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 <clock_legacy.h>
8 #include <dm.h>
9 #include <div64.h>
10 #include <errno.h>
11 #include <serial.h>
12 #include <asm/io.h>
13 #include <asm/addrspace.h>
14 #include <asm/types.h>
15 #include <dm/pinctrl.h>
16 #include <linux/bitops.h>
17 #include <mach/ar71xx_regs.h>
18
19 #define AR933X_UART_DATA_REG 0x00
20 #define AR933X_UART_CS_REG 0x04
21 #define AR933X_UART_CLK_REG 0x08
22
23 #define AR933X_UART_DATA_TX_RX_MASK 0xff
24 #define AR933X_UART_DATA_RX_CSR BIT(8)
25 #define AR933X_UART_DATA_TX_CSR BIT(9)
26 #define AR933X_UART_CS_IF_MODE_S 2
27 #define AR933X_UART_CS_IF_MODE_M 0x3
28 #define AR933X_UART_CS_IF_MODE_DTE 1
29 #define AR933X_UART_CS_IF_MODE_DCE 2
30 #define AR933X_UART_CS_TX_RDY_ORIDE BIT(7)
31 #define AR933X_UART_CS_RX_RDY_ORIDE BIT(8)
32 #define AR933X_UART_CLK_STEP_M 0xffff
33 #define AR933X_UART_CLK_SCALE_M 0xfff
34 #define AR933X_UART_CLK_SCALE_S 16
35 #define AR933X_UART_CLK_STEP_S 0
36
37 struct ar933x_serial_priv {
38 void __iomem *regs;
39 };
40
41 /*
42 * Baudrate algorithm come from Linux/drivers/tty/serial/ar933x_uart.c
43 * baudrate = (clk / (scale + 1)) * (step * (1 / 2^17))
44 */
ar933x_serial_get_baud(u32 clk,u32 scale,u32 step)45 static u32 ar933x_serial_get_baud(u32 clk, u32 scale, u32 step)
46 {
47 u64 t;
48 u32 div;
49
50 div = (2 << 16) * (scale + 1);
51 t = clk;
52 t *= step;
53 t += (div / 2);
54 do_div(t, div);
55
56 return t;
57 }
58
ar933x_serial_get_scale_step(u32 clk,u32 baud,u32 * scale,u32 * step)59 static void ar933x_serial_get_scale_step(u32 clk, u32 baud,
60 u32 *scale, u32 *step)
61 {
62 u32 tscale, baudrate;
63 long min_diff;
64
65 *scale = 0;
66 *step = 0;
67
68 min_diff = baud;
69 for (tscale = 0; tscale < AR933X_UART_CLK_SCALE_M; tscale++) {
70 u64 tstep;
71 int diff;
72
73 tstep = baud * (tscale + 1);
74 tstep *= (2 << 16);
75 do_div(tstep, clk);
76
77 if (tstep > AR933X_UART_CLK_STEP_M)
78 break;
79
80 baudrate = ar933x_serial_get_baud(clk, tscale, tstep);
81 diff = abs(baudrate - baud);
82 if (diff < min_diff) {
83 min_diff = diff;
84 *scale = tscale;
85 *step = tstep;
86 }
87 }
88 }
89
ar933x_serial_setbrg(struct udevice * dev,int baudrate)90 static int ar933x_serial_setbrg(struct udevice *dev, int baudrate)
91 {
92 struct ar933x_serial_priv *priv = dev_get_priv(dev);
93 u32 val, scale, step;
94
95 val = get_serial_clock();
96 ar933x_serial_get_scale_step(val, baudrate, &scale, &step);
97
98 val = (scale & AR933X_UART_CLK_SCALE_M)
99 << AR933X_UART_CLK_SCALE_S;
100 val |= (step & AR933X_UART_CLK_STEP_M)
101 << AR933X_UART_CLK_STEP_S;
102 writel(val, priv->regs + AR933X_UART_CLK_REG);
103
104 return 0;
105 }
106
ar933x_serial_putc(struct udevice * dev,const char c)107 static int ar933x_serial_putc(struct udevice *dev, const char c)
108 {
109 struct ar933x_serial_priv *priv = dev_get_priv(dev);
110 u32 data;
111
112 data = readl(priv->regs + AR933X_UART_DATA_REG);
113 if (!(data & AR933X_UART_DATA_TX_CSR))
114 return -EAGAIN;
115
116 data = (u32)c | AR933X_UART_DATA_TX_CSR;
117 writel(data, priv->regs + AR933X_UART_DATA_REG);
118
119 return 0;
120 }
121
ar933x_serial_getc(struct udevice * dev)122 static int ar933x_serial_getc(struct udevice *dev)
123 {
124 struct ar933x_serial_priv *priv = dev_get_priv(dev);
125 u32 data;
126
127 data = readl(priv->regs + AR933X_UART_DATA_REG);
128 if (!(data & AR933X_UART_DATA_RX_CSR))
129 return -EAGAIN;
130
131 writel(AR933X_UART_DATA_RX_CSR, priv->regs + AR933X_UART_DATA_REG);
132 return data & AR933X_UART_DATA_TX_RX_MASK;
133 }
134
ar933x_serial_pending(struct udevice * dev,bool input)135 static int ar933x_serial_pending(struct udevice *dev, bool input)
136 {
137 struct ar933x_serial_priv *priv = dev_get_priv(dev);
138 u32 data;
139
140 data = readl(priv->regs + AR933X_UART_DATA_REG);
141 if (input)
142 return (data & AR933X_UART_DATA_RX_CSR) ? 1 : 0;
143 else
144 return (data & AR933X_UART_DATA_TX_CSR) ? 0 : 1;
145 }
146
ar933x_serial_probe(struct udevice * dev)147 static int ar933x_serial_probe(struct udevice *dev)
148 {
149 struct ar933x_serial_priv *priv = dev_get_priv(dev);
150 fdt_addr_t addr;
151 u32 val;
152
153 addr = dev_read_addr(dev);
154 if (addr == FDT_ADDR_T_NONE)
155 return -EINVAL;
156
157 priv->regs = map_physmem(addr, AR933X_UART_SIZE,
158 MAP_NOCACHE);
159
160 /*
161 * UART controller configuration:
162 * - no DMA
163 * - no interrupt
164 * - DCE mode
165 * - no flow control
166 * - set RX ready oride
167 * - set TX ready oride
168 */
169 val = (AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S) |
170 AR933X_UART_CS_TX_RDY_ORIDE | AR933X_UART_CS_RX_RDY_ORIDE;
171 writel(val, priv->regs + AR933X_UART_CS_REG);
172 return 0;
173 }
174
175 static const struct dm_serial_ops ar933x_serial_ops = {
176 .putc = ar933x_serial_putc,
177 .pending = ar933x_serial_pending,
178 .getc = ar933x_serial_getc,
179 .setbrg = ar933x_serial_setbrg,
180 };
181
182 static const struct udevice_id ar933x_serial_ids[] = {
183 { .compatible = "qca,ar9330-uart" },
184 { }
185 };
186
187 U_BOOT_DRIVER(serial_ar933x) = {
188 .name = "serial_ar933x",
189 .id = UCLASS_SERIAL,
190 .of_match = ar933x_serial_ids,
191 .priv_auto = sizeof(struct ar933x_serial_priv),
192 .probe = ar933x_serial_probe,
193 .ops = &ar933x_serial_ops,
194 };
195
196 #ifdef CONFIG_DEBUG_UART_AR933X
197
198 #include <debug_uart.h>
199
_debug_uart_init(void)200 static inline void _debug_uart_init(void)
201 {
202 void __iomem *regs = (void *)CONFIG_DEBUG_UART_BASE;
203 u32 val, scale, step;
204
205 /*
206 * UART controller configuration:
207 * - no DMA
208 * - no interrupt
209 * - DCE mode
210 * - no flow control
211 * - set RX ready oride
212 * - set TX ready oride
213 */
214 val = (AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S) |
215 AR933X_UART_CS_TX_RDY_ORIDE | AR933X_UART_CS_RX_RDY_ORIDE;
216 writel(val, regs + AR933X_UART_CS_REG);
217
218 ar933x_serial_get_scale_step(CONFIG_DEBUG_UART_CLOCK,
219 CONFIG_BAUDRATE, &scale, &step);
220
221 val = (scale & AR933X_UART_CLK_SCALE_M)
222 << AR933X_UART_CLK_SCALE_S;
223 val |= (step & AR933X_UART_CLK_STEP_M)
224 << AR933X_UART_CLK_STEP_S;
225 writel(val, regs + AR933X_UART_CLK_REG);
226 }
227
_debug_uart_putc(int c)228 static inline void _debug_uart_putc(int c)
229 {
230 void __iomem *regs = (void *)CONFIG_DEBUG_UART_BASE;
231 u32 data;
232
233 do {
234 data = readl(regs + AR933X_UART_DATA_REG);
235 } while (!(data & AR933X_UART_DATA_TX_CSR));
236
237 data = (u32)c | AR933X_UART_DATA_TX_CSR;
238 writel(data, regs + AR933X_UART_DATA_REG);
239 }
240
241 DEBUG_UART_FUNCS
242
243 #endif
244