1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * (C) Copyright 2016 Beniamino Galvani <b.galvani@gmail.com>
4 */
5
6 #include <common.h>
7 #include <dm.h>
8 #include <errno.h>
9 #include <fdtdec.h>
10 #include <linux/compiler.h>
11 #include <serial.h>
12
13 struct meson_uart {
14 u32 wfifo;
15 u32 rfifo;
16 u32 control;
17 u32 status;
18 u32 misc;
19 };
20
21 struct meson_serial_platdata {
22 struct meson_uart *reg;
23 };
24
25 /* AML_UART_STATUS bits */
26 #define AML_UART_PARITY_ERR BIT(16)
27 #define AML_UART_FRAME_ERR BIT(17)
28 #define AML_UART_TX_FIFO_WERR BIT(18)
29 #define AML_UART_RX_EMPTY BIT(20)
30 #define AML_UART_TX_FULL BIT(21)
31 #define AML_UART_TX_EMPTY BIT(22)
32 #define AML_UART_XMIT_BUSY BIT(25)
33 #define AML_UART_ERR (AML_UART_PARITY_ERR | \
34 AML_UART_FRAME_ERR | \
35 AML_UART_TX_FIFO_WERR)
36
37 /* AML_UART_CONTROL bits */
38 #define AML_UART_TX_EN BIT(12)
39 #define AML_UART_RX_EN BIT(13)
40 #define AML_UART_TX_RST BIT(22)
41 #define AML_UART_RX_RST BIT(23)
42 #define AML_UART_CLR_ERR BIT(24)
43
meson_serial_init(struct meson_uart * uart)44 static void meson_serial_init(struct meson_uart *uart)
45 {
46 u32 val;
47
48 val = readl(&uart->control);
49 val |= (AML_UART_RX_RST | AML_UART_TX_RST | AML_UART_CLR_ERR);
50 writel(val, &uart->control);
51 val &= ~(AML_UART_RX_RST | AML_UART_TX_RST | AML_UART_CLR_ERR);
52 writel(val, &uart->control);
53 val |= (AML_UART_RX_EN | AML_UART_TX_EN);
54 writel(val, &uart->control);
55 }
56
meson_serial_probe(struct udevice * dev)57 static int meson_serial_probe(struct udevice *dev)
58 {
59 struct meson_serial_platdata *plat = dev->platdata;
60 struct meson_uart *const uart = plat->reg;
61
62 meson_serial_init(uart);
63
64 return 0;
65 }
66
meson_serial_getc(struct udevice * dev)67 static int meson_serial_getc(struct udevice *dev)
68 {
69 struct meson_serial_platdata *plat = dev->platdata;
70 struct meson_uart *const uart = plat->reg;
71
72 if (readl(&uart->status) & AML_UART_RX_EMPTY)
73 return -EAGAIN;
74
75 return readl(&uart->rfifo) & 0xff;
76 }
77
meson_serial_putc(struct udevice * dev,const char ch)78 static int meson_serial_putc(struct udevice *dev, const char ch)
79 {
80 struct meson_serial_platdata *plat = dev->platdata;
81 struct meson_uart *const uart = plat->reg;
82
83 if (readl(&uart->status) & AML_UART_TX_FULL)
84 return -EAGAIN;
85
86 writel(ch, &uart->wfifo);
87
88 return 0;
89 }
90
meson_serial_pending(struct udevice * dev,bool input)91 static int meson_serial_pending(struct udevice *dev, bool input)
92 {
93 struct meson_serial_platdata *plat = dev->platdata;
94 struct meson_uart *const uart = plat->reg;
95 uint32_t status = readl(&uart->status);
96
97 if (input)
98 return !(status & AML_UART_RX_EMPTY);
99 else
100 return !(status & AML_UART_TX_FULL);
101 }
102
meson_serial_ofdata_to_platdata(struct udevice * dev)103 static int meson_serial_ofdata_to_platdata(struct udevice *dev)
104 {
105 struct meson_serial_platdata *plat = dev->platdata;
106 fdt_addr_t addr;
107
108 addr = devfdt_get_addr(dev);
109 if (addr == FDT_ADDR_T_NONE)
110 return -EINVAL;
111
112 plat->reg = (struct meson_uart *)addr;
113
114 return 0;
115 }
116
117 static const struct dm_serial_ops meson_serial_ops = {
118 .putc = meson_serial_putc,
119 .pending = meson_serial_pending,
120 .getc = meson_serial_getc,
121 };
122
123 static const struct udevice_id meson_serial_ids[] = {
124 { .compatible = "amlogic,meson-uart" },
125 { .compatible = "amlogic,meson-gx-uart" },
126 { }
127 };
128
129 U_BOOT_DRIVER(serial_meson) = {
130 .name = "serial_meson",
131 .id = UCLASS_SERIAL,
132 .of_match = meson_serial_ids,
133 .probe = meson_serial_probe,
134 .ops = &meson_serial_ops,
135 .ofdata_to_platdata = meson_serial_ofdata_to_platdata,
136 .platdata_auto_alloc_size = sizeof(struct meson_serial_platdata),
137 };
138
139 #ifdef CONFIG_DEBUG_UART_MESON
140
141 #include <debug_uart.h>
142
_debug_uart_init(void)143 static inline void _debug_uart_init(void)
144 {
145 }
146
_debug_uart_putc(int ch)147 static inline void _debug_uart_putc(int ch)
148 {
149 struct meson_uart *regs = (struct meson_uart *)CONFIG_DEBUG_UART_BASE;
150
151 while (readl(®s->status) & AML_UART_TX_FULL)
152 ;
153
154 writel(ch, ®s->wfifo);
155 }
156
157 DEBUG_UART_FUNCS
158
159 #endif
160