1 /*
2  * (C) Copyright 2016 Beniamino Galvani <b.galvani@gmail.com>
3  *
4  * SPDX-License-Identifier:	GPL-2.0+
5  */
6 
7 #include <common.h>
8 #include <dm.h>
9 #include <errno.h>
10 #include <fdtdec.h>
11 #include <linux/compiler.h>
12 #include <serial.h>
13 
14 DECLARE_GLOBAL_DATA_PTR;
15 
16 struct meson_uart {
17 	u32 wfifo;
18 	u32 rfifo;
19 	u32 control;
20 	u32 status;
21 	u32 misc;
22 };
23 
24 struct meson_serial_platdata {
25 	struct meson_uart *reg;
26 };
27 
28 /* AML_UART_STATUS bits */
29 #define AML_UART_PARITY_ERR		BIT(16)
30 #define AML_UART_FRAME_ERR		BIT(17)
31 #define AML_UART_TX_FIFO_WERR		BIT(18)
32 #define AML_UART_RX_EMPTY		BIT(20)
33 #define AML_UART_TX_FULL		BIT(21)
34 #define AML_UART_TX_EMPTY		BIT(22)
35 #define AML_UART_XMIT_BUSY		BIT(25)
36 #define AML_UART_ERR			(AML_UART_PARITY_ERR | \
37 					 AML_UART_FRAME_ERR  | \
38 					 AML_UART_TX_FIFO_WERR)
39 
40 /* AML_UART_CONTROL bits */
41 #define AML_UART_TX_EN			BIT(12)
42 #define AML_UART_RX_EN			BIT(13)
43 #define AML_UART_TX_RST			BIT(22)
44 #define AML_UART_RX_RST			BIT(23)
45 #define AML_UART_CLR_ERR		BIT(24)
46 
47 static void meson_serial_init(struct meson_uart *uart)
48 {
49 	u32 val;
50 
51 	val = readl(&uart->control);
52 	val |= (AML_UART_RX_RST | AML_UART_TX_RST | AML_UART_CLR_ERR);
53 	writel(val, &uart->control);
54 	val &= ~(AML_UART_RX_RST | AML_UART_TX_RST | AML_UART_CLR_ERR);
55 	writel(val, &uart->control);
56 	val |= (AML_UART_RX_EN | AML_UART_TX_EN);
57 	writel(val, &uart->control);
58 }
59 
60 static int meson_serial_probe(struct udevice *dev)
61 {
62 	struct meson_serial_platdata *plat = dev->platdata;
63 	struct meson_uart *const uart = plat->reg;
64 
65 	meson_serial_init(uart);
66 
67 	return 0;
68 }
69 
70 static int meson_serial_getc(struct udevice *dev)
71 {
72 	struct meson_serial_platdata *plat = dev->platdata;
73 	struct meson_uart *const uart = plat->reg;
74 
75 	if (readl(&uart->status) & AML_UART_RX_EMPTY)
76 		return -EAGAIN;
77 
78 	return readl(&uart->rfifo) & 0xff;
79 }
80 
81 static int meson_serial_putc(struct udevice *dev, const char ch)
82 {
83 	struct meson_serial_platdata *plat = dev->platdata;
84 	struct meson_uart *const uart = plat->reg;
85 
86 	if (readl(&uart->status) & AML_UART_TX_FULL)
87 		return -EAGAIN;
88 
89 	writel(ch, &uart->wfifo);
90 
91 	return 0;
92 }
93 
94 static int meson_serial_pending(struct udevice *dev, bool input)
95 {
96 	struct meson_serial_platdata *plat = dev->platdata;
97 	struct meson_uart *const uart = plat->reg;
98 	uint32_t status = readl(&uart->status);
99 
100 	if (input)
101 		return !(status & AML_UART_RX_EMPTY);
102 	else
103 		return !(status & AML_UART_TX_FULL);
104 }
105 
106 static int meson_serial_ofdata_to_platdata(struct udevice *dev)
107 {
108 	struct meson_serial_platdata *plat = dev->platdata;
109 	fdt_addr_t addr;
110 
111 	addr = devfdt_get_addr(dev);
112 	if (addr == FDT_ADDR_T_NONE)
113 		return -EINVAL;
114 
115 	plat->reg = (struct meson_uart *)addr;
116 
117 	return 0;
118 }
119 
120 static const struct dm_serial_ops meson_serial_ops = {
121 	.putc = meson_serial_putc,
122 	.pending = meson_serial_pending,
123 	.getc = meson_serial_getc,
124 };
125 
126 static const struct udevice_id meson_serial_ids[] = {
127 	{ .compatible = "amlogic,meson-uart" },
128 	{ }
129 };
130 
131 U_BOOT_DRIVER(serial_meson) = {
132 	.name		= "serial_meson",
133 	.id		= UCLASS_SERIAL,
134 	.of_match	= meson_serial_ids,
135 	.probe		= meson_serial_probe,
136 	.ops		= &meson_serial_ops,
137 	.flags		= DM_FLAG_PRE_RELOC,
138 	.ofdata_to_platdata = meson_serial_ofdata_to_platdata,
139 	.platdata_auto_alloc_size = sizeof(struct meson_serial_platdata),
140 };
141 
142 #ifdef CONFIG_DEBUG_UART_MESON
143 
144 #include <debug_uart.h>
145 
146 static inline void _debug_uart_init(void)
147 {
148 }
149 
150 static inline void _debug_uart_putc(int ch)
151 {
152 	struct meson_uart *regs = (struct meson_uart *)CONFIG_DEBUG_UART_BASE;
153 
154 	while (readl(&regs->status) & AML_UART_TX_FULL)
155 		;
156 
157 	writel(ch, &regs->wfifo);
158 }
159 
160 DEBUG_UART_FUNCS
161 
162 #endif
163