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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>
This commit is contained in:
Benjamin Fair 2016-10-14 01:13:33 +00:00 committed by Andrew F. Davis
parent 11bebd7cab
commit 529b541e8b
2 changed files with 6 additions and 0 deletions
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4
drivers/ti/uart/aarch64/16550_console.S
View File

@ -66,6 +66,10 @@ func console_16550_core_init
/* 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]

2
include/drivers/ti/uart/uart_16550.h
View File

@ -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