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83d290c5 | 1 | // SPDX-License-Identifier: GPL-2.0+ |
3917c269 SW |
2 | /* |
3 | * (C) Copyright 2016 Stephen Warren <swarren@wwwdotorg.org> | |
4 | * | |
5 | * Derived from pl01x code: | |
6 | * | |
7 | * (C) Copyright 2000 | |
8 | * Rob Taylor, Flying Pig Systems. robt@flyingpig.com. | |
9 | * | |
10 | * (C) Copyright 2004 | |
11 | * ARM Ltd. | |
12 | * Philippe Robin, <philippe.robin@arm.com> | |
3917c269 SW |
13 | */ |
14 | ||
15 | /* Simple U-Boot driver for the BCM283x mini UART */ | |
16 | ||
17 | #include <common.h> | |
18 | #include <dm.h> | |
19 | #include <errno.h> | |
20 | #include <watchdog.h> | |
9dfeffe2 | 21 | #include <asm/gpio.h> |
3917c269 SW |
22 | #include <asm/io.h> |
23 | #include <serial.h> | |
24 | #include <dm/platform_data/serial_bcm283x_mu.h> | |
9dfeffe2 | 25 | #include <dm/pinctrl.h> |
3917c269 | 26 | #include <linux/compiler.h> |
9f755f5d | 27 | |
3917c269 SW |
28 | struct bcm283x_mu_regs { |
29 | u32 io; | |
30 | u32 iir; | |
31 | u32 ier; | |
32 | u32 lcr; | |
33 | u32 mcr; | |
34 | u32 lsr; | |
35 | u32 msr; | |
36 | u32 scratch; | |
37 | u32 cntl; | |
38 | u32 stat; | |
39 | u32 baud; | |
40 | }; | |
41 | ||
42 | #define BCM283X_MU_LCR_DATA_SIZE_8 3 | |
43 | ||
44 | #define BCM283X_MU_LSR_TX_IDLE BIT(6) | |
45 | /* This actually means not full, but is named not empty in the docs */ | |
46 | #define BCM283X_MU_LSR_TX_EMPTY BIT(5) | |
47 | #define BCM283X_MU_LSR_RX_READY BIT(0) | |
48 | ||
49 | struct bcm283x_mu_priv { | |
50 | struct bcm283x_mu_regs *regs; | |
51 | }; | |
52 | ||
293b9814 AG |
53 | static int bcm283x_mu_serial_getc(struct udevice *dev); |
54 | ||
3917c269 SW |
55 | static int bcm283x_mu_serial_setbrg(struct udevice *dev, int baudrate) |
56 | { | |
57 | struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev); | |
58 | struct bcm283x_mu_priv *priv = dev_get_priv(dev); | |
59 | struct bcm283x_mu_regs *regs = priv->regs; | |
60 | u32 divider; | |
61 | ||
fc8523a1 | 62 | if (plat->skip_init) |
293b9814 | 63 | goto out; |
3917c269 SW |
64 | |
65 | divider = plat->clock / (baudrate * 8); | |
66 | ||
67 | writel(BCM283X_MU_LCR_DATA_SIZE_8, ®s->lcr); | |
68 | writel(divider - 1, ®s->baud); | |
69 | ||
293b9814 AG |
70 | out: |
71 | /* Flush the RX queue - all data in there is bogus */ | |
72 | while (bcm283x_mu_serial_getc(dev) != -EAGAIN) ; | |
73 | ||
3917c269 SW |
74 | return 0; |
75 | } | |
76 | ||
77 | static int bcm283x_mu_serial_probe(struct udevice *dev) | |
78 | { | |
79 | struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev); | |
80 | struct bcm283x_mu_priv *priv = dev_get_priv(dev); | |
81 | ||
82 | priv->regs = (struct bcm283x_mu_regs *)plat->base; | |
83 | ||
84 | return 0; | |
85 | } | |
86 | ||
87 | static int bcm283x_mu_serial_getc(struct udevice *dev) | |
88 | { | |
89 | struct bcm283x_mu_priv *priv = dev_get_priv(dev); | |
90 | struct bcm283x_mu_regs *regs = priv->regs; | |
91 | u32 data; | |
92 | ||
93 | /* Wait until there is data in the FIFO */ | |
94 | if (!(readl(®s->lsr) & BCM283X_MU_LSR_RX_READY)) | |
95 | return -EAGAIN; | |
96 | ||
97 | data = readl(®s->io); | |
98 | ||
99 | return (int)data; | |
100 | } | |
101 | ||
102 | static int bcm283x_mu_serial_putc(struct udevice *dev, const char data) | |
103 | { | |
104 | struct bcm283x_mu_priv *priv = dev_get_priv(dev); | |
105 | struct bcm283x_mu_regs *regs = priv->regs; | |
106 | ||
107 | /* Wait until there is space in the FIFO */ | |
108 | if (!(readl(®s->lsr) & BCM283X_MU_LSR_TX_EMPTY)) | |
109 | return -EAGAIN; | |
110 | ||
111 | /* Send the character */ | |
112 | writel(data, ®s->io); | |
113 | ||
114 | return 0; | |
115 | } | |
116 | ||
117 | static int bcm283x_mu_serial_pending(struct udevice *dev, bool input) | |
118 | { | |
119 | struct bcm283x_mu_priv *priv = dev_get_priv(dev); | |
120 | struct bcm283x_mu_regs *regs = priv->regs; | |
cb97ad47 FV |
121 | unsigned int lsr; |
122 | ||
cb97ad47 | 123 | lsr = readl(®s->lsr); |
3917c269 SW |
124 | |
125 | if (input) { | |
126 | WATCHDOG_RESET(); | |
e3a46e3e | 127 | return (lsr & BCM283X_MU_LSR_RX_READY) ? 1 : 0; |
3917c269 | 128 | } else { |
e3a46e3e | 129 | return (lsr & BCM283X_MU_LSR_TX_IDLE) ? 0 : 1; |
3917c269 SW |
130 | } |
131 | } | |
132 | ||
133 | static const struct dm_serial_ops bcm283x_mu_serial_ops = { | |
134 | .putc = bcm283x_mu_serial_putc, | |
135 | .pending = bcm283x_mu_serial_pending, | |
136 | .getc = bcm283x_mu_serial_getc, | |
137 | .setbrg = bcm283x_mu_serial_setbrg, | |
138 | }; | |
139 | ||
9f755f5d FV |
140 | #if CONFIG_IS_ENABLED(OF_CONTROL) |
141 | static const struct udevice_id bcm283x_mu_serial_id[] = { | |
142 | {.compatible = "brcm,bcm2835-aux-uart"}, | |
143 | {} | |
144 | }; | |
145 | ||
9dfeffe2 AG |
146 | /* |
147 | * Check if this serial device is muxed | |
148 | * | |
149 | * The serial device will only work properly if it has been muxed to the serial | |
150 | * pins by firmware. Check whether that happened here. | |
151 | * | |
152 | * @return true if serial device is muxed, false if not | |
153 | */ | |
154 | static bool bcm283x_is_serial_muxed(void) | |
155 | { | |
156 | int serial_gpio = 15; | |
157 | struct udevice *dev; | |
158 | ||
159 | if (uclass_first_device(UCLASS_PINCTRL, &dev) || !dev) | |
160 | return false; | |
161 | ||
162 | if (pinctrl_get_gpio_mux(dev, 0, serial_gpio) != BCM2835_GPIO_ALT5) | |
163 | return false; | |
164 | ||
165 | return true; | |
166 | } | |
167 | ||
9f755f5d FV |
168 | static int bcm283x_mu_serial_ofdata_to_platdata(struct udevice *dev) |
169 | { | |
170 | struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev); | |
171 | fdt_addr_t addr; | |
172 | ||
9dfeffe2 AG |
173 | /* Don't spawn the device if it's not muxed */ |
174 | if (!bcm283x_is_serial_muxed()) | |
175 | return -ENODEV; | |
176 | ||
a821c4af | 177 | addr = devfdt_get_addr(dev); |
9f755f5d FV |
178 | if (addr == FDT_ADDR_T_NONE) |
179 | return -EINVAL; | |
180 | ||
181 | plat->base = addr; | |
80d5001c | 182 | plat->clock = dev_read_u32_default(dev, "clock", 1); |
bceab8d5 AG |
183 | |
184 | /* | |
185 | * TODO: Reinitialization doesn't always work for now, just skip | |
186 | * init always - we know we're already initialized | |
187 | */ | |
188 | plat->skip_init = true; | |
80d5001c | 189 | |
9f755f5d FV |
190 | return 0; |
191 | } | |
192 | #endif | |
193 | ||
3917c269 SW |
194 | U_BOOT_DRIVER(serial_bcm283x_mu) = { |
195 | .name = "serial_bcm283x_mu", | |
196 | .id = UCLASS_SERIAL, | |
9f755f5d FV |
197 | .of_match = of_match_ptr(bcm283x_mu_serial_id), |
198 | .ofdata_to_platdata = of_match_ptr(bcm283x_mu_serial_ofdata_to_platdata), | |
3917c269 SW |
199 | .platdata_auto_alloc_size = sizeof(struct bcm283x_mu_serial_platdata), |
200 | .probe = bcm283x_mu_serial_probe, | |
201 | .ops = &bcm283x_mu_serial_ops, | |
202 | .flags = DM_FLAG_PRE_RELOC, | |
203 | .priv_auto_alloc_size = sizeof(struct bcm283x_mu_priv), | |
204 | }; |