1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright (C) 2015-2016 Wills Wang <wills.wang@live.com>
4 */
5
6 #include <common.h>
7 #include <dm.h>
8 #include <div64.h>
9 #include <errno.h>
10 #include <serial.h>
11 #include <asm/io.h>
12 #include <asm/addrspace.h>
13 #include <asm/types.h>
14 #include <dm/pinctrl.h>
15 #include <mach/ar71xx_regs.h>
16
17 #define AR933X_UART_DATA_REG 0x00
18 #define AR933X_UART_CS_REG 0x04
19 #define AR933X_UART_CLK_REG 0x08
20
21 #define AR933X_UART_DATA_TX_RX_MASK 0xff
22 #define AR933X_UART_DATA_RX_CSR BIT(8)
23 #define AR933X_UART_DATA_TX_CSR BIT(9)
24 #define AR933X_UART_CS_IF_MODE_S 2
25 #define AR933X_UART_CS_IF_MODE_M 0x3
26 #define AR933X_UART_CS_IF_MODE_DTE 1
27 #define AR933X_UART_CS_IF_MODE_DCE 2
28 #define AR933X_UART_CS_TX_RDY_ORIDE BIT(7)
29 #define AR933X_UART_CS_RX_RDY_ORIDE BIT(8)
30 #define AR933X_UART_CLK_STEP_M 0xffff
31 #define AR933X_UART_CLK_SCALE_M 0xfff
32 #define AR933X_UART_CLK_SCALE_S 16
33 #define AR933X_UART_CLK_STEP_S 0
34
35 struct ar933x_serial_priv {
36 void __iomem *regs;
37 };
38
39 /*
40 * Baudrate algorithm come from Linux/drivers/tty/serial/ar933x_uart.c
41 * baudrate = (clk / (scale + 1)) * (step * (1 / 2^17))
42 */
ar933x_serial_get_baud(u32 clk,u32 scale,u32 step)43 static u32 ar933x_serial_get_baud(u32 clk, u32 scale, u32 step)
44 {
45 u64 t;
46 u32 div;
47
48 div = (2 << 16) * (scale + 1);
49 t = clk;
50 t *= step;
51 t += (div / 2);
52 do_div(t, div);
53
54 return t;
55 }
56
ar933x_serial_get_scale_step(u32 clk,u32 baud,u32 * scale,u32 * step)57 static void ar933x_serial_get_scale_step(u32 clk, u32 baud,
58 u32 *scale, u32 *step)
59 {
60 u32 tscale, baudrate;
61 long min_diff;
62
63 *scale = 0;
64 *step = 0;
65
66 min_diff = baud;
67 for (tscale = 0; tscale < AR933X_UART_CLK_SCALE_M; tscale++) {
68 u64 tstep;
69 int diff;
70
71 tstep = baud * (tscale + 1);
72 tstep *= (2 << 16);
73 do_div(tstep, clk);
74
75 if (tstep > AR933X_UART_CLK_STEP_M)
76 break;
77
78 baudrate = ar933x_serial_get_baud(clk, tscale, tstep);
79 diff = abs(baudrate - baud);
80 if (diff < min_diff) {
81 min_diff = diff;
82 *scale = tscale;
83 *step = tstep;
84 }
85 }
86 }
87
ar933x_serial_setbrg(struct udevice * dev,int baudrate)88 static int ar933x_serial_setbrg(struct udevice *dev, int baudrate)
89 {
90 struct ar933x_serial_priv *priv = dev_get_priv(dev);
91 u32 val, scale, step;
92
93 val = get_serial_clock();
94 ar933x_serial_get_scale_step(val, baudrate, &scale, &step);
95
96 val = (scale & AR933X_UART_CLK_SCALE_M)
97 << AR933X_UART_CLK_SCALE_S;
98 val |= (step & AR933X_UART_CLK_STEP_M)
99 << AR933X_UART_CLK_STEP_S;
100 writel(val, priv->regs + AR933X_UART_CLK_REG);
101
102 return 0;
103 }
104
ar933x_serial_putc(struct udevice * dev,const char c)105 static int ar933x_serial_putc(struct udevice *dev, const char c)
106 {
107 struct ar933x_serial_priv *priv = dev_get_priv(dev);
108 u32 data;
109
110 data = readl(priv->regs + AR933X_UART_DATA_REG);
111 if (!(data & AR933X_UART_DATA_TX_CSR))
112 return -EAGAIN;
113
114 data = (u32)c | AR933X_UART_DATA_TX_CSR;
115 writel(data, priv->regs + AR933X_UART_DATA_REG);
116
117 return 0;
118 }
119
ar933x_serial_getc(struct udevice * dev)120 static int ar933x_serial_getc(struct udevice *dev)
121 {
122 struct ar933x_serial_priv *priv = dev_get_priv(dev);
123 u32 data;
124
125 data = readl(priv->regs + AR933X_UART_DATA_REG);
126 if (!(data & AR933X_UART_DATA_RX_CSR))
127 return -EAGAIN;
128
129 writel(AR933X_UART_DATA_RX_CSR, priv->regs + AR933X_UART_DATA_REG);
130 return data & AR933X_UART_DATA_TX_RX_MASK;
131 }
132
ar933x_serial_pending(struct udevice * dev,bool input)133 static int ar933x_serial_pending(struct udevice *dev, bool input)
134 {
135 struct ar933x_serial_priv *priv = dev_get_priv(dev);
136 u32 data;
137
138 data = readl(priv->regs + AR933X_UART_DATA_REG);
139 if (input)
140 return (data & AR933X_UART_DATA_RX_CSR) ? 1 : 0;
141 else
142 return (data & AR933X_UART_DATA_TX_CSR) ? 0 : 1;
143 }
144
ar933x_serial_probe(struct udevice * dev)145 static int ar933x_serial_probe(struct udevice *dev)
146 {
147 struct ar933x_serial_priv *priv = dev_get_priv(dev);
148 fdt_addr_t addr;
149 u32 val;
150
151 addr = devfdt_get_addr(dev);
152 if (addr == FDT_ADDR_T_NONE)
153 return -EINVAL;
154
155 priv->regs = map_physmem(addr, AR933X_UART_SIZE,
156 MAP_NOCACHE);
157
158 /*
159 * UART controller configuration:
160 * - no DMA
161 * - no interrupt
162 * - DCE mode
163 * - no flow control
164 * - set RX ready oride
165 * - set TX ready oride
166 */
167 val = (AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S) |
168 AR933X_UART_CS_TX_RDY_ORIDE | AR933X_UART_CS_RX_RDY_ORIDE;
169 writel(val, priv->regs + AR933X_UART_CS_REG);
170 return 0;
171 }
172
173 static const struct dm_serial_ops ar933x_serial_ops = {
174 .putc = ar933x_serial_putc,
175 .pending = ar933x_serial_pending,
176 .getc = ar933x_serial_getc,
177 .setbrg = ar933x_serial_setbrg,
178 };
179
180 static const struct udevice_id ar933x_serial_ids[] = {
181 { .compatible = "qca,ar9330-uart" },
182 { }
183 };
184
185 U_BOOT_DRIVER(serial_ar933x) = {
186 .name = "serial_ar933x",
187 .id = UCLASS_SERIAL,
188 .of_match = ar933x_serial_ids,
189 .priv_auto_alloc_size = sizeof(struct ar933x_serial_priv),
190 .probe = ar933x_serial_probe,
191 .ops = &ar933x_serial_ops,
192 };
193
194 #ifdef CONFIG_DEBUG_UART_AR933X
195
196 #include <debug_uart.h>
197
_debug_uart_init(void)198 static inline void _debug_uart_init(void)
199 {
200 void __iomem *regs = (void *)CONFIG_DEBUG_UART_BASE;
201 u32 val, scale, step;
202
203 /*
204 * UART controller configuration:
205 * - no DMA
206 * - no interrupt
207 * - DCE mode
208 * - no flow control
209 * - set RX ready oride
210 * - set TX ready oride
211 */
212 val = (AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S) |
213 AR933X_UART_CS_TX_RDY_ORIDE | AR933X_UART_CS_RX_RDY_ORIDE;
214 writel(val, regs + AR933X_UART_CS_REG);
215
216 ar933x_serial_get_scale_step(CONFIG_DEBUG_UART_CLOCK,
217 CONFIG_BAUDRATE, &scale, &step);
218
219 val = (scale & AR933X_UART_CLK_SCALE_M)
220 << AR933X_UART_CLK_SCALE_S;
221 val |= (step & AR933X_UART_CLK_STEP_M)
222 << AR933X_UART_CLK_STEP_S;
223 writel(val, regs + AR933X_UART_CLK_REG);
224 }
225
_debug_uart_putc(int c)226 static inline void _debug_uart_putc(int c)
227 {
228 void __iomem *regs = (void *)CONFIG_DEBUG_UART_BASE;
229 u32 data;
230
231 do {
232 data = readl(regs + AR933X_UART_DATA_REG);
233 } while (!(data & AR933X_UART_DATA_TX_CSR));
234
235 data = (u32)c | AR933X_UART_DATA_TX_CSR;
236 writel(data, regs + AR933X_UART_DATA_REG);
237 }
238
239 DEBUG_UART_FUNCS
240
241 #endif
242