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3917c269 SW |
1 | /* |
2 | * (C) Copyright 2016 Stephen Warren <swarren@wwwdotorg.org> | |
3 | * | |
4 | * Derived from pl01x code: | |
5 | * | |
6 | * (C) Copyright 2000 | |
7 | * Rob Taylor, Flying Pig Systems. robt@flyingpig.com. | |
8 | * | |
9 | * (C) Copyright 2004 | |
10 | * ARM Ltd. | |
11 | * Philippe Robin, <philippe.robin@arm.com> | |
12 | * | |
13 | * SPDX-License-Identifier: GPL-2.0+ | |
14 | */ | |
15 | ||
16 | /* Simple U-Boot driver for the BCM283x mini UART */ | |
17 | ||
18 | #include <common.h> | |
19 | #include <dm.h> | |
20 | #include <errno.h> | |
21 | #include <watchdog.h> | |
22 | #include <asm/io.h> | |
23 | #include <serial.h> | |
24 | #include <dm/platform_data/serial_bcm283x_mu.h> | |
25 | #include <linux/compiler.h> | |
26 | #include <fdtdec.h> | |
27 | ||
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 | ||
53 | static int bcm283x_mu_serial_setbrg(struct udevice *dev, int baudrate) | |
54 | { | |
55 | struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev); | |
56 | struct bcm283x_mu_priv *priv = dev_get_priv(dev); | |
57 | struct bcm283x_mu_regs *regs = priv->regs; | |
58 | u32 divider; | |
59 | ||
60 | if (plat->skip_init) | |
61 | return 0; | |
62 | ||
63 | divider = plat->clock / (baudrate * 8); | |
64 | ||
65 | writel(BCM283X_MU_LCR_DATA_SIZE_8, ®s->lcr); | |
66 | writel(divider - 1, ®s->baud); | |
67 | ||
68 | return 0; | |
69 | } | |
70 | ||
71 | static int bcm283x_mu_serial_probe(struct udevice *dev) | |
72 | { | |
73 | struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev); | |
74 | struct bcm283x_mu_priv *priv = dev_get_priv(dev); | |
75 | ||
76 | priv->regs = (struct bcm283x_mu_regs *)plat->base; | |
77 | ||
78 | return 0; | |
79 | } | |
80 | ||
81 | static int bcm283x_mu_serial_getc(struct udevice *dev) | |
82 | { | |
83 | struct bcm283x_mu_priv *priv = dev_get_priv(dev); | |
84 | struct bcm283x_mu_regs *regs = priv->regs; | |
85 | u32 data; | |
86 | ||
87 | /* Wait until there is data in the FIFO */ | |
88 | if (!(readl(®s->lsr) & BCM283X_MU_LSR_RX_READY)) | |
89 | return -EAGAIN; | |
90 | ||
91 | data = readl(®s->io); | |
92 | ||
93 | return (int)data; | |
94 | } | |
95 | ||
96 | static int bcm283x_mu_serial_putc(struct udevice *dev, const char data) | |
97 | { | |
98 | struct bcm283x_mu_priv *priv = dev_get_priv(dev); | |
99 | struct bcm283x_mu_regs *regs = priv->regs; | |
100 | ||
101 | /* Wait until there is space in the FIFO */ | |
102 | if (!(readl(®s->lsr) & BCM283X_MU_LSR_TX_EMPTY)) | |
103 | return -EAGAIN; | |
104 | ||
105 | /* Send the character */ | |
106 | writel(data, ®s->io); | |
107 | ||
108 | return 0; | |
109 | } | |
110 | ||
111 | static int bcm283x_mu_serial_pending(struct udevice *dev, bool input) | |
112 | { | |
113 | struct bcm283x_mu_priv *priv = dev_get_priv(dev); | |
114 | struct bcm283x_mu_regs *regs = priv->regs; | |
115 | unsigned int lsr = readl(®s->lsr); | |
116 | ||
117 | if (input) { | |
118 | WATCHDOG_RESET(); | |
e3a46e3e | 119 | return (lsr & BCM283X_MU_LSR_RX_READY) ? 1 : 0; |
3917c269 | 120 | } else { |
e3a46e3e | 121 | return (lsr & BCM283X_MU_LSR_TX_IDLE) ? 0 : 1; |
3917c269 SW |
122 | } |
123 | } | |
124 | ||
125 | static const struct dm_serial_ops bcm283x_mu_serial_ops = { | |
126 | .putc = bcm283x_mu_serial_putc, | |
127 | .pending = bcm283x_mu_serial_pending, | |
128 | .getc = bcm283x_mu_serial_getc, | |
129 | .setbrg = bcm283x_mu_serial_setbrg, | |
130 | }; | |
131 | ||
132 | U_BOOT_DRIVER(serial_bcm283x_mu) = { | |
133 | .name = "serial_bcm283x_mu", | |
134 | .id = UCLASS_SERIAL, | |
135 | .platdata_auto_alloc_size = sizeof(struct bcm283x_mu_serial_platdata), | |
136 | .probe = bcm283x_mu_serial_probe, | |
137 | .ops = &bcm283x_mu_serial_ops, | |
138 | .flags = DM_FLAG_PRE_RELOC, | |
139 | .priv_auto_alloc_size = sizeof(struct bcm283x_mu_priv), | |
140 | }; |