dwc2_dma_desc),
 			hs_ep->desc_list, hs_ep->desc_list_dma);
 		hs_ep->desc_list = NULL;