1 files changed, 68 insertions, 0 deletions

diff --git a/drivers/usb/dwc2/core.c b/drivers/usb/dwc2/core.c
index 1d129884cc39..27d2c9b8a034 100644
--- a/drivers/usb/dwc2/core.c
+++ b/drivers/usb/dwc2/core.c
@@ -507,6 +507,72 @@ void dwc2_disable_host_interrupts(struct dwc2_hsotg *hsotg)
 	writel(intmsk, hsotg->regs + GINTMSK);
 }
 
+/*
+ * dwc2_calculate_dynamic_fifo() - Calculates the default fifo size
+ * For system that have a total fifo depth that is smaller than the default
+ * RX + TX fifo size.
+ *
+ * @hsotg: Programming view of DWC_otg controller
+ */
+static void dwc2_calculate_dynamic_fifo(struct dwc2_hsotg *hsotg)
+{
+	struct dwc2_core_params *params = hsotg->core_params;
+	struct dwc2_hw_params *hw = &hsotg->hw_params;
+	u32 rxfsiz, nptxfsiz, ptxfsiz, total_fifo_size;
+
+	total_fifo_size = hw->total_fifo_size;
+	rxfsiz = params->host_rx_fifo_size;
+	nptxfsiz = params->host_nperio_tx_fifo_size;
+	ptxfsiz = params->host_perio_tx_fifo_size;
+
+	/*
+	 * Will use Method 2 defined in the DWC2 spec: minimum FIFO depth
+	 * allocation with support for high bandwidth endpoints. Synopsys
+	 * defines MPS(Max Packet size) for a periodic EP=1024, and for
+	 * non-periodic as 512.
+	 */
+	if (total_fifo_size < (rxfsiz + nptxfsiz + ptxfsiz)) {
+		/*
+		 * For Buffer DMA mode/Scatter Gather DMA mode
+		 * 2 * ((Largest Packet size / 4) + 1 + 1) + n
+		 * with n = number of host channel.
+		 * 2 * ((1024/4) + 2) = 516
+		 */
+		rxfsiz = 516 + hw->host_channels;
+
+		/*
+		 * min non-periodic tx fifo depth
+		 * 2 * (largest non-periodic USB packet used / 4)
+		 * 2 * (512/4) = 256
+		 */
+		nptxfsiz = 256;
+
+		/*
+		 * min periodic tx fifo depth
+		 * (largest packet size*MC)/4
+		 * (1024 * 3)/4 = 768
+		 */
+		ptxfsiz = 768;
+
+		params->host_rx_fifo_size = rxfsiz;
+		params->host_nperio_tx_fifo_size = nptxfsiz;
+		params->host_perio_tx_fifo_size = ptxfsiz;
+	}
+
+	/*
+	 * If the summation of RX, NPTX and PTX fifo sizes is still
+	 * bigger than the total_fifo_size, then we have a problem.
+	 *
+	 * We won't be able to allocate as many endpoints. Right now,
+	 * we're just printing an error message, but ideally this FIFO
+	 * allocation algorithm would be improved in the future.
+	 *
+	 * FIXME improve this FIFO allocation algorithm.
+	 */
+	if (unlikely(total_fifo_size < (rxfsiz + nptxfsiz + ptxfsiz)))
+		dev_err(hsotg->dev, "invalid fifo sizes\n");
+}
+
 static void dwc2_config_fifos(struct dwc2_hsotg *hsotg)
 {
 	struct dwc2_core_params *params = hsotg->core_params;
@@ -515,6 +581,8 @@ static void dwc2_config_fifos(struct dwc2_hsotg *hsotg)
 	if (!params->enable_dynamic_fifo)
 		return;
 
+	dwc2_calculate_dynamic_fifo(hsotg);
+
 	/* Rx FIFO */
 	grxfsiz = readl(hsotg->regs + GRXFSIZ);
 	dev_dbg(hsotg->dev, "initial grxfsiz=%08x\n", grxfsiz);