linux-kernel - [PATCH v5 09/14] tty: serial: qcom-geni-serial: refactor qcom_geni_serial_send_chunk

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Message-Id: <20221202085554.59637-10-brgl@bgdev.pl>
Date:   Fri,  2 Dec 2022 09:55:49 +0100
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jirislaby@...nel.org>,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        Vinod Koul <vkoul@...nel.org>, Alex Elder <elder@...nel.org>,
        Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc:     linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-serial@...r.kernel.org,
        Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: [PATCH v5 09/14] tty: serial: qcom-geni-serial: refactor qcom_geni_serial_send_chunk_fifo()

From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>

Shuffle the code a bit, drop unneeded variables, make types of others
more consistent and use uart_xmit_advance() instead of handling
tail->xmit manually.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
---
 drivers/tty/serial/qcom_geni_serial.c | 28 ++++++++++-----------------
 1 file changed, 10 insertions(+), 18 deletions(-)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 91336d2d20fc..40daf58eb1e7 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -93,7 +93,7 @@
 #define IO_MACRO_IO2_IO3_SWAP		0x4640
 
 /* We always configure 4 bytes per FIFO word */
-#define BYTES_PER_FIFO_WORD		4
+#define BYTES_PER_FIFO_WORD		4U
 
 struct qcom_geni_private_data {
 	/* NOTE: earlycon port will have NULL here */
@@ -704,36 +704,28 @@ static void qcom_geni_serial_start_rx(struct uart_port *uport)
 	writel(irq_en, uport->membase + SE_GENI_M_IRQ_EN);
 }
 
-static int qcom_geni_serial_send_chunk_fifo(struct uart_port *uport,
-					    unsigned int chunk)
+static void qcom_geni_serial_send_chunk_fifo(struct uart_port *uport,
+					     unsigned int chunk)
 {
 	struct qcom_geni_serial_port *port = to_dev_port(uport);
 	struct circ_buf *xmit = &uport->state->xmit;
-	size_t remaining = chunk;
-	int i, tail = xmit->tail;
-
-	for (i = 0; i < chunk; ) {
-		unsigned int tx_bytes;
-		u8 buf[sizeof(u32)];
-		int c;
+	unsigned int tx_bytes, c, remaining = chunk;
+	u8 buf[BYTES_PER_FIFO_WORD];
 
+	while (remaining) {
 		memset(buf, 0, sizeof(buf));
-		tx_bytes = min_t(size_t, remaining, BYTES_PER_FIFO_WORD);
+		tx_bytes = min(remaining, BYTES_PER_FIFO_WORD);
 
 		for (c = 0; c < tx_bytes ; c++) {
-			buf[c] = xmit->buf[tail++];
-			tail &= UART_XMIT_SIZE - 1;
+			buf[c] = xmit->buf[xmit->tail];
+			uart_xmit_advance(uport, 1);
 		}
 
 		iowrite32_rep(uport->membase + SE_GENI_TX_FIFOn, buf, 1);
 
-		i += tx_bytes;
-		uport->icount.tx += tx_bytes;
 		remaining -= tx_bytes;
 		port->tx_remaining -= tx_bytes;
 	}
-
-	return tail;
 }
 
 static void qcom_geni_serial_handle_tx(struct uart_port *uport, bool done,
@@ -778,7 +770,7 @@ static void qcom_geni_serial_handle_tx(struct uart_port *uport, bool done,
 					uport->membase + SE_GENI_M_IRQ_EN);
 	}
 
-	xmit->tail = qcom_geni_serial_send_chunk_fifo(uport, chunk);
+	qcom_geni_serial_send_chunk_fifo(uport, chunk);
 
 	/*
 	 * The tx fifo watermark is level triggered and latched. Though we had
-- 
2.37.2