diff mbox series

[v5,6/7] serial: 8250_em: Use pseudo offset for UART_FCR

Message ID 20230227114152.22265-7-biju.das.jz@bp.renesas.com
State New
Headers show
Series Update Renesas {EMMA mobile, RZ/V2M} UART Port type | expand

Commit Message

Biju Das Feb. 27, 2023, 11:41 a.m. UTC
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.

Define UART_FCR_EM macro with a high value to avoid overlapping
with existing UART_* register defines and define another macro
UART_FCR_EM_HW for the real offset.

Use these macros in serial8250_em_serial{_in/_out} function to
read/write FCR register.

Suggested-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
v4->v5:
 * Updated commit description.
 * Retained UART_FCR in serial8250_em_serial_out() and is removed
   from next patch.
v4:
 * New patch. Used UART_FCR_EM for read/write of FCR register.
---
 drivers/tty/serial/8250/8250_em.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/tty/serial/8250/8250_em.c b/drivers/tty/serial/8250/8250_em.c
index dcf1761e8ef5..7614ced9377e 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 +36,15 @@  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:
+	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;
@@ -55,6 +65,8 @@  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) */