[PATCH v10 3/3] tty: samsung_tty: 32-bit access for TX/RX hold registers

From: Hyunki Koo
Date: Wed May 06 2020 - 04:03:10 EST


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@xxxxxxxxxxx>
Reviewed-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
Tested on Odroid HC1 (Exynos5422):
Tested-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
---
drivers/tty/serial/samsung_tty.c | 62 ++++++++++++++++++++++++++++++++++++----
1 file 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,
--
2.15.0.rc1