1 files changed, 74 insertions, 0 deletions
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index d406a75456a0..7913d1b50e38 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -125,6 +125,80 @@ int dwc3_gadget_set_link_state(struct dwc3 *dwc, enum dwc3_link_state state)
 	return -ETIMEDOUT;
 }
 
+/**
+ * dwc3_gadget_resize_tx_fifos - reallocate fifo spaces for current use-case
+ * @dwc: pointer to our context structure
+ *
+ * This function will a best effort FIFO allocation in order
+ * to improve FIFO usage and throughput, while still allowing
+ * us to enable as many endpoints as possible.
+ *
+ * Keep in mind that this operation will be highly dependent
+ * on the configured size for RAM1 - which contains TxFifo -,
+ * the amount of endpoints enabled on coreConsultant tool, and
+ * the width of the Master Bus.
+ *
+ * In the ideal world, we would always be able to satisfy the
+ * following equation:
+ *
+ * ((512 + 2 * MDWIDTH-Bytes) + (Number of IN Endpoints - 1) * \
+ * (3 * (1024 + MDWIDTH-Bytes) + MDWIDTH-Bytes)) / MDWIDTH-Bytes
+ *
+ * Unfortunately, due to many variables that's not always the case.
+ */
+int dwc3_gadget_resize_tx_fifos(struct dwc3 *dwc)
+{
+	int		last_fifo_depth = 0;
+	int		ram1_depth;
+	int		fifo_size;
+	int		mdwidth;
+	int		num;
+
+	if (!dwc->needs_fifo_resize)
+		return 0;
+
+	ram1_depth = DWC3_RAM1_DEPTH(dwc->hwparams.hwparams7);
+	mdwidth = DWC3_MDWIDTH(dwc->hwparams.hwparams0);
+
+	/* MDWIDTH is represented in bits, we need it in bytes */
+	mdwidth >>= 3;
+
+	/*
+	 * FIXME For now we will only allocate 1 wMaxPacketSize space
+	 * for each enabled endpoint, later patches will come to
+	 * improve this algorithm so that we better use the internal
+	 * FIFO space
+	 */
+	for (num = 0; num < DWC3_ENDPOINTS_NUM; num++) {
+		struct dwc3_ep	*dep = dwc->eps[num];
+		int		fifo_number = dep->number >> 1;
+		int		tmp;
+
+		if (!(dep->number & 1))
+			continue;
+
+		if (!(dep->flags & DWC3_EP_ENABLED))
+			continue;
+
+		tmp = dep->endpoint.maxpacket;
+		tmp += mdwidth;
+		tmp += mdwidth;
+
+		fifo_size = DIV_ROUND_UP(tmp, mdwidth);
+		fifo_size |= (last_fifo_depth << 16);
+
+		dev_vdbg(dwc->dev, "%s: Fifo Addr %04x Size %d\n",
+				dep->name, last_fifo_depth, fifo_size & 0xffff);
+
+		dwc3_writel(dwc->regs, DWC3_GTXFIFOSIZ(fifo_number),
+				fifo_size);
+
+		last_fifo_depth += (fifo_size & 0xffff);
+	}
+
+	return 0;
+}
+
 void dwc3_map_buffer_to_dma(struct dwc3_request *req)
 {
 	struct dwc3			*dwc = req->dep->dwc;