1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * 16550 serial console support. |
4 | * |
5 | * Original copied from <file:arch/ppc/boot/common/ns16550.c> |
6 | * (which had no copyright) |
7 | * Modifications: 2006 (c) MontaVista Software, Inc. |
8 | * |
9 | * Modified by: Mark A. Greer <mgreer@mvista.com> |
10 | */ |
11 | #include <stdarg.h> |
12 | #include <stddef.h> |
13 | #include "types.h" |
14 | #include "string.h" |
15 | #include "stdio.h" |
16 | #include "io.h" |
17 | #include "ops.h" |
18 | #include "of.h" |
19 | |
20 | #define UART_DLL 0 /* Out: Divisor Latch Low */ |
21 | #define UART_DLM 1 /* Out: Divisor Latch High */ |
22 | #define UART_FCR 2 /* Out: FIFO Control Register */ |
23 | #define UART_LCR 3 /* Out: Line Control Register */ |
24 | #define UART_MCR 4 /* Out: Modem Control Register */ |
25 | #define UART_LSR 5 /* In: Line Status Register */ |
26 | #define UART_LSR_THRE 0x20 /* Transmit-hold-register empty */ |
27 | #define UART_LSR_DR 0x01 /* Receiver data ready */ |
28 | #define UART_MSR 6 /* In: Modem Status Register */ |
29 | #define UART_SCR 7 /* I/O: Scratch Register */ |
30 | |
31 | static unsigned char *reg_base; |
32 | static u32 reg_shift; |
33 | |
34 | static int ns16550_open(void) |
35 | { |
36 | out_8(addr: reg_base + (UART_FCR << reg_shift), val: 0x06); |
37 | return 0; |
38 | } |
39 | |
40 | static void ns16550_putc(unsigned char c) |
41 | { |
42 | while ((in_8(addr: reg_base + (UART_LSR << reg_shift)) & UART_LSR_THRE) == 0); |
43 | out_8(addr: reg_base, val: c); |
44 | } |
45 | |
46 | static unsigned char ns16550_getc(void) |
47 | { |
48 | while ((in_8(addr: reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) == 0); |
49 | return in_8(addr: reg_base); |
50 | } |
51 | |
52 | static u8 ns16550_tstc(void) |
53 | { |
54 | return ((in_8(addr: reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) != 0); |
55 | } |
56 | |
57 | int ns16550_console_init(void *devp, struct serial_console_data *scdp) |
58 | { |
59 | int n; |
60 | u32 reg_offset; |
61 | |
62 | if (dt_get_virtual_reg(node: devp, addr: (void **)®_base, nres: 1) < 1) { |
63 | printf(fmt: "virt reg parse fail...\r\n" ); |
64 | return -1; |
65 | } |
66 | |
67 | n = getprop(devp, name: "reg-offset" , buf: ®_offset, buflen: sizeof(reg_offset)); |
68 | if (n == sizeof(reg_offset)) |
69 | reg_base += be32_to_cpu(reg_offset); |
70 | |
71 | n = getprop(devp, name: "reg-shift" , buf: ®_shift, buflen: sizeof(reg_shift)); |
72 | if (n != sizeof(reg_shift)) |
73 | reg_shift = 0; |
74 | else |
75 | reg_shift = be32_to_cpu(reg_shift); |
76 | |
77 | scdp->open = ns16550_open; |
78 | scdp->putc = ns16550_putc; |
79 | scdp->getc = ns16550_getc; |
80 | scdp->tstc = ns16550_tstc; |
81 | scdp->close = NULL; |
82 | |
83 | return 0; |
84 | } |
85 | |