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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
0c176fa8 MG |
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" | |
c93f8084 | 18 | #include "of.h" |
0c176fa8 MG |
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(reg_base + (UART_FCR << reg_shift), 0x06); | |
37 | return 0; | |
38 | } | |
39 | ||
40 | static void ns16550_putc(unsigned char c) | |
41 | { | |
42 | while ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_THRE) == 0); | |
43 | out_8(reg_base, c); | |
44 | } | |
45 | ||
46 | static unsigned char ns16550_getc(void) | |
47 | { | |
48 | while ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) == 0); | |
49 | return in_8(reg_base); | |
50 | } | |
51 | ||
52 | static u8 ns16550_tstc(void) | |
53 | { | |
54 | return ((in_8(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; | |
2f0b45f8 | 60 | u32 reg_offset; |
0c176fa8 | 61 | |
c93f8084 BH |
62 | if (dt_get_virtual_reg(devp, (void **)®_base, 1) < 1) { |
63 | printf("virt reg parse fail...\r\n"); | |
da0a5f0c | 64 | return -1; |
c93f8084 | 65 | } |
0c176fa8 | 66 | |
2f0b45f8 JL |
67 | n = getprop(devp, "reg-offset", ®_offset, sizeof(reg_offset)); |
68 | if (n == sizeof(reg_offset)) | |
c93f8084 | 69 | reg_base += be32_to_cpu(reg_offset); |
2f0b45f8 | 70 | |
0c176fa8 MG |
71 | n = getprop(devp, "reg-shift", ®_shift, sizeof(reg_shift)); |
72 | if (n != sizeof(reg_shift)) | |
73 | reg_shift = 0; | |
c93f8084 BH |
74 | else |
75 | reg_shift = be32_to_cpu(reg_shift); | |
0c176fa8 MG |
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 | } |