[PATCH v1 2/4] usb: dwc2: Port FIFO configuration sync from Linux v6.3

[Oleksij Rempel <o.rempel@pengutronix.de>]

This patch ports the FIFO configuration from Linux kernel v6.3. The
change mainly syncs the code with the kernel and removes an unused
register read and value assignment in the first step of the loop
(txfsz = dwc2_readl(dwc2, DPTXFSIZN(ep));).

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 drivers/usb/dwc2/gadget.c | 29 +++++++++++++----------------
 1 file changed, 13 insertions(+), 16 deletions(-)

diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
index 028f3c877a..bb55888abf 100644
--- a/drivers/usb/dwc2/gadget.c
+++ b/drivers/usb/dwc2/gadget.c
@@ -1549,9 +1549,8 @@ static void dwc2_gadget_setup_fifo(struct dwc2 *dwc2)
 	u32 np_tx_fifo_size = dwc2->params.g_np_tx_fifo_size;
 	u32 rx_fifo_size = dwc2->params.g_rx_fifo_size;
 	u32 fifo_size = dwc2->hw_params.total_fifo_size;
-	u32 *tx_fifo_size = dwc2->params.g_tx_fifo_size;
-	u32 size, depth;
-	u32 txfsz;
+	u32 *txfsz = dwc2->params.g_tx_fifo_size;
+	u32 size, val;
 
 	/* Reset fifo map if not correctly cleared during previous session */
 	WARN_ON(dwc2->fifo_map);
@@ -1578,19 +1577,17 @@ static void dwc2_gadget_setup_fifo(struct dwc2 *dwc2)
 	 * them to endpoints dynamically according to maxpacket size value of
 	 * given endpoint.
 	 */
-
-	for (ep = 1; ep < dwc2->num_eps; ep++) {
-		txfsz = dwc2_readl(dwc2, DPTXFSIZN(ep));
-		depth = tx_fifo_size[ep];
-
-		if (addr + depth > fifo_size)
-			dwc2_err(dwc2, "insufficient fifo memory\n");
-
-		txfsz = depth << FIFOSIZE_DEPTH_SHIFT;
-		txfsz |= addr & 0xffff;
-		dwc2_writel(dwc2, txfsz, DPTXFSIZN(ep));
-
-		addr += depth;
+	for (ep = 1; ep < DWC2_MAX_EPS_CHANNELS; ep++) {
+		if (!txfsz[ep])
+			continue;
+		val = addr;
+		val |= txfsz[ep] << FIFOSIZE_DEPTH_SHIFT;
+		WARN_ONCE(addr + txfsz[ep] > fifo_size,
+			  "insufficient fifo memory");
+		addr += txfsz[ep];
+
+		dwc2_writel(dwc2, val, DPTXFSIZN(ep));
+		val = dwc2_readl(dwc2, DPTXFSIZN(ep));
 	}
 
 	dwc2_writel(dwc2, dwc2->hw_params.total_fifo_size |
-- 
2.39.2