1 /*
2  * Copyright (C) 2012-2015 Panasonic Corporation
3  * Copyright (C) 2015      Socionext Inc.
4  *   Author: Masahiro Yamada <yamada.masahiro@socionext.com>
5  *
6  * SPDX-License-Identifier:	GPL-2.0+
7  */
8 
9 #include <linux/serial_reg.h>
10 #include <asm/io.h>
11 #include <asm/errno.h>
12 #include <dm/device.h>
13 #include <dm/platform_data/serial-uniphier.h>
14 #include <mapmem.h>
15 #include <serial.h>
16 #include <fdtdec.h>
17 
18 /*
19  * Note: Register map is slightly different from that of 16550.
20  */
21 struct uniphier_serial {
22 	u32 rx;			/* In:  Receive buffer */
23 #define tx rx			/* Out: Transmit buffer */
24 	u32 ier;		/* Interrupt Enable Register */
25 	u32 iir;		/* In: Interrupt ID Register */
26 	u32 char_fcr;		/* Charactor / FIFO Control Register */
27 	u32 lcr_mcr;		/* Line/Modem Control Register */
28 #define LCR_SHIFT	8
29 #define LCR_MASK	(0xff << (LCR_SHIFT))
30 	u32 lsr;		/* In: Line Status Register */
31 	u32 msr;		/* In: Modem Status Register */
32 	u32 __rsv0;
33 	u32 __rsv1;
34 	u32 dlr;		/* Divisor Latch Register */
35 };
36 
37 struct uniphier_serial_private_data {
38 	struct uniphier_serial __iomem *membase;
39 };
40 
41 #define uniphier_serial_port(dev)	\
42 	((struct uniphier_serial_private_data *)dev_get_priv(dev))->membase
43 
44 static int uniphier_serial_setbrg(struct udevice *dev, int baudrate)
45 {
46 	struct uniphier_serial_platform_data *plat = dev_get_platdata(dev);
47 	struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
48 	const unsigned int mode_x_div = 16;
49 	unsigned int divisor;
50 
51 	divisor = DIV_ROUND_CLOSEST(plat->uartclk, mode_x_div * baudrate);
52 
53 	writel(divisor, &port->dlr);
54 
55 	return 0;
56 }
57 
58 static int uniphier_serial_getc(struct udevice *dev)
59 {
60 	struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
61 
62 	if (!(readl(&port->lsr) & UART_LSR_DR))
63 		return -EAGAIN;
64 
65 	return readl(&port->rx);
66 }
67 
68 static int uniphier_serial_putc(struct udevice *dev, const char c)
69 {
70 	struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
71 
72 	if (!(readl(&port->lsr) & UART_LSR_THRE))
73 		return -EAGAIN;
74 
75 	writel(c, &port->tx);
76 
77 	return 0;
78 }
79 
80 static int uniphier_serial_pending(struct udevice *dev, bool input)
81 {
82 	struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
83 
84 	if (input)
85 		return readl(&port->lsr) & UART_LSR_DR;
86 	else
87 		return !(readl(&port->lsr) & UART_LSR_THRE);
88 }
89 
90 static int uniphier_serial_probe(struct udevice *dev)
91 {
92 	u32 tmp;
93 	struct uniphier_serial_private_data *priv = dev_get_priv(dev);
94 	struct uniphier_serial_platform_data *plat = dev_get_platdata(dev);
95 	struct uniphier_serial __iomem *port;
96 
97 	port = map_sysmem(plat->base, sizeof(struct uniphier_serial));
98 	if (!port)
99 		return -ENOMEM;
100 
101 	priv->membase = port;
102 
103 	tmp = readl(&port->lcr_mcr);
104 	tmp &= ~LCR_MASK;
105 	tmp |= UART_LCR_WLEN8 << LCR_SHIFT;
106 	writel(tmp, &port->lcr_mcr);
107 
108 	return 0;
109 }
110 
111 static int uniphier_serial_remove(struct udevice *dev)
112 {
113 	unmap_sysmem(uniphier_serial_port(dev));
114 
115 	return 0;
116 }
117 
118 #ifdef CONFIG_OF_CONTROL
119 static const struct udevice_id uniphier_uart_of_match[] = {
120 	{ .compatible = "socionext,uniphier-uart" },
121 	{ /* sentinel */ }
122 };
123 
124 static int uniphier_serial_ofdata_to_platdata(struct udevice *dev)
125 {
126 	struct uniphier_serial_platform_data *plat = dev_get_platdata(dev);
127 	DECLARE_GLOBAL_DATA_PTR;
128 
129 	plat->base = fdtdec_get_addr(gd->fdt_blob, dev->of_offset, "reg");
130 	plat->uartclk = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
131 				       "clock-frequency", 0);
132 
133 	return 0;
134 }
135 #endif
136 
137 static const struct dm_serial_ops uniphier_serial_ops = {
138 	.setbrg = uniphier_serial_setbrg,
139 	.getc = uniphier_serial_getc,
140 	.putc = uniphier_serial_putc,
141 	.pending = uniphier_serial_pending,
142 };
143 
144 U_BOOT_DRIVER(uniphier_serial) = {
145 	.name = DRIVER_NAME,
146 	.id = UCLASS_SERIAL,
147 	.of_match = of_match_ptr(uniphier_uart_of_match),
148 	.ofdata_to_platdata = of_match_ptr(uniphier_serial_ofdata_to_platdata),
149 	.probe = uniphier_serial_probe,
150 	.remove = uniphier_serial_remove,
151 	.priv_auto_alloc_size = sizeof(struct uniphier_serial_private_data),
152 	.platdata_auto_alloc_size =
153 				sizeof(struct uniphier_serial_platform_data),
154 	.ops = &uniphier_serial_ops,
155 	.flags = DM_FLAG_PRE_RELOC,
156 };
157