serial: samsung: 32-bit access for TX/RX hold registers

Support 32-bit access for the TX/RX hold registers UTXH and URXH.

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>
Link: https://lore.kernel.org/r/20200506080242.18623-3-hyunki00.koo@samsung.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 57 insertions, 5 deletions

diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
index 326b0164609c..6ef614d8648c 100644
--- a/drivers/tty/serial/samsung_tty.c
+++ b/drivers/tty/serial/samsung_tty.c
@@ -154,10 +154,33 @@ struct s3c24xx_uart_port {
 #define portaddrl(port, reg) \
 	((unsigned long *)(unsigned long)((port)->membase + (reg)))
 
-#define rd_reg(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_reg(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))
 
 /* Byte-order aware bit setting/clearing functions. */
@@ -1974,7 +1997,7 @@ 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 +2023,27 @@ 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)
@@ -2587,6 +2627,18 @@ module_platform_driver(samsung_serial_driver);
  * Early console.
  */
 
+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;
+	}
+}
+
 struct samsung_early_console_data {
 	u32 txfull_mask;
 };
@@ -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,