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serial: nulldev: Implement "pending" function to fix tstc return "true"
[people/ms/u-boot.git] / drivers / serial / altera_uart.c
CommitLineData
c9d4f46b
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1/*
2 * (C) Copyright 2004, Psyent Corporation <www.psyent.com>
3 * Scott McNutt <smcnutt@psyent.com>
4 *
1a459660 5 * SPDX-License-Identifier: GPL-2.0+
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6 */
7
c9d4f46b 8#include <common.h>
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9#include <dm.h>
10#include <errno.h>
b207d645 11#include <serial.h>
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12#include <asm/io.h>
13
14DECLARE_GLOBAL_DATA_PTR;
15
16/* status register */
17#define ALTERA_UART_TMT BIT(5) /* tx empty */
18#define ALTERA_UART_TRDY BIT(6) /* tx ready */
19#define ALTERA_UART_RRDY BIT(7) /* rx ready */
c9d4f46b 20
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21struct altera_uart_regs {
22 u32 rxdata; /* Rx data reg */
23 u32 txdata; /* Tx data reg */
24 u32 status; /* Status reg */
25 u32 control; /* Control reg */
26 u32 divisor; /* Baud rate divisor reg */
27 u32 endofpacket; /* End-of-packet reg */
28};
29
30struct altera_uart_platdata {
31 struct altera_uart_regs *regs;
32 unsigned int uartclk;
33};
86450710 34
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35static int altera_uart_setbrg(struct udevice *dev, int baudrate)
36{
37 struct altera_uart_platdata *plat = dev->platdata;
38 struct altera_uart_regs *const regs = plat->regs;
39 u32 div;
c9d4f46b 40
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41 div = (plat->uartclk / baudrate) - 1;
42 writel(div, &regs->divisor);
c9d4f46b 43
da2f838d 44 return 0;
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45}
46
da2f838d 47static int altera_uart_putc(struct udevice *dev, const char ch)
b207d645 48{
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49 struct altera_uart_platdata *plat = dev->platdata;
50 struct altera_uart_regs *const regs = plat->regs;
c9d4f46b 51
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52 if (!(readl(&regs->status) & ALTERA_UART_TRDY))
53 return -EAGAIN;
c9d4f46b 54
da2f838d 55 writel(ch, &regs->txdata);
c9d4f46b 56
da2f838d 57 return 0;
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58}
59
da2f838d 60static int altera_uart_pending(struct udevice *dev, bool input)
c9d4f46b 61{
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62 struct altera_uart_platdata *plat = dev->platdata;
63 struct altera_uart_regs *const regs = plat->regs;
64 u32 st = readl(&regs->status);
65
66 if (input)
67 return st & ALTERA_UART_RRDY ? 1 : 0;
68 else
69 return !(st & ALTERA_UART_TMT);
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70}
71
da2f838d 72static int altera_uart_getc(struct udevice *dev)
c9d4f46b 73{
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74 struct altera_uart_platdata *plat = dev->platdata;
75 struct altera_uart_regs *const regs = plat->regs;
76
77 if (!(readl(&regs->status) & ALTERA_UART_RRDY))
78 return -EAGAIN;
79
80 return readl(&regs->rxdata) & 0xff;
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81}
82
da2f838d 83static int altera_uart_probe(struct udevice *dev)
c9d4f46b 84{
da2f838d 85 return 0;
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86}
87
da2f838d 88static int altera_uart_ofdata_to_platdata(struct udevice *dev)
c9d4f46b 89{
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90 struct altera_uart_platdata *plat = dev_get_platdata(dev);
91
a821c4af 92 plat->regs = map_physmem(devfdt_get_addr(dev),
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93 sizeof(struct altera_uart_regs),
94 MAP_NOCACHE);
e160f7d4 95 plat->uartclk = fdtdec_get_int(gd->fdt_blob, dev_of_offset(dev),
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96 "clock-frequency", 0);
97
98 return 0;
c9d4f46b 99}
b207d645 100
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101static const struct dm_serial_ops altera_uart_ops = {
102 .putc = altera_uart_putc,
103 .pending = altera_uart_pending,
104 .getc = altera_uart_getc,
105 .setbrg = altera_uart_setbrg,
106};
107
108static const struct udevice_id altera_uart_ids[] = {
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109 { .compatible = "altr,uart-1.0" },
110 {}
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111};
112
113U_BOOT_DRIVER(altera_uart) = {
114 .name = "altera_uart",
115 .id = UCLASS_SERIAL,
116 .of_match = altera_uart_ids,
117 .ofdata_to_platdata = altera_uart_ofdata_to_platdata,
118 .platdata_auto_alloc_size = sizeof(struct altera_uart_platdata),
119 .probe = altera_uart_probe,
120 .ops = &altera_uart_ops,
121 .flags = DM_FLAG_PRE_RELOC,
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122};
123
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124#ifdef CONFIG_DEBUG_UART_ALTERA_UART
125
126#include <debug_uart.h>
127
e03c17d0 128static inline void _debug_uart_init(void)
b207d645 129{
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130 struct altera_uart_regs *regs = (void *)CONFIG_DEBUG_UART_BASE;
131 u32 div;
132
133 div = (CONFIG_DEBUG_UART_CLOCK / CONFIG_BAUDRATE) - 1;
134 writel(div, &regs->divisor);
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135}
136
da2f838d 137static inline void _debug_uart_putc(int ch)
b207d645 138{
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139 struct altera_uart_regs *regs = (void *)CONFIG_DEBUG_UART_BASE;
140
141 while (1) {
142 u32 st = readl(&regs->status);
143
144 if (st & ALTERA_UART_TRDY)
145 break;
146 }
147
148 writel(ch, &regs->txdata);
b207d645 149}
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150
151DEBUG_UART_FUNCS
152
153#endif