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From:   Hyunki Koo <hyunki00.koo@gmail.com>
To:     gregkh@linuxfoundation.org, robh+dt@kernel.org, krzk@kernel.org
Cc:     Hyunki Koo <hyunki00.koo@samsung.com>,
        Kukjin Kim <kgene@kernel.org>, Jiri Slaby <jslaby@suse.com>,
        linux-serial@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-samsung-soc@vger.kernel.org
Subject: [PATCH v7 2/2] Support 32-bit access for the TX/RX hold registers UTXH and URXH.
Date:   Sat, 11 Apr 2020 21:33:24 +0900
Message-Id: <20200411123325.30501-1-hyunki00.koo@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Hyunki Koo <hyunki00.koo@samsung.com>

This is required for some newer SoCs.

Signed-off-by: Hyunki Koo <hyunki00.koo@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Tested on Odroid HC1 (Exynos5422):
Tested-by: Krzysztof Kozlowski <krzk@kernel.org>
---
v2: 
line 954 : change rd_regl to rd_reg in for backward compatibility.
line 2031: Add init value for ourport->port.iotype  to UPIO_MEM 
v3:
line 2031: remove redundant init value  for ourport->port.iotype 
v4:
correct variable types and change misleading function name
v5:
add dt-binding and go as first patch in this series.
v6:
no change in this patch, only chaged in [PATCH v6 1/2]
v7:
add reviewed by and tested by
---
 drivers/tty/serial/samsung_tty.c | 76 +++++++++++++++++++++++++++-----
 1 file changed, 64 insertions(+), 12 deletions(-)

diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
index 73f951d65b93..bdf1d4d12cb1 100644
--- a/drivers/tty/serial/samsung_tty.c
+++ b/drivers/tty/serial/samsung_tty.c
@@ -154,12 +154,47 @@ struct s3c24xx_uart_port {
 #define portaddrl(port, reg) \
 	((unsigned long *)(unsigned long)((port)->membase + (reg)))
 
-#define rd_regb(port, reg) (readb_relaxed(portaddr(port, reg)))
+static u32 rd_reg(struct uart_port *port, u32 reg)
+{
+	switch (port->iotype) {
+	case UPIO_MEM:
+		return readb_relaxed(portaddr(port, reg));
+	case UPIO_MEM32:
+		return readl_relaxed(portaddr(port, reg));
+	default:
+		return 0;
+	}
+	return 0;
+}
+
 #define rd_regl(port, reg) (readl_relaxed(portaddr(port, reg)))
 
-#define wr_regb(port, reg, val) writeb_relaxed(val, portaddr(port, reg))
+static void wr_reg(struct uart_port *port, u32 reg, u32 val)
+{
+	switch (port->iotype) {
+	case UPIO_MEM:
+		writeb_relaxed(val, portaddr(port, reg));
+		break;
+	case UPIO_MEM32:
+		writel_relaxed(val, portaddr(port, reg));
+		break;
+	}
+}
+
 #define wr_regl(port, reg, val) writel_relaxed(val, portaddr(port, reg))
 
+static void wr_reg_barrier(struct uart_port *port, u32 reg, u32 val)
+{
+	switch (port->iotype) {
+	case UPIO_MEM:
+		writeb(val, portaddr(port, reg));
+		break;
+	case UPIO_MEM32:
+		writel(val, portaddr(port, reg));
+		break;
+	}
+}
+
 /* Byte-order aware bit setting/clearing functions. */
 
 static inline void s3c24xx_set_bit(struct uart_port *port, int idx,
@@ -714,7 +749,7 @@ static void s3c24xx_serial_rx_drain_fifo(struct s3c24xx_uart_port *ourport)
 		fifocnt--;
 
 		uerstat = rd_regl(port, S3C2410_UERSTAT);
-		ch = rd_regb(port, S3C2410_URXH);
+		ch = rd_reg(port, S3C2410_URXH);
 
 		if (port->flags & UPF_CONS_FLOW) {
 			int txe = s3c24xx_serial_txempty_nofifo(port);
@@ -826,7 +861,7 @@ static irqreturn_t s3c24xx_serial_tx_chars(int irq, void *id)
 	}
 
 	if (port->x_char) {
-		wr_regb(port, S3C2410_UTXH, port->x_char);
+		wr_reg(port, S3C2410_UTXH, port->x_char);
 		port->icount.tx++;
 		port->x_char = 0;
 		goto out;
@@ -852,7 +887,7 @@ static irqreturn_t s3c24xx_serial_tx_chars(int irq, void *id)
 		if (rd_regl(port, S3C2410_UFSTAT) & ourport->info->tx_fifofull)
 			break;
 
-		wr_regb(port, S3C2410_UTXH, xmit->buf[xmit->tail]);
+		wr_reg(port, S3C2410_UTXH, xmit->buf[xmit->tail]);
 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 		port->icount.tx++;
 		count--;
@@ -916,7 +951,7 @@ static unsigned int s3c24xx_serial_tx_empty(struct uart_port *port)
 /* no modem control lines */
 static unsigned int s3c24xx_serial_get_mctrl(struct uart_port *port)
 {
-	unsigned int umstat = rd_regb(port, S3C2410_UMSTAT);
+	unsigned int umstat = rd_reg(port, S3C2410_UMSTAT);
 
 	if (umstat & S3C2410_UMSTAT_CTS)
 		return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
@@ -1974,7 +2009,7 @@ static int s3c24xx_serial_probe(struct platform_device *pdev)
 	struct device_node *np = pdev->dev.of_node;
 	struct s3c24xx_uart_port *ourport;
 	int index = probe_index;
-	int ret;
+	int ret, prop = 0;
 
 	if (np) {
 		ret = of_alias_get_id(np, "serial");
@@ -2000,10 +2035,27 @@ static int s3c24xx_serial_probe(struct platform_device *pdev)
 			dev_get_platdata(&pdev->dev) :
 			ourport->drv_data->def_cfg;
 
-	if (np)
+	if (np) {
 		of_property_read_u32(np,
 			"samsung,uart-fifosize", &ourport->port.fifosize);
 
+		if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
+			switch (prop) {
+			case 1:
+				ourport->port.iotype = UPIO_MEM;
+				break;
+			case 4:
+				ourport->port.iotype = UPIO_MEM32;
+				break;
+			default:
+				dev_warn(&pdev->dev, "unsupported reg-io-width (%d)\n",
+						prop);
+				ret = -EINVAL;
+				break;
+			}
+		}
+	}
+
 	if (ourport->drv_data->fifosize[index])
 		ourport->port.fifosize = ourport->drv_data->fifosize[index];
 	else if (ourport->info->fifosize)
@@ -2185,7 +2237,7 @@ static int s3c24xx_serial_get_poll_char(struct uart_port *port)
 	if (s3c24xx_serial_rx_fifocnt(ourport, ufstat) == 0)
 		return NO_POLL_CHAR;
 
-	return rd_regb(port, S3C2410_URXH);
+	return rd_reg(port, S3C2410_URXH);
 }
 
 static void s3c24xx_serial_put_poll_char(struct uart_port *port,
@@ -2200,7 +2252,7 @@ static void s3c24xx_serial_put_poll_char(struct uart_port *port,
 
 	while (!s3c24xx_serial_console_txrdy(port, ufcon))
 		cpu_relax();
-	wr_regb(port, S3C2410_UTXH, c);
+	wr_reg(port, S3C2410_UTXH, c);
 }
 
 #endif /* CONFIG_CONSOLE_POLL */
@@ -2212,7 +2264,7 @@ s3c24xx_serial_console_putchar(struct uart_port *port, int ch)
 
 	while (!s3c24xx_serial_console_txrdy(port, ufcon))
 		cpu_relax();
-	wr_regb(port, S3C2410_UTXH, ch);
+	wr_reg(port, S3C2410_UTXH, ch);
 }
 
 static void
@@ -2612,7 +2664,7 @@ static void samsung_early_putc(struct uart_port *port, int c)
 	else
 		samsung_early_busyuart(port);
 
-	writeb(c, port->membase + S3C2410_UTXH);
+	wr_reg_barrier(port, S3C2410_UTXH, c);
 }
 
 static void samsung_early_write(struct console *con, const char *s,
-- 
2.17.1