drivers: ti: uart: Add TI specific 16550 initialization
On TI platforms the UART is disabled by default and must be explicitly
enabled using the MDR1 register.
NOTE: The original definition of
http://www.ti.com/lit/ds/symlink/pc16550d.pdf has no MDR register, but
many TI SoCs implementing 16550 do have a quirky MDR register
implemented. So, this should be enabled with TI_16550_MDR_QUIRK
NOTE: In such implementation, the CSR register does not exist.
Signed-off-by: Benjamin Fair <b-fair@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Andrew F. Davis <afd@ti.com>
diff --git a/drivers/ti/uart/aarch64/16550_console.S b/drivers/ti/uart/aarch64/16550_console.S
index 56e7e5c..d46fa61 100644
--- a/drivers/ti/uart/aarch64/16550_console.S
+++ b/drivers/ti/uart/aarch64/16550_console.S
@@ -66,6 +66,10 @@
/* no interrupt */
mov w3, #0
str w3, [x0, #UARTIER]
+#ifdef TI_16550_MDR_QUIRK
+ /* UART must be enabled on some platforms via the MDR register */
+ str w3, [x0, #UARTMDR1]
+#endif /* TI_16550_MDR_QUIRK */
/* enable fifo, DMA */
mov w3, #(UARTFCR_FIFOEN | UARTFCR_DMAEN)
str w3, [x0, #UARTFCR]
diff --git a/include/drivers/ti/uart/uart_16550.h b/include/drivers/ti/uart/uart_16550.h
index 9eba41a..b00f664 100644
--- a/include/drivers/ti/uart/uart_16550.h
+++ b/include/drivers/ti/uart/uart_16550.h
@@ -23,6 +23,8 @@
#define UARTMSR 0x18
#define UARTSPR 0x1c
#define UARTCSR 0x20
+/* Some instances have MDR1 defined as well */
+#define UARTMDR1 0x20
#define UARTRXFIFOCFG 0x24
#define UARTMIE 0x28
#define UARTVNDR 0x2c