UART_FCR shares the same offset with UART_IIR. We cannot use
UART_FCR in serial8250_em_serial_in() as it overlaps with
UART_IIR.
This patch introduces a macro UART_FCR_EM with a high value to
avoid overlapping with existing UART_* register defines.
This will help us to use UART_FCR_EM consistently in serial8250_em_
serial{_in/_out} function to read/write FCR register.
Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
Suggested-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
---
v4:
* New patch. Used UART_FCR_EM for read/write of FCR register.
---
drivers/tty/serial/8250/8250_em.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/8250/8250_em.c b/drivers/tty/serial/8250/8250_em.c
index 499d7a8847ec..4165fd3bb17a 100644
--- a/drivers/tty/serial/8250/8250_em.c
+++ b/drivers/tty/serial/8250/8250_em.c
@@ -19,6 +19,13 @@
#define UART_DLL_EM 9
#define UART_DLM_EM 10
+/*
+ * A high value for UART_FCR_EM avoids overlapping with existing UART_*
+ * register defines. UART_FCR_EM_HW is the real HW register offset.
+ */
+#define UART_FCR_EM 0x10003
+#define UART_FCR_EM_HW 3
+
struct serial8250_em_priv {
int line;
};
@@ -29,12 +36,14 @@ static void serial8250_em_serial_out(struct uart_port *p, int offset, int value)
case UART_TX: /* TX @ 0x00 */
writeb(value, p->membase);
break;
- case UART_FCR: /* FCR @ 0x0c (+1) */
case UART_LCR: /* LCR @ 0x10 (+1) */
case UART_MCR: /* MCR @ 0x14 (+1) */
case UART_SCR: /* SCR @ 0x20 (+1) */
writel(value, p->membase + ((offset + 1) << 2));
break;
+ case UART_FCR_EM:
+ writel(value, p->membase + (UART_FCR_EM_HW << 2));
+ break;
case UART_IER: /* IER @ 0x04 */
value &= 0x0f; /* only 4 valid bits - not Xscale */
fallthrough;
@@ -54,6 +63,8 @@ static unsigned int serial8250_em_serial_in(struct uart_port *p, int offset)
case UART_MSR: /* MSR @ 0x1c (+1) */
case UART_SCR: /* SCR @ 0x20 (+1) */
return readl(p->membase + ((offset + 1) << 2));
+ case UART_FCR_EM:
+ return readl(p->membase + (UART_FCR_EM_HW << 2));
case UART_IER: /* IER @ 0x04 */
case UART_IIR: /* IIR @ 0x08 */
case UART_DLL_EM: /* DLL @ 0x24 (+9) */
--
2.25.1
