1 /*
2  * Copyright (C) 2012-2015 Masahiro Yamada <yamada.masahiro@socionext.com>
3  *
4  * SPDX-License-Identifier:	GPL-2.0+
5  */
6 
7 #include <linux/io.h>
8 #include <linux/serial_reg.h>
9 #include <asm/errno.h>
10 #include <dm/device.h>
11 #include <dm/platform_data/serial-uniphier.h>
12 #include <mapmem.h>
13 #include <serial.h>
14 #include <fdtdec.h>
15 
16 /*
17  * Note: Register map is slightly different from that of 16550.
18  */
19 struct uniphier_serial {
20 	u32 rx;			/* In:  Receive buffer */
21 #define tx rx			/* Out: Transmit buffer */
22 	u32 ier;		/* Interrupt Enable Register */
23 	u32 iir;		/* In: Interrupt ID Register */
24 	u32 char_fcr;		/* Charactor / FIFO Control Register */
25 	u32 lcr_mcr;		/* Line/Modem Control Register */
26 #define LCR_SHIFT	8
27 #define LCR_MASK	(0xff << (LCR_SHIFT))
28 	u32 lsr;		/* In: Line Status Register */
29 	u32 msr;		/* In: Modem Status Register */
30 	u32 __rsv0;
31 	u32 __rsv1;
32 	u32 dlr;		/* Divisor Latch Register */
33 };
34 
35 struct uniphier_serial_private_data {
36 	struct uniphier_serial __iomem *membase;
37 };
38 
39 #define uniphier_serial_port(dev)	\
40 	((struct uniphier_serial_private_data *)dev_get_priv(dev))->membase
41 
42 static int uniphier_serial_setbrg(struct udevice *dev, int baudrate)
43 {
44 	struct uniphier_serial_platform_data *plat = dev_get_platdata(dev);
45 	struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
46 	const unsigned int mode_x_div = 16;
47 	unsigned int divisor;
48 
49 	divisor = DIV_ROUND_CLOSEST(plat->uartclk, mode_x_div * baudrate);
50 
51 	writel(divisor, &port->dlr);
52 
53 	return 0;
54 }
55 
56 static int uniphier_serial_getc(struct udevice *dev)
57 {
58 	struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
59 
60 	if (!(readl(&port->lsr) & UART_LSR_DR))
61 		return -EAGAIN;
62 
63 	return readl(&port->rx);
64 }
65 
66 static int uniphier_serial_putc(struct udevice *dev, const char c)
67 {
68 	struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
69 
70 	if (!(readl(&port->lsr) & UART_LSR_THRE))
71 		return -EAGAIN;
72 
73 	writel(c, &port->tx);
74 
75 	return 0;
76 }
77 
78 static int uniphier_serial_pending(struct udevice *dev, bool input)
79 {
80 	struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
81 
82 	if (input)
83 		return readl(&port->lsr) & UART_LSR_DR;
84 	else
85 		return !(readl(&port->lsr) & UART_LSR_THRE);
86 }
87 
88 static int uniphier_serial_probe(struct udevice *dev)
89 {
90 	u32 tmp;
91 	struct uniphier_serial_private_data *priv = dev_get_priv(dev);
92 	struct uniphier_serial_platform_data *plat = dev_get_platdata(dev);
93 	struct uniphier_serial __iomem *port;
94 
95 	port = map_sysmem(plat->base, sizeof(struct uniphier_serial));
96 	if (!port)
97 		return -ENOMEM;
98 
99 	priv->membase = port;
100 
101 	tmp = readl(&port->lcr_mcr);
102 	tmp &= ~LCR_MASK;
103 	tmp |= UART_LCR_WLEN8 << LCR_SHIFT;
104 	writel(tmp, &port->lcr_mcr);
105 
106 	return 0;
107 }
108 
109 static int uniphier_serial_remove(struct udevice *dev)
110 {
111 	unmap_sysmem(uniphier_serial_port(dev));
112 
113 	return 0;
114 }
115 
116 #ifdef CONFIG_OF_CONTROL
117 static const struct udevice_id uniphier_uart_of_match[] = {
118 	{ .compatible = "socionext,uniphier-uart" },
119 	{ /* sentinel */ }
120 };
121 
122 static int uniphier_serial_ofdata_to_platdata(struct udevice *dev)
123 {
124 	struct uniphier_serial_platform_data *plat = dev_get_platdata(dev);
125 	DECLARE_GLOBAL_DATA_PTR;
126 
127 	plat->base = fdtdec_get_addr(gd->fdt_blob, dev->of_offset, "reg");
128 	plat->uartclk = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
129 				       "clock-frequency", 0);
130 
131 	return 0;
132 }
133 #endif
134 
135 static const struct dm_serial_ops uniphier_serial_ops = {
136 	.setbrg = uniphier_serial_setbrg,
137 	.getc = uniphier_serial_getc,
138 	.putc = uniphier_serial_putc,
139 	.pending = uniphier_serial_pending,
140 };
141 
142 U_BOOT_DRIVER(uniphier_serial) = {
143 	.name = DRIVER_NAME,
144 	.id = UCLASS_SERIAL,
145 	.of_match = of_match_ptr(uniphier_uart_of_match),
146 	.ofdata_to_platdata = of_match_ptr(uniphier_serial_ofdata_to_platdata),
147 	.probe = uniphier_serial_probe,
148 	.remove = uniphier_serial_remove,
149 	.priv_auto_alloc_size = sizeof(struct uniphier_serial_private_data),
150 	.platdata_auto_alloc_size =
151 				sizeof(struct uniphier_serial_platform_data),
152 	.ops = &uniphier_serial_ops,
153 	.flags = DM_FLAG_PRE_RELOC,
154 };
155